Structure-Based Prediction of G-Protein-Coupled Receptor Ligand Function: A β-Adrenoceptor Case Study
Abstract

The spectacular advances in G-protein-coupled receptor (GPCR) structure determination have opened up new possibilities for structure-based GPCR ligand discovery. The structure-based prediction of whether a ligand stimulates (full/partial agonist), blocks (antagonist), or reduces (inverse agonist) GPCR signaling activity is, however, still challenging. A total of 31 β1 (β1R) and β2 (β2R) adrenoceptor crystal structures, including antagonist, inverse agonist, and partial/full agonist-bound structures, allowed us to explore the possibilities and limitations of structure-based prediction of GPCR ligand function. We used all unique protein–ligand interaction fingerprints (IFPs) derived from all ligand-bound β-adrenergic crystal structure monomers to post-process the docking poses of known β1R/β2R partial/full agonists, antagonists/inverse agonists, and physicochemically similar decoys in each of the β1R/β2R structures. The systematic analysis of these 1920 unique IFP–structure combinations offered new insights into the relative impact of protein conformation and IFP scoring on selective virtual screening (VS) for ligands with a specific functional effect. Our studies show that ligands with the same function can be efficiently classified on the basis of their protein–ligand interaction profile. Small differences between the receptor conformation (used for docking) and reference IFP (used for scoring of the docking poses) determine, however, the enrichment of specific ligand types in VS hit lists. Interestingly, the selective enrichment of partial/full agonists can be achieved by using agonist IFPs to post-process docking poses in agonist-bound as well as antagonist-bound structures. We have identified optimal structure–IFP combinations for the identification and discrimination of antagonists/inverse agonist and partial/full agonists, and defined a predicted IFP for the small full agonist norepinephrine that gave the highest retrieval rate of agonists over antagonists for all structures (with an enrichment factor of 46 for agonists and 8 for antagonists on average at a 1% false-positive rate). This β-adrenoceptor case study provides new insights into the opportunities for selective structure-based discovery of GPCR ligands with a desired function and emphasizes the importance of IFPs in scoring docking poses.
Introduction
Results and Discussion
Subtle Ligand-Type-Dependent Structural Changes in the Receptor Binding Sites

Function abbreviations, based: ANT, antagonist; AGO, agonist; i, inverse; p, partial; f, full.
Not validated. (34)
Covalently bound ligand.
Ligand and extracellular part of the receptor were not resolved due to weak electron density.
This column indicates whether a ligand has a signaling preference for the β-arrestin over the G-protein pathway or not according to the following references:
Casella et al., (78)
Drake et al., (79)
Kahsai et al., (80)
Kaya et al., (81)
Kim et al., (82)
Liu et al., (83)
Rajagopal et al., (84)
Warne et al., (32) and
Weiss et al. (52)
Although these ligands are generally considered as antagonists/inverse agonists, they can also have a partial agonist effect depending on the activation state of the receptor. (85, 86)
Color coding: red, full/partial agonist; blue, antagonist/inverse agonist; cyan, unvalidated antagonist. Ligands with a circle icon do not show a signaling preference or it is not known for these compounds; ligands with a triangle icon have been shown to have a β-arrestin signaling bias.
The receptor is in its active state.
The signaling bias is subtype specific according to Casella et al. (78)
The observed difference between the signaling pathways was small for these ligands. More information regarding the pharmacological properties of the co-crystallized ligands is detailed in Table S1.
Figure 1

Figure 1. (A,B) Visual and (C) quantitative comparisons of the pockets from all X-ray structures. Pocket residues (carbon atoms are colored blue, salmon, white, and gray for ANT/iAGO, f/pAGO, FAB-complexed, and ligand-free structures, respectively) of all chains of all crystal structures (listed in panel C by their PDB code followed by their chain identifier) are shown superimposed with the cartoon representation of β2R (PDB code 2RH1 (21)) and bucindolol (green carbon atoms, PDB code 4AMI (32)), as seen from the side (panel A) and from the top (panel B). Panel C gives an overview of aaverage all-atom rmsd using the pocket residues (Å) compared to all 16 f/pAGO and all 27 ANT/iAGO structures (full overview in Supporting Information, Figure S2); bthe average Z-score of the distances between G2.61, D3.32, N7.39, and S5.42 (full overview in Supporting Information, Figures S3 and S4); and cthe pocket volume (Å3, Supporting Information, Figure S5). dThe side chains of the ECL2 residues are not all fully resolved, thereby influencing the pocket volume (Figure S5) as well as rmsd values. The red and blue background coloring mark values associated with f/pAGO and ANT/iAGO properties, respectively. Icons represent f/pAGO (red), ANT/iAGO (blue), or unvalidated ANT (cyan) with no or unknown signaling preference (circles) or β-arrestin-biased ligands (triangles) (see Table 1).
Identification of Ligand-Type-Specific Molecular Interaction Profiles
Figure 2

Figure 2. Overview of the unique interaction fingerprints of all cocrystallized ligands. The colors indicate the presence of an interaction (as seen from the residue) according to the colors described at the bottom of the figure. Identical IFPs for multiple monomers within a PDB entry are grouped (e.g., 2VT4_chainA-D). The last two columns describe the amount of times (as a percentage of the total comparisons) an IFP comparison results in a score ≥0.6 when compared with the ANT/iAGO reference IFPs (a blue background indicates a high percentage) and the f/pAGO reference IFPs (a red background indicates a high percentage). aThe IFP of the highest scoring docking pose of norepinephrine in 2Y03-chainA (see Figure 6). Names and icons represent f/pAGO (red), ANT/iAGO (blue), or unvalidated ANT (34) (cyan) with no or unknown signaling preference (circle) or β-arrestin-biased ligands (triangle) (see Table 1).
Selective Retrieval of f/pAGO over ANT/iAGO in Structure-Based Virtual Screening
Figure 3

Figure 3. Overall enrichment at 1% false positive rate (FP-rate) for the retrieval of 25 partial/full agonists and 25 inverse agonists/antagonists over a set of 980 decoy molecules using IFP scoring (A). Full ROC curves visualizing the retrieval rate (TP-rate) of f/pAGO (red) and ANT/iAGO (blue) in the best ANT/iAGO structure (B) and best f/pAGO structure (C, legend shown in panel B). The structures are indicated by their PDB code followed by an underscore and the chain identifier (except when there was only one chain or all chains of the structure had similar performance). The 2D structures represent the co-crystallized ligand for selected structures. The ANT/iAGO axis is scaled from 0 to 60 and the f/pAGO axis from 0 to 100. *1 = 3ZPQ_A, 3ZPQ_dock, 2Y00_B; *2 = 4AMJ_B, 3ZPQ_B. Icons represent f/pAGO (red), ANT/iAGO (blue), or unvalidated ANT (34) (cyan) with no or unknown signaling preference (circle) or β-arrestin-biased ligands (triangle) (see Table 1).
Figure 4

Figure 4. Enrichment factors at a 1% false positive rate using all reference IFPs (columns) on all β-adrenergic monomers for the retrieval of for f/pAGO (A) and ANT/iAGO (B) over physicochemically similar decoys. The white to red and white to blue gradients as background color mark a low to high enrichment for f/pAGO (A) and ANT/iAGO, respectively. Icons represent f/pAGO (red), ANT/iAGO (blue), or unvalidated ANT (34) (cyan) with no or unknown signaling preference (circle) or β-arrestin-biased ligands (triangle) (see Table 1).
Selective Structure-Based Virtual Screening for Ligands with the Desired Functional Effect
Figure 5

Figure 5. Analysis of VS runs using the IFPs (D,E) and structures (F,G) of the most f/p AGO-selective (2Y02_A) and ANT/iAGO-selective (2VT4_A) protein–ligand complexes (see Figure 3A), showing that both the reference IFP and protein structure determine enrichment and functional selectivity of the VS study. The binding modes of the selected f/pAGO (A, 2Y02_A) and selected ANT/iAGO (B, 2VT4_A) protein–ligand complex, a docked ligand with the same efficacy class (green carbon atoms), and their corresponding IFPs (C) for the displayed residues. EF1% results for agonists and antagonist versus the decoys when using the reference IFP of the selected f/pAGO (D) and selected ANT/iAGO (E) for scoring docked compounds in all 48 protein structures. EF1% results for f/pAGO and ANT/iAGO versus the decoys when using the 38 unique reference IFPs of all ligand–protein complexes for rescoring the docked compounds in the 2Y02_A (F) and 2VT4_A (G) structure. Icons represent f/pAGO (red), ANT/iAGO (blue), or unvalidated ANT (34) (cyan) with no or unknown signaling preference (circle) or β-arrestin-biased ligands (triangle) (see Table 1).
Selective Structure-Based Virtual Screening for Partial/Full Agonists with a Computationally Predicted Norepinephrine Interaction Fingerprint
Figure 6

Figure 6. EF1% results for agonists and antagonists (A) when using the reference IFP of docked norepinephrine (Figure 2) in 2Y03_A (B). The individual ROC plots for the retrieval of agonists (red curve) and antagonists (blue curve) in the selected ANT/iAGO structure 2VT4_A (C) and f/pAGO structure 2Y02_A (D). Icons represent f/pAGO (red), ANT/iAGO (blue), or unvalidated ANT (34) (cyan) with no or unknown signaling preference (circle) or β-arrestin-biased ligands (triangle) (see Table 1).
Biased Signaling
Conclusions
Materials and Methods
Crystal Structures Retrieval and Preparation
Consideration of Alternative Ligand Ring Conformations in 3ZPQ
Pocket and Ligand Analyses
Compound Preparation and Docking
Interaction Fingerprint Calculation and Scoring
Virtual Screening Assessment
Supporting Information
Pharmacological details of all co-crystallized ligands, additional analyses of the pockets from the β-adrenergic X-rays (rmsd, distances, pocket contraction, binding modes, volumes), additional IFP analyses (interaction frequency per pocket residue, cross-comparison), two conformations of arylpiperazine 19, the 2D chemical structures of all docked ligands, and a scatter plot describing the overall enrichment using the ChemPLP scoring function. This material is available free of charge via the Internet at http://pubs.acs.org.
Terms & Conditions
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Acknowledgment
We thank Dr. Chris G. Tate (MRC Laboratory of Molecular Biology, Cambridge, UK) for kindly providing the high-resolution cyanopindolol β1R (4BVN) structure and for his feedback on the manuscript. This research was financially supported by The Netherlands Organization for Scientific Research (NWO VENI Grant 700.59.408 to C.d.G. and TOP PUNT Grant to R.L.). A.J.K., R.L., I.J.P.d.E., and C.d.G. participate in the European Cooperation in Science and Technology Action CM1207 [GPCR-Ligand Interactions, Structures, and Transmembrane Signalling: A European Research Network (GLISTEN)].
References
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- 14Hollenstein, K.; Kean, J.; Bortolato, A.; Cheng, R. K.; Dore, A. S.; Jazayeri, A.; Cooke, R. M.; Weir, M.; Marshall, F. H. Structure of Class B Gpcr Corticotropin-Releasing Factor Receptor 1 Nature 2013, 499, 438– 443Google Scholar14https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtFWku7nN&md5=429ae98fb6d5bf65c5ef3b6a612ea3a0Structure of class B GPCR corticotropin-releasing factor receptor 1Hollenstein, Kaspar; Kean, James; Bortolato, Andrea; Cheng, Robert K. Y.; Dore, Andrew S.; Jazayeri, Ali; Cooke, Robert M.; Weir, Malcolm; Marshall, Fiona H.Nature (London, United Kingdom) (2013), 499 (7459), 438-443CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)Structural anal. of class B G-protein-coupled receptors (GPCRs), cell-surface proteins that respond to peptide hormones, has been restricted to the amino-terminal extracellular domain, thus providing little understanding of the membrane-spanning signal transduction domain. The corticotropin-releasing factor receptor type 1 (CRF1R) is a class B receptor which mediates the response to stress and has been considered a drug target for depression and anxiety. Here we report the crystal structure of the transmembrane domain of the human corticotropin-releasing factor receptor type 1 in complex with the small-mol. antagonist CP-376395. The structure provides detailed insight into the architecture of class B receptors. Atomic details of the interactions of the receptor with the non-peptide ligand that binds deep within the receptor are described. This structure provides a model for all class B GPCRs and may aid in the design of new small-mol. drugs for diseases of brain and metab.
- 15Siu, F. Y.; He, M.; de Graaf, C.; Han, G. W.; Yang, D.; Zhang, Z.; Zhou, C.; Xu, Q.; Wacker, D.; Joseph, J. S.; Liu, W.; Lau, J.; Cherezov, V.; Katritch, V.; Wang, M. W.; Stevens, R. C. Structure of the Human Glucagon Class B G-Protein-Coupled Receptor Nature 2013, 499, 444– 449Google Scholar15https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtFWktbzN&md5=ba4801075b7fc13454710def7f083710Structure of the human glucagon class B G-protein-coupled receptorSiu, Fai Yiu; He, Min; de Graaf, Chris; Han, Gye Won; Yang, Dehua; Zhang, Zhiyun; Zhou, Caihong; Xu, Qingping; Wacker, Daniel; Joseph, Jeremiah S.; Liu, Wei; Lau, Jesper; Cherezov, Vadim; Katritch, Vsevolod; Wang, Ming-Wei; Stevens, Raymond C.Nature (London, United Kingdom) (2013), 499 (7459), 444-449CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)Binding of the glucagon peptide to the glucagon receptor (GCGR) triggers the release of glucose from the liver during fasting; thus GCGR plays an important role in glucose homeostasis. Here we report the crystal structure of the seven transmembrane helical domain of human GCGR at 3.4 Å resoln., complemented by extensive site-specific mutagenesis, and a hybrid model of glucagon bound to GCGR to understand the mol. recognition of the receptor for its native ligand. Beyond the shared seven transmembrane fold, the GCGR transmembrane domain deviates from class A G-protein-coupled receptors with a large ligand-binding pocket and the first transmembrane helix having a 'stalk' region that extends three alpha-helical turns above the plane of the membrane. The stalk positions the extracellular domain (∼12 kilodaltons) relative to the membrane to form the glucagon-binding site that captures the peptide and facilitates the insertion of glucagon's amino terminus into the seven transmembrane domain.
- 16Wu, H.; Wang, C.; Gregory, K. J.; Han, G. W.; Cho, H. P.; Xia, Y.; Niswender, C. M.; Katritch, V.; Meiler, J.; Cherezov, V.; Conn, P. J.; Stevens, R. C. Structure of a Class C Gpcr Metabotropic Glutamate Receptor 1 Bound to an Allosteric Modulator Science 2014, 344, 58– 64Google Scholar16https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXlt1eht78%253D&md5=e552ac4646b8e67c52d1f5e0aa42ec5aStructure of a Class C GPCR Metabotropic Glutamate Receptor 1 Bound to an Allosteric ModulatorWu, Huixian; Wang, Chong; Gregory, Karen J.; Han, Gye Won; Cho, Hyekyung P.; Xia, Yan; Niswender, Colleen M.; Katritch, Vsevolod; Meiler, Jens; Cherezov, Vadim; Conn, P. Jeffrey; Stevens, Raymond C.Science (Washington, DC, United States) (2014), 344 (6179), 58-64CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)The excitatory neurotransmitter glutamate induces modulatory actions via the metabotropic glutamate receptors (mGlus), which are class C G protein-coupled receptors (GPCRs). The authors detd. the structure of the human mGlu1 receptor seven-transmembrane (7TM) domain bound to a neg. allosteric modulator, FITM, at a resoln. of 2.8 angstroms. The modulator binding site partially overlaps with the orthosteric binding sites of class A GPCRs but is more restricted than most other GPCRs. The authors obsd. a parallel 7TM dimer mediated by cholesterols, which suggests that signaling initiated by glutamate's interaction with the extracellular domain might be mediated via 7TM interactions within the full-length receptor dimer. A combination of crystallog., structure-activity relationships, mutagenesis, and full-length dimer modeling provides insights about the allosteric modulation and activation mechanism of class C GPCRs.
- 17Wang, C.; Wu, H.; Katritch, V.; Han, G. W.; Huang, X. P.; Liu, W.; Siu, F. Y.; Roth, B. L.; Cherezov, V.; Stevens, R. C. Structure of the Human Smoothened Receptor Bound to an Antitumour Agent Nature 2013, 497, 338– 343Google Scholar17https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXmvFylsb0%253D&md5=fdd96ac77bcf93d5c8da46e5630795b2Structure of the human smoothened receptor bound to an antitumour agentWang, Chong; Wu, Huixian; Katritch, Vsevolod; Han, Gye Won; Huang, Xi-Ping; Liu, Wei; Siu, Fai Yiu; Roth, Bryan L.; Cherezov, Vadim; Stevens, Raymond C.Nature (London, United Kingdom) (2013), 497 (7449), 338-343CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)The smoothened (SMO) receptor, a key signal transducer in the hedgehog signalling pathway, is responsible for the maintenance of normal embryonic development and is implicated in carcinogenesis. It is classified as a class frizzled (class F) G-protein-coupled receptor (GPCR), although the canonical hedgehog signalling pathway involves the GLI transcription factors and the sequence similarity with class A GPCRs is less than 10%. Here we report the crystal structure of the transmembrane domain of the human SMO receptor bound to the small-mol. antagonist LY2940680 at 2.5 Å resoln. Although the SMO receptor shares the seven-transmembrane helical (7TM) fold, most of the conserved motifs for class A GPCRs are absent, and the structure reveals an unusually complex arrangement of long extracellular loops stabilized by four disulfide bonds. The ligand binds at the extracellular end of the seven-transmembrane-helix bundle and forms extensive contacts with the loops.
- 18Rodriguez, D.; Gao, Z. G.; Moss, S. M.; Jacobson, K. A.; Carlsson, J. Molecular Docking Screening Using Agonist-Bound Gpcr Structures: Probing the a Adenosine Receptor J. Chem. Inf. Model. 2015, 55, 550– 563Google Scholar18https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhsVWgtbs%253D&md5=0faec5c3d810a9ef32e5f374b6f9b447Molecular Docking Screening Using Agonist-Bound GPCR Structures: Probing the A2A Adenosine ReceptorRodriguez, David; Gao, Zhang-Guo; Moss, Steven M.; Jacobson, Kenneth A.; Carlsson, JensJournal of Chemical Information and Modeling (2015), 55 (3), 550-563CODEN: JCISD8; ISSN:1549-9596. (American Chemical Society)Crystal structures of G protein-coupled receptors (GPCRs) have recently revealed the mol. basis of ligand binding and activation, which has provided exciting opportunities for structure-based drug design. The A2A adenosine receptor (A2AAR) is a promising therapeutic target for cardiovascular diseases, but progress in this area is limited by the lack of novel agonist scaffolds. The authors carried out docking screens of 6.7 million com. available mols. against active-like conformations of the A2AAR to investigate whether these structures could guide the discovery of agonists. Nine out of the 20 predicted agonists were confirmed to be A2AAR ligands, but none of these activated the ARs. The difficulties in discovering AR agonists using structure-based methods originated from limited at.-level understanding of the activation mechanism and a chem. bias toward antagonists in the screened library. In particular, the compn. of the screened library was found to strongly reduce the likelihood of identifying AR agonists, which reflected the high ligand complexity required for receptor activation. Extension of this anal. to other pharmaceutically relevant GPCRs suggested that library screening may not be suitable for targets requiring a complex receptor-ligand interaction network. The authors' results provide specific directions for the future development of novel A2AAR agonists and general strategies for structure-based drug discovery.
- 19White, J. F.; Noinaj, N.; Shibata, Y.; Love, J.; Kloss, B.; Xu, F.; Gvozdenovic-Jeremic, J.; Shah, P.; Shiloach, J.; Tate, C. G.; Grisshammer, R. Structure of the Agonist-Bound Neurotensin Receptor Nature 2012, 490, 508– 513Google Scholar19https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhsVykt7%252FP&md5=c55a071640dec7edae7a69d715bea675Structure of the agonist-bound neurotensin receptorWhite, Jim F.; Noinaj, Nicholas; Shibata, Yoko; Love, James; Kloss, Brian; Xu, Feng; Gvozdenovic-Jeremic, Jelena; Shah, Priyanka; Shiloach, Joseph; Tate, Christopher G.; Grisshammer, ReinhardNature (London, United Kingdom) (2012), 490 (7421), 508-513CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)Neurotensin (NTS) is a 13-amino-acid peptide that functions as both a neurotransmitter and a hormone through the activation of the neurotensin receptor NTSR1, a G-protein-coupled receptor (GPCR). In the brain, NTS modulates the activity of dopaminergic systems, opioid-independent analgesia, and the inhibition of food intake; in the gut, NTS regulates a range of digestive processes. Here we present the structure at 2.8 Å resoln. of Rattus norvegicus NTSR1 in an active-like state, bound to NTS8-13, the carboxy-terminal portion of NTS responsible for agonist-induced activation of the receptor. The peptide agonist binds to NTSR1 in an extended conformation nearly perpendicular to the membrane plane, with the C terminus oriented towards the receptor core. Our findings provide, to our knowledge, the first insight into the binding mode of a peptide agonist to a GPCR and may support the development of non-peptide ligands that could be useful in the treatment of neurol. disorders, cancer and obesity.
- 20Weichert, D.; Kruse, A. C.; Manglik, A.; Hiller, C.; Zhang, C.; Hubner, H.; Kobilka, B. K.; Gmeiner, P. Covalent Agonists for Studying G Protein-Coupled Receptor Activation Proc. Natl. Acad. Sci. U.S.A. 2014, 111, 10744– 10748Google Scholar20https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhtFyqtbnN&md5=a131bb7711d9a1826c77c3b598dee470Covalent agonists for studying G protein-coupled receptor activationWeichert, Dietmar; Kruse, Andrew C.; Manglik, Aashish; Hiller, Christine; Zhang, Cheng; Huebner, Harald; Kobilka, Brian K.; Gmeiner, PeterProceedings of the National Academy of Sciences of the United States of America (2014), 111 (29), 10744-10748CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)Structural studies on G protein-coupled receptors (GPCRs) provide important insights into the architecture and function of these important drug targets. However, the crystn. of GPCRs in active states is particularly challenging, requiring the formation of stable and conformationally homogeneous ligand-receptor complexes. Native hormones, neurotransmitters, and synthetic agonists that bind with low affinity are ineffective at stabilizing an active state for crystallogenesis. To promote structural studies on the pharmacol. highly relevant class of aminergic GPCRs, the authors here present the development of covalently binding mol. tools activating Gs-, Gi-, and Gq-coupled receptors. The covalent agonists are derived from the monoamine neurotransmitters noradrenaline, dopamine, serotonin, and histamine, and they were accessed using a general and versatile synthetic strategy. The authors demonstrate that the tool compds. presented herein display an efficient covalent binding mode and that the resp. covalent ligand-receptor complexes activate G proteins comparable to the natural neurotransmitters. A crystal structure of the β2-adrenoreceptor in complex with a covalent noradrenaline analog and a conformationally selective antibody (nanobody) verified that these agonists can be used to facilitate crystallogenesis.
- 21Cherezov, V.; Rosenbaum, D. M.; Hanson, M. A.; Rasmussen, S. G.; Thian, F. S.; Kobilka, T. S.; Choi, H. J.; Kuhn, P.; Weis, W. I.; Kobilka, B. K.; Stevens, R. C. High-Resolution Crystal Structure of an Engineered Human Beta2-Adrenergic G Protein-Coupled Receptor Science 2007, 318, 1258– 1265Google Scholar21https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhtlGmur7I&md5=12c5bacb8464a4b243fe9341192b5b3bHigh-Resolution Crystal Structure of an Engineered Human β2-Adrenergic G Protein-Coupled ReceptorCherezov, Vadim; Rosenbaum, Daniel M.; Hanson, Michael A.; Rasmussen, Soren G. F.; Thian, Foon Sun; Kobilka, Tong Sun; Choi, Hee-Jung; Kuhn, Peter; Weis, William I.; Kobilka, Brian K.; Stevens, Raymond C.; Takeda, S.; Kadowaki, S.; Haga, T.; Takaesu, H.; Mitaku, S.; Fredriksson, R.; Lagerstrom, M. C.; Lundin, L. G.; Schioth, H. B.; Pierce, K. L.; Premont, R. T.; Lefkowitz, R. J.; Lefkowitz, R. J.; Shenoy, S. K.; Rosenbaum, D. M.Science (Washington, DC, United States) (2007), 318 (5854), 1258-1265CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)Second extracellular loop, which in the β2-adrenergic receptor contains an unusual pair of disulfide bonds and an extra helix. This loop and the absence Heterotrimeric guanine nucleotide-binding protein (G protein)-coupled receptors constitute the largest family of eukaryotic signal transduction proteins that communicate across the membrane. We report the crystal structure of a human β2-adrenergic receptor-T4 lysozyme fusion protein bound to the partial inverse agonist carazolol at 2.4 angstrom resoln. The structure provides a high-resoln. view of a human G protein-coupled receptor bound to a diffusible ligand. Ligand-binding site accessibility is enabled by the second extracellular loop, which is held out of the binding cavity by a pair of closely spaced disulfide bridges and a short helical segment within the loop. Cholesterol, a necessary component for crystn., mediates an intriguing parallel assocn. of receptor mols. in the crystal lattice. Although the location of carazolol in the β2-adrenergic receptor is very similar to that of retinal in rhodopsin, structural differences in the ligand-binding site and other regions highlight the challenges in using rhodopsin as a template model for this large receptor family.
- 22Rasmussen, S. G.; Choi, H. J.; Rosenbaum, D. M.; Kobilka, T. S.; Thian, F. S.; Edwards, P. C.; Burghammer, M.; Ratnala, V. R.; Sanishvili, R.; Fischetti, R. F.; Schertler, G. F.; Weis, W. I.; Kobilka, B. K. Crystal Structure of the Human Beta2 Adrenergic G-Protein-Coupled Receptor Nature 2007, 450, 383– 387Google Scholar22https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhtlajs77N&md5=79026a0a69ddb4b0ea25063e409ad2cdCrystal structure of the human β2 adrenergic G-protein-coupled receptorRasmussen, Soren G. F.; Choi, Hee-Jung; Rosenbaum, Daniel M.; Kobilka, Tong Sun; Thian, Foon Sun; Edwards, Patricia C.; Burghammer, Manfred; Ratnala, Venkata R. P.; Sanishvili, Ruslan; Fischetti, Robert F.; Schertler, Gebhard F. X.; Weis, William I.; Kobilka, Brian K.Nature (London, United Kingdom) (2007), 450 (7168), 383-387CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)Structural anal. of G-protein-coupled receptors (GPCRs) for hormones and neurotransmitters has been hindered by their low natural abundance, inherent structural flexibility, and instability in detergent solns. Here we report a structure of the human β2 adrenoceptor (β2AR), which was crystd. in a lipid environment when bound to an inverse agonist and in complex with a Fab that binds to the third intracellular loop. Diffraction data were obtained by high-brilliance microcrystallog. and the structure detd. at 3.4 Å/3.7 Å resoln. The cytoplasmic ends of the β2AR transmembrane segments and the connecting loops are well resolved, whereas the extracellular regions of the β2AR are not seen. The β2AR structure differs from rhodopsin in having weaker interactions between the cytoplasmic ends of transmembrane (TM)3 and TM6, involving the conserved E/DRY sequences. These differences may be responsible for the relatively high basal activity and structural instability of the β2AR, and contribute to the challenges in obtaining diffraction-quality crystals of non-rhodopsin GPCRs.
- 23Hanson, M. A.; Cherezov, V.; Griffith, M. T.; Roth, C. B.; Jaakola, V. P.; Chien, E. Y.; Velasquez, J.; Kuhn, P.; Stevens, R. C. A Specific Cholesterol Binding Site Is Established by the 2.8 a Structure of the Human Beta2-Adrenergic Receptor Structure 2008, 16, 897– 905Google Scholar23https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXmvFertbo%253D&md5=d72699c59a8b79c2c45e89dcd391e7cbA Specific Cholesterol Binding Site Is Established by the 2.8 Å Structure of the Human β2-Adrenergic ReceptorHanson, Michael A.; Cherezov, Vadim; Griffith, Mark T.; Roth, Christopher B.; Jaakola, Veli-Pekka; Chien, Ellen Y. T.; Velasquez, Jeffrey; Kuhn, Peter; Stevens, Raymond C.Structure (Cambridge, MA, United States) (2008), 16 (6), 897-905CODEN: STRUE6; ISSN:0969-2126. (Cell Press)The role of cholesterol in eukaryotic membrane protein function has been attributed primarily to an influence on membrane fluidity and curvature. We present the 2.8 Å resoln. crystal structure of a thermally stabilized human β2-adrenergic receptor (β2AR) bound to cholesterol and the partial inverse agonist timolol. The receptors pack as monomers in an antiparallel assocn. with two distinct cholesterol mols. bound per receptor, but not in the packing interface, thereby indicating a structurally relevant cholesterol-binding site between helixes I, II, III, and IV. Thermal stability anal. using isothermal denaturation confirms that a cholesterol analog significantly enhances the stability of the receptor. A consensus motif is defined that predicts cholesterol binding for 44% of human class A receptors, suggesting that specific sterol binding is important to the structure and stability of other G protein-coupled receptors (GPCRs), and that this site may provide a target for therapeutic discovery.
- 24Warne, T.; Serrano-Vega, M. J.; Baker, J. G.; Moukhametzianov, R.; Edwards, P. C.; Henderson, R.; Leslie, A. G.; Tate, C. G.; Schertler, G. F. Structure of a Beta1-Adrenergic G-Protein-Coupled Receptor Nature 2008, 454, 486– 491Google Scholar24https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXovV2mtLg%253D&md5=de1d476a6ff0b995cd344c248d1bc490Structure of a β1-adrenergic G-protein-coupled receptorWarne, Tony; Serrano-Vega, Maria J.; Baker, Jillian G.; Moukhametzianov, Rouslan; Edwards, Patricia C.; Henderson, Richard; Leslie, Andrew G. W.; Tate, Christopher G.; Schertler, Gebhard F. X.Nature (London, United Kingdom) (2008), 454 (7203), 486-491CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)G-protein-coupled receptors have a major role in transmembrane signaling in most eukaryotes and many are important drug targets. Here we report the 2.7Å resoln. crystal structure of a β1-adrenergic receptor in complex with high affinity antagonist cyanopindolol. The modified turkey (Meleagris gallopavo) receptor was selected to be in its antagonist conformation and its thermostability improved by earlier limited mutagenesis. The ligand-binding pocket comprises 15 side chains from amino acid residues in 4 transmembrane α-helixes and extracellular loop 2. This loop defines the entrance of the ligand-binding pocket and is stabilized by two disulfide bonds and a sodium ion. Binding of cyanopindolol to the β1-adrenergic receptor and binding of Carazolol to the β2-adrenergic receptor involve similar interactions. A short well-defined helix in cytoplasmic loop 2, not obsd. in either rhodopsin or the β2-adrenergic receptor, directly interacts by means of a tyrosine with the highly conserved DRY motif at the end of helix 3 that is essential for receptor activation.
- 25Bokoch, M. P.; Zou, Y.; Rasmussen, S. G.; Liu, C. W.; Nygaard, R.; Rosenbaum, D. M.; Fung, J. J.; Choi, H. J.; Thian, F. S.; Kobilka, T. S.; Puglisi, J. D.; Weis, W. I.; Pardo, L.; Prosser, R. S.; Mueller, L.; Kobilka, B. K. Ligand-Specific Regulation of the Extracellular Surface of a G-Protein-Coupled Receptor Nature 2010, 463, 108– 112Google Scholar25https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhvFeksQ%253D%253D&md5=58c5abb3edeb50453344fb47ebda7a2cLigand-specific regulation of the extracellular surface of a G-protein-coupled receptorBokoch, Michael P.; Zou, Yaozhong; Rasmussen, Soren G. F.; Liu, Corey W.; Nygaard, Rie; Rosenbaum, Daniel M.; Fung, Juan Jose; Choi, Hee-Jung; Thian, Foon Sun; Kobilka, Tong Sun; Puglisi, Joseph D.; Weis, William I.; Pardo, Leonardo; Prosser, R. Scott; Mueller, Luciano; Kobilka, Brian K.Nature (London, United Kingdom) (2010), 463 (7277), 108-112CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)G protein-coupled receptors (GPCRs) are seven-transmembrane proteins that mediate most cellular responses to hormones and neurotransmitters. They are the largest group of therapeutic targets for a broad spectrum of diseases. Recent crystal structures of GPCRs have revealed structural conservation extending from the orthosteric ligand-binding site in the transmembrane core to the cytoplasmic G protein-coupling domains. In contrast, the extracellular surface (ECS) of GPCRs is remarkably diverse and is therefore an ideal target for the discovery of subtype-selective drugs. However, little is known about the functional role of the ECS in receptor activation, or about conformational coupling of this surface to the native ligand-binding pocket. Here we use NMR spectroscopy to investigate ligand-specific conformational changes around a central structural feature in the ECS of the β2 adrenergic receptor (β2AR): a salt bridge linking extracellular loops 2 and 3. Small-mol. drugs that bind within the transmembrane core and exhibit different efficacies towards G protein activation (agonist, neutral antagonist, and inverse agonist) also stabilize distinct conformations of the ECS. We thereby demonstrate conformational coupling between the ECS and the orthosteric binding site, showing that drugs targeting this diverse surface could function as allosteric modulators with high subtype selectivity. Moreover, these studies provide a new insight into the dynamic behavior of GPCRs not addressable by static, inactive-state crystal structures.
- 26Wacker, D.; Fenalti, G.; Brown, M. A.; Katritch, V.; Abagyan, R.; Cherezov, V.; Stevens, R. C. Conserved Binding Mode of Human Beta2 Adrenergic Receptor Inverse Agonists and Antagonist Revealed by X-Ray Crystallography J. Am. Chem. Soc. 2010, 132, 11443– 11445Google ScholarThere is no corresponding record for this reference.
- 27Moukhametzianov, R.; Warne, T.; Edwards, P. C.; Serrano-Vega, M. J.; Leslie, A. G.; Tate, C. G.; Schertler, G. F. Two Distinct Conformations of Helix 6 Observed in Antagonist-Bound Structures of a Beta1-Adrenergic Receptor Proc. Natl. Acad. Sci. U.S.A. 2011, 108, 8228– 8232Google Scholar27https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXmsF2jsb8%253D&md5=7888634ffd4ff20895c6c02c4ed10496Two distinct conformations of helix 6 observed in antagonist-bound structures of a β1-adrenergic receptorMoukhametzianov, Rouslan; Warne, Tony; Edwards, Patricia C.; Serrano-Vega, Maria J.; Leslie, Andrew G. W.; Tate, Christopher G.; Schertler, Gebhard F. X.Proceedings of the National Academy of Sciences of the United States of America (2011), 108 (20), 8228-8232, S8228/1-S8228/5CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)The β1-adrenergic receptor (β1AR) is a G-protein-coupled receptor whose inactive state structure was detd. using a thermostabilized mutant (β1AR-M23). However, it was not thought to be in a fully inactivated state because there was no salt bridge between Arg139 and Glu285 linking the cytoplasmic ends of transmembrane helixes 3 and 6 (the R3.50-D/E6.30 "ionic lock"). Here we compare eight new structures of β1AR-M23, detd. from crystallog. independent mols. in four different crystals with three different antagonists bound. These structures are all in the inactive R state and show clear electron d. for cytoplasmic loop 3 linking transmembrane helixes 5 and 6 that had not been seen previously. Despite significantly different crystal packing interactions, there are only two distinct conformations of the cytoplasmic end of helix 6, bent and straight. In the bent conformation, the Arg139-Glu285 salt bridge is present, as in the crystal structure of dark-state rhodopsin. The straight conformation, obsd. in previously solved structures of β-receptors, results in the ends of helixes 3 and 6 being too far apart for the ionic lock to form. In the bent conformation, the R3.50-E6.30 distance is significantly longer than in rhodopsin, suggesting that the interaction is also weaker, which could explain the high basal activity in β1AR compared to rhodopsin. Many mutations that increase the constitutive activity of G-protein-coupled receptors are found in the bent region at the cytoplasmic end of helix 6, supporting the idea that this region plays an important role in receptor activation.
- 28Rasmussen, S. G.; Choi, H. J.; Fung, J. J.; Pardon, E.; Casarosa, P.; Chae, P. S.; Devree, B. T.; Rosenbaum, D. M.; Thian, F. S.; Kobilka, T. S.; Schnapp, A.; Konetzki, I.; Sunahara, R. K.; Gellman, S. H.; Pautsch, A.; Steyaert, J.; Weis, W. I.; Kobilka, B. K. Structure of a Nanobody-Stabilized Active State of the Beta(2) Adrenoceptor Nature 2011, 469, 175– 180Google Scholar28https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXkvFartA%253D%253D&md5=3a1d3bac6d92c9d54cf1ddd14d56ab8cStructure of a nanobody-stabilized active state of the β2 adrenoceptorRasmussen, Soren G. F.; Choi, Hee-Jung; Fung, Juan Jose; Pardon, Els; Casarosa, Paola; Chae, Pil Seok; DeVree, Brian T.; Rosenbaum, Daniel M.; Thian, Foon Sun; Kobilka, Tong Sun; Schnapp, Andreas; Konetzki, Ingo; Sunahara, Roger K.; Gellman, Samuel H.; Pautsch, Alexander; Steyaert, Jan; Weis, William I.; Kobilka, Brian K.Nature (London, United Kingdom) (2011), 469 (7329), 175-180CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)G protein coupled receptors (GPCRs) exhibit a spectrum of functional behaviors in response to natural and synthetic ligands. Recent crystal structures provide insights into inactive states of several GPCRs. Efforts to obtain an agonist-bound active-state GPCR structure have proven difficult due to the inherent instability of this state in the absence of a G protein. We generated a camelid antibody fragment (nanobody) to the human β2 adrenergic receptor (β2AR) that exhibits G protein-like behavior, and obtained an agonist-bound, active-state crystal structure of the receptor-nanobody complex. Comparison with the inactive β2AR structure reveals subtle changes in the binding pocket; however, these small changes are assocd. with an 11 Å outward movement of the cytoplasmic end of transmembrane segment 6, and rearrangements of transmembrane segments 5 and 7 that are remarkably similar to those obsd. in opsin, an active form of rhodopsin. This structure provides insights into the process of agonist binding and activation.
- 29Rasmussen, S. G.; DeVree, B. T.; Zou, Y.; Kruse, A. C.; Chung, K. Y.; Kobilka, T. S.; Thian, F. S.; Chae, P. S.; Pardon, E.; Calinski, D.; Mathiesen, J. M.; Shah, S. T.; Lyons, J. A.; Caffrey, M.; Gellman, S. H.; Steyaert, J.; Skiniotis, G.; Weis, W. I.; Sunahara, R. K.; Kobilka, B. K. Crystal Structure of the Beta2 Adrenergic Receptor-Gs Protein Complex Nature 2011, 477, 549– 555Google Scholar29https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXht1equrrL&md5=d22a43dd677ac255d138b1aedff357d3Crystal structure of the β2 adrenergic receptor-Gs protein complexRasmussen, Soren G. F.; DeVree, Brian T.; Zou, Yao-Zhong; Kruse, Andrew C.; Chung, Ka-Young; Kobilka, Tong-Sun; Thian, Foon-Sun; Chae, Pil-Seok; Pardon, Els; Calinski, Diane; Mathiesen, Jesper M.; Shah, Syed T. A.; Lyons, Joseph A.; Caffrey, Martin; Gellman, Samuel H.; Steyaert, Jan; Skiniotis, Georgios; Weis, William I.; Sunahara, Roger K.; Kobilka, Brian K.Nature (London, United Kingdom) (2011), 477 (7366), 549-555CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)G protein-coupled receptors (GPCRs) are responsible for the majority of cellular responses to hormones and neurotransmitters as well as the senses of sight, olfaction and taste. The paradigm of GPCR signalling is the activation of a heterotrimeric GTP binding protein (G protein) by an agonist-occupied receptor. The β2 adrenergic receptor (β2AR) activation of Gs, the stimulatory G protein for adenylyl cyclase, has long been a model system for GPCR signalling. Here we present the crystal structure of the active state ternary complex composed of agonist-occupied monomeric β2AR and nucleotide-free Gs heterotrimer. The principal interactions between the β2AR and Gs involve the amino- and carboxy-terminal α-helixes of Gs, with conformational changes propagating to the nucleotide-binding pocket. The largest conformational changes in the β2AR include a 14 Å outward movement at the cytoplasmic end of transmembrane segment 6 (TM6) and an α-helical extension of the cytoplasmic end of TM5. The most surprising observation is a major displacement of the α-helical domain of Gαs relative to the Ras-like GTPase domain. This crystal structure represents the first high-resoln. view of transmembrane signalling by a GPCR.
- 30Rosenbaum, D. M.; Zhang, C.; Lyons, J. A.; Holl, R.; Aragao, D.; Arlow, D. H.; Rasmussen, S. G.; Choi, H. J.; Devree, B. T.; Sunahara, R. K.; Chae, P. S.; Gellman, S. H.; Dror, R. O.; Shaw, D. E.; Weis, W. I.; Caffrey, M.; Gmeiner, P.; Kobilka, B. K. Structure and Function of an Irreversible Agonist-Beta(2) Adrenoceptor Complex Nature 2011, 469, 236– 240Google Scholar30https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXkvFehsQ%253D%253D&md5=8629b93e43fb692395e2aa6f8bb011a9Structure and function of an irreversible agonist-β2 adrenoceptor complexRosenbaum, Daniel M.; Zhang, Cheng; Lyons, Joseph A.; Holl, Ralph; Aragao, David; Arlow, Daniel H.; Rasmussen, Soren G. F.; Choi, Hee-Jung; DeVree, Brian T.; Sunahara, Roger K.; Chae, Pil Seok; Gellman, Samuel H.; Dror, Ron O.; Shaw, David E.; Weis, William I.; Caffrey, Martin; Gmeiner, Peter; Kobilka, Brian K.Nature (London, United Kingdom) (2011), 469 (7329), 236-240CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)G-protein-coupled receptors (GPCRs) are eukaryotic integral membrane proteins that modulate biol. function by initiating cellular signaling in response to chem. diverse agonists. Despite recent progress in the structural biol. of GPCRs, the mol. basis for agonist binding and allosteric modulation of these proteins is poorly understood. Structural knowledge of agonist-bound states is essential for deciphering the mechanism of receptor activation, and for structure-guided design and optimization of ligands. However, the crystn. of agonist-bound GPCRs has been hampered by modest affinities and rapid off-rates of available agonists. Using the inactive structure of the human β2 adrenergic receptor (β2AR) as a guide, we designed a β2AR agonist that can be covalently tethered to a specific site on the receptor through a disulfide bond. The covalent β2AR-agonist complex forms efficiently, and is capable of activating a heterotrimeric G protein. We crystd. a covalent agonist-bound β2AR-T4L fusion protein in lipid bilayers through the use of the lipidic mesophase method, and detd. its structure at 3.5 Å resoln. A comparison to the inactive structure and an antibody-stabilized active structure (companion paper) shows how binding events at both the extracellular and intracellular surfaces are required to stabilize an active conformation of the receptor. The structures are in agreement with long-timescale (up to 30 μs) mol. dynamics simulations showing that an agonist-bound active conformation spontaneously relaxes to an inactive-like conformation in the absence of a G protein or stabilizing antibody.
- 31Warne, T.; Moukhametzianov, R.; Baker, J. G.; Nehme, R.; Edwards, P. C.; Leslie, A. G.; Schertler, G. F.; Tate, C. G. The Structural Basis for Agonist and Partial Agonist Action on a Beta(1)-Adrenergic Receptor Nature 2011, 469, 241– 244Google ScholarThere is no corresponding record for this reference.
- 32Warne, T.; Edwards, P. C.; Leslie, A. G.; Tate, C. G. Crystal Structures of a Stabilized Beta1-Adrenoceptor Bound to the Biased Agonists Bucindolol and Carvedilol Structure 2012, 20, 841– 849Google ScholarThere is no corresponding record for this reference.
- 33Zou, Y.; Weis, W. I.; Kobilka, B. K. N-Terminal T4 Lysozyme Fusion Facilitates Crystallization of a G Protein Coupled Receptor PLoS One 2012, 7e46039Google ScholarThere is no corresponding record for this reference.
- 34Christopher, J. A.; Brown, J.; Dore, A. S.; Errey, J. C.; Koglin, M.; Marshall, F. H.; Myszka, D. G.; Rich, R. L.; Tate, C. G.; Tehan, B.; Warne, T.; Congreve, M. Biophysical Fragment Screening of the Beta1-Adrenergic Receptor: Identification of High Affinity Arylpiperazine Leads Using Structure-Based Drug Design J. Med. Chem. 2013, 56, 3446– 3455Google ScholarThere is no corresponding record for this reference.
- 35Huang, J.; Chen, S.; Zhang, J. J.; Huang, X. Y. Crystal Structure of Oligomeric Beta1-Adrenergic G Protein-Coupled Receptors in Ligand-Free Basal State Nat. Struct. Mol. Biol. 2013, 20, 419– 425Google Scholar35https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXivF2jur8%253D&md5=2da0ac305cfcec221964c2c8fd37ec58Crystal structure of oligomeric β1-adrenergic G protein-coupled receptors in ligand-free basal stateHuang, Jianyun; Chen, Shuai; Zhang, J. Jillian; Huang, Xin-YunNature Structural & Molecular Biology (2013), 20 (4), 419-425CODEN: NSMBCU; ISSN:1545-9993. (Nature Publishing Group)G protein-coupled receptors (GPCRs) mediate transmembrane signaling. Before ligand binding, GPCRs exist in a basal state. Crystal structures of several GPCRs bound with antagonists or agonists have been solved. However, the crystal structure of the ligand-free basal state of a GPCR, the starting point of GPCR activation and function, had not yet been detd. Here we report the x-ray crystal structure of the ligand-free basal state of a GPCR in a lipid membrane-like environment. Oligomeric turkey β1-adrenergic receptors display two dimer interfaces. One interface involves the transmembrane domain (TM) 1, TM2, the C-terminal H8 and extracellular loop 1. The other interface engages residues from TM4, TM5, intracellular loop 2 and extracellular loop 2. Structural comparisons show that this ligand-free state is in an inactive conformation. This provides the structural basis of GPCR dimerization and oligomerization.
- 36Carlsson, J.; Coleman, R. G.; Setola, V.; Irwin, J. J.; Fan, H.; Schlessinger, A.; Sali, A.; Roth, B. L.; Shoichet, B. K. Ligand Discovery from a Dopamine D3 Receptor Homology Model and Crystal Structure Nat. Chem. Biol. 2011, 7, 769– 778Google Scholar36https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtFylsLvP&md5=7242aa512079a348678b309d352ecdb9Ligand discovery from a dopamine D3 receptor homology model and crystal structureCarlsson, Jens; Coleman, Ryan G.; Setola, Vincent; Irwin, John J.; Fan, Hao; Schlessinger, Avner; Sali, Andrej; Roth, Bryan L.; Shoichet, Brian K.Nature Chemical Biology (2011), 7 (11), 769-778CODEN: NCBABT; ISSN:1552-4450. (Nature Publishing Group)G protein-coupled receptors (GPCRs) are intensely studied as drug targets and for their role in signaling. With the detn. of the first crystal structures, interest in structure-based ligand discovery increased. Unfortunately, for most GPCRs no exptl. structures are available. The detn. of the D3 receptor structure and the challenge to the community to predict it enabled a fully prospective comparison of ligand discovery from a modeled structure vs. that of the subsequently released crystal structure. Over 3.3 million mols. were docked against a homol. model, and 26 of the highest ranking were tested for binding. Six had affinities ranging from 0.2 to 3.1 μM. Subsequently, the crystal structure was released and the docking screen repeated. Of the 25 compds. selected, five had affinities ranging from 0.3 to 3.0 μM. One of the new ligands from the homol. model screen was optimized for affinity to 81 nM. The feasibility of docking screens against modeled GPCRs more generally is considered.
- 37Carlsson, J.; Yoo, L.; Gao, Z. G.; Irwin, J. J.; Shoichet, B. K.; Jacobson, K. A. Structure-Based Discovery of A2a Adenosine Receptor Ligands J. Med. Chem. 2010, 53, 3748– 3755Google Scholar37https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXkvFaqsL8%253D&md5=c36c941d52d2cec06387d79c4c423d46Structure-Based Discovery of A2A Adenosine Receptor LigandsCarlsson, Jens; Yoo, Lena; Gao, Zhan-Guo; Irwin, John J.; Shoichet, Brian K.; Jacobson, Kenneth A.Journal of Medicinal Chemistry (2010), 53 (9), 3748-3755CODEN: JMCMAR; ISSN:0022-2623. (American Chemical Society)The recent detn. of X-ray structures of pharmacol. relevant GPCRs has made these targets accessible to structure-based ligand discovery. Here we explore whether novel chemotypes may be discovered for the A2A adenosine receptor, based on complementarity to its recently detd. structure. The A2A adenosine receptor signals in the periphery and the CNS, with agonists explored as anti-inflammatory drugs and antagonists explored for neurodegenerative diseases. We used mol. docking to screen a 1.4 million compd. database against the X-ray structure computationally and tested 20 high-ranking, previously unknown mols. exptl. Of these 35% showed substantial activity with affinities between 200 nM and 9 μM. For the most potent of these new inhibitors, over 50-fold specificity was obsd. for the A2A vs. the related A1 and A3 subtypes. These high hit rates and affinities at least partly reflect the bias of com. libraries toward GPCR-like chemotypes, an issue that we attempt to investigate quant. Despite this bias, many of the most potent new ligands were novel, dissimilar from known ligands, providing new lead structures for modulation of this medically important target.
- 38de Graaf, C.; Kooistra, A. J.; Vischer, H. F.; Katritch, V.; Kuijer, M.; Shiroishi, M.; Iwata, S.; Shimamura, T.; Stevens, R. C.; de Esch, I. J.; Leurs, R. Crystal Structure-Based Virtual Screening for Fragment-Like Ligands of the Human Histamine H(1) Receptor J. Med. Chem. 2011, 54, 8195– 8206Google ScholarThere is no corresponding record for this reference.
- 39Katritch, V.; Jaakola, V. P.; Lane, J. R.; Lin, J.; Ijzerman, A. P.; Yeager, M.; Kufareva, I.; Stevens, R. C.; Abagyan, R. Structure-Based Discovery of Novel Chemotypes for Adenosine a(2a) Receptor Antagonists J. Med. Chem. 2010, 53, 1799– 1809Google Scholar39https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXptlKqsw%253D%253D&md5=5a54df43f6edd20d83e7e5942e2f9811Structure-Based Discovery of Novel Chemotypes for Adenosine A2A Receptor AntagonistsKatritch, Vsevolod; Jaakola, Veli-Pekka; Lane, J. Robert; Lin, Judy; IJzerman, Adriaan P.; Yeager, Mark; Kufareva, Irina; Stevens, Raymond C.; Abagyan, RubenJournal of Medicinal Chemistry (2010), 53 (4), 1799-1809CODEN: JMCMAR; ISSN:0022-2623. (American Chemical Society)The recent progress in crystallog. of G-protein coupled receptors opens an unprecedented venue for structure-based GPCR drug discovery. To test efficiency of the structure-based approach, we performed mol. docking and virtual ligand screening (VLS) of more than 4 million com. available "drug-like" and "lead-like" compds. against the A2AAR 2.6 Å resoln. crystal structure. Out of 56 high ranking compds. tested in A2AAR binding assays, 23 showed affinities under 10 μM, 11 of those had sub-μM affinities and two compds. had affinities under 60 nM. The identified hits represent at least 9 different chem. scaffolds and are characterized by very high ligand efficiency (0.3-0.5 kcal/mol per heavy atom). Significant A2AAR antagonist activities were confirmed for 10 out of 13 ligands tested in functional assays. High success rate, novelty, and diversity of the chem. scaffolds and strong ligand efficiency of the A2AAR antagonists identified in this study suggest practical applicability of receptor-based VLS in GPCR drug discovery.
- 40Kolb, P.; Rosenbaum, D. M.; Irwin, J. J.; Fung, J. J.; Kobilka, B. K.; Shoichet, B. K. Structure-Based Discovery of Beta2-Adrenergic Receptor Ligands Proc. Natl. Acad. Sci. U.S.A. 2009, 106, 6843– 6848Google Scholar40https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXlsV2qsro%253D&md5=4d1a4cb2aa3925aa4c99c6b0496417a7Structure-based discovery of β2-adrenergic receptor ligandsKolb, Peter; Rosenbaum, Daniel M.; Irwin, John J.; Fung, Juan Jose; Kobilka, Brian K.; Shoichet, Brian K.Proceedings of the National Academy of Sciences of the United States of America (2009), 106 (16), 6843-6848CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)Aminergic G protein-coupled receptors (GPCRs) have been a major focus of pharmaceutical research for many years. Due partly to the lack of reliable receptor structures, drug discovery efforts have been largely ligand-based. The recently detd. X-ray structure of the β2-adrenergic receptor offers an opportunity to investigate the advantages and limitations inherent in a structure-based approach to ligand discovery against this and related GPCR targets. Approx. 1 million com. available, "lead-like" mols. were docked against the β2-adrenergic receptor structure. On testing of 25 high-ranking mols., 6 were active with binding affinities <4 μM, with the best mol. binding with a Ki of 9 nM (95% confidence interval 7-10 nM). Five of these mols. were inverse agonists. The high hit rate, the high affinity of the most potent mol., the discovery of unprecedented chemotypes among the new inhibitors, and the apparent bias toward inverse agonists among the docking hits, have implications for structure-based approaches against GPCRs that recognize small org. mols.
- 41Mysinger, M. M.; Weiss, D. R.; Ziarek, J. J.; Gravel, S.; Doak, A. K.; Karpiak, J.; Heveker, N.; Shoichet, B. K.; Volkman, B. F. Structure-Based Ligand Discovery for the Protein-Protein Interface of Chemokine Receptor Cxcr4 Proc. Natl. Acad. Sci. U.S.A. 2012, 109, 5517– 5522Google ScholarThere is no corresponding record for this reference.
- 42de Graaf, C.; Rognan, D. Customizing G Protein-Coupled Receptor Models for Structure-Based Virtual Screening Curr. Pharm. Des. 2009, 15, 4026– 4048Google Scholar42https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtlKlu7Y%253D&md5=e3aefb5a191d0507cca6766ce191e82cCustomizing G protein-coupled receptor models for structure-based virtual screeningde Graaf, Chris; Rognan, DidierCurrent Pharmaceutical Design (2009), 15 (35), 4026-4048CODEN: CPDEFP; ISSN:1381-6128. (Bentham Science Publishers Ltd.)This review will focus on the construction, refinement, and validation of G Protein-coupled receptor models for the purpose of structure-based virtual screening. Practical tips and tricks derived from concrete modeling and virtual screening exercises to overcome the problems and pitfalls assocd. with the different steps of the receptor modeling workflow will be presented. These examples will not only include rhodopsin-like (class A), but also secretine-like (class B), and glutamate-like (class C) receptors. In addn., the review will present a careful comparative anal. of current crystal structures and their implication on homol. modeling. The following themes will be discussed: (i) the use of exptl. anchors in guiding the modeling procedure; (ii) amino acid sequence alignments; (iii) ligand binding mode accommodation and binding cavity expansion; (iv) proline-induced kinks in transmembrane helixes; (v) binding mode prediction and virtual screening by receptor-ligand interaction fingerprint scoring; (vi) extracellular loop modeling; (vii) virtual filtering schemes. Finally, an overview of several successful structure-based screening shows that receptor models, despite structural inaccuracies, can be efficiently used to find novel ligands.
- 43Kooistra, A. J.; Roumen, L.; Leurs, R.; de Esch, I. J.; de Graaf, C. From Heptahelical Bundle to Hits from the Haystack: Structure-Based Virtual Screening for GPCR Ligands. Methods Enzymol. 2013, 522, 279– 336.Google ScholarThere is no corresponding record for this reference.
- 44Palczewski, K.; Kumasaka, T.; Hori, T.; Behnke, C. A.; Motoshima, H.; Fox, B. A.; Le Trong, I.; Teller, D. C.; Okada, T.; Stenkamp, R. E.; Yamamoto, M.; Miyano, M. Crystal Structure of Rhodopsin: A G Protein-Coupled Receptor Science 2000, 289, 739– 745Google Scholar44https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXlslOqs78%253D&md5=b3d229fc696247ec0f4a6efa10490922Crystal structure of rhodopsin: A G protein-coupled receptorPalczewski, Krzysztof; Kumasaka, Takashi; Hori, Tetsuya; Behnke, Craig A.; Motoshima, Hiroyuki; Fox, Brian A.; Le Trong, Isolde; Teller, David C.; Okada, Tetsuji; Stenkamp, Ronald E.; Yamamoto, Masaki; Miyano, MasashiScience (Washington, D. C.) (2000), 289 (5480), 739-745CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)Heterotrimeric guanine nucleotide-binding protein (G protein)-coupled receptors (GPCRs) respond to a variety of different external stimuli and activate G proteins. GPCRs share many structural features, including a bundle of seven transmembrane α-helixes connected by six loops of varying lengths. We detd. the structure of rhodopsin from diffraction data extending to 2.8 angstroms resoln. The highly organized structure in the extracellular region, including a conserved disulfide bridge, forms a basis for the arrangement of the seven-helix transmembrane motif. The ground-state chromophore, 11-cis-retinal, holds the transmembrane region of the protein in the inactive conformation. Interactions of the chromophore with a cluster of key residues det. the wavelength of the max. absorption. Changes in these interactions among rhodopsins facilitate color discrimination. Identification of a set of residues that mediate interactions between the transmembrane helixes and the cytoplasmic surface, where G-protein activation occurs, also suggests a possible structural change upon photoactivation.
- 45de Graaf, C.; Rein, C.; Piwnica, D.; Giordanetto, F.; Rognan, D. Structure-Based Discovery of Allosteric Modulators of Two Related Class B G-Protein-Coupled Receptors ChemMedChem 2011, 6, 2159– 2169Google ScholarThere is no corresponding record for this reference.
- 46Kellenberger, E.; Springael, J. Y.; Parmentier, M.; Hachet-Haas, M.; Galzi, J. L.; Rognan, D. Identification of Nonpeptide Ccr5 Receptor Agonists by Structure-Based Virtual Screening J. Med. Chem. 2007, 50, 1294– 1303Google Scholar46https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhvFKrur4%253D&md5=67ef5036ec130b7fb77980a76b79decbIdentification of Nonpeptide CCR5 Receptor Agonists by Structure-based Virtual ScreeningKellenberger, Esther; Springael, Jean-Yves; Parmentier, Marc; Hachet-Haas, Muriel; Galzi, Jean-Luc; Rognan, DidierJournal of Medicinal Chemistry (2007), 50 (6), 1294-1303CODEN: JMCMAR; ISSN:0022-2623. (American Chemical Society)A three-dimensional model of the chemokine receptor CCR5 has been built to fulfill structural peculiarities of its α-helix bundle and to distinguish known CCR5 antagonists from randomly chosen drug-like decoys. In silico screening of a library of 1.6 million com. available compds. against the CCR5 model by sequential filters (drug-likeness, 2-D pharmacophore, 3-D docking, scaffold clustering) yielded a hit list of 59 compds., out of which 10 exhibited a detectable binding affinity to the CCR5 receptor. Unexpectedly, most binders tested in a functional assay were shown to be agonists of the CCR5 receptor. A follow-up database query based on similarity to the most potent binders identified three new CCR5 agonists. Despite a moderate affinity of all nonpeptide ligands for the CCR5 receptor, one of the agonists was shown to promote efficient receptor internalization, which is a process therapeutically favorable for protection against HIV-1 infection.
- 47Kiss, R.; Kiss, B.; Konczol, A.; Szalai, F.; Jelinek, I.; Laszlo, V.; Noszal, B.; Falus, A.; Keseru, G. M. Discovery of Novel Human Histamine H4 Receptor Ligands by Large-Scale Structure-Based Virtual Screening J. Med. Chem. 2008, 51, 3145– 3153Google Scholar47https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXlslamsr0%253D&md5=adf561bdcae37e2e7898812c83e0e7b5Discovery of Novel Human Histamine H4 Receptor Ligands by Large-Scale Structure-Based Virtual ScreeningKiss, Robert; Kiss, Bela; Konczol, Arpad; Szalai, Ferenc; Jelinek, Ivett; Laszlo, Valeria; Noszal, Bela; Falus, Andras; Keseru, Gyorgy M.Journal of Medicinal Chemistry (2008), 51 (11), 3145-3153CODEN: JMCMAR; ISSN:0022-2623. (American Chemical Society)A structure-based virtual screening (SBVS) was conducted on a ligand-supported homol. model of the human histamine H4 receptor (hH4R). More than 8.7 million 3D structures derived from different vendor databases were investigated by docking to the hH4R binding site using FlexX. A total of 255 selected compds. were tested by radioligand binding assay and 16 of them possessed significant [3H]histamine displacement. Several novel scaffolds were identified that can be used to develop selective H4 ligands in the future. As far as we know, this is the first SBVS reported on H4R, representing one of the largest virtual screens validated by the biol. evaluation of the virtual hits.
- 48Salo, O. M.; Raitio, K. H.; Savinainen, J. R.; Nevalainen, T.; Lahtela-Kakkonen, M.; Laitinen, J. T.; Jarvinen, T.; Poso, A. Virtual Screening of Novel Cb2 Ligands Using a Comparative Model of the Human Cannabinoid Cb2 Receptor J. Med. Chem. 2005, 48, 7166– 7171Google Scholar48https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhtFWku7bM&md5=58c0fef5e385196c9e21da4c5bd3fe32Virtual Screening of Novel CB2 Ligands Using a Comparative Model of the Human Cannabinoid CB2 ReceptorSalo, Outi M. H.; Raitio, Katri H.; Savinainen, Juha R.; Nevalainen, Tapio; Lahtela-Kakkonen, Maija; Laitinen, Jarmo T.; Jaervinen, Tomi; Poso, AnttiJournal of Medicinal Chemistry (2005), 48 (23), 7166-7171CODEN: JMCMAR; ISSN:0022-2623. (American Chemical Society)To identify novel selective CB2 lead compds., a comparative model of the CB2 receptor was constructed using the high-resoln. bovine rhodopsin X-ray structure as a template. The CB2 model was utilized both in building the database queries and in filtering the hit compds. by a docking and scoring method. In G-protein activation assays, 1-isoquinolyl[3-(trifluoromethyl)phenyl]methanone (40, NRB 04079) was found to act as a selective agonist at the human CB2 receptor.
- 49Tikhonova, I. G.; Sum, C. S.; Neumann, S.; Engel, S.; Raaka, B. M.; Costanzi, S.; Gershengorn, M. C. Discovery of Novel Agonists and Antagonists of the Free Fatty Acid Receptor 1 (Ffar1) Using Virtual Screening J. Med. Chem. 2008, 51, 625– 633Google Scholar49https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXmtFylsg%253D%253D&md5=99001918ff4dab865830c39e659dabb3Discovery of novel agonists and antagonists of the free fatty acid receptor 1 (FFAR1) using virtual screeningTikhonova, Irina G.; Sum, Chi Shing; Neumann, Susanne; Engel, Stanislav; Raaka, Bruce M.; Costanzi, Stefano; Gershengorn, Marvin C.Journal of Medicinal Chemistry (2008), 51 (3), 625-633CODEN: JMCMAR; ISSN:0022-2623. (American Chemical Society)The G-protein-coupled receptor free fatty acid receptor 1 (FFAR1), previously named GPR40, is a possible novel target for the treatment of type 2 diabetes. In an attempt to identify new ligands for this receptor, we performed virtual screening (VS) based on 2-dimensional (2D) similarity, 3-dimensional (3D) pharmacophore searches, and docking studies by the structure of known agonists and our model of the ligand binding site, which was validated by mutagenesis. VS of a database of 2.6 million compds. followed by extn. of structural neighbors of functionally confirmed hits resulted in identification of 15 compds. active at FFAR1 either as full agonists, partial agonists, or pure antagonists. Site-directed mutagenesis and docking studies revealed different patterns of ligand-receptor interactions and provided important information on the role of specific amino acids in binding and activation of FFAR1.
- 50Varady, J.; Wu, X.; Fang, X.; Min, J.; Hu, Z.; Levant, B.; Wang, S. Molecular Modeling of the Three-Dimensional Structure of Dopamine 3 (D3) Subtype Receptor: Discovery of Novel and Potent D3 Ligands through a Hybrid Pharmacophore- and Structure-Based Database Searching Approach J. Med. Chem. 2003, 46, 4377– 4392Google Scholar50https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXmvVGhu7s%253D&md5=758611e234bf6b517e3e91a6dfd895b7Molecular Modeling of the Three-Dimensional Structure of Dopamine 3 (D3) Subtype Receptor: Discovery of Novel and Potent D3 Ligands through a Hybrid Pharmacophore- and Structure-Based Database Searching ApproachVarady, Judith; Wu, Xihan; Fang, Xueliang; Min, Ji; Hu, Zengjian; Levant, Beth; Wang, ShaomengJournal of Medicinal Chemistry (2003), 46 (21), 4377-4392CODEN: JMCMAR; ISSN:0022-2623. (American Chemical Society)The dopamine 3 (D3) subtype receptor has been implicated in several neurol. conditions, and potent and selective D3 ligands may have therapeutic potential for the treatment of drug addiction, Parkinson's disease, and schizophrenia. In this paper, we report computational homol. modeling of the D3 receptor based upon the high-resoln. x-ray structure of rhodopsin, extensive structural refinement in the presence of explicit lipid bilayer and water environment, and validation of the refined D3 structural models using exptl. data. We further describe the development, validation, and application of a hybrid computational screening approach for the discovery of several classes of novel and potent D3 ligands. This computational approach employs stepwise pharmacophore and structure-based searching of a large three-dimensional chem. database for the identification of potential D3 ligands. The obtained hits are then subjected to structural novelty screening, and the most promising compds. are tested in a D3 binding assay. Using this approach we identified four compds. with Ki values better than 100 nM and eight compds. with Ki values better than 1 μM out of 20 compds. selected for testing in the D3 receptor binding assay. Our results suggest that the D3 structural models obtained from this study may be useful for the discovery and design of novel and potent D3 ligands. Furthermore, the employed hybrid approach may be more effective for lead discovery from a large chem. database than either pharmacophore-based or structure-based database screening alone.
- 51Kooistra, A. J.; Leurs, R.; de Esch, I. J.; de Graaf, C. From Three-Dimensional GPCR Structure to Rational Ligand Discovery. Adv. Exp. Med. Biol. 2014, 796, 129– 157Google ScholarThere is no corresponding record for this reference.
- 52Weiss, D. R.; Ahn, S.; Sassano, M. F.; Kleist, A.; Zhu, X.; Strachan, R.; Roth, B. L.; Lefkowitz, R. J.; Shoichet, B. K. Conformation Guides Molecular Efficacy in Docking Screens of Activated Beta-2 Adrenergic G Protein Coupled Receptor ACS Chem. Biol. 2013, 8, 1018– 1026Google ScholarThere is no corresponding record for this reference.
- 53Moitessier, N.; Englebienne, P.; Lee, D.; Lawandi, J.; Corbeil, C. R. Towards the Development of Universal, Fast and Highly Accurate Docking/Scoring Methods: A Long Way to Go Br. J. Pharmacol. 2008, 153 (Suppl 1) S7– 26Google Scholar53https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXislSjt7w%253D&md5=4f6b8d64743100c0c58240c9874a1e65Towards the development of universal, fast and highly accurate docking/scoring methods: a long way to goMoitessier, N.; Englebienne, P.; Lee, D.; Lawandi, J.; Corbeil, C. R.British Journal of Pharmacology (2008), 153 (Suppl. 1), S7-S26CODEN: BJPCBM; ISSN:0007-1188. (Nature Publishing Group)A review. Accelerating the drug discovery process requires predictive computational protocols capable of reducing or simplifying the synthetic and/or combinatorial challenge. Docking-based virtual screening methods have been developed and successfully applied to a no. of pharmaceutical targets. In this review, we first present the current status of docking and scoring methods, with exhaustive lists of these. We next discuss reported comparative studies, outlining criteria for their interpretation. In the final section, we describe some of the remaining developments that would potentially lead to a universally applicable docking/scoring method. Published online 26 Nov. 2007.
- 54Sabio, M.; Jones, K.; Topiol, S. Use of the X-Ray Structure of the Beta2-Adrenergic Receptor for Drug Discovery. Part 2: Identification of Active Compounds Bioorg. Med. Chem. Lett. 2008, 18, 5391– 5395Google Scholar54https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXht1CqsrfP&md5=e91ea267e0851bc0e08b310b3f8966eeUse of the X-ray structure of the β2-adrenergic receptor for drug discovery. Part 2: Identification of active compoundsSabio, Michael; Jones, Kenneth; Topiol, SidBioorganic & Medicinal Chemistry Letters (2008), 18 (20), 5391-5395CODEN: BMCLE8; ISSN:0960-894X. (Elsevier Ltd.)The recently published X-ray structures of the β2-adrenergic receptor are the first examples of ligand-mediated GPCR crystal structures. We have previously performed computational studies that examine the potential viability of these structures for use in drug design, exploiting known ligand activities. Our previous study and a newly reported β2/Timolol X-ray complex provide validation of the computational approaches. In the present work, we use the X-ray structures to ext., via in silico high-throughput docking, compds. from proprietary and com. databases and demonstrate the successful identification of active compds. by radioligand binding.
- 55de Graaf, C.; Rognan, D. Selective Structure-Based Virtual Screening for Full and Partial Agonists of the Beta2 Adrenergic Receptor J. Med. Chem. 2008, 51, 4978– 4985Google Scholar55https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXptl2gtr8%253D&md5=e4c2d724a9356d1223b53334c6357327Selective Structure-Based Virtual Screening for Full and Partial Agonists of the β2 Adrenergic Receptorde Graaf, Chris; Rognan, DidierJournal of Medicinal Chemistry (2008), 51 (16), 4978-4985CODEN: JMCMAR; ISSN:0022-2623. (American Chemical Society)The recently solved high-resoln. X-ray structure of the β2 adrenergic receptor has been challenged for its ability to discriminate inverse agonists/antagonists from partial/full agonists. Whereas the X-ray structure of the ground state receptor was unsuitable to distinguish true ligands with different functional effects, modifying this structure to reflect early conformational events in receptor activation led to a receptor model able to selectively retrieve full and partial agonists by structure-based virtual screening. The use of a topol. scoring function based on mol. interaction fingerprints was shown to be mandatory to properly rank docking poses and achieve acceptable enrichments for partial and full agonists only.
- 56Katritch, V.; Reynolds, K. A.; Cherezov, V.; Hanson, M. A.; Roth, C. B.; Yeager, M.; Abagyan, R. Analysis of Full and Partial Agonists Binding to Beta2-Adrenergic Receptor Suggests a Role of Transmembrane Helix V in Agonist-Specific Conformational Changes J. Mol. Recognit. 2009, 22, 307– 318Google Scholar56https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXnslGis7k%253D&md5=01e2c841b200697382e551b3cf104451Analysis of full and partial agonists binding to β2-adrenergic receptor suggests a role of transmembrane helix V in agonist-specific conformational changesKatritch, Vsevolod; Reynolds, Kimberly A.; Cherezov, Vadim; Hanson, Michael A.; Roth, Christopher B.; Yeager, Mark; Abagyan, RubenJournal of Molecular Recognition (2009), 22 (4), 307-318CODEN: JMORE4; ISSN:0952-3499. (John Wiley & Sons Ltd.)The 2.4 Å crystal structure of the β2-adrenergic receptor (β2AR) in complex with the high-affinity inverse agonist (-)-carazolol provides a detailed structural framework for the anal. of ligand recognition by adrenergic receptors. Insights into agonist binding and the corresponding conformational changes triggering G-protein coupled receptor (GPCR) activation mechanism are of special interest. While the carazolol pocket captured in the β2AR crystal structure accommodates (-)-isoproterenol and other agonists without steric clashes, a finite movement of the flexible extracellular part of TM-V helix (TM-Ve) obtained by receptor optimization in the presence of docked ligand can further improve the calcd. binding affinities for agonist compds. Tilting of TM-Ve towards the receptor axis provides a more complete description of polar receptor-ligand interactions for full and partial agonists, by enabling optimal engagement of agonists with two exptl. identified anchor sites, formed by Asp 113/Asn 312 and Ser 203/Ser 204/Ser 207 side chains. Further, receptor models incorporating a flexible TM-V backbone allow reliable prediction of binding affinities for a set of diverse ligands, suggesting potential utility of this approach to design of effective and subtype-specific agonists for adrenergic receptors. Systematic differences in capacity of partial, full and inverse agonists to induce TM-V helix tilt in the β2AR model suggest potential role of TM-V as a conformational "rheostat" involved in the whole spectrum of β2AR responses to small mol. signals.
- 57Reynolds, K. A.; Katritch, V.; Abagyan, R. Identifying Conformational Changes of the Beta(2) Adrenoceptor That Enable Accurate Prediction of Ligand/Receptor Interactions and Screening for Gpcr Modulators J. Comput. Aided Mol. Des. 2009, 23, 273– 288Google Scholar57https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXkt1yitLw%253D&md5=48e809569368d89fb9ba2c36bddc3f3bIdentifying conformational changes of the β2 adrenoceptor that enable accurate prediction of ligand/receptor interactions and screening for GPCR modulatorsReynolds, Kimberly A.; Katritch, Vsevolod; Abagyan, RubenJournal of Computer-Aided Molecular Design (2009), 23 (5), 273-288CODEN: JCADEQ; ISSN:0920-654X. (Springer)The new β2 Adrenoceptor (β2AR) crystal structures provide a high-resoln. snapshot of receptor interactions with two particular partial inverse agonists, (-)-carazolol and timolol. However, both exptl. and computational studies of GPCR structure are significantly complicated by the existence of multiple conformational states coupled to ligand type and receptor activity. Agonists and antagonists induce or stabilize distinct changes in receptor structure that mediate a range of pharmacol. activities. In this work, the authors (1) established that the existing β2AR crystallog. conformers can be extended to describe ligand/receptor interactions for addnl. antagonist types, (2) generated agonist-bound receptor conformations, and (3) validated these models for agonist and antagonist virtual ligand screening (VLS). Using a ligand directed refinement protocol, the authors derived a single agonist-bound receptor conformation that selectively retrieved a diverse set of full and partial β2AR agonists in VLS trials. Addnl., the impact of extracellular loop two conformation on VLS was assessed by docking studies with rhodopsin-based β2AR homol. models, and loop-deleted receptor models. A general strategy for constructing and selecting agonist-bound receptor pocket conformations is presented, which may prove broadly useful in creating agonist and antagonist bound models for other GPCRs.
- 58Vilar, S.; Karpiak, J.; Berk, B.; Costanzi, S. In Silico Analysis of the Binding of Agonists and Blockers to the Beta2-Adrenergic Receptor J. Mol. Graph. Model. 2011, 29, 809– 817Google Scholar58https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXjvFSlsLY%253D&md5=7401c0929f01c3cf9bf41962f2bdaa7dIn silico analysis of the binding of agonists and blockers to the β2-adrenergic receptorVilar, Santiago; Karpiak, Joel; Berk, Barkin; Costanzi, StefanoJournal of Molecular Graphics & Modelling (2011), 29 (6), 809-817CODEN: JMGMFI; ISSN:1093-3263. (Elsevier Ltd.)Activation of G protein-coupled receptors (GPCRs) is a complex phenomenon. Here, we applied Induced Fit Docking (IFD) in tandem with linear discriminant anal. (LDA) to generate hypotheses on the conformational changes induced to the β2-adrenergic receptor by agonist binding, preliminary to the sequence of events that characterize activation of the receptor. This anal., corroborated by a follow-up mol. dynamics study, suggested that agonists induce subtle movements to the fifth transmembrane domain (TM5) of the receptor. Furthermore, mol. dynamics also highlighted a correlation between movements of TM5 and the second extracellular loop (EL2), suggesting that freedom of motion of EL2 is required for the agonist-induced TM5 displacement. Importantly, we also showed that the IFD/LDA procedure can be used as a computational means to distinguish agonists from blockers on the basis of the differential conformational changes induced to the receptor. In particular, the two most predictive models obtained are based on the RMSD induced to Ser207 and on the counterclockwise rotation induced to TM5.
- 59Kooistra, A. J.; Kuhne, S.; de Esch, I. J.; Leurs, R.; de Graaf, C. A Structural Chemogenomics Analysis of Aminergic Gpcrs: Lessons for Histamine Receptor Ligand Design Br. J. Pharmacol. 2013, 170, 101– 126Google Scholar59https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtlSgtbnE&md5=08ae55b9565885165e76d98e2db1befaA structural chemogenomics analysis of aminergic GPCRs: lessons for histamine receptor ligand designKooistra, A. J.; Kuhne, S.; de Esch, I. J. P.; Leurs, R.; de Graaf, C.British Journal of Pharmacology (2013), 170 (1), 101-126CODEN: BJPCBM; ISSN:1476-5381. (Wiley-Blackwell)Background and Purpose Chemogenomics focuses on the discovery of new connections between chem. and biol. space leading to the discovery of new protein targets and biol. active mols. G-protein coupled receptors (GPCRs) are a particularly interesting protein family for chemogenomics studies because there is an overwhelming amt. of ligand binding affinity data available. The increasing no. of aminergic GPCR crystal structures now for the first time allows the integration of chemogenomics studies with high-resoln. structural analyses of GPCR-ligand complexes. Exptl. Approach In this study, we have combined ligand affinity data, receptor mutagenesis studies, and amino acid sequence analyses to high-resoln. structural analyses of (hist)aminergic GPCR-ligand interactions. This integrated structural chemogenomics anal. is used to more accurately describe the mol. and structural determinants of ligand affinity and selectivity in different key binding regions of the crystd. aminergic GPCRs, and histamine receptors in particular. Key Results Our investigations highlight interesting correlations and differences between ligand similarity and ligand binding site similarity of different aminergic receptors. Apparent discrepancies can be explained by combining detailed anal. of crystd. or predicted protein-ligand binding modes, receptor mutation studies, and ligand structure-selectivity relationships that identify local differences in essential pharmacophore features in the ligand binding sites of different receptors. Conclusions and Implications We have performed structural chemogenomics studies that identify links between (hist)aminergic receptor ligands and their binding sites and binding modes. This knowledge can be used to identify structure-selectivity relationships that increase our understanding of ligand binding to (hist)aminergic receptors and hence can be used in future GPCR ligand discovery and design.
- 60Strader, C. D.; Candelore, M. R.; Hill, W. S.; Sigal, I. S.; Dixon, R. A. Identification of Two Serine Residues Involved in Agonist Activation of the Beta-Adrenergic Receptor J. Biol. Chem. 1989, 264, 13572– 13578Google Scholar60https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL1MXlsVOht78%253D&md5=0e8e69f212b17a3c54a024d7497d79a7Identification of two serine residues involved in agonist activation of the β-adrenergic receptorStrader, Catherine D.; Candelore, Mari Rios; Hill, Wendy S.; Sigal, Irving S.; Dixon, Richard A. F.Journal of Biological Chemistry (1989), 264 (23), 13572-8CODEN: JBCHA3; ISSN:0021-9258.Pharmacophore mapping of the ligand-binding domain of the β-adrenergic receptor has revealed specific mol. interactions which are important for agonist and antagonist binding to the receptor. Previous site-directed mutagenesis expts. have demonstrated that the binding of amine agonists and antagonists to the receptor involves an interaction between the amine group of the ligand and the carboxylate side chain of Asp113 in the 3rd hydrophobic domain of the receptor. Two serine residues, at positions 204 and 207 in the 5th hydrophobic domain of the β-adrenergic receptor, which are crit. for agonist binding and activation of the receptor have now been identified. These serine residues are conserved with G-protein-coupled receptors which bind catecholamine agonists, but not with receptors whose endogenous ligands do not have the catechol moiety. Removal of the OH side chain from either Ser204 or Ser207 by substitution of the serine residue with an alanine attenuates the activity of catecholamine agonists at the receptor. The effects of these mutations on agonist activity are mimicked selectively by the removal of the catechol OH moieties from the arom. ring of the agonist. The data suggest that the interaction of catecholamine agonists with the β-adrenergic receptor involves 2 H bonds, one between the OH side chain of Ser204 and the meta-OH group of the ligand and a second between the OH side chain of Ser207 and the para-OH group of the ligand.
- 61Kikkawa, H.; Kurose, H.; Isogaya, M.; Sato, Y.; Nagao, T. Differential Contribution of Two Serine Residues of Wild Type and Constitutively Active Beta2-Adrenoceptors to the Interaction with Beta2-Selective Agonists Br. J. Pharmacol. 1997, 121, 1059– 1064Google Scholar61https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXkvFeqsrY%253D&md5=c52765a64a652721b71b6f00bc315318Differential contribution of two serine residues of wild type and constitutively active β2-adrenoceptors to the interaction with β2-selective agonistsKikkawa, Hideo; Kurose, Hitoshi; Isogaya, Masafumi; Sato, Yoji; Nagao, TakuBritish Journal of Pharmacology (1997), 121 (6), 1059-1064CODEN: BJPCBM; ISSN:0007-1188. (Stockton)The authors have studied the difference in receptor binding activity between partial and full β2-adrenoceptor agonists and the abilities of the agonists to interact with Ser204 and Ser207 in the fifth transmembrane region of the β2-adrenoceptor, amino acid residues that are important for activation of the β2-adrenoceptor. In the binding study with [125I]-iodocyanopindolol, the Ki values of (±)-salbutamol, (±)-salmeterol, TA-2005 and (-)-isoprenaline for the β2-adrenoceptor expressed in COS-7 cell membranes were 3340, 21.0, 12.0 and 904 nM, resp. The β1/β2 selectively of these agonists was in the order of (±)-salmeterol (332-fold) > A-2005 (52.8) > (±)-salbutamol (6.8) > (-)-isoprenaline (1.1), and the β3-/β2-adrenoceptor selectivity of these agonists was in the order of TA-2005 (150-fold) > (±)-salmeterol (88.6) > (±)-salbutamol (10.4) > (-)-isoprenaline (3.2). The maximal activation of adenylyl cyclase by stimulation of the β1-, β2- and β3-adrenoceptors by TA-2005 was 32, 100 and 100% of that by (-)-isoprenaline, resp., indicating that TA-2005 is a full agonist at the β2- and β3-adrenoceptors and a partial agonist at the β1-adrenoceptor. (±)-Salbutamol and (±)-salmeterol were partial agonists at both β1- (8%) and 9% of (-)-isoprenaline and β2- (83% and 74% of (-)-isoprenaline) adrenoceptors. The affinities of full agonists, TA-2005 and (-)-isoprenaline, were markedly decreased by substitution of Ala for Ser204 (S204A) of the β2-adrenoceptor, whereas this substitution slightly reduced the affinities of partial agonists, (±)-salbutamol and (±)-salmeterol. Although the affinities of full agonists for the S207A-β2-adrenoceptor were decrease, those of partial agonists for the S207A-β2-adrenoceptor were essentially the same as for the wild type receptor. The constitutively active mutant (L266S, L272A) of the β2-adrenoceptor had an increased affinity for all four agonists. The affinities of full agonists were decreased by substitution of Ser204 of the constitutively active mutant, whereas the degree of decrease was smaller than that caused by the substitution of the wild type receptor. Although the affinities of (±)-salbutamol and (±)-salmeterol for the S207A-β2-adrenoceptor were essentially the same as those for the wild type β2-adrenoceptor, the affinities of (±)-salbutamol and (±)-salmeterol for the constitutively active β2-adrenoceptor were decreased by substitution of Ser207. These results suggest that Ser204 and Ser207 of the wild type and constitutively active β2-adrenoceptors differentially interacted with β2-selective agonists.
- 62Liapakis, G.; Ballesteros, J. A.; Papachristou, S.; Chan, W. C.; Chen, X.; Javitch, J. A. The Forgotten Serine. A Critical Role for Ser-2035.42 in Ligand Binding to and Activation of the Beta 2-Adrenergic Receptor J. Biol. Chem. 2000, 275, 37779– 37788Google Scholar62https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXoslWgtLY%253D&md5=5a7eb8b4b3706808b9679e36ad5a59cbThe forgotten serine. A critical role for Ser-2035.42 in ligand binding to and activation of the β2-adrenergic receptorLiapakis, George; Ballesteros, Juan A.; Papachristou, Stavros; Chan, Wai Chi; Chen, Xun; Javitch, Jonathan A.Journal of Biological Chemistry (2000), 275 (48), 37779-37788CODEN: JBCHA3; ISSN:0021-9258. (American Society for Biochemistry and Molecular Biology)Previous work in the β2-adrenergic receptor demonstrated crit. interactions between Ser-204 and Ser-207 in the fifth membrane-spanning segment and the meta-OH and para-OH, resp., of catecholamine agonists. Using the substituted cysteine accessibility method in the β2-adrenergic receptor, we have found that in addn. to Ser-204 and Ser-207, Ser-203 is also accessible on the surface of the binding-site crevice and is occluded by bound agonist. Mutation of Ser-203 to Ala, Val, or Cys reduced the binding affinity and adenylyl cyclase-activating potency of agonists contg. a meta-OH, whereas their affinities and potencies were largely preserved by mutation of Ser-203 to Thr, which maintained an OH at this position. Thus both Ser-203 and Ser-204 appear to interact with the meta-OH of catecholamines, perhaps through a bifurcated H bond. Furthermore, the removal of the OH at position 203 led to a significant loss of affinity of antagonists with nitrogen in their heterocyclic ring structure. The greatest effect was seen with pindolol, a partial agonist, suggesting that a H bond between the heterocyclic ring and Ser-203 may play a role in partial agonism. In contrast, the affinities of antagonists such as propranolol or alprenolol, which have cyclic structures without H-bonding capability, were unaltered after mutation of Ser-203.
- 63Sato, T.; Kobayashi, H.; Nagao, T.; Kurose, H. Ser203 as Well as Ser204 and Ser207 in Fifth Transmembrane Domain of the Human Beta2-Adrenoceptor Contributes to Agonist Binding and Receptor Activation Br. J. Pharmacol. 1999, 128, 272– 274Google Scholar63https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXmsFWhu7k%253D&md5=7acd5d9079efc31a5a197705965777acSer203 as well as Ser204 and Ser207 in fifth transmembrane domain of the human β2-adrenoceptor contributes to agonist binding and receptor activationSato, Takayuki; Kobayashi, Hiroyuki; Nagao, Taku; Kurose, HitoshiBritish Journal of Pharmacology (1999), 128 (2), 272-274CODEN: BJPCBM; ISSN:0007-1188. (Stockton Press)We examd. the contribution of Ser203 of the human β2-adrenoceptor (β2-AR) to the interaction with isoprenaline. The affinity of (-)-isoprenaline was reduced by substitution of an alanine for Ser203, as well as for Ser204 and Ser207. An (-)-isoprenaline deriv. with only one hydroxyl group, at the meta-position, showed reduced affinity for wild-type β2-AR and S207A-β2-AR and even lower affinities for S203A-β2-AR and S204A-β2-AR. By contrast, an (-)-isoprenaline deriv. with only a para-hydroxyl group showed reduced affinity for wild-type β2-AR but the serine to alanine mutations did not cause further decreases. The EC50 value for cAMP generation in response to (-)-isoprenaline was increased, by about 120 fold, for each alanine-substituted β2-AR mutant. These results suggest that Ser203 of the human β2-AR is important for both ligand binding and receptor activation.
- 64Ambrosio, C.; Molinari, P.; Cotecchia, S.; Costa, T. Catechol-Binding Serines of Beta(2)-Adrenergic Receptors Control the Equilibrium between Active and Inactive Receptor States Mol. Pharmacol. 2000, 57, 198– 210Google Scholar64https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXhslCrsg%253D%253D&md5=0b24e04150e47c0c1fcc468a363435a2Catechol-binding serines of β2-adrenergic receptors control the equilibrium between active and inactive receptor statesAmbrosio, Caterina; Molinari, Paola; Cotecchia, Susanna; Costa, TommasoMolecular Pharmacology (2000), 57 (1), 198-210CODEN: MOPMA3; ISSN:0026-895X. (American Society for Pharmacology and Experimental Therapeutics)The binding free energy for the interaction between serines 204 and 207 of the fifth transmembrane helix of the β2-adrenergic receptor (β2-AR) and catecholic hydroxyl (OH) groups of adrenergic agonists was analyzed using double mutant cycles. Binding affinities for catecholic and noncatecholic agonists were measured in wild-type and mutant receptors, carrying alanine replacement of the two serines (S204A, S207A β2-AR), a constitutive activating mutation, or both. The free energy coupling between the losses of binding energy attributable to OH deletion from the ligand and from the receptor indicates a strong interaction (nonadditivity) as expected for a direct binding between the two sets of groups. However, the authors also measured a significant interaction between the deletion of OH groups from the receptor and the constitutive activating mutation. This suggests that a fraction of the decrease in agonist affinity caused by serine mutagenesis may involve a shift in the conformational equil. of the receptor toward the inactive state. Direct measurements using a transient transfection assay confirm this prediction. The constitutive activity of the (S204A, S207A) β2-AR mutant is 50 to 60% lower than that of the wild-type β2-AR. The authors conclude that S204 and S207 do not only provide a docking site for the agonist, but also control the equil. of the receptor between active (R*) and inactive (R) forms.
- 65Marcou, G.; Rognan, D. Optimizing Fragment and Scaffold Docking by Use of Molecular Interaction Fingerprints J. Chem. Inf. Model. 2007, 47, 195– 207Google Scholar65https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28Xht12iurzL&md5=0c9137a39d40fbcc83546aec17b595baOptimizing Fragment and Scaffold Docking by Use of Molecular Interaction FingerprintsMarcou, Gilles; Rognan, DidierJournal of Chemical Information and Modeling (2007), 47 (1), 195-207CODEN: JCISD8; ISSN:1549-9596. (American Chemical Society)Protein-ligand interaction fingerprints have been used to postprocess docking poses of three ligand data sets: a set of 40 low-mol.-wt. compds. from the Protein Data Bank, a collection of 40 scaffolds from pharmaceutically relevant protein ligands, and a database of 19 scaffolds extd. from true cdk2 inhibitors seeded in 2230 scaffold decoys. Four popular docking tools (FlexX, Glide, Gold, and Surflex) were used to generate poses for ligands of the three data sets. In all cases, scoring by the similarity of interaction fingerprints to a given ref. was statistically superior to conventional scoring functions in posing low-mol.-wt. fragments, predicting protein-bound scaffold coordinates according to the known binding mode of related ligands, and screening a scaffold library to enrich a hit list in true cdk2-targeted scaffolds.
- 66Verlinde, C. L.; Hol, W. G. Structure-Based Drug Design: Progress, Results and Challenges Structure 1994, 2, 577– 587Google Scholar66https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2cXmt1SrtLs%253D&md5=024f2fe4d5d0c1d6e74880c889988e9aStructure-based drug design: progress, results and challengesVerlinde, Christophe L. M. J.; Hol, Wim G. J.Structure (Cambridge, MA, United States) (1994), 2 (7), 577-87CODEN: STRUE6; ISSN:0969-2126.A review with 85 refs. Protein structure-based drug design is rapidly gaining momentum. The new opportunities, developments and results in this field are almost unbelievable compared with the situation less than a decade ago.
- 67Jones, G.; Willett, P.; Glen, R. C.; Leach, A. R.; Taylor, R. Development and Validation of a Genetic Algorithm for Flexible Docking J. Mol. Biol. 1997, 267, 727– 748Google Scholar67https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXis1KntLo%253D&md5=476a2b1d8f80f3ba418052fe29d735caDevelopment and validation of a genetic algorithm for flexible dockingJones, Gareth; Willett, Peter; Glen, Robert C.; Leach, Andrew R.; Taylor, RobinJournal of Molecular Biology (1997), 267 (3), 727-748CODEN: JMOBAK; ISSN:0022-2836. (Academic)Prediction of small mol. binding modes to macromols. of known three-dimensional structure is a problem of paramount importance in rational drug design (the "docking" problem). We report the development and validation of the program GOLD (Genetic Optimization for Ligand Docking). GOLD is an automated ligand docking program that uses a genetic algorithm to explore the full range of ligand conformational flexibility with partial flexibility of the protein and satisfies the fundamental requirement that the ligand must displace loosely bound water on binding. Numerous enhancements and modifications have been applied to the original technique resulting in a substantial increase in the reliability and the applicability of the algorithm. The advanced algorithm has been tested on a dataset of 100 complexes extd. from the Brookhaven Protein Data Bank. When used to dock the ligand back into the binding site, GOLD achieved a 71% success rate in identifying the exptl. binding mode.
- 68Evers, A.; Klebe, G. Successful Virtual Screening for a Submicromolar Antagonist of the Neurokinin-1 Receptor Based on a Ligand-Supported Homology Model J. Med. Chem. 2004, 47, 5381– 5392Google Scholar68https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXnvFSrsLo%253D&md5=5bcb463baad85c2eff133c5fd4d7d53bSuccessful virtual screening for a submicromolar antagonist of the neurokinin-1 receptor based on a ligand-supported homology modelEvers, Andreas; Klebe, GerhardJournal of Medicinal Chemistry (2004), 47 (22), 5381-5392CODEN: JMCMAR; ISSN:0022-2623. (American Chemical Society)The neurokinin-1 (NK1) receptor belongs to the family of G-protein-coupled receptors (GPCRs), which represents one of the most relevant target families in small-mol. drug design. In this paper, we describe a homol. modeling of the NK1 receptor based on the high-resoln. X-ray structure of rhodopsin and the successful virtual screening based on this protein model. The NK1 receptor model has been generated using our new MOBILE (modeling binding sites including ligand information explicitly) approach. Starting with preliminary homol. models, it generates improved models of the protein binding pocket together with bound ligands. Ligand information is used as an integral part in the homol. modeling process. For the construction of the NK1 receptor, antagonist CP-96345 was used to restrain the modeling. The quality of the obtained model was validated by probing its ability to accommodate addnl. known NK1 antagonists from structurally diverse classes. On the basis of the generated model and on the anal. of known NK1 antagonists, a pharmacophore model was deduced, which subsequently guided the 2D and 3D database search with UNITY. As a following step, the remaining hits were docked into the modeled binding pocket of the NK1 receptor. Finally, seven compds. were selected for biochem. testing, from which one showed affinity in the submicromolar range. Our results suggest that ligand-supported homol. models of GPCRs may be used as effective platforms for structure-based drug design.
- 69Barril, X.; Morley, S. D. Unveiling the Full Potential of Flexible Receptor Docking Using Multiple Crystallographic Structures J. Med. Chem. 2005, 48, 4432– 4443Google Scholar69https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXktlKisbk%253D&md5=9a5b15df10784020470cd2972d737995Unveiling the Full Potential of Flexible Receptor Docking Using Multiple Crystallographic StructuresBarril, Xavier; Morley, S. DavidJournal of Medicinal Chemistry (2005), 48 (13), 4432-4443CODEN: JMCMAR; ISSN:0022-2623. (American Chemical Society)One of the current challenges in docking studies is the inclusion of receptor flexibility. This is crucial because the binding sites of many therapeutic targets sample a wide range of conformational states, which has major consequences on mol. recognition. In this paper, we make use of very large sets of x-ray structures of cyclin dependent kinase 2 (CDK2) and heat shock protein 90 (HSP90) to assess the performance of flexible receptor docking in binding-mode prediction and virtual screening expts. Flexible receptor docking performs much better than rigid receptor docking in the former application. Regarding the latter, we observe a significant improvement in the prediction of binding affinities, but owing to an increase in the no. of false positives, this is not translated into better hit rates. A simple scoring scheme to correct this limitation is presented. More importantly, pitfalls inherent to flexible receptor docking have been identified and guidelines are presented to avoid them.
- 70Bissantz, C.; Bernard, P.; Hibert, M.; Rognan, D. Protein-Based Virtual Screening of Chemical Databases. Ii. Are Homology Models of G-Protein Coupled Receptors Suitable Targets? Proteins 2003, 50, 5– 25Google ScholarThere is no corresponding record for this reference.
- 71Katritch, V.; Rueda, M.; Abagyan, R. Ligand-Guided Receptor Optimization Methods Mol. Biol. 2012, 857, 189– 205Google Scholar71https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC383itFWmtQ%253D%253D&md5=8401e92ffbc4b6df8acd7f635388e56fLigand-guided receptor optimizationKatritch Vsevolod; Rueda Manuel; Abagyan RubenMethods in molecular biology (Clifton, N.J.) (2012), 857 (), 189-205 ISSN:.Receptor models generated by homology or even obtained by crystallography often have their binding pockets suboptimal for ligand docking and virtual screening applications due to insufficient accuracy or induced fit bias. Knowledge of previously discovered receptor ligands provides key information that can be used for improving docking and screening performance of the receptor. Here, we present a comprehensive ligand-guided receptor optimization (LiBERO) algorithm that exploits ligand information for selecting the best performing protein models from an ensemble. The energetically feasible protein conformers are generated through normal mode analysis and Monte Carlo conformational sampling. The algorithm allows iteration of the conformer generation and selection steps until convergence of a specially developed fitness function which quantifies the conformer's ability to select known ligands from decoys in a small-scale virtual screening test. Because of the requirement for a large number of computationally intensive docking calculations, the automated algorithm has been implemented to use Linux clusters allowing easy parallel scaling. Here, we will discuss the setup of LiBERO calculations, selection of parameters, and a range of possible uses of the algorithm which has already proven itself in several practical applications to binding pocket optimization and prospective virtual ligand screening.
- 72Tehan, B. G.; Bortolato, A.; Blaney, F. E.; Weir, M. P.; Mason, J. S. Unifying Family a Gpcr Theories of Activation Pharmacol. Ther. 2014, 143, 51– 60Google Scholar72https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXjsVKkuro%253D&md5=ed0d1494a2030427df48d1dee6f31a33Unifying Family A GPCR Theories of ActivationTehan, Benjamin G.; Bortolato, Andrea; Blaney, Frank E.; Weir, Malcolm P.; Mason, Jonathan S.Pharmacology & Therapeutics (2014), 143 (1), 51-60CODEN: PHTHDT; ISSN:0163-7258. (Elsevier)A review. Several new pairs of active and inactive GPCR structures have recently been solved enabling detailed structural insight into the activation process, not only of rhodopsin but now also of the β2 adrenergic, M2 muscarinic and adenosine A2A receptors. Combined with structural analyses they have enabled us to examine the different recent theories proposed for GPCR activation and show that they are all indeed parts of the same process, and are intrinsically related through their effect on the central hydrophobic core of GPCRs. This new unifying general process of activation is consistent with the identification of known constitutively active mutants and an in-depth conservational anal. of significant residues implicated in the process.
- 73Meng, X. Y.; Zhang, H. X.; Mezei, M.; Cui, M. Molecular Docking: A Powerful Approach for Structure-Based Drug Discovery Curr. Comput. Aided Drug Des. 2011, 7, 146– 157Google Scholar73https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXnsFyrsLY%253D&md5=b1712e0c9091fae4c71c280b296b61f4Molecular docking: A powerful approach for structure-based drug discoveryMeng, Xuan-Yu; Zhang, Hong-Xing; Mezei, Mihaly; Cui, MengCurrent Computer-Aided Drug Design (2011), 7 (2), 146-157CODEN: CCDDAS; ISSN:1573-4099. (Bentham Science Publishers Ltd.)A review. Mol. docking has become an increasingly important tool for drug discovery. In this review, we present a brief introduction of the available mol. docking methods, and their development and applications in drug discovery. The relevant basic theories, including sampling algorithms and scoring functions, are summarized. The differences in and performance of available docking software are also discussed. Flexible receptor mol. docking approaches, esp. those including backbone flexibility in receptors, are a challenge for available docking methods. A recently developed Local Move Monte Carlo (LMMC) based approach is introduced as a potential soln. to flexible receptor docking problems. Three application examples of mol. docking approaches for drug discovery are provided.
- 74Rognan, D.; Desaphy, J. Molecular Interaction Fingerprints. Scaffold Hopping in Medicinal Chemistry; Wiley-VCH Verlag GmbH & Co. KGaA: Weinheim, 2013; pp 215– 230.Google ScholarThere is no corresponding record for this reference.
- 75Ring, A. M.; Manglik, A.; Kruse, A. C.; Enos, M. D.; Weis, W. I.; Garcia, K. C.; Kobilka, B. K. Adrenaline-Activated Structure of Beta2-Adrenoceptor Stabilized by an Engineered Nanobody Nature 2013, 502, 575– 579Google ScholarThere is no corresponding record for this reference.
- 76Andrews, S. P.; Brown, G. A.; Christopher, J. A. Structure-Based and Fragment-Based Gpcr Drug Discovery ChemMedChem 2014, 9, 256– 275Google ScholarThere is no corresponding record for this reference.
- 77Miller-Gallacher, J. L.; Nehme, R.; Warne, T.; Edwards, P. C.; Schertler, G. F.; Leslie, A. G.; Tate, C. G. The 2.1 a Resolution Structure of Cyanopindolol-Bound Beta1-Adrenoceptor Identifies an Intramembrane Na+ Ion That Stabilises the Ligand-Free Receptor PLoS One 2014, 9e92727Google ScholarThere is no corresponding record for this reference.
- 78Casella, I.; Ambrosio, C.; Gro, M. C.; Molinari, P.; Costa, T. Divergent Agonist Selectivity in Activating Beta1- and Beta2-Adrenoceptors for G-Protein and Arrestin Coupling Biochem. J. 2011, 438, 191– 202Google ScholarThere is no corresponding record for this reference.
- 79Drake, M. T.; Violin, J. D.; Whalen, E. J.; Wisler, J. W.; Shenoy, S. K.; Lefkowitz, R. J. Beta-Arrestin-Biased Agonism at the Beta2-Adrenergic Receptor J. Biol. Chem. 2008, 283, 5669– 5676Google ScholarThere is no corresponding record for this reference.
- 80Kahsai, A. W.; Xiao, K.; Rajagopal, S.; Ahn, S.; Shukla, A. K.; Sun, J.; Oas, T. G.; Lefkowitz, R. J. Multiple Ligand-Specific Conformations of the Beta2-Adrenergic Receptor Nat. Chem. Biol. 2011, 7, 692– 700Google Scholar80https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtVGksrjF&md5=166f9b98dc5dd8625ec831cf3176ca61Multiple ligand-specific conformations of the β2-adrenergic receptorKahsai, Alem W.; Xiao, Kunhong; Rajagopal, Sudarshan; Ahn, Seungkirl; Shukla, Arun K.; Sun, Jinpeng; Oas, Terrence G.; Lefkowitz, Robert J.Nature Chemical Biology (2011), 7 (10), 692-700CODEN: NCBABT; ISSN:1552-4450. (Nature Publishing Group)Seven-transmembrane receptors (7TMRs), also called G protein-coupled receptors (GPCRs), represent the largest class of drug targets, and they can signal through several distinct mechanisms including those mediated by G proteins and the multifunctional adaptor proteins β-arrestins. Moreover, several receptor ligands with differential efficacies toward these distinct signaling pathways have been identified. However, the structural basis and mechanism underlying this 'biased agonism' remains largely unknown. Here, we develop a quant. mass spectrometry strategy that measures specific reactivities of individual side chains to investigate dynamic conformational changes in the β2-adrenergic receptor occupied by nine functionally distinct ligands. Unexpectedly, only a minority of residues showed reactivity patterns consistent with classical agonism, whereas the majority showed distinct patterns of reactivity even between functionally similar ligands. These findings demonstrate, contrary to two-state models for receptor activity, that there is significant variability in receptor conformations induced by different ligands, which has significant implications for the design of new therapeutic agents.
- 81Kaya, A. I.; Onaran, H. O.; Ozcan, G.; Ambrosio, C.; Costa, T.; Balli, S.; Ugur, O. Cell Contact-Dependent Functional Selectivity of Beta2-Adrenergic Receptor Ligands in Stimulating Camp Accumulation and Extracellular Signal-Regulated Kinase Phosphorylation J. Biol. Chem. 2012, 287, 6362– 6374Google ScholarThere is no corresponding record for this reference.
- 82Kim, I. M.; Tilley, D. G.; Chen, J.; Salazar, N. C.; Whalen, E. J.; Violin, J. D.; Rockman, H. A. Beta-Blockers Alprenolol and Carvedilol Stimulate Beta-Arrestin-Mediated Egfr Transactivation Proc. Natl. Acad. Sci. U.S.A. 2008, 105, 14555– 14560Google ScholarThere is no corresponding record for this reference.
- 83Liu, J. J.; Horst, R.; Katritch, V.; Stevens, R. C.; Wuthrich, K. Biased Signaling Pathways in Beta2-Adrenergic Receptor Characterized by 19f-Nmr Science 2012, 335, 1106– 1110Google ScholarThere is no corresponding record for this reference.
- 84Rajagopal, S.; Ahn, S.; Rominger, D. H.; Gowen-MacDonald, W.; Lam, C. M.; Dewire, S. M.; Violin, J. D.; Lefkowitz, R. J. Quantifying Ligand Bias at Seven-Transmembrane Receptors Mol. Pharmacol. 2011, 80, 367– 377Google Scholar84https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhs1ektb7J&md5=3af41d68a6e41d477610338f8e7041f0Quantifying ligand bias at seven-transmembrane receptorsRajagopal, Sudarshan; Ahn, Seungkirl; Rominger, David H.; Gowen-MacDonald, William; Lam, Christopher M.; DeWire, Scott M.; Violin, Jonathan D.; Lefkowitz, Robert J.Molecular Pharmacology (2011), 80 (3), 367-377CODEN: MOPMA3; ISSN:0026-895X. (American Society for Pharmacology and Experimental Therapeutics)Seven transmembrane receptors (7TMRs), commonly referred to as G protein-coupled receptors, form a large part of the "druggable" genome. 7TMRs can signal through parallel pathways simultaneously, such as through heterotrimeric G proteins from different families, or, as more recently appreciated, through the multifunctional adapters, β-arrestins. Biased agonists, which signal with different efficacies to a receptor's multiple downstream pathways, are useful tools for deconvoluting this signaling complexity. These compds. may also be of therapeutic use because they have distinct functional and therapeutic profiles from "balanced agonists.". Although some methods have been proposed to identify biased ligands, no comparison of these methods applied to the same set of data has been performed. Therefore, at this time, there are no generally accepted methods to quantify the relative bias of different ligands, making studies of biased signaling difficult. Here, we use complementary computational approaches for the quantification of ligand bias and demonstrate their application to two well known drug targets, the β2 adrenergic and angiotensin II type 1A receptors. The strategy outlined here allows a quantification of ligand bias and the identification of weakly biased compds. This general method should aid in deciphering complex signaling pathways and may be useful for the development of novel biased therapeutic ligands as drugs.
- 85Baker, J. G. The Selectivity of Beta-Adrenoceptor Agonists at Human Beta1-, Beta2- and Beta3-Adrenoceptors Br. J. Pharmacol. 2010, 160, 1048– 1061Google Scholar85https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXpsFGjtrw%253D&md5=daff8f97b1dfc4732135d3aa79e7de0fThe selectivity of β-adrenoceptor agonists at human β1-, β2- and β3-adrenoceptorsBaker, Jillian G.British Journal of Pharmacology (2010), 160 (5), 1048-1061CODEN: BJPCBM; ISSN:1476-5381. (Wiley-Blackwell)There are two important properties of receptor-ligand interactions: affinity (the ability of the ligand to bind to the receptor) and efficacy (the ability of the receptor-ligand complex to induce a response). Ligands are classified as agonists or antagonists depending on whether or not they have efficacy. In theory, it is possible to develop selective agonists based on selective affinity, selective intrinsic efficacy or both. This study examd. the affinity and intrinsic efficacy of β-adrenoceptor agonists at the three human β-adrenoceptors to det. whether the current agonists are subtype selective because of affinity or intrinsic efficacy. Stable clonal CHO-K1 cell lines, transfected with either the human β1, β2 or β3-adrenoceptor, were used, and whole-cell [3H]-CGP 12177 radioligand binding and [3H]-cAMP accumulation were measured. Several agonists were highly subtype selective because of selective affinity (e.g. salmeterol and formoterol, for the β2-adrenoceptor over the β1 or β3), while others (e.g. isoprenaline) had little affinity-selectivity. However, the intrinsic efficacy of salmeterol, formoterol and isoprenaline was similar across all three receptor subtypes. Other ligands (e.g. denopamine for β1; clenbuterol, AZ 40140d, salbutamol for β2) were found to have subtype-selective intrinsic efficacy. Several ligands appeared to activate two agonist conformations of the β1- and β3-adrenoceptors. There are agonists with subtype selectivity based upon both selective affinity and selective intrinsic efficacy. Therefore, there is scope to develop better selective agonists based upon both selective affinity and selective intrinsic efficacy.
- 86Maack, C.; Bohm, M.; Vlaskin, L.; Dabew, E.; Lorenz, K.; Schafers, H. J.; Lohse, M. J.; Engelhardt, S. Partial Agonist Activity of Bucindolol Is Dependent on the Activation State of the Human Beta1-Adrenergic Receptor Circulation 2003, 108, 348– 353Google ScholarThere is no corresponding record for this reference.
- 87Warne, T.; Tate, C. G. The Importance of Interactions with Helix 5 in Determining the Efficacy of Beta-Adrenoceptor Ligands Biochem. Soc. Trans. 2013, 41, 159– 165Google Scholar87https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhs1eitbw%253D&md5=973475a15b9f36e8c47fafe58a740ad1The importance of interactions with helix 5 in determining the efficacy of β-adrenoceptor ligandsWarne, Tony; Tate, Christopher G.Biochemical Society Transactions (2013), 41 (1), 159-165CODEN: BCSTB5; ISSN:0300-5127. (Portland Press Ltd.)A review. Structures of the inactive state of the thermostabilized β1-adrenoceptor have been detd. bound to eight different ligands, including full agonists, partial agonists, inverse agonists and biased agonists. Comparison of the structures shows distinct differences within the binding pocket that correlate with the pharmacol. properties of the ligands. These data suggest that full agonists stabilize a structure with a contracted binding pocket and a rotamer change of serine (5.46) compared with when antagonists are bound. Inverse agonists may prevent both of these occurrences, whereas partial agonists stabilize a contraction of the binding pocket but not the rotamer change of serine (5.46). It is likely that subtle changes in the interactions between transmembrane helix 5 (H5) and H3/H4 on agonist binding promote the formation of the activated state.
- 88Baker, J. G. The Selectivity of Beta-Adrenoceptor Antagonists at the Human Beta1, Beta2 and Beta3 Adrenoceptors Br. J. Pharmacol. 2005, 144, 317– 322Google Scholar88https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhtVGms70%253D&md5=33cba45e9739901cf686d6cfbb096eedThe selectivity of β-adrenoceptor antagonists at the human β1, β2 and β3 adrenoceptorsBaker, Jillian G.British Journal of Pharmacology (2005), 144 (3), 317-322CODEN: BJPCBM; ISSN:0007-1188. (Nature Publishing Group)β-Adrenoceptor antagonists (β-blockers) are one of the most widely used classes of drugs in cardiovascular medicine (hypertension, ischemic heart disease and increasingly in heart failure) as well as in the management of anxiety, migraine and glaucoma. Where known, the mode of action in cardiovascular disease is from antagonism of endogenous catecholamine responses in the heart (mainly at β1-adrenoceptors), while the worrisome side effects of bronchospasm result from airway β2-adrenoceptor blockade. The aim of this study was to det. the selectivity of β-antagonists for the human β-adrenoceptor subtypes. 3H-CGP 12177 whole cell-binding studies were undertaken in CHO cell lines stably expressing either the human β1-, β2- or the β3-adrenoceptor to det. the affinity of ligands for each receptor subtype in the same cell background. In this study, the selectivity of well-known subtype-selective ligands was clearly demonstrated: thus, the selective β1 antagonist CGP 20712A was 501-fold selective over β2 and 4169-fold selective over β3; the β2-selective antagonist ICI 118551 was 550- and 661-fold selective over β1 and β3, resp., and the selective β3 compd. CL 316243 was 10-fold selective over β2 and more than 129-fold selective over β1. Those β2-adrenoceptor agonists used clin. for the treatment of asthma and COPD were β2 selective: 29-, 61- and 2818-fold for salbutamol, terbutaline and salmeterol over β1, resp. There was little difference in the affinity of these ligands between β1 and β3 adrenoceptors. The clin. used β-antagonists studied ranged from bisoprolol (14-fold β1-selective) to timolol (26-fold β2-selective). However, the majority showed little selectivity for the β1- over the β2-adrenoceptor, with many actually being more β2-selective. This study shows that the β1/β2 selectivity of most clin. used β-blockers is poor in intact cells, and that some compds. that are traditionally classed as β1-selective' actually have higher affinity for the β2-adrenoceptor. There is therefore considerable potential for developing more selective β-antagonists for clin. use and thereby reducing the side-effect profile of β-blockers.
- 89Selvam, B.; Wereszczynski, J.; Tikhonova, I. G. Comparison of Dynamics of Extracellular Accesses to the Beta(1) and Beta(2) Adrenoceptors Binding Sites Uncovers the Potential of Kinetic Basis of Antagonist Selectivity Chem. Biol. Drug Des. 2012, 80, 215– 226Google Scholar89https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhtVOrtbjN&md5=7ee251bd9b2a2b95bb36de3c76e6d6edComparison of dynamics of extracellular accesses to the β1 and β2 adrenoceptors binding sites uncovers the potential of kinetic basis of antagonist selectivitySelvam, Balaji; Wereszczynski, Jeff; Tikhonova, Irina G.Chemical Biology & Drug Design (2012), 80 (2), 215-226CODEN: CBDDAL; ISSN:1747-0277. (Wiley-Blackwell)From the mol. mechanism of antagonist unbinding in the β1 and β2 adrenoceptors investigated by steered mol. dynamics, we attempt to provide further possibilities of ligand subtype and subspecies selectivity. We have simulated unbinding of β1-selective Esmolol and β2-selective ICI-118551 from both receptors to the extracellular environment and found distinct mol. features of unbinding. By calcg. work profiles, we show different preference in antagonist unbinding pathways between the receptors, in particular, perpendicular to the membrane pathway is favorable in the β1 adrenoceptor, whereas the lateral pathway involving helixes 5, 6 and 7 is preferable in the β2 adrenoceptor. The estd. free energy change of unbinding based on the preferable pathway correlates with the exptl. ligand selectivity. We then show that the non-conserved K347 (6.58) appears to facilitate in guiding Esmolol to the extracellular surface via hydrogen bonds in the β1 adrenoceptor. In contrast, hydrophobic and arom. interactions dominate in driving ICI-118551 through the easiest pathway in the β2 adrenoceptor. We show how our study can stimulate design of selective antagonists and discuss other possible mol. reasons of ligand selectivity, involving sequential binding of agonists and glycosylation of the receptor extracellular surface.
- 90Sheftel, S.; Muratore, K. E.; Black, M.; Costanzi, S. Graph Analysis of β2 Adrenergic Receptor Structures: A “Social Network” of GPCR Residues In Silico Pharmacol. 2013, DOI: 10.1186/2193-9616-1-16Google ScholarThere is no corresponding record for this reference.
- 91Sato, M.; Hirokawa, T. Extended Template-Based Modeling and Evaluation Method Using Consensus of Binding Mode of Gpcrs for Virtual Screening J. Chem. Inf. Model. 2014, 54, 3153– 3161Google Scholar91https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhvVWlt73P&md5=1fb1ca77ee20452623e118041b46a5b7Extended Template-Based Modeling and Evaluation Method Using Consensus of Binding Mode of GPCRs for Virtual ScreeningSato, Miwa; Hirokawa, TakatsuguJournal of Chemical Information and Modeling (2014), 54 (11), 3153-3161CODEN: JCISD8; ISSN:1549-9596. (American Chemical Society)G-protein-coupled receptors (GPCRs) are a pharmaceutically important protein family because they mediate numerous physiol. functions. The crystal structures of several GPCR subtypes have been detd. recently, encouraging efforts to apply structure-based virtual screening (SBVS) along with ligand-based virtual screening (LBVS) to improve the hit rate of active ligands from large chem. libraries. Three-dimensional models are also necessary for GPCR targets whose structures are unknown. Current challenges include the selection of structural templates from available structurally known GPCRs to use for accurate modeling and understanding the diversity of sites recognizing distinct ligands. We have developed and validated an extended template-based modeling and evaluation method for SBVS. Models were generated using a fragmental template procedure in addn. to typical template-based modeling methods. The reliability of the models was evaluated using a virtual screening test with known active ligands and decoys and the consensus of the binding mode using the protein-ligand interaction fingerprint (PLIF) derived from the results of docking simulations. This novel workflow was applied to three targets with known structures (human dopamine receptor 3, human histamine H1 receptor, and human delta opioid receptor) and to a target with an unknown structure (human serotonin 2A receptor). In each case, model structures having high ligand selectivity with consensus binding mode were generated.
- 92Deng, Z.; Chuaqui, C.; Singh, J. Structural Interaction Fingerprint (Sift): A Novel Method for Analyzing Three-Dimensional Protein-Ligand Binding Interactions J. Med. Chem. 2004, 47, 337– 344Google Scholar92https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXps1yrsrs%253D&md5=a652b70184155c107202cbe3bc74596aStructural Interaction Fingerprint (SIFt): A Novel Method for Analyzing Three-Dimensional Protein-Ligand Binding InteractionsDeng, Zhan; Chuaqui, Claudio; Singh, JuswinderJournal of Medicinal Chemistry (2004), 47 (2), 337-344CODEN: JMCMAR; ISSN:0022-2623. (American Chemical Society)Representing and understanding the three-dimensional (3D) structural information of protein-ligand complexes is a crit. step in the rational drug discovery process. Traditional anal. methods are proving inadequate and inefficient in dealing with the massive amt. of structural information being generated from x-ray crystallog., NMR, and in silico approaches such as structure-based docking expts. Here, we present SIFt (structural interaction fingerprint), a novel method for representing and analyzing 3D protein-ligand binding interactions. Key to this approach is the generation of an interaction fingerprint that translates 3D structural binding information from a protein-ligand complex into a one-dimensional binary string. Each fingerprint represents the "structural interaction profile" of the complex that can be used to organize, analyze, and visualize the rich amt. of information encoded in ligand-receptor complexes and also to assist database mining. We have applied SIFt to tackle three common tasks in structure-based drug design. The first involved the anal. and organization of a typical set of results generated from a docking study. Using SIFt, docking poses with similar binding modes were identified, clustered, and subsequently compared with conventional scoring function information. A second application of SIFt was to analyze ∼90 known x-ray crystal structures of protein kinase-inhibitor complexes obtained from the Protein Databank. Using SIFt, we were able to organize the structures and reveal striking similarities and diversity between their small mol. binding interactions. Finally, we have shown how SIFt can be used as an effective mol. filter during the virtual chem. library screening process to select mols. with desirable binding mode(s) and/or desirable interaction patterns with the protein target. In summary, SIFt shows promise to fully leverage the wealth of information being generated in rational drug design.
- 93Desaphy, J.; Raimbaud, E.; Ducrot, P.; Rognan, D. Encoding Protein-Ligand Interaction Patterns in Fingerprints and Graphs J. Chem. Inf. Model. 2013, 53, 623– 637Google Scholar93https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXivFCgtrc%253D&md5=48809ef8ecd09a323f8956b5f0fa3068Encoding Protein-Ligand Interaction Patterns in Fingerprints and GraphsDesaphy, Jeremy; Raimbaud, Eric; Ducrot, Pierre; Rognan, DidierJournal of Chemical Information and Modeling (2013), 53 (3), 623-637CODEN: JCISD8; ISSN:1549-9596. (American Chemical Society)We herewith present a novel and universal method to convert protein-ligand coordinates into a simple fingerprint of 210 integers registering the corresponding mol. interaction pattern. Each interaction (hydrophobic, arom., hydrogen bond, ionic bond, metal complexation) is detected on the fly and phys. described by a pseudoatom centered either on the interacting ligand atom, the interacting protein atom, or the geometric center of both interacting atoms. Counting all possible triplets of interaction pseudoatoms within six distance ranges, and pruning the full integer vector to keep the most frequent triplets enables the definition of a simple (210 integers) and coordinate frame-invariant interaction pattern descriptor (TIFP) that can be applied to compare any pair of protein-ligand complexes. TIFP fingerprints have been calcd. for ca. 10 000 druggable protein-ligand complexes therefore enabling a wide comparison of relationships between interaction pattern similarity and ligand or binding site pairwise similarity. We notably show that interaction pattern similarity strongly depends on binding site similarity. In addn. to the TIFP fingerprint which registers intermol. interactions between a ligand and its target protein, we developed two tools (Ishape, Grim) to align protein-ligand complexes from their interaction patterns. Ishape is based on the overlap of interaction pseudoatoms using a smooth Gaussian function, whereas Grim utilizes a std. clique detection algorithm to match interaction pattern graphs. Both tools are complementary and enable protein-ligand complex alignments capitalizing on both global and local pattern similarities. The new fingerprint and companion alignment tools have been successfully used in three scenarios: (i) interaction-biased alignment of protein-ligand complexes, (ii) postprocessing docking poses according to known interaction patterns for a particular target, and (iii) virtual screening for bioisosteric scaffolds sharing similar interaction patterns.
- 94Venhorst, J.; Nunez, S.; Terpstra, J. W.; Kruse, C. G. Assessment of Scaffold Hopping Efficiency by Use of Molecular Interaction Fingerprints J. Med. Chem. 2008, 51, 3222– 3229Google Scholar94https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXlt1Ggsb8%253D&md5=7da870006c5a2ca68198207ba2031a87Assessment of scaffold hopping efficiency by use of molecular interaction fingerprintsVenhorst, Jennifer; Nunez, Sara; Terpstra, Jan Willem; Kruse, Chris G.Journal of Medicinal Chemistry (2008), 51 (11), 3222-3229CODEN: JMCMAR; ISSN:0022-2623. (American Chemical Society)A novel scoring algorithm based on mol. interaction fingerprints (IFPs) was comparatively evaluated in its scaffold hopping efficiency against four virtual screening stds. (GlideXP, Gold, ROCS, and a Bayesian classifier). Decoy databases for the two targets under examn., adenosine deaminase and retinoid X receptor alpha, were obtained from the Directory of Useful Decoys and were further enriched with approx. 5% of active ligands. Structure and ligand-based methods were used to generate the ligand poses, and a Tanimoto metric was chosen for the calcn. of the similarity interaction fingerprint between the ref. ligand and the screening database. Database enrichments were found to strongly depend on the pose generator algorithm. In spite of these dependencies, enrichments using mol. IFPs were comparable to those obtained with GlideXP, Gold, ROCS, and the Bayesian classifier. More interestingly, the mol. IFP scoring algorithm outperformed these methods at scaffold hopping enrichment, regardless of the pose generator algorithm.
- 95Jansen, C.; Wang, H.; Kooistra, A. J.; de Graaf, C.; Orrling, K. M.; Tenor, H.; Seebeck, T.; Bailey, D.; de Esch, I. J.; Ke, H.; Leurs, R. Discovery of Novel Trypanosoma Brucei Phosphodiesterase B1 Inhibitors by Virtual Screening against the Unliganded Tbrpdeb1 Crystal Structure J. Med. Chem. 2013, 56, 2087– 2096Google Scholar95https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXis1Sks70%253D&md5=bec516865a92d993296ce45a8adaf046Discovery of Novel Trypanosoma brucei Phosphodiesterase B1 Inhibitors by Virtual Screening against the Unliganded TbrPDEB1 Crystal StructureJansen, Chimed; Wang, Huanchen; Kooistra, Albert J.; de Graaf, Chris; Orrling, Kristina M.; Tenor, Hermann; Seebeck, Thomas; Bailey, David; de Esch, Iwan J. P.; Ke, Hengming; Leurs, RobJournal of Medicinal Chemistry (2013), 56 (5), 2087-2096CODEN: JMCMAR; ISSN:0022-2623. (American Chemical Society)Trypanosoma brucei cyclic nucleotide phosphodiesterase B1 (TbrPDEB1) and TbrPDEB2 have recently been validated as new therapeutic targets for human African trypanosomiasis by both genetic and pharmacol. means. In this study the crystal structure of the catalytic domain of the unliganded TbrPDEB1 and its use for the in silico screening for new TbrPDEB1 inhibitors with novel scaffolds are reported. The TbrPDEB1 crystal structure shows the characteristic folds of human PDE enzymes but also contains the parasite-specific P-pocket found in the structures of Leishmania major PDEB1 and Trypanosoma cruzi PDEC. The unliganded TbrPDEB1 X-ray structure was subjected to a structure-based in silico screening approach that combines mol. docking simulations with a protein-ligand interaction fingerprint (IFP) scoring method. This approach identified six novel TbrPDEB1 inhibitors with IC50 values of 10-80 μM, which may be further optimized as potential selective TbrPDEB inhibitors.
- 96Mpamhanga, C. P.; Spinks, D.; Tulloch, L. B.; Shanks, E. J.; Robinson, D. A.; Collie, I. T.; Fairlamb, A. H.; Wyatt, P. G.; Frearson, J. A.; Hunter, W. N.; Gilbert, I. H.; Brenk, R. One Scaffold, Three Binding Modes: Novel and Selective Pteridine Reductase 1 Inhibitors Derived from Fragment Hits Discovered by Virtual Screening J. Med. Chem. 2009, 52, 4454– 4465Google Scholar96https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXnt1Onsb0%253D&md5=6a091094ac8ffbe07f05c74d36a5a175One Scaffold, Three Binding Modes: Novel and Selective Pteridine Reductase 1 Inhibitors Derived from Fragment Hits Discovered by Virtual ScreeningMpamhanga, Chidochangu P.; Spinks, Daniel; Tulloch, Lindsay B.; Shanks, Emma J.; Robinson, David A.; Collie, Iain T.; Fairlamb, Alan H.; Wyatt, Paul G.; Frearson, Julie A.; Hunter, William N.; Gilbert, Ian H.; Brenk, RuthJournal of Medicinal Chemistry (2009), 52 (14), 4454-4465CODEN: JMCMAR; ISSN:0022-2623. (American Chemical Society)The enzyme pteridine reductase 1 (PTR1) is a potential target for new compds. to treat human African trypanosomiasis. A virtual screening campaign for fragments inhibiting PTR1 was carried out. Two novel chem. series were identified contg. aminobenzothiazole and aminobenzimidazole scaffolds, resp. One of the hits (2-amino-5-chlorobenzimidazole) was subjected to crystal structure anal. and a high resoln. crystal structure in complex with PTR1 was obtained, confirming the predicted binding mode. However, the crystal structures of two analogs (2-aminobenzimidazole and 1-(3,4-dichlorobenzyl)-2-aminobenzimidazole) in complex with PTR1 revealed two alternative binding modes. In these complexes, previously unobserved protein movements and water-mediated protein-ligand contacts occurred, which prohibited a correct prediction of the binding modes. On the basis of the alternative binding mode of 1-(3,4-dichlorobenzyl)-2-aminobenzimidazole, derivs. were designed and selective PTR1 inhibitors with low nanomolar potency and favorable physicochem. properties were obtained.
- 97Richter, L.; de Graaf, C.; Sieghart, W.; Varagic, Z.; Morzinger, M.; de Esch, I. J.; Ecker, G. F.; Ernst, M. Diazepam-Bound Gabaa Receptor Models Identify New Benzodiazepine Binding-Site Ligands Nat. Chem. Biol. 2012, 8, 455– 464Google Scholar97https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XksVegs7c%253D&md5=1fe4a778d6a7c585bcd3d44bcf22d631Diazepam-bound GABAA receptor models identify new benzodiazepine binding-site ligandsRichter, Lars; de Graaf, Chris; Sieghart, Werner; Varagic, Zdravko; Moerzinger, Martina; de Esch, Iwan J. P.; Ecker, Gerhard F.; Ernst, MargotNature Chemical Biology (2012), 8 (5), 455-464CODEN: NCBABT; ISSN:1552-4450. (Nature Publishing Group)Benzodiazepines exert their anxiolytic, anticonvulsant, muscle-relaxant and sedative-hypnotic properties by allosterically enhancing the action of GABA at GABAA receptors via their benzodiazepine-binding site. Although these drugs have been used clin. since 1960, the mol. basis of this interaction is still not known. By using multiple homol. models and an unbiased docking protocol, we identified a binding hypothesis for the diazepam-bound structure of the benzodiazepine site, which was confirmed by exptl. evidence. Moreover, two independent virtual screening approaches based on this structure identified known benzodiazepine-site ligands from different structural classes and predicted potential new ligands for this site. Receptor-binding assays and electrophysiol. studies on recombinant receptors confirmed these predictions and thus identified new chemotypes for the benzodiazepine-binding site. Our results support the validity of the diazepam-bound structure of the benzodiazepine-binding pocket, demonstrate its suitability for drug discovery and pave the way for structure-based drug design.
- 98Daval, S. B.; Kellenberger, E.; Bonnet, D.; Utard, V.; Galzi, J. L.; Ilien, B. Exploration of the Orthosteric/Allosteric Interface in Human M1Muscarinic Receptors by Bitopic Fluorescent Ligands Mol. Pharmacol. 2013, 84, 71– 85Google ScholarThere is no corresponding record for this reference.
- 99Istyastono, E. P.; Kooistra, A. J.; Vischer, H. F.; Kuijer, M.; Roumen, L.; Nijmeijer, S.; Smits, R. A.; de Esch, I. J.; Leurs, R.; de Graaf, C. Structure-based virtual screening for fragment- like ligands of the G protein-coupled histamine H4 receptor Med. Chem Commun. 2015, DOI: 10.1039/C5MD00022JGoogle ScholarThere is no corresponding record for this reference.
- 100Weis, W. I.; Kobilka, B. K. Structural Insights into G-Protein-Coupled Receptor Activation Curr. Opin. Struct. Biol. 2008, 18, 734– 740Google Scholar100https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhsVOisr%252FP&md5=bacd34911d03123f807710277411d4ecStructural insights into G-protein-coupled receptor activationWeis, William I.; Kobilka, Brian K.Current Opinion in Structural Biology (2008), 18 (6), 734-740CODEN: COSBEF; ISSN:0959-440X. (Elsevier B.V.)A review. G-protein-coupled receptors (GPCRs) are the largest family of eukaryotic plasma membrane receptors, and are responsible for the majority of cellular responses to external signals. GPCRs share a common architecture comprising seven transmembrane (TM) helixes. The binding of an activating ligand enables the receptor to catalyze the exchange of GTP for GDP in a heterotrimeric G protein. GPCRs are in conformational equil. between inactive and activating states. Crystallog. and spectroscopic studies of the visual pigment, rhodopsin, and 2 β-adrenergic receptors have defined some of the conformational changes assocd. with activation.
- 101Petrongolo, C.; Macchia, B.; Macchia, F.; Martinelli, A. Molecular Orbital Studies on the Mechanism of Drug-Receptor Interaction. 2. Beta-Adrenergic Drugs. An Approach to Explain the Role of the Aromatic Moiety J. Med. Chem. 1977, 20, 1645– 1653Google ScholarThere is no corresponding record for this reference.
- 102Swaminath, G.; Xiang, Y.; Lee, T. W.; Steenhuis, J.; Parnot, C.; Kobilka, B. K. Sequential Binding of Agonists to the Beta2 Adrenoceptor. Kinetic Evidence for Intermediate Conformational States J. Biol. Chem. 2004, 279, 686– 691Google ScholarThere is no corresponding record for this reference.
- 103Strader, C. D.; Candelore, M. R.; Hill, W. S.; Dixon, R. A.; Sigal, I. S. A Single Amino Acid Substitution in the Beta-Adrenergic Receptor Promotes Partial Agonist Activity from Antagonists J. Biol. Chem. 1989, 264, 16470– 16477Google ScholarThere is no corresponding record for this reference.
- 104Korb, O.; Stutzle, T.; Exner, T. E. Empirical Scoring Functions for Advanced Protein-Ligand Docking with Plants J. Chem. Inf. Model. 2009, 49, 84– 96Google Scholar104https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXisVSquw%253D%253D&md5=fce960b75b9f8906354b7c97ff84c092Empirical Scoring Functions for Advanced Protein-Ligand Docking with PLANTSKorb, Oliver; Stuetzle, Thomas; Exner, Thomas E.Journal of Chemical Information and Modeling (2009), 49 (1), 84-96CODEN: JCISD8; ISSN:1549-9596. (American Chemical Society)In this paper we present two empirical scoring functions, PLANTSCHEMPLP and PLANTSPLP, designed for our docking algorithm PLANTS (Protein-Ligand ANT System), which is based on ant colony optimization (ACO). They are related, regarding their functional form, to parts of already published scoring functions and force fields. The parametrization procedure described here was able to identify several parameter settings showing an excellent performance for the task of pose prediction on two test sets comprising 298 complexes in total. Up to 87% of the complexes of the Astex diverse set and 77% of the CCDC/Astex clean listnc (noncovalently bound complexes of the clean list) could be reproduced with root-mean-square deviations of less than 2 Å with respect to the exptl. detd. structures. A comparison with the state-of-the-art docking tool GOLD clearly shows that this is, esp. for the druglike Astex diverse set, an improvement in pose prediction performance. Addnl., optimized parameter settings for the search algorithm were identified, which can be used to balance pose prediction reliability and search speed.
- 105Kooistra, A. J.; Vischer, H. F.; McNaught-Flores, D. A.; De Esch, I. J. P.; Leurs, R.; de Graaf, C. Structure-Based Virtual Screening for Gpcr Ligands with a Specific Functional Effect, unpublished, 2014.Google ScholarThere is no corresponding record for this reference.
- 106de Graaf, C.; Foata, N.; Engkvist, O.; Rognan, D. Molecular Modeling of the Second Extracellular Loop of G-Protein Coupled Receptors and Its Implication on Structure-Based Virtual Screening Proteins 2008, 71, 599– 620Google ScholarThere is no corresponding record for this reference.
- 107Rajagopal, S.; Rajagopal, K.; Lefkowitz, R. J. Teaching Old Receptors New Tricks: Biasing Seven-Transmembrane Receptors Nat. Rev. Drug Discovery 2010, 9, 373– 386Google Scholar107https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXlsVWjs7k%253D&md5=ff525016c0ba5aa0ebc4ed86f87594d0Teaching old receptors new tricks: biasing seven-transmembrane receptorsRajagopal, Sudarshan; Rajagopal, Keshava; Lefkowitz, Robert J.Nature Reviews Drug Discovery (2010), 9 (5), 373-386CODEN: NRDDAG; ISSN:1474-1776. (Nature Publishing Group)A review. Seven-transmembrane receptors (7TMRs; also known as G protein-coupled receptors) are the largest class of receptors in the human genome and are common targets for therapeutics. Originally identified as mediators of 7TMR desensitization, β-arrestins (arrestin 2 and arrestin 3) are now recognized as true adaptor proteins that transduce signals to multiple effector pathways. Signaling that is mediated by β-arrestins has distinct biochem. and functional consequences from those mediated by G proteins, and several biased ligands and receptors have been identified that preferentially signal through either G protein- or β-arrestin-mediated pathways. These ligands are not only useful tools for investigating the biochem. of 7TMR signaling, but they also have the potential to be developed into new classes of therapeutics.
- 108van der Westhuizen, E. T.; Breton, B.; Christopoulos, A.; Bouvier, M. Quantification of Ligand Bias for Clinically Relevant Beta2-Adrenergic Receptor Ligands: Implications for Drug Taxonomy Mol. Pharmacol. 2014, 85, 492– 509Google ScholarThere is no corresponding record for this reference.
- 109Reiner, S.; Ambrosio, M.; Hoffmann, C.; Lohse, M. J. Differential Signaling of the Endogenous Agonists at the Beta2-Adrenergic Receptor J. Biol. Chem. 2010, 285, 36188– 36198Google ScholarThere is no corresponding record for this reference.
- 110Copik, A. J.; Baldys, A.; Nguyen, K.; Sahdeo, S.; Ho, H.; Kosaka, A.; Dietrich, P. J.; Fitch, B.; Raymond, J. R.; Ford, A. P.; Button, D.; Milla, M. E. Isoproterenol Acts as a Biased Agonist of the Alpha-1a-Adrenoceptor That Selectively Activates the Mapk/Erk Pathway PLoS One 2015, 10e0115701Google ScholarThere is no corresponding record for this reference.
- 111Nijmeijer, S.; Vischer, H. F.; Sirci, F.; Schultes, S.; Engelhardt, H.; de Graaf, C.; Rosethorne, E. M.; Charlton, S. J.; Leurs, R. Detailed Analysis of Biased Histamine H(4) Receptor Signalling by Jnj 7777120 Analogues Br. J. Pharmacol. 2013, 170, 78– 88Google Scholar111https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtlSgtbnJ&md5=490a939b05f2dd3508e96d21f541a783Detailed analysis of biased histamine H4 receptor signalling by JNJ 7777120 analoguesNijmeijer, S.; Vischer, H. F.; Sirci, F.; Schultes, S.; Engelhardt, H.; de Graaf, C.; Rosethorne, E. M.; Charlton, S. J.; Leurs, R.British Journal of Pharmacology (2013), 170 (1), 78-88CODEN: BJPCBM; ISSN:1476-5381. (Wiley-Blackwell)Background and Purpose The histamine H4 receptor, originally thought to signal merely through Gαi proteins, has recently been shown to also recruit and signal via β-arrestin2. Following the discovery that the ref. antagonist indolecarboxamide JNJ 7777120 appears to be a partial agonist in β-arrestin2 recruitment, we have identified addnl. biased hH4R ligands that preferentially couple to Gαi or β-arrestin2 proteins. In this study, we explored ligand and receptor regions that are important for biased hH4R signalling. Exptl. Approach We evaluated a series of 48 indolecarboxamides with subtle structural differences for their ability to induce hH4R-mediated Gαi protein signalling or β-arrestin2 recruitment. Subsequently, a Fingerprints for Ligands and Proteins three-dimensional quant. structure-activity relationship anal. correlated intrinsic activity values with structural ligand requirements. Moreover, a hH4R homol. model was used to identify receptor regions important for biased hH4R signalling. Key Results One indolecarboxamide (75) with a nitro substituent on position R7 of the arom. ring displayed an equal preference for the Gαi and β-arrestin2 pathway and was classified as unbiased hH4R ligand. The other 47 indolecarboxamides were β-arrestin2-biased agonists. Intrinsic activities of the unbiased as well as β-arrestin2-biased indolecarboxamides to induce β-arrestin2 recruitment could be correlated with different ligand features and hH4R regions. Conclusion and Implications Small structural modifications resulted in diverse intrinsic activities for unbiased (75) and β-arrestin2-biased indolecarboxamides. Anal. of ligand and receptor features revealed efficacy hotspots responsible for biased-β-arrestin2 recruitment. This knowledge is useful for the design of hH4R ligands with biased intrinsic activities and aids our understanding of the mechanism of H4R activation.
- 112Nijmeijer, S.; Vischer, H. F.; Rosethorne, E. M.; Charlton, S. J.; Leurs, R. Analysis of Multiple Histamine H(4) Receptor Compound Classes Uncovers Galphai Protein- and Beta-Arrestin2-Biased Ligands Mol. Pharmacol. 2012, 82, 1174– 1182Google ScholarThere is no corresponding record for this reference.
- 113Galandrin, S.; Bouvier, M. Distinct Signaling Profiles of Beta1 and Beta2 Adrenergic Receptor Ligands toward Adenylyl Cyclase and Mitogen-Activated Protein Kinase Reveals the Pluridimensionality of Efficacy Mol. Pharmacol. 2006, 70, 1575– 1584Google ScholarThere is no corresponding record for this reference.
- 114Surgand, J. S.; Rodrigo, J.; Kellenberger, E.; Rognan, D. A Chemogenomic Analysis of the Transmembrane Binding Cavity of Human G-Protein-Coupled Receptors Proteins 2006, 62, 509– 538Google Scholar114https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BD2MnovFyrtw%253D%253D&md5=5f60612975dbffa52e440cd2d7ab080cA chemogenomic analysis of the transmembrane binding cavity of human G-protein-coupled receptorsSurgand Jean-Sebastien; Rodrigo Jordi; Kellenberger Esther; Rognan DidierProteins (2006), 62 (2), 509-38 ISSN:.The amino acid sequences of 369 human nonolfactory G-protein-coupled receptors (GPCRs) have been aligned at the seven transmembrane domain (TM) and used to extract the nature of 30 critical residues supposed--from the X-ray structure of bovine rhodopsin bound to retinal--to line the TM binding cavity of ground-state receptors. Interestingly, the clustering of human GPCRs from these 30 residues mirrors the recently described phylogenetic tree of full-sequence human GPCRs (Fredriksson et al., Mol Pharmacol 2003;63:1256-1272) with few exceptions. A TM cavity could be found for all investigated GPCRs with physicochemical properties matching that of their cognate ligands. The current approach allows a very fast comparison of most human GPCRs from the focused perspective of the predicted TM cavity and permits to easily detect key residues that drive ligand selectivity or promiscuity.
- 115Gregory, K. J.; Sexton, P. M.; Tobin, A. B.; Christopoulos, A. Stimulus Bias Provides Evidence for Conformational Constraints in the Structure of a G Protein-Coupled Receptor J. Biol. Chem. 2012, 287, 37066– 37077Google ScholarThere is no corresponding record for this reference.
- 116Audet, M.; Bouvier, M. Insights into Signaling from the Beta2-Adrenergic Receptor Structure Nat. Chem. Biol. 2008, 4, 397– 403Google Scholar116https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXnt1ejtbo%253D&md5=e4c4cdb057fff9a03192129c6577e900Insights into signaling from the β2-adrenergic receptor structureAudet, Martin; Bouvier, MichelNature Chemical Biology (2008), 4 (7), 397-403CODEN: NCBABT; ISSN:1552-4450. (Nature Publishing Group)A review. With more than 800 members, the G protein-coupled receptor family constitutes the largest group of membrane proteins involved in signal transduction. Until the end of last year, high-resoln. three-dimensional structures were available for only one of them-the light receptor rhodopsin. Recently the structure of the β2-adrenergic receptor has been obtained, and it revealed interesting differences with the structure of rhodopsin. Analyses of these differences raise important questions about the binding modes of diffusible ligands in the receptor and allow formulation of testable hypotheses about the structural determinants linking drug binding to specific signaling responses. The three-dimensional structure derived from the β2-adrenergic receptor crystal has been used to virtually dock ligands with distinct activities. The different binding modes of these ligands, which correlated with their reported efficacy profiles, suggest that it could be possible to predict the structural determinants of drug signaling efficacies.
- 117Costanzi, S. Modeling G Protein-Coupled Receptors in Complex with Biased Agonists Trends Pharmacol. Sci. 2014, 35, 277– 283Google ScholarThere is no corresponding record for this reference.
- 118Jaakola, V. P.; Griffith, M. T.; Hanson, M. A.; Cherezov, V.; Chien, E. Y.; Lane, J. R.; Ijzerman, A. P.; Stevens, R. C. The 2.6 Angstrom Crystal Structure of a Human A2a Adenosine Receptor Bound to an Antagonist Science 2008, 322, 1211– 1217Google Scholar118https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtlyqtbfN&md5=5bdb862b41f345c244f3c162e058206bThe 2.6 Angstrom Crystal Structure of a Human A2A Adenosine Receptor Bound to an AntagonistJaakola, Veli-Pekka; Griffith, Mark T.; Hanson, Michael A.; Cherezov, Vadim; Chien, Ellen Y. T.; Lane, J. Robert; IJzerman, Adriaan P.; Stevens, Raymond C.Science (Washington, DC, United States) (2008), 322 (5905), 1211-1217CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)The adenosine class of heterotrimeric guanine nucleotide-binding protein (G protein)-coupled receptors (GPCRs) mediates the important role of extracellular adenosine in many physiol. processes and is antagonized by caffeine. The authors have detd. the crystal structure of the human A2A adenosine receptor, in complex with a high-affinity subtype-selective antagonist, ZM241385, to 2.6 angstrom resoln. Four disulfide bridges in the extracellular domain, combined with a subtle repacking of the transmembrane helixes relative to the adrenergic and rhodopsin receptor structures, define a pocket distinct from that of other structurally detd. GPCRs. The arrangement allows for the binding of the antagonist in an extended conformation, perpendicular to the membrane plane. The binding site highlights an integral role for the extracellular loops, together with the helical core, in ligand recognition by this class of GPCRs and suggests a role for ZM241385 in restricting the movement of a tryptophan residue important in the activation mechanism of the class A receptors.
- 119Xu, F.; Wu, H.; Katritch, V.; Han, G. W.; Jacobson, K. A.; Gao, Z. G.; Cherezov, V.; Stevens, R. C. Structure of an Agonist-Bound Human A2a Adenosine Receptor Science 2011, 332, 322– 327Google Scholar119https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXksFWjt7s%253D&md5=b1e074f38f45c95d4cc3b40378b24923Structure of an Agonist-Bound Human A2A Adenosine ReceptorXu, Fei; Wu, Huixian; Katritch, Vsevolod; Han, Gye Won; Jacobson, Kenneth A.; Gao, Zhan-Guo; Cherezov, Vadim; Stevens, Raymond C.Science (Washington, DC, United States) (2011), 332 (6027), 322-327CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)Activation of G protein-coupled receptors upon agonist binding is a crit. step in the signaling cascade for this family of cell surface proteins. We report the crystal structure of the A2A adenosine receptor (A2AAR) bound to an agonist UK-432097 at 2.7 angstrom resoln. Relative to inactive, antagonist-bound A2AAR, the agonist-bound structure displays an outward tilt and rotation of the cytoplasmic half of helix VI, a movement of helix V, and an axial shift of helix III, resembling the changes assocd. with the active-state opsin structure. Addnl., a seesaw movement of helix VII and a shift of extracellular loop 3 are likely specific to A2AAR and its ligand. The results define the mol. UK-432097 as a "conformationally selective agonist" capable of receptor stabilization in a specific active-state configuration.
- 120Haga, K.; Kruse, A. C.; Asada, H.; Yurugi-Kobayashi, T.; Shiroishi, M.; Zhang, C.; Weis, W. I.; Okada, T.; Kobilka, B. K.; Haga, T.; Kobayashi, T. Structure of the Human M2Muscarinic Acetylcholine Receptor Bound to an Antagonist Nature 2012, 482, 547– 551Google Scholar120https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xht1ejsro%253D&md5=c33b8d9303d58db7dfdd4c18ec4f597bStructure of the human M2 muscarinic acetylcholine receptor bound to an antagonistHaga, Kazuko; Kruse, Andrew C.; Asada, Hidetsugu; Yurugi-Kobayashi, Takami; Shiroishi, Mitsunori; Zhang, Cheng; Weis, William I.; Okada, Tetsuji; Kobilka, Brian K.; Haga, Tatsuya; Kobayashi, TakuyaNature (London, United Kingdom) (2012), 482 (7386), 547-551CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)The X-ray crystal structure of the M2 muscarinic acetylcholine receptor, which is essential for the physiol. control of cardiovascular function, is reported.
- 121Kruse, A. C.; Ring, A. M.; Manglik, A.; Hu, J.; Hu, K.; Eitel, K.; Hubner, H.; Pardon, E.; Valant, C.; Sexton, P. M.; Christopoulos, A.; Felder, C. C.; Gmeiner, P.; Steyaert, J.; Weis, W. I.; Garcia, K. C.; Wess, J.; Kobilka, B. K. Activation and Allosteric Modulation of a Muscarinic Acetylcholine Receptor Nature 2013, 504, 101– 106Google Scholar121https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhvVyisLjP&md5=ecddab0ab467321ac243b86bb82b71f8Activation and allosteric modulation of a muscarinic acetylcholine receptorKruse, Andrew C.; Ring, Aaron M.; Manglik, Aashish; Hu, Jianxin; Hu, Kelly; Eitel, Katrin; Huebner, Harald; Pardon, Els; Valant, Celine; Sexton, Patrick M.; Christopoulos, Arthur; Felder, Christian C.; Gmeiner, Peter; Steyaert, Jan; Weis, William I.; Garcia, K. Christopher; Wess, Juergen; Kobilka, Brian K.Nature (London, United Kingdom) (2013), 504 (7478), 101-106CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)Despite recent advances in crystallog. and the availability of G-protein-coupled receptor (GPCR) structures, little is known about the mechanism of their activation process, as only the β2 adrenergic receptor (β2AR) and rhodopsin have been crystd. in fully active conformations. Here we report the structure of an agonist-bound, active state of the human M2 muscarinic acetylcholine receptor stabilized by a G-protein mimetic camelid antibody fragment isolated by conformational selection using yeast surface display. In addn. to the expected changes in the intracellular surface, the structure reveals larger conformational changes in the extracellular region and orthosteric binding site than obsd. in the active states of the β2AR and rhodopsin. We also report the structure of the M2 receptor simultaneously bound to the orthosteric agonist iperoxo and the pos. allosteric modulator LY2119620. This structure reveals that LY2119620 recognizes a largely pre-formed binding site in the extracellular vestibule of the iperoxo-bound receptor, inducing a slight contraction of this outer binding pocket. These structures offer important insights into the activation mechanism and allosteric modulation of muscarinic receptors.
- 122Zhang, J.; Zhang, K.; Gao, Z. G.; Paoletta, S.; Zhang, D.; Han, G. W.; Li, T.; Ma, L.; Zhang, W.; Muller, C. E.; Yang, H.; Jiang, H.; Cherezov, V.; Katritch, V.; Jacobson, K. A.; Stevens, R. C.; Wu, B.; Zhao, Q. Agonist-Bound Structure of the Human P2y12 Receptor Nature 2014, 509, 119– 122Google Scholar122https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXntlyis7k%253D&md5=7fdb421ab2f3757a7e7134d586de84bfAgonist-bound structure of the human P2Y12 receptorZhang, Jin; Zhang, Kaihua; Gao, Zhan-Guo; Paoletta, Silvia; Zhang, Dandan; Han, Gye Won; Li, Tingting; Ma, Limin; Zhang, Wenru; Mueller, Christa E.; Yang, Huaiyu; Jiang, Hualiang; Cherezov, Vadim; Katritch, Vsevolod; Jacobson, Kenneth A.; Stevens, Raymond C.; Wu, Beili; Zhao, QiangNature (London, United Kingdom) (2014), 509 (7498), 119-122CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)The P2Y12 receptor (P2Y12R), one of eight members of the P2YR family expressed in humans, is one of the most prominent clin. drug targets for inhibition of platelet aggregation. Although mutagenesis and modeling studies of the P2Y12R provided useful insights into ligand binding, the agonist and antagonist recognition and function at the P2Y12R remain poorly understood at the mol. level. Here we report the structures of the human P2Y12R in complex with the full agonist 2-methylthio-adenosine-5'-diphosphate (2MeSADP, a close analog of endogenous agonist ADP) at 2.5 Å resoln., and the corresponding ATP deriv. 2-methylthio-adenosine-5'-triphosphate (2MeSATP) at 3.1 Å resoln. These structures, together with the structure of the P2Y12R with antagonist Et 6-(4-((benzylsulfonyl)carbamoyl)piperidin-1-yl)-5-cyano-2-methylnicotinate (AZD1283), reveal striking conformational changes between nucleotide and non-nucleotide ligand complexes in the extracellular regions. Further anal. of these changes provides insight into a distinct ligand binding landscape in the δ-group of class A G-protein-coupled receptors (GPCRs). Agonist and non-nucleotide antagonist adopt different orientations in the P2Y12R, with only partially overlapped binding pockets. The agonist-bound P2Y12R structure answers long-standing questions surrounding P2Y12R-agonist recognition, and reveals interactions with several residues that had not been reported to be involved in agonist binding. As a first example, to our knowledge, of a GPCR in which agonist access to the binding pocket requires large-scale rearrangements in the highly malleable extracellular region, the structural and docking studies will therefore provide invaluable insight into the pharmacol. and mechanisms of action of agonists and different classes of antagonists for the P2Y12R and potentially for other closely related P2YRs.
- 123Zhang, K.; Zhang, J.; Gao, Z. G.; Zhang, D.; Zhu, L.; Han, G. W.; Moss, S. M.; Paoletta, S.; Kiselev, E.; Lu, W.; Fenalti, G.; Zhang, W.; Muller, C. E.; Yang, H.; Jiang, H.; Cherezov, V.; Katritch, V.; Jacobson, K. A.; Stevens, R. C.; Wu, B.; Zhao, Q. Structure of the Human P2y12 Receptor in Complex with an Antithrombotic Drug Nature 2014, 509, 115– 118Google Scholar123https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXntlyisrg%253D&md5=539bb91325c547737bc98baf59f3ff26Structure of the human P2Y12 receptor in complex with an antithrombotic drugZhang, Kaihua; Zhang, Jin; Gao, Zhan-Guo; Zhang, Dandan; Zhu, Lan; Han, Gye Won; Moss, Steven M.; Paoletta, Silvia; Kiselev, Evgeny; Lu, Weizhen; Fenalti, Gustavo; Zhang, Wenru; Mueller, Christa E.; Yang, Huaiyu; Jiang, Hualiang; Cherezov, Vadim; Katritch, Vsevolod; Jacobson, Kenneth A.; Stevens, Raymond C.; Wu, Beili; Zhao, QiangNature (London, United Kingdom) (2014), 509 (7498), 115-118CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)P2Y receptors (P2YRs), a family of purinergic G-protein-coupled receptors (GPCRs), are activated by extracellular nucleotides. There are a total of eight distinct functional P2YRs expressed in human, which are subdivided into P2Y1-like receptors and P2Y12-like receptors. Their ligands are generally charged mols. with relatively low bioavailability and stability in vivo, which limits the authors' understanding of this receptor family. P2Y12R regulates platelet activation and thrombus formation, and several antithrombotic drugs targeting P2Y12R-including the prodrugs clopidogrel (Plavix) and prasugrel (Effient) that are metabolized and bind covalently, and the nucleoside analog ticagrelor (Brilinta) that acts directly on the receptor-have been approved for the prevention of stroke and myocardial infarction. However, limitations of these drugs (for example, a very long half-life of clopidogrel action and a characteristic adverse effect profile of ticagrelor) suggest that there is an unfulfilled medical need for developing a new generation of P2Y12R inhibitors. Here the authors report the 2.6 Å resoln. crystal structure of human P2Y12R in complex with a non-nucleotide reversible antagonist, AZD1283. The structure reveals a distinct straight conformation of helix V, which sets P2Y12R apart from all other known class A GPCR structures. With AZD1283 bound, the highly conserved disulfide bridge in GPCRs between helix III and extracellular loop 2 is not obsd. and appears to be dynamic. Along with the details of the AZD1283-binding site, anal. of the extracellular interface reveals an adjacent ligand-binding region and suggests that both pockets could be required for dinucleotide binding. The structure provides essential insights for the development of improved P2Y12R ligands and allosteric modulators as drug candidates.
- 124Bernstein, F. C.; Koetzle, T. F.; Williams, G. J.; Meyer, E. F., Jr.; Brice, M. D.; Rodgers, J. R.; Kennard, O.; Shimanouchi, T.; Tasumi, M. The Protein Data Bank: A Computer-Based Archival File for Macromolecular Structures J. Mol. Biol. 1977, 112, 535– 542Google Scholar124https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaE2sXkvVert7o%253D&md5=07736506e495f157c600cf51a253a0a0The Protein Data Bank: a computer-based archival file for macromolecular structuresBernstein, Frances C.; Koetzle, Thomas F.; Williams, Graheme J. B.; Meyer, Edgar F., Jr.; Brice, Michael D.; Rodgers, John R.; Kennard, Olga; Shimanouchi, Takehiko; Tasumi, MitsuoJournal of Molecular Biology (1977), 112 (3), 535-42CODEN: JMOBAK; ISSN:0022-2836.The Protein Data Bank is a computer-based archival file for macromol. structures. The Bank stores in a uniform format at. coordinates and partial bond connectivities, as derived from crystallog. studies. Text included in each data entry gives pertinent information for the structure at hand (e.g., species from which the mol. was obtained, resoln. of diffraction data, literature citations, and specifications of secondary structure). In addn., the Protein Data Bank stores structure factors and phases. Input of data and general maintenance functions are at Brookhaven National Lab. All data are available on magnetic tape for public distribution.
- 125Molecular Operating Environment (Moe), 2012.10; Chemical Computing Group Inc.: Montreal, Canada, 2012.Google ScholarThere is no corresponding record for this reference.
- 126Ballesteros, J. A.; Weinstein, H. Integrated Methods for the Construction of Three-Dimensional Models and Computational Probing of Structure-Function Relations of G Protein-Coupled Receptors Methods Neurosci. 1995, 25, 366– 428Google Scholar126https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2MXmt1Kmtrk%253D&md5=d3f99e9d07cea245a770f3f099bc8cc7Integrated methods for the construction of three-dimensional models and computational probing of structure-function relations in G protein-coupled receptorsBallesteros, Juan A.; Weinstein, HarelMethods in Neurosciences (1995), 25 (), 366-428CODEN: MENEE5; ISSN:1043-9471.A review, with 135 refs., on approaches that can be used to resolve the apparent ambiguities that burden the pharmacol. testing of G protein-coupled receptor (GPCR) models, based on the integration of structural information about the receptor, about mutants, and about the changes induced by ligand binding.
- 127van Linden, O. P.; Kooistra, A. J.; Leurs, R.; de Esch, I. J.; de Graaf, C. Klifs: A Knowledge-Based Structural Database to Navigate Kinase-Ligand Interaction Space J. Med. Chem. 2014, 57, 249– 277Google ScholarThere is no corresponding record for this reference.
- 128Carey, F. A.; Sundberg, R. J. Advanced Organic Chemistry: Part A: Structure and Mechanisms. Springer: Berlin, 2007.Google ScholarThere is no corresponding record for this reference.
- 129Durrant, J. D.; de Oliveira, C. A.; McCammon, J. A. Povme: An Algorithm for Measuring Binding-Pocket Volumes J. Mol. Graph. Model. 2011, 29, 773– 776Google Scholar129https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhsFOnsrw%253D&md5=3eedaede6cb9bb248b041dc6f220a657POVME: An algorithm for measuring binding-pocket volumesDurrant, Jacob D.; de Oliveira, Cesar Augusto F.; McCammon, J. AndrewJournal of Molecular Graphics & Modelling (2011), 29 (5), 773-776CODEN: JMGMFI; ISSN:1093-3263. (Elsevier Ltd.)Researchers engaged in computer-aided drug design often wish to measure the vol. of a ligand-binding pocket in order to predict pharmacol. We have recently developed a simple algorithm, called POVME (POcket Vol. MEasurer), for this purpose. POVME is Python implemented, fast, and freely available. To demonstrate its utility, we use the new algorithm to study three members of the matrix-metalloproteinase family of proteins. Despite the structural similarity of these proteins, differences in binding-pocket dynamics are easily identified.
- 130Calculator, 5.1.4; ChemAxon Kft.: Budapest, Hungary.Google ScholarThere is no corresponding record for this reference.
- 131Corina, 3.4.9; Molecular Networks GmbH: Erlangen, Germany.Google ScholarThere is no corresponding record for this reference.
- 132Sadowski, J.; Gasteiger, J.; Klebe, G. Comparison of Automatic Three-Dimensional Model Builders Using 639 X-Ray Structures J. Chem. Inf. Comput. Sci. 1994, 34, 1000– 1008Google Scholar132https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2cXkvVajsbY%253D&md5=246e4d66f11178a18daad2563c48331cComparison of Automatic Three-Dimensional Model Builders Using 639 X-ray StructuresSadowski, Jens; Gasteiger, Johann; Klebe, GerhardJournal of Chemical Information and Computer Sciences (1994), 34 (4), 1000-8CODEN: JCISD8; ISSN:0095-2338.Several criteria were defined to select a dataset of high-quality x-ray structures from the Cambridge file resulting in 639 mols. Six currently available programs for automatic 3D structure generation were compared by converting the connectivity tables, including appropriate stereodescriptors from this dataset of 639 mol. structures into 3D geometries: CONCORD, ALCOGEN, Chem-X, MOLGEO, COBRA, and CORINA. The geometries produced by the different programs were evaluated in terms of several quality criteria and discussed in detail. These criteria measure how well the different programs reproduce the x-ray geometries of the 639 input structures. Accordingly, the major strengths and weaknesses of the programs are indicated.
- 133Verdonk, M. L.; Cole, J. C.; Hartshorn, M. J.; Murray, C. W.; Taylor, R. D. Improved Protein-Ligand Docking Using Gold Proteins 2003, 52, 609– 623Google Scholar133https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXmvFGrsLg%253D&md5=73a627d99dab6de1ae364c8e8e5f0feaImproved protein-ligand docking using GOLDVerdonk, Marcel L.; Cole, Jason C.; Hartshorn, Michael J.; Murray, Christopher W.; Taylor, Richard D.Proteins: Structure, Function, and Genetics (2003), 52 (4), 609-623CODEN: PSFGEY; ISSN:0887-3585. (Wiley-Liss, Inc.)The Chemscore function was implemented as a scoring function for the protein-ligand docking program GOLD, and its performance compared to the original Goldscore function and two consensus docking protocols, "Goldscore-CS" and "Chemscore-GS," in terms of docking accuracy, prediction of binding affinities, and speed. In the "Goldscore-CS" protocol, dockings produced with the Goldscore function are scored and ranked with the Chemscore function; in the "Chemscore-GS" protocol, dockings produced with the Chemscore function are scored and ranked with the Goldscore function. Comparisons were made for a "clean" set of 224 protein-ligand complexes, and for two subsets of this set, one for which the ligands are "drug-like," the other for which they are "fragment-like.". For "drug-like" and "fragment-like" ligands, the docking accuracies obtained with Chemscore and Goldscore functions are similar. For larger ligands, Goldscore gives superior results. Docking with the Chemscore function is up to three times faster than docking with the Goldscore function. Both combined docking protocols give significant improvements in docking accuracy over the use of the Goldscore or Chemscore function alone. "Goldscore-CS" gives success rates of up to 81% (top-ranked GOLD soln. within 2.0 Å of the exptl. binding mode) for the "clean list," but at the cost of long search times. For most virtual screening applications, "Chemscore-GS" seems optimal; search settings that give docking speeds of around 0.25-1.3 min/compd. have success rates of about 78% for "drug-like" compds. and 85% for "fragment-like" compds. In terms of producing binding energy ests., the Goldscore function appears to perform better than the Chemscore function and the two consensus protocols, particularly for faster search settings. Even at docking speeds of around 1-2 min/compd., the Goldscore function predicts binding energies with a std. deviation of ∼10.5 kJ/mol.
- 134McMartin, C.; Bohacek, R. S. Qxp: Powerful, Rapid Computer Algorithms for Structure-Based Drug Design J. Comput. Aided Mol. Des. 1997, 11, 333– 344Google Scholar134https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXmt1ygtbc%253D&md5=aa79379af0fbd2cc7e774df00625d650QXP: powerful, rapid computer algorithms for structure-based drug designMcmartin, Colin; Bohacek, Regine S.Journal of Computer-Aided Molecular Design (1997), 11 (4), 333-344CODEN: JCADEQ; ISSN:0920-654X. (Kluwer)New methods for docking, template fitting and building pseudo-receptors are described. Full conformational searches are carried out for flexible cyclic and acyclic mols. QXP (quick explore) search algorithms are derived from the method of Monte Carlo perturbation with energy minimization in Cartesian space. An addnl. fast search step is introduced between the initial perturbation and energy minimization. The fast search produces approx. low-energy structures, which are likely to minimize to a low energy. For template fitting, QXP uses a superposition force field which automatically assigns short-range attractive forces to similar atoms in different mols. The docking algorithms were evaluated using x-ray data for 12 protein-ligand complexes. The ligands had ≤24 rotatable bonds and ranged from highly polar to mostly nonpolar. Docking searches of the randomly disordered ligands gave rms differences between the lowest energy docked structure and the energy-minimized x-ray structure, of less than 0.76 Å for 10 of the ligands. For all the ligands, the rms difference between the energy-minimized x-ray structure and the closest docked structure was less than 0.4 Å, when parts of one of the mols. which are in the solvent were excluded from the rms calcn. Template fitting was tested using four ACE inhibitors. Three ACE templates have been previously published. A single run using QXP generated a series of templates which contained examples of each of the three. A pseudo-receptor, complementary to an ACE template, was built out of small mols., such as pyrrole, cyclo-pentanone and propane. When individually energy minimized in the pseudo-receptor, each of the four ACE inhibitors moved with an rms of less than 0.25 Å. After random perturbation, the inhibitors were docked into the pseudo-receptor. Each lowest energy docked structure matched the energy-minimized geometry with an rms of less than 0.08 Å. Thus, the pseudo-receptor shows steric and chem. complementarity to all four mols. The QXP program is reliable, easy to use and sufficiently rapid for routine application in structure-based drug design.
- 135Oechem Tk, 1.7.2.4; OpenEye Scientific Software Inc.: Santa Fe, NM.Google ScholarThere is no corresponding record for this reference.
- 136Jain, A. N.; Nicholls, A. Recommendations for Evaluation of Computational Methods J. Comput. Aided Mol. Des. 2008, 22, 133– 139Google Scholar136https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXjsFOnsb0%253D&md5=9576e150079dcbf6e4bfea5070082016Recommendations for evaluation of computational methodsJain, Ajay N.; Nicholls, AnthonyJournal of Computer-Aided Molecular Design (2008), 22 (3-4), 133-139CODEN: JCADEQ; ISSN:0920-654X. (Springer)A review. The field of computational chem., particularly as applied to drug design, has become increasingly important in terms of the practical application of predictive modeling to pharmaceutical research and development. Tools for exploiting protein structures or sets of ligands known to bind particular targets can be used for binding-mode prediction, virtual screening, and prediction of activity. A serious weakness within the field is a lack of stds. with respect to quant. evaluation of methods, data set prepn., and data set sharing. Our goal should be to report new methods or comparative evaluations of methods in a manner that supports decision making for practical applications. Here we propose a modest beginning, with recommendations for requirements on statistical reporting, requirements for data sharing, and best practices for benchmark prepn. and usage.
- 137Hawkins, P. C.; Warren, G. L.; Skillman, A. G.; Nicholls, A. How to Do an Evaluation: Pitfalls and Traps J. Comput. Aided Mol. Des. 2008, 22, 179– 190Google Scholar137https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXjsFOnsLk%253D&md5=3e176941c4a526f3a97519ce02007792How to do an evaluation: pitfalls and trapsHawkins, Paul C. D.; Warren, Gregory L.; Skillman, A. Geoffrey; Nicholls, AnthonyJournal of Computer-Aided Molecular Design (2008), 22 (3-4), 179-190CODEN: JCADEQ; ISSN:0920-654X. (Springer)The recent literature is replete with papers evaluating computational tools (often those operating on 3D structures) for their performance in a certain set of tasks. Most commonly these papers compare a no. of docking tools for their performance in cognate re-docking (pose prediction) and/or virtual screening. Related papers have been published on ligand-based tools: pose prediction by conformer generators and virtual screening using a variety of ligand-based approaches. The reliability of these comparisons is critically affected by a no. of factors usually ignored by the authors, including bias in the datasets used in virtual screening, the metrics used to assess performance in virtual screening and pose prediction and errors in crystal structures used.
- 138Scior, T.; Bender, A.; Tresadern, G.; Medina-Franco, J. L.; Martinez-Mayorga, K.; Langer, T.; Cuanalo-Contreras, K.; Agrafiotis, D. K. Recognizing Pitfalls in Virtual Screening: A Critical Review J. Chem. Inf. Model. 2012, 52, 867– 881Google Scholar138https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xkt1eiurg%253D&md5=ad61b3289039c03844085a8b8de9e1e4Recognizing Pitfalls in Virtual Screening: A Critical ReviewScior, Thomas; Bender, Andreas; Tresadern, Gary; Medina-Franco, Jose L.; Martinez-Mayorga, Karina; Langer, Thierry; Cuanalo-Contreras, Karina; Agrafiotis, Dimitris K.Journal of Chemical Information and Modeling (2012), 52 (4), 867-881CODEN: JCISD8; ISSN:1549-9596. (American Chemical Society)A review. The aim of virtual screening (VS) is to identify bioactive compds. through computational means, by employing knowledge about the protein target (structure-based VS) or known bioactive ligands (ligand-based VS). In VS, a large no. of mols. are ranked according to their likelihood to be bioactive compds., with the aim to enrich the top fraction of the resulting list (which can be tested in bioassays afterward). At its core, VS attempts to improve the odds of identifying bioactive mols. by maximizing the true pos. rate, i.e., by ranking the truly active mols. as high as possible (and, correspondingly, the truly inactive ones as low as possible). In choosing the right approach, the researcher is faced with many questions: where does the optimal balance between efficiency and accuracy lie when evaluating a particular algorithm; do some methods perform better than others and in what particular situations; and what do retrospective results tell us about the prospective utility of a particular method. Given the multitude of settings, parameters, and data sets the practitioner can choose from, there are many pitfalls that lurk along the way which might render VS less efficient or downright useless. This review attempts to catalog published and unpublished problems, shortcomings, failures, and tech. traps of VS methods with the aim to avoid pitfalls by making the user aware of them in the first place.
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Abstract
Figure 1
Figure 1. (A,B) Visual and (C) quantitative comparisons of the pockets from all X-ray structures. Pocket residues (carbon atoms are colored blue, salmon, white, and gray for ANT/iAGO, f/pAGO, FAB-complexed, and ligand-free structures, respectively) of all chains of all crystal structures (listed in panel C by their PDB code followed by their chain identifier) are shown superimposed with the cartoon representation of β2R (PDB code 2RH1 (21)) and bucindolol (green carbon atoms, PDB code 4AMI (32)), as seen from the side (panel A) and from the top (panel B). Panel C gives an overview of aaverage all-atom rmsd using the pocket residues (Å) compared to all 16 f/pAGO and all 27 ANT/iAGO structures (full overview in Supporting Information, Figure S2); bthe average Z-score of the distances between G2.61, D3.32, N7.39, and S5.42 (full overview in Supporting Information, Figures S3 and S4); and cthe pocket volume (Å3, Supporting Information, Figure S5). dThe side chains of the ECL2 residues are not all fully resolved, thereby influencing the pocket volume (Figure S5) as well as rmsd values. The red and blue background coloring mark values associated with f/pAGO and ANT/iAGO properties, respectively. Icons represent f/pAGO (red), ANT/iAGO (blue), or unvalidated ANT (cyan) with no or unknown signaling preference (circles) or β-arrestin-biased ligands (triangles) (see Table 1).
Figure 2
Figure 2. Overview of the unique interaction fingerprints of all cocrystallized ligands. The colors indicate the presence of an interaction (as seen from the residue) according to the colors described at the bottom of the figure. Identical IFPs for multiple monomers within a PDB entry are grouped (e.g., 2VT4_chainA-D). The last two columns describe the amount of times (as a percentage of the total comparisons) an IFP comparison results in a score ≥0.6 when compared with the ANT/iAGO reference IFPs (a blue background indicates a high percentage) and the f/pAGO reference IFPs (a red background indicates a high percentage). aThe IFP of the highest scoring docking pose of norepinephrine in 2Y03-chainA (see Figure 6). Names and icons represent f/pAGO (red), ANT/iAGO (blue), or unvalidated ANT (34) (cyan) with no or unknown signaling preference (circle) or β-arrestin-biased ligands (triangle) (see Table 1).
Figure 3
Figure 3. Overall enrichment at 1% false positive rate (FP-rate) for the retrieval of 25 partial/full agonists and 25 inverse agonists/antagonists over a set of 980 decoy molecules using IFP scoring (A). Full ROC curves visualizing the retrieval rate (TP-rate) of f/pAGO (red) and ANT/iAGO (blue) in the best ANT/iAGO structure (B) and best f/pAGO structure (C, legend shown in panel B). The structures are indicated by their PDB code followed by an underscore and the chain identifier (except when there was only one chain or all chains of the structure had similar performance). The 2D structures represent the co-crystallized ligand for selected structures. The ANT/iAGO axis is scaled from 0 to 60 and the f/pAGO axis from 0 to 100. *1 = 3ZPQ_A, 3ZPQ_dock, 2Y00_B; *2 = 4AMJ_B, 3ZPQ_B. Icons represent f/pAGO (red), ANT/iAGO (blue), or unvalidated ANT (34) (cyan) with no or unknown signaling preference (circle) or β-arrestin-biased ligands (triangle) (see Table 1).
Figure 4
Figure 4. Enrichment factors at a 1% false positive rate using all reference IFPs (columns) on all β-adrenergic monomers for the retrieval of for f/pAGO (A) and ANT/iAGO (B) over physicochemically similar decoys. The white to red and white to blue gradients as background color mark a low to high enrichment for f/pAGO (A) and ANT/iAGO, respectively. Icons represent f/pAGO (red), ANT/iAGO (blue), or unvalidated ANT (34) (cyan) with no or unknown signaling preference (circle) or β-arrestin-biased ligands (triangle) (see Table 1).
Figure 5
Figure 5. Analysis of VS runs using the IFPs (D,E) and structures (F,G) of the most f/p AGO-selective (2Y02_A) and ANT/iAGO-selective (2VT4_A) protein–ligand complexes (see Figure 3A), showing that both the reference IFP and protein structure determine enrichment and functional selectivity of the VS study. The binding modes of the selected f/pAGO (A, 2Y02_A) and selected ANT/iAGO (B, 2VT4_A) protein–ligand complex, a docked ligand with the same efficacy class (green carbon atoms), and their corresponding IFPs (C) for the displayed residues. EF1% results for agonists and antagonist versus the decoys when using the reference IFP of the selected f/pAGO (D) and selected ANT/iAGO (E) for scoring docked compounds in all 48 protein structures. EF1% results for f/pAGO and ANT/iAGO versus the decoys when using the 38 unique reference IFPs of all ligand–protein complexes for rescoring the docked compounds in the 2Y02_A (F) and 2VT4_A (G) structure. Icons represent f/pAGO (red), ANT/iAGO (blue), or unvalidated ANT (34) (cyan) with no or unknown signaling preference (circle) or β-arrestin-biased ligands (triangle) (see Table 1).
Figure 6
Figure 6. EF1% results for agonists and antagonists (A) when using the reference IFP of docked norepinephrine (Figure 2) in 2Y03_A (B). The individual ROC plots for the retrieval of agonists (red curve) and antagonists (blue curve) in the selected ANT/iAGO structure 2VT4_A (C) and f/pAGO structure 2Y02_A (D). Icons represent f/pAGO (red), ANT/iAGO (blue), or unvalidated ANT (34) (cyan) with no or unknown signaling preference (circle) or β-arrestin-biased ligands (triangle) (see Table 1).
References
ARTICLE SECTIONSThis article references 138 other publications.
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- 6Urban, J. D.; Clarke, W. P.; von Zastrow, M.; Nichols, D. E.; Kobilka, B.; Weinstein, H.; Javitch, J. A.; Roth, B. L.; Christopoulos, A.; Sexton, P. M.; Miller, K. J.; Spedding, M.; Mailman, R. B. Functional Selectivity and Classical Concepts of Quantitative Pharmacology J. Pharmacol. Exp. Ther. 2007, 320, 1– 13Google Scholar6https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXjsFersw%253D%253D&md5=54465473b5996d0755baeee89eeb0ba9Functional selectivity and classical concepts of quantitative pharmacologyUrban, Jonathan D.; Clarke, William P.; von Zastrow, Mark; Nichols, David E.; Kobilka, Brian; Weinstein, Harel; Javitch, Jonathan A.; Roth, Bryan L.; Christopoulos, Arthur; Sexton, Patrick M.; Miller, Keith J.; Spedding, Michael; Mailman, Richard B.Journal of Pharmacology and Experimental Therapeutics (2007), 320 (1), 1-13CODEN: JPETAB; ISSN:0022-3565. (American Society for Pharmacology and Experimental Therapeutics)A review. The concept of intrinsic efficacy has been enshrined in pharmacol. for half of a century, yet recent data have revealed that many ligands can differentially activate signaling pathways mediated via a single G protein-coupled receptor in a manner that challenges the traditional definition of intrinsic efficacy. Some terms for this phenomenon include functional selectivity, agonist-directed trafficking, and biased agonism. At the extreme, functionally selective ligands may be both agonists and antagonists at different functions mediated by the same receptor. Data illustrating this phenomenon are presented from serotonin, opioid, dopamine, vasopressin, and adrenergic receptor systems. A variety of mechanisms may influence this apparently ubiquitous phenomenon. It may be initiated by differences in ligand-induced intermediate conformational states, as shown for the β2-adrenergic receptor. Subsequent mechanisms that may play a role include diversity of G proteins, scaffolding and signaling partners, and receptor oligomers. Clearly, expanded research is needed to elucidate the proximal (e.g., how functionally selective ligands cause conformational changes that initiate differential signaling), intermediate (mechanisms that translate conformation changes into differential signaling), and distal mechanisms (differential effects on target tissue or organism). Besides the heuristically interesting nature of functional selectivity, there is a clear impact on drug discovery, because this mechanism raises the possibility of selecting or designing novel ligands that differentially activate only a subset of functions of a single receptor, thereby optimizing therapeutic action. It also may be timely to revise classic concepts in quant. pharmacol. and relevant pharmacol. conventions to incorporate these new concepts.
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- 9Jacobson, K. A.; Costanzi, S. New Insights for Drug Design from the X-Ray Crystallographic Structures of G-Protein-Coupled Receptors Mol. Pharmacol. 2012, 82, 361– 371Google Scholar9https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhtlShu7nE&md5=8e4646b652271c9129971a34d01e4eb7New insights for drug design from the X-ray crystallographic structures of G-protein-coupled receptorsJacobson, Kenneth A.; Costanzi, StefanoMolecular Pharmacology (2012), 82 (3), 361-371CODEN: MOPMA3; ISSN:1521-0111. (American Society for Pharmacology and Experimental Therapeutics)A review. Methodol. advances in x-ray crystallog. have made possible the recent soln. of x-ray structures of pharmaceutically important G protein-coupled receptors (GPCRs), including receptors for biogenic amines, peptides, a nucleoside, and a sphingolipid. These high-resoln. structures have greatly increased our understanding of ligand recognition and receptor activation. Conformational changes assocd. with activation common to several receptors entail outward movements of the intracellular side of transmembrane helix 6 (TM6) and movements of TM5 toward TM6. Movements assocd. with specific agonists or receptors were also described [e.g., extracellular loop (EL) 3 in the A2A adenosine receptor]. The binding sites of different receptors partly overlap but differ significantly in ligand orientation, depth, and breadth of contact areas in TM regions and the involvement of the ELs. A current challenge is how to use this structural information for the rational design of novel potent and selective ligands. For example, new chemotypes were discovered as antagonists of various GPCRs by subjecting chem. libraries to in silico docking in the x-ray structures. The vast majority of GPCR structures and their ligand complexes are still unsolved, and no structures are known outside of family A GPCRs. Mol. modeling, informed by supporting information from site-directed mutagenesis and structure-activity relationships, was validated as a useful tool to extend structural insights to related GPCRs and to analyze docking of other ligands in already crystd. GPCRs.
- 10Katritch, V.; Cherezov, V.; Stevens, R. C. Structure-Function of the G Protein-Coupled Receptor Superfamily Annu. Rev. Pharmacol. Toxicol. 2013, 53, 531– 556Google Scholar10https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXjt1Wgurc%253D&md5=5e8c26100a9eb33a32755af09199138dStructure-function of the G protein-coupled receptor superfamilyKatritch, Vsevolod; Cherezov, Vadim; Stevens, Raymond C.Annual Review of Pharmacology and Toxicology (2013), 53 (), 531-556CODEN: ARPTDI; ISSN:0362-1642. (Annual Reviews Inc.)A review. During the past few years, crystallog. of G protein-coupled receptors (GPCRs) has experienced exponential growth, resulting in the detn. of the structures of 16 distinct receptors-9 of them in 2012 alone. Including closely related subtype homol. models, this coverage amts. to approx. 12% of the human GPCR superfamily. The adrenergic, rhodopsin, and adenosine receptor systems are also described by agonist-bound active-state structures, including a structure of the receptor-G protein complex for the β2-adrenergic receptor. Biochem. and biophys. techniques, such as NMR and hydrogen-deuterium exchange coupled with mass spectrometry, are providing complementary insights into ligand-dependent dynamic equil. between different functional states. Addnl. details revealed by high-resoln. structures illustrate the receptors as allosteric machines that are controlled not only by ligands but also by ions, lipids, cholesterol, and water. This wealth of data is helping redefine the authors' knowledge of how GPCRs recognize such a diverse array of ligands and how they transmit signals 30 angstroms across the cell membrane; it also is shedding light on a structural basis of GPCR allosteric modulation and biased signaling.
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- 12Venkatakrishnan, A. J.; Deupi, X.; Lebon, G.; Tate, C. G.; Schertler, G. F.; Babu, M. M. Molecular Signatures of G-Protein-Coupled Receptors Nature 2013, 494, 185– 194Google Scholar12https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXis1Wrt7Y%253D&md5=5dd040bf5f3b4b81249c02d493a1fbf3Molecular signatures of G-protein-coupled receptorsVenkatakrishnan, A. J.; Deupi, Xavier; Lebon, Guillaume; Tate, Christopher G.; Schertler, Gebhard F.; Babu, M. MadanNature (London, United Kingdom) (2013), 494 (7436), 185-194CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)A review. G-protein-coupled receptors (GPCRs) are physiol. important membrane proteins that sense signaling mols. such as hormones and neurotransmitters, and are the targets of several prescribed drugs. Recent exciting developments are providing unprecedented insights into the structure and function of several medically important GPCRs. Here, through a systematic anal. of high-resoln. GPCR structures, we uncover a conserved network of non-covalent contacts that defines the GPCR fold. Furthermore, our comparative anal. reveals characteristic features of ligand binding and conformational changes during receptor activation. A holistic understanding that integrates mol. and systems biol. of GPCRs holds promise for new therapeutics and personalized medicine.
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- 14Hollenstein, K.; Kean, J.; Bortolato, A.; Cheng, R. K.; Dore, A. S.; Jazayeri, A.; Cooke, R. M.; Weir, M.; Marshall, F. H. Structure of Class B Gpcr Corticotropin-Releasing Factor Receptor 1 Nature 2013, 499, 438– 443Google Scholar14https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtFWku7nN&md5=429ae98fb6d5bf65c5ef3b6a612ea3a0Structure of class B GPCR corticotropin-releasing factor receptor 1Hollenstein, Kaspar; Kean, James; Bortolato, Andrea; Cheng, Robert K. Y.; Dore, Andrew S.; Jazayeri, Ali; Cooke, Robert M.; Weir, Malcolm; Marshall, Fiona H.Nature (London, United Kingdom) (2013), 499 (7459), 438-443CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)Structural anal. of class B G-protein-coupled receptors (GPCRs), cell-surface proteins that respond to peptide hormones, has been restricted to the amino-terminal extracellular domain, thus providing little understanding of the membrane-spanning signal transduction domain. The corticotropin-releasing factor receptor type 1 (CRF1R) is a class B receptor which mediates the response to stress and has been considered a drug target for depression and anxiety. Here we report the crystal structure of the transmembrane domain of the human corticotropin-releasing factor receptor type 1 in complex with the small-mol. antagonist CP-376395. The structure provides detailed insight into the architecture of class B receptors. Atomic details of the interactions of the receptor with the non-peptide ligand that binds deep within the receptor are described. This structure provides a model for all class B GPCRs and may aid in the design of new small-mol. drugs for diseases of brain and metab.
- 15Siu, F. Y.; He, M.; de Graaf, C.; Han, G. W.; Yang, D.; Zhang, Z.; Zhou, C.; Xu, Q.; Wacker, D.; Joseph, J. S.; Liu, W.; Lau, J.; Cherezov, V.; Katritch, V.; Wang, M. W.; Stevens, R. C. Structure of the Human Glucagon Class B G-Protein-Coupled Receptor Nature 2013, 499, 444– 449Google Scholar15https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtFWktbzN&md5=ba4801075b7fc13454710def7f083710Structure of the human glucagon class B G-protein-coupled receptorSiu, Fai Yiu; He, Min; de Graaf, Chris; Han, Gye Won; Yang, Dehua; Zhang, Zhiyun; Zhou, Caihong; Xu, Qingping; Wacker, Daniel; Joseph, Jeremiah S.; Liu, Wei; Lau, Jesper; Cherezov, Vadim; Katritch, Vsevolod; Wang, Ming-Wei; Stevens, Raymond C.Nature (London, United Kingdom) (2013), 499 (7459), 444-449CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)Binding of the glucagon peptide to the glucagon receptor (GCGR) triggers the release of glucose from the liver during fasting; thus GCGR plays an important role in glucose homeostasis. Here we report the crystal structure of the seven transmembrane helical domain of human GCGR at 3.4 Å resoln., complemented by extensive site-specific mutagenesis, and a hybrid model of glucagon bound to GCGR to understand the mol. recognition of the receptor for its native ligand. Beyond the shared seven transmembrane fold, the GCGR transmembrane domain deviates from class A G-protein-coupled receptors with a large ligand-binding pocket and the first transmembrane helix having a 'stalk' region that extends three alpha-helical turns above the plane of the membrane. The stalk positions the extracellular domain (∼12 kilodaltons) relative to the membrane to form the glucagon-binding site that captures the peptide and facilitates the insertion of glucagon's amino terminus into the seven transmembrane domain.
- 16Wu, H.; Wang, C.; Gregory, K. J.; Han, G. W.; Cho, H. P.; Xia, Y.; Niswender, C. M.; Katritch, V.; Meiler, J.; Cherezov, V.; Conn, P. J.; Stevens, R. C. Structure of a Class C Gpcr Metabotropic Glutamate Receptor 1 Bound to an Allosteric Modulator Science 2014, 344, 58– 64Google Scholar16https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXlt1eht78%253D&md5=e552ac4646b8e67c52d1f5e0aa42ec5aStructure of a Class C GPCR Metabotropic Glutamate Receptor 1 Bound to an Allosteric ModulatorWu, Huixian; Wang, Chong; Gregory, Karen J.; Han, Gye Won; Cho, Hyekyung P.; Xia, Yan; Niswender, Colleen M.; Katritch, Vsevolod; Meiler, Jens; Cherezov, Vadim; Conn, P. Jeffrey; Stevens, Raymond C.Science (Washington, DC, United States) (2014), 344 (6179), 58-64CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)The excitatory neurotransmitter glutamate induces modulatory actions via the metabotropic glutamate receptors (mGlus), which are class C G protein-coupled receptors (GPCRs). The authors detd. the structure of the human mGlu1 receptor seven-transmembrane (7TM) domain bound to a neg. allosteric modulator, FITM, at a resoln. of 2.8 angstroms. The modulator binding site partially overlaps with the orthosteric binding sites of class A GPCRs but is more restricted than most other GPCRs. The authors obsd. a parallel 7TM dimer mediated by cholesterols, which suggests that signaling initiated by glutamate's interaction with the extracellular domain might be mediated via 7TM interactions within the full-length receptor dimer. A combination of crystallog., structure-activity relationships, mutagenesis, and full-length dimer modeling provides insights about the allosteric modulation and activation mechanism of class C GPCRs.
- 17Wang, C.; Wu, H.; Katritch, V.; Han, G. W.; Huang, X. P.; Liu, W.; Siu, F. Y.; Roth, B. L.; Cherezov, V.; Stevens, R. C. Structure of the Human Smoothened Receptor Bound to an Antitumour Agent Nature 2013, 497, 338– 343Google Scholar17https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXmvFylsb0%253D&md5=fdd96ac77bcf93d5c8da46e5630795b2Structure of the human smoothened receptor bound to an antitumour agentWang, Chong; Wu, Huixian; Katritch, Vsevolod; Han, Gye Won; Huang, Xi-Ping; Liu, Wei; Siu, Fai Yiu; Roth, Bryan L.; Cherezov, Vadim; Stevens, Raymond C.Nature (London, United Kingdom) (2013), 497 (7449), 338-343CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)The smoothened (SMO) receptor, a key signal transducer in the hedgehog signalling pathway, is responsible for the maintenance of normal embryonic development and is implicated in carcinogenesis. It is classified as a class frizzled (class F) G-protein-coupled receptor (GPCR), although the canonical hedgehog signalling pathway involves the GLI transcription factors and the sequence similarity with class A GPCRs is less than 10%. Here we report the crystal structure of the transmembrane domain of the human SMO receptor bound to the small-mol. antagonist LY2940680 at 2.5 Å resoln. Although the SMO receptor shares the seven-transmembrane helical (7TM) fold, most of the conserved motifs for class A GPCRs are absent, and the structure reveals an unusually complex arrangement of long extracellular loops stabilized by four disulfide bonds. The ligand binds at the extracellular end of the seven-transmembrane-helix bundle and forms extensive contacts with the loops.
- 18Rodriguez, D.; Gao, Z. G.; Moss, S. M.; Jacobson, K. A.; Carlsson, J. Molecular Docking Screening Using Agonist-Bound Gpcr Structures: Probing the a Adenosine Receptor J. Chem. Inf. Model. 2015, 55, 550– 563Google Scholar18https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhsVWgtbs%253D&md5=0faec5c3d810a9ef32e5f374b6f9b447Molecular Docking Screening Using Agonist-Bound GPCR Structures: Probing the A2A Adenosine ReceptorRodriguez, David; Gao, Zhang-Guo; Moss, Steven M.; Jacobson, Kenneth A.; Carlsson, JensJournal of Chemical Information and Modeling (2015), 55 (3), 550-563CODEN: JCISD8; ISSN:1549-9596. (American Chemical Society)Crystal structures of G protein-coupled receptors (GPCRs) have recently revealed the mol. basis of ligand binding and activation, which has provided exciting opportunities for structure-based drug design. The A2A adenosine receptor (A2AAR) is a promising therapeutic target for cardiovascular diseases, but progress in this area is limited by the lack of novel agonist scaffolds. The authors carried out docking screens of 6.7 million com. available mols. against active-like conformations of the A2AAR to investigate whether these structures could guide the discovery of agonists. Nine out of the 20 predicted agonists were confirmed to be A2AAR ligands, but none of these activated the ARs. The difficulties in discovering AR agonists using structure-based methods originated from limited at.-level understanding of the activation mechanism and a chem. bias toward antagonists in the screened library. In particular, the compn. of the screened library was found to strongly reduce the likelihood of identifying AR agonists, which reflected the high ligand complexity required for receptor activation. Extension of this anal. to other pharmaceutically relevant GPCRs suggested that library screening may not be suitable for targets requiring a complex receptor-ligand interaction network. The authors' results provide specific directions for the future development of novel A2AAR agonists and general strategies for structure-based drug discovery.
- 19White, J. F.; Noinaj, N.; Shibata, Y.; Love, J.; Kloss, B.; Xu, F.; Gvozdenovic-Jeremic, J.; Shah, P.; Shiloach, J.; Tate, C. G.; Grisshammer, R. Structure of the Agonist-Bound Neurotensin Receptor Nature 2012, 490, 508– 513Google Scholar19https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhsVykt7%252FP&md5=c55a071640dec7edae7a69d715bea675Structure of the agonist-bound neurotensin receptorWhite, Jim F.; Noinaj, Nicholas; Shibata, Yoko; Love, James; Kloss, Brian; Xu, Feng; Gvozdenovic-Jeremic, Jelena; Shah, Priyanka; Shiloach, Joseph; Tate, Christopher G.; Grisshammer, ReinhardNature (London, United Kingdom) (2012), 490 (7421), 508-513CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)Neurotensin (NTS) is a 13-amino-acid peptide that functions as both a neurotransmitter and a hormone through the activation of the neurotensin receptor NTSR1, a G-protein-coupled receptor (GPCR). In the brain, NTS modulates the activity of dopaminergic systems, opioid-independent analgesia, and the inhibition of food intake; in the gut, NTS regulates a range of digestive processes. Here we present the structure at 2.8 Å resoln. of Rattus norvegicus NTSR1 in an active-like state, bound to NTS8-13, the carboxy-terminal portion of NTS responsible for agonist-induced activation of the receptor. The peptide agonist binds to NTSR1 in an extended conformation nearly perpendicular to the membrane plane, with the C terminus oriented towards the receptor core. Our findings provide, to our knowledge, the first insight into the binding mode of a peptide agonist to a GPCR and may support the development of non-peptide ligands that could be useful in the treatment of neurol. disorders, cancer and obesity.
- 20Weichert, D.; Kruse, A. C.; Manglik, A.; Hiller, C.; Zhang, C.; Hubner, H.; Kobilka, B. K.; Gmeiner, P. Covalent Agonists for Studying G Protein-Coupled Receptor Activation Proc. Natl. Acad. Sci. U.S.A. 2014, 111, 10744– 10748Google Scholar20https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhtFyqtbnN&md5=a131bb7711d9a1826c77c3b598dee470Covalent agonists for studying G protein-coupled receptor activationWeichert, Dietmar; Kruse, Andrew C.; Manglik, Aashish; Hiller, Christine; Zhang, Cheng; Huebner, Harald; Kobilka, Brian K.; Gmeiner, PeterProceedings of the National Academy of Sciences of the United States of America (2014), 111 (29), 10744-10748CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)Structural studies on G protein-coupled receptors (GPCRs) provide important insights into the architecture and function of these important drug targets. However, the crystn. of GPCRs in active states is particularly challenging, requiring the formation of stable and conformationally homogeneous ligand-receptor complexes. Native hormones, neurotransmitters, and synthetic agonists that bind with low affinity are ineffective at stabilizing an active state for crystallogenesis. To promote structural studies on the pharmacol. highly relevant class of aminergic GPCRs, the authors here present the development of covalently binding mol. tools activating Gs-, Gi-, and Gq-coupled receptors. The covalent agonists are derived from the monoamine neurotransmitters noradrenaline, dopamine, serotonin, and histamine, and they were accessed using a general and versatile synthetic strategy. The authors demonstrate that the tool compds. presented herein display an efficient covalent binding mode and that the resp. covalent ligand-receptor complexes activate G proteins comparable to the natural neurotransmitters. A crystal structure of the β2-adrenoreceptor in complex with a covalent noradrenaline analog and a conformationally selective antibody (nanobody) verified that these agonists can be used to facilitate crystallogenesis.
- 21Cherezov, V.; Rosenbaum, D. M.; Hanson, M. A.; Rasmussen, S. G.; Thian, F. S.; Kobilka, T. S.; Choi, H. J.; Kuhn, P.; Weis, W. I.; Kobilka, B. K.; Stevens, R. C. High-Resolution Crystal Structure of an Engineered Human Beta2-Adrenergic G Protein-Coupled Receptor Science 2007, 318, 1258– 1265Google Scholar21https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhtlGmur7I&md5=12c5bacb8464a4b243fe9341192b5b3bHigh-Resolution Crystal Structure of an Engineered Human β2-Adrenergic G Protein-Coupled ReceptorCherezov, Vadim; Rosenbaum, Daniel M.; Hanson, Michael A.; Rasmussen, Soren G. F.; Thian, Foon Sun; Kobilka, Tong Sun; Choi, Hee-Jung; Kuhn, Peter; Weis, William I.; Kobilka, Brian K.; Stevens, Raymond C.; Takeda, S.; Kadowaki, S.; Haga, T.; Takaesu, H.; Mitaku, S.; Fredriksson, R.; Lagerstrom, M. C.; Lundin, L. G.; Schioth, H. B.; Pierce, K. L.; Premont, R. T.; Lefkowitz, R. J.; Lefkowitz, R. J.; Shenoy, S. K.; Rosenbaum, D. M.Science (Washington, DC, United States) (2007), 318 (5854), 1258-1265CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)Second extracellular loop, which in the β2-adrenergic receptor contains an unusual pair of disulfide bonds and an extra helix. This loop and the absence Heterotrimeric guanine nucleotide-binding protein (G protein)-coupled receptors constitute the largest family of eukaryotic signal transduction proteins that communicate across the membrane. We report the crystal structure of a human β2-adrenergic receptor-T4 lysozyme fusion protein bound to the partial inverse agonist carazolol at 2.4 angstrom resoln. The structure provides a high-resoln. view of a human G protein-coupled receptor bound to a diffusible ligand. Ligand-binding site accessibility is enabled by the second extracellular loop, which is held out of the binding cavity by a pair of closely spaced disulfide bridges and a short helical segment within the loop. Cholesterol, a necessary component for crystn., mediates an intriguing parallel assocn. of receptor mols. in the crystal lattice. Although the location of carazolol in the β2-adrenergic receptor is very similar to that of retinal in rhodopsin, structural differences in the ligand-binding site and other regions highlight the challenges in using rhodopsin as a template model for this large receptor family.
- 22Rasmussen, S. G.; Choi, H. J.; Rosenbaum, D. M.; Kobilka, T. S.; Thian, F. S.; Edwards, P. C.; Burghammer, M.; Ratnala, V. R.; Sanishvili, R.; Fischetti, R. F.; Schertler, G. F.; Weis, W. I.; Kobilka, B. K. Crystal Structure of the Human Beta2 Adrenergic G-Protein-Coupled Receptor Nature 2007, 450, 383– 387Google Scholar22https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhtlajs77N&md5=79026a0a69ddb4b0ea25063e409ad2cdCrystal structure of the human β2 adrenergic G-protein-coupled receptorRasmussen, Soren G. F.; Choi, Hee-Jung; Rosenbaum, Daniel M.; Kobilka, Tong Sun; Thian, Foon Sun; Edwards, Patricia C.; Burghammer, Manfred; Ratnala, Venkata R. P.; Sanishvili, Ruslan; Fischetti, Robert F.; Schertler, Gebhard F. X.; Weis, William I.; Kobilka, Brian K.Nature (London, United Kingdom) (2007), 450 (7168), 383-387CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)Structural anal. of G-protein-coupled receptors (GPCRs) for hormones and neurotransmitters has been hindered by their low natural abundance, inherent structural flexibility, and instability in detergent solns. Here we report a structure of the human β2 adrenoceptor (β2AR), which was crystd. in a lipid environment when bound to an inverse agonist and in complex with a Fab that binds to the third intracellular loop. Diffraction data were obtained by high-brilliance microcrystallog. and the structure detd. at 3.4 Å/3.7 Å resoln. The cytoplasmic ends of the β2AR transmembrane segments and the connecting loops are well resolved, whereas the extracellular regions of the β2AR are not seen. The β2AR structure differs from rhodopsin in having weaker interactions between the cytoplasmic ends of transmembrane (TM)3 and TM6, involving the conserved E/DRY sequences. These differences may be responsible for the relatively high basal activity and structural instability of the β2AR, and contribute to the challenges in obtaining diffraction-quality crystals of non-rhodopsin GPCRs.
- 23Hanson, M. A.; Cherezov, V.; Griffith, M. T.; Roth, C. B.; Jaakola, V. P.; Chien, E. Y.; Velasquez, J.; Kuhn, P.; Stevens, R. C. A Specific Cholesterol Binding Site Is Established by the 2.8 a Structure of the Human Beta2-Adrenergic Receptor Structure 2008, 16, 897– 905Google Scholar23https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXmvFertbo%253D&md5=d72699c59a8b79c2c45e89dcd391e7cbA Specific Cholesterol Binding Site Is Established by the 2.8 Å Structure of the Human β2-Adrenergic ReceptorHanson, Michael A.; Cherezov, Vadim; Griffith, Mark T.; Roth, Christopher B.; Jaakola, Veli-Pekka; Chien, Ellen Y. T.; Velasquez, Jeffrey; Kuhn, Peter; Stevens, Raymond C.Structure (Cambridge, MA, United States) (2008), 16 (6), 897-905CODEN: STRUE6; ISSN:0969-2126. (Cell Press)The role of cholesterol in eukaryotic membrane protein function has been attributed primarily to an influence on membrane fluidity and curvature. We present the 2.8 Å resoln. crystal structure of a thermally stabilized human β2-adrenergic receptor (β2AR) bound to cholesterol and the partial inverse agonist timolol. The receptors pack as monomers in an antiparallel assocn. with two distinct cholesterol mols. bound per receptor, but not in the packing interface, thereby indicating a structurally relevant cholesterol-binding site between helixes I, II, III, and IV. Thermal stability anal. using isothermal denaturation confirms that a cholesterol analog significantly enhances the stability of the receptor. A consensus motif is defined that predicts cholesterol binding for 44% of human class A receptors, suggesting that specific sterol binding is important to the structure and stability of other G protein-coupled receptors (GPCRs), and that this site may provide a target for therapeutic discovery.
- 24Warne, T.; Serrano-Vega, M. J.; Baker, J. G.; Moukhametzianov, R.; Edwards, P. C.; Henderson, R.; Leslie, A. G.; Tate, C. G.; Schertler, G. F. Structure of a Beta1-Adrenergic G-Protein-Coupled Receptor Nature 2008, 454, 486– 491Google Scholar24https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXovV2mtLg%253D&md5=de1d476a6ff0b995cd344c248d1bc490Structure of a β1-adrenergic G-protein-coupled receptorWarne, Tony; Serrano-Vega, Maria J.; Baker, Jillian G.; Moukhametzianov, Rouslan; Edwards, Patricia C.; Henderson, Richard; Leslie, Andrew G. W.; Tate, Christopher G.; Schertler, Gebhard F. X.Nature (London, United Kingdom) (2008), 454 (7203), 486-491CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)G-protein-coupled receptors have a major role in transmembrane signaling in most eukaryotes and many are important drug targets. Here we report the 2.7Å resoln. crystal structure of a β1-adrenergic receptor in complex with high affinity antagonist cyanopindolol. The modified turkey (Meleagris gallopavo) receptor was selected to be in its antagonist conformation and its thermostability improved by earlier limited mutagenesis. The ligand-binding pocket comprises 15 side chains from amino acid residues in 4 transmembrane α-helixes and extracellular loop 2. This loop defines the entrance of the ligand-binding pocket and is stabilized by two disulfide bonds and a sodium ion. Binding of cyanopindolol to the β1-adrenergic receptor and binding of Carazolol to the β2-adrenergic receptor involve similar interactions. A short well-defined helix in cytoplasmic loop 2, not obsd. in either rhodopsin or the β2-adrenergic receptor, directly interacts by means of a tyrosine with the highly conserved DRY motif at the end of helix 3 that is essential for receptor activation.
- 25Bokoch, M. P.; Zou, Y.; Rasmussen, S. G.; Liu, C. W.; Nygaard, R.; Rosenbaum, D. M.; Fung, J. J.; Choi, H. J.; Thian, F. S.; Kobilka, T. S.; Puglisi, J. D.; Weis, W. I.; Pardo, L.; Prosser, R. S.; Mueller, L.; Kobilka, B. K. Ligand-Specific Regulation of the Extracellular Surface of a G-Protein-Coupled Receptor Nature 2010, 463, 108– 112Google Scholar25https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhvFeksQ%253D%253D&md5=58c5abb3edeb50453344fb47ebda7a2cLigand-specific regulation of the extracellular surface of a G-protein-coupled receptorBokoch, Michael P.; Zou, Yaozhong; Rasmussen, Soren G. F.; Liu, Corey W.; Nygaard, Rie; Rosenbaum, Daniel M.; Fung, Juan Jose; Choi, Hee-Jung; Thian, Foon Sun; Kobilka, Tong Sun; Puglisi, Joseph D.; Weis, William I.; Pardo, Leonardo; Prosser, R. Scott; Mueller, Luciano; Kobilka, Brian K.Nature (London, United Kingdom) (2010), 463 (7277), 108-112CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)G protein-coupled receptors (GPCRs) are seven-transmembrane proteins that mediate most cellular responses to hormones and neurotransmitters. They are the largest group of therapeutic targets for a broad spectrum of diseases. Recent crystal structures of GPCRs have revealed structural conservation extending from the orthosteric ligand-binding site in the transmembrane core to the cytoplasmic G protein-coupling domains. In contrast, the extracellular surface (ECS) of GPCRs is remarkably diverse and is therefore an ideal target for the discovery of subtype-selective drugs. However, little is known about the functional role of the ECS in receptor activation, or about conformational coupling of this surface to the native ligand-binding pocket. Here we use NMR spectroscopy to investigate ligand-specific conformational changes around a central structural feature in the ECS of the β2 adrenergic receptor (β2AR): a salt bridge linking extracellular loops 2 and 3. Small-mol. drugs that bind within the transmembrane core and exhibit different efficacies towards G protein activation (agonist, neutral antagonist, and inverse agonist) also stabilize distinct conformations of the ECS. We thereby demonstrate conformational coupling between the ECS and the orthosteric binding site, showing that drugs targeting this diverse surface could function as allosteric modulators with high subtype selectivity. Moreover, these studies provide a new insight into the dynamic behavior of GPCRs not addressable by static, inactive-state crystal structures.
- 26Wacker, D.; Fenalti, G.; Brown, M. A.; Katritch, V.; Abagyan, R.; Cherezov, V.; Stevens, R. C. Conserved Binding Mode of Human Beta2 Adrenergic Receptor Inverse Agonists and Antagonist Revealed by X-Ray Crystallography J. Am. Chem. Soc. 2010, 132, 11443– 11445Google ScholarThere is no corresponding record for this reference.
- 27Moukhametzianov, R.; Warne, T.; Edwards, P. C.; Serrano-Vega, M. J.; Leslie, A. G.; Tate, C. G.; Schertler, G. F. Two Distinct Conformations of Helix 6 Observed in Antagonist-Bound Structures of a Beta1-Adrenergic Receptor Proc. Natl. Acad. Sci. U.S.A. 2011, 108, 8228– 8232Google Scholar27https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXmsF2jsb8%253D&md5=7888634ffd4ff20895c6c02c4ed10496Two distinct conformations of helix 6 observed in antagonist-bound structures of a β1-adrenergic receptorMoukhametzianov, Rouslan; Warne, Tony; Edwards, Patricia C.; Serrano-Vega, Maria J.; Leslie, Andrew G. W.; Tate, Christopher G.; Schertler, Gebhard F. X.Proceedings of the National Academy of Sciences of the United States of America (2011), 108 (20), 8228-8232, S8228/1-S8228/5CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)The β1-adrenergic receptor (β1AR) is a G-protein-coupled receptor whose inactive state structure was detd. using a thermostabilized mutant (β1AR-M23). However, it was not thought to be in a fully inactivated state because there was no salt bridge between Arg139 and Glu285 linking the cytoplasmic ends of transmembrane helixes 3 and 6 (the R3.50-D/E6.30 "ionic lock"). Here we compare eight new structures of β1AR-M23, detd. from crystallog. independent mols. in four different crystals with three different antagonists bound. These structures are all in the inactive R state and show clear electron d. for cytoplasmic loop 3 linking transmembrane helixes 5 and 6 that had not been seen previously. Despite significantly different crystal packing interactions, there are only two distinct conformations of the cytoplasmic end of helix 6, bent and straight. In the bent conformation, the Arg139-Glu285 salt bridge is present, as in the crystal structure of dark-state rhodopsin. The straight conformation, obsd. in previously solved structures of β-receptors, results in the ends of helixes 3 and 6 being too far apart for the ionic lock to form. In the bent conformation, the R3.50-E6.30 distance is significantly longer than in rhodopsin, suggesting that the interaction is also weaker, which could explain the high basal activity in β1AR compared to rhodopsin. Many mutations that increase the constitutive activity of G-protein-coupled receptors are found in the bent region at the cytoplasmic end of helix 6, supporting the idea that this region plays an important role in receptor activation.
- 28Rasmussen, S. G.; Choi, H. J.; Fung, J. J.; Pardon, E.; Casarosa, P.; Chae, P. S.; Devree, B. T.; Rosenbaum, D. M.; Thian, F. S.; Kobilka, T. S.; Schnapp, A.; Konetzki, I.; Sunahara, R. K.; Gellman, S. H.; Pautsch, A.; Steyaert, J.; Weis, W. I.; Kobilka, B. K. Structure of a Nanobody-Stabilized Active State of the Beta(2) Adrenoceptor Nature 2011, 469, 175– 180Google Scholar28https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXkvFartA%253D%253D&md5=3a1d3bac6d92c9d54cf1ddd14d56ab8cStructure of a nanobody-stabilized active state of the β2 adrenoceptorRasmussen, Soren G. F.; Choi, Hee-Jung; Fung, Juan Jose; Pardon, Els; Casarosa, Paola; Chae, Pil Seok; DeVree, Brian T.; Rosenbaum, Daniel M.; Thian, Foon Sun; Kobilka, Tong Sun; Schnapp, Andreas; Konetzki, Ingo; Sunahara, Roger K.; Gellman, Samuel H.; Pautsch, Alexander; Steyaert, Jan; Weis, William I.; Kobilka, Brian K.Nature (London, United Kingdom) (2011), 469 (7329), 175-180CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)G protein coupled receptors (GPCRs) exhibit a spectrum of functional behaviors in response to natural and synthetic ligands. Recent crystal structures provide insights into inactive states of several GPCRs. Efforts to obtain an agonist-bound active-state GPCR structure have proven difficult due to the inherent instability of this state in the absence of a G protein. We generated a camelid antibody fragment (nanobody) to the human β2 adrenergic receptor (β2AR) that exhibits G protein-like behavior, and obtained an agonist-bound, active-state crystal structure of the receptor-nanobody complex. Comparison with the inactive β2AR structure reveals subtle changes in the binding pocket; however, these small changes are assocd. with an 11 Å outward movement of the cytoplasmic end of transmembrane segment 6, and rearrangements of transmembrane segments 5 and 7 that are remarkably similar to those obsd. in opsin, an active form of rhodopsin. This structure provides insights into the process of agonist binding and activation.
- 29Rasmussen, S. G.; DeVree, B. T.; Zou, Y.; Kruse, A. C.; Chung, K. Y.; Kobilka, T. S.; Thian, F. S.; Chae, P. S.; Pardon, E.; Calinski, D.; Mathiesen, J. M.; Shah, S. T.; Lyons, J. A.; Caffrey, M.; Gellman, S. H.; Steyaert, J.; Skiniotis, G.; Weis, W. I.; Sunahara, R. K.; Kobilka, B. K. Crystal Structure of the Beta2 Adrenergic Receptor-Gs Protein Complex Nature 2011, 477, 549– 555Google Scholar29https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXht1equrrL&md5=d22a43dd677ac255d138b1aedff357d3Crystal structure of the β2 adrenergic receptor-Gs protein complexRasmussen, Soren G. F.; DeVree, Brian T.; Zou, Yao-Zhong; Kruse, Andrew C.; Chung, Ka-Young; Kobilka, Tong-Sun; Thian, Foon-Sun; Chae, Pil-Seok; Pardon, Els; Calinski, Diane; Mathiesen, Jesper M.; Shah, Syed T. A.; Lyons, Joseph A.; Caffrey, Martin; Gellman, Samuel H.; Steyaert, Jan; Skiniotis, Georgios; Weis, William I.; Sunahara, Roger K.; Kobilka, Brian K.Nature (London, United Kingdom) (2011), 477 (7366), 549-555CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)G protein-coupled receptors (GPCRs) are responsible for the majority of cellular responses to hormones and neurotransmitters as well as the senses of sight, olfaction and taste. The paradigm of GPCR signalling is the activation of a heterotrimeric GTP binding protein (G protein) by an agonist-occupied receptor. The β2 adrenergic receptor (β2AR) activation of Gs, the stimulatory G protein for adenylyl cyclase, has long been a model system for GPCR signalling. Here we present the crystal structure of the active state ternary complex composed of agonist-occupied monomeric β2AR and nucleotide-free Gs heterotrimer. The principal interactions between the β2AR and Gs involve the amino- and carboxy-terminal α-helixes of Gs, with conformational changes propagating to the nucleotide-binding pocket. The largest conformational changes in the β2AR include a 14 Å outward movement at the cytoplasmic end of transmembrane segment 6 (TM6) and an α-helical extension of the cytoplasmic end of TM5. The most surprising observation is a major displacement of the α-helical domain of Gαs relative to the Ras-like GTPase domain. This crystal structure represents the first high-resoln. view of transmembrane signalling by a GPCR.
- 30Rosenbaum, D. M.; Zhang, C.; Lyons, J. A.; Holl, R.; Aragao, D.; Arlow, D. H.; Rasmussen, S. G.; Choi, H. J.; Devree, B. T.; Sunahara, R. K.; Chae, P. S.; Gellman, S. H.; Dror, R. O.; Shaw, D. E.; Weis, W. I.; Caffrey, M.; Gmeiner, P.; Kobilka, B. K. Structure and Function of an Irreversible Agonist-Beta(2) Adrenoceptor Complex Nature 2011, 469, 236– 240Google Scholar30https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXkvFehsQ%253D%253D&md5=8629b93e43fb692395e2aa6f8bb011a9Structure and function of an irreversible agonist-β2 adrenoceptor complexRosenbaum, Daniel M.; Zhang, Cheng; Lyons, Joseph A.; Holl, Ralph; Aragao, David; Arlow, Daniel H.; Rasmussen, Soren G. F.; Choi, Hee-Jung; DeVree, Brian T.; Sunahara, Roger K.; Chae, Pil Seok; Gellman, Samuel H.; Dror, Ron O.; Shaw, David E.; Weis, William I.; Caffrey, Martin; Gmeiner, Peter; Kobilka, Brian K.Nature (London, United Kingdom) (2011), 469 (7329), 236-240CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)G-protein-coupled receptors (GPCRs) are eukaryotic integral membrane proteins that modulate biol. function by initiating cellular signaling in response to chem. diverse agonists. Despite recent progress in the structural biol. of GPCRs, the mol. basis for agonist binding and allosteric modulation of these proteins is poorly understood. Structural knowledge of agonist-bound states is essential for deciphering the mechanism of receptor activation, and for structure-guided design and optimization of ligands. However, the crystn. of agonist-bound GPCRs has been hampered by modest affinities and rapid off-rates of available agonists. Using the inactive structure of the human β2 adrenergic receptor (β2AR) as a guide, we designed a β2AR agonist that can be covalently tethered to a specific site on the receptor through a disulfide bond. The covalent β2AR-agonist complex forms efficiently, and is capable of activating a heterotrimeric G protein. We crystd. a covalent agonist-bound β2AR-T4L fusion protein in lipid bilayers through the use of the lipidic mesophase method, and detd. its structure at 3.5 Å resoln. A comparison to the inactive structure and an antibody-stabilized active structure (companion paper) shows how binding events at both the extracellular and intracellular surfaces are required to stabilize an active conformation of the receptor. The structures are in agreement with long-timescale (up to 30 μs) mol. dynamics simulations showing that an agonist-bound active conformation spontaneously relaxes to an inactive-like conformation in the absence of a G protein or stabilizing antibody.
- 31Warne, T.; Moukhametzianov, R.; Baker, J. G.; Nehme, R.; Edwards, P. C.; Leslie, A. G.; Schertler, G. F.; Tate, C. G. The Structural Basis for Agonist and Partial Agonist Action on a Beta(1)-Adrenergic Receptor Nature 2011, 469, 241– 244Google ScholarThere is no corresponding record for this reference.
- 32Warne, T.; Edwards, P. C.; Leslie, A. G.; Tate, C. G. Crystal Structures of a Stabilized Beta1-Adrenoceptor Bound to the Biased Agonists Bucindolol and Carvedilol Structure 2012, 20, 841– 849Google ScholarThere is no corresponding record for this reference.
- 33Zou, Y.; Weis, W. I.; Kobilka, B. K. N-Terminal T4 Lysozyme Fusion Facilitates Crystallization of a G Protein Coupled Receptor PLoS One 2012, 7e46039Google ScholarThere is no corresponding record for this reference.
- 34Christopher, J. A.; Brown, J.; Dore, A. S.; Errey, J. C.; Koglin, M.; Marshall, F. H.; Myszka, D. G.; Rich, R. L.; Tate, C. G.; Tehan, B.; Warne, T.; Congreve, M. Biophysical Fragment Screening of the Beta1-Adrenergic Receptor: Identification of High Affinity Arylpiperazine Leads Using Structure-Based Drug Design J. Med. Chem. 2013, 56, 3446– 3455Google ScholarThere is no corresponding record for this reference.
- 35Huang, J.; Chen, S.; Zhang, J. J.; Huang, X. Y. Crystal Structure of Oligomeric Beta1-Adrenergic G Protein-Coupled Receptors in Ligand-Free Basal State Nat. Struct. Mol. Biol. 2013, 20, 419– 425Google Scholar35https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXivF2jur8%253D&md5=2da0ac305cfcec221964c2c8fd37ec58Crystal structure of oligomeric β1-adrenergic G protein-coupled receptors in ligand-free basal stateHuang, Jianyun; Chen, Shuai; Zhang, J. Jillian; Huang, Xin-YunNature Structural & Molecular Biology (2013), 20 (4), 419-425CODEN: NSMBCU; ISSN:1545-9993. (Nature Publishing Group)G protein-coupled receptors (GPCRs) mediate transmembrane signaling. Before ligand binding, GPCRs exist in a basal state. Crystal structures of several GPCRs bound with antagonists or agonists have been solved. However, the crystal structure of the ligand-free basal state of a GPCR, the starting point of GPCR activation and function, had not yet been detd. Here we report the x-ray crystal structure of the ligand-free basal state of a GPCR in a lipid membrane-like environment. Oligomeric turkey β1-adrenergic receptors display two dimer interfaces. One interface involves the transmembrane domain (TM) 1, TM2, the C-terminal H8 and extracellular loop 1. The other interface engages residues from TM4, TM5, intracellular loop 2 and extracellular loop 2. Structural comparisons show that this ligand-free state is in an inactive conformation. This provides the structural basis of GPCR dimerization and oligomerization.
- 36Carlsson, J.; Coleman, R. G.; Setola, V.; Irwin, J. J.; Fan, H.; Schlessinger, A.; Sali, A.; Roth, B. L.; Shoichet, B. K. Ligand Discovery from a Dopamine D3 Receptor Homology Model and Crystal Structure Nat. Chem. Biol. 2011, 7, 769– 778Google Scholar36https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtFylsLvP&md5=7242aa512079a348678b309d352ecdb9Ligand discovery from a dopamine D3 receptor homology model and crystal structureCarlsson, Jens; Coleman, Ryan G.; Setola, Vincent; Irwin, John J.; Fan, Hao; Schlessinger, Avner; Sali, Andrej; Roth, Bryan L.; Shoichet, Brian K.Nature Chemical Biology (2011), 7 (11), 769-778CODEN: NCBABT; ISSN:1552-4450. (Nature Publishing Group)G protein-coupled receptors (GPCRs) are intensely studied as drug targets and for their role in signaling. With the detn. of the first crystal structures, interest in structure-based ligand discovery increased. Unfortunately, for most GPCRs no exptl. structures are available. The detn. of the D3 receptor structure and the challenge to the community to predict it enabled a fully prospective comparison of ligand discovery from a modeled structure vs. that of the subsequently released crystal structure. Over 3.3 million mols. were docked against a homol. model, and 26 of the highest ranking were tested for binding. Six had affinities ranging from 0.2 to 3.1 μM. Subsequently, the crystal structure was released and the docking screen repeated. Of the 25 compds. selected, five had affinities ranging from 0.3 to 3.0 μM. One of the new ligands from the homol. model screen was optimized for affinity to 81 nM. The feasibility of docking screens against modeled GPCRs more generally is considered.
- 37Carlsson, J.; Yoo, L.; Gao, Z. G.; Irwin, J. J.; Shoichet, B. K.; Jacobson, K. A. Structure-Based Discovery of A2a Adenosine Receptor Ligands J. Med. Chem. 2010, 53, 3748– 3755Google Scholar37https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXkvFaqsL8%253D&md5=c36c941d52d2cec06387d79c4c423d46Structure-Based Discovery of A2A Adenosine Receptor LigandsCarlsson, Jens; Yoo, Lena; Gao, Zhan-Guo; Irwin, John J.; Shoichet, Brian K.; Jacobson, Kenneth A.Journal of Medicinal Chemistry (2010), 53 (9), 3748-3755CODEN: JMCMAR; ISSN:0022-2623. (American Chemical Society)The recent detn. of X-ray structures of pharmacol. relevant GPCRs has made these targets accessible to structure-based ligand discovery. Here we explore whether novel chemotypes may be discovered for the A2A adenosine receptor, based on complementarity to its recently detd. structure. The A2A adenosine receptor signals in the periphery and the CNS, with agonists explored as anti-inflammatory drugs and antagonists explored for neurodegenerative diseases. We used mol. docking to screen a 1.4 million compd. database against the X-ray structure computationally and tested 20 high-ranking, previously unknown mols. exptl. Of these 35% showed substantial activity with affinities between 200 nM and 9 μM. For the most potent of these new inhibitors, over 50-fold specificity was obsd. for the A2A vs. the related A1 and A3 subtypes. These high hit rates and affinities at least partly reflect the bias of com. libraries toward GPCR-like chemotypes, an issue that we attempt to investigate quant. Despite this bias, many of the most potent new ligands were novel, dissimilar from known ligands, providing new lead structures for modulation of this medically important target.
- 38de Graaf, C.; Kooistra, A. J.; Vischer, H. F.; Katritch, V.; Kuijer, M.; Shiroishi, M.; Iwata, S.; Shimamura, T.; Stevens, R. C.; de Esch, I. J.; Leurs, R. Crystal Structure-Based Virtual Screening for Fragment-Like Ligands of the Human Histamine H(1) Receptor J. Med. Chem. 2011, 54, 8195– 8206Google ScholarThere is no corresponding record for this reference.
- 39Katritch, V.; Jaakola, V. P.; Lane, J. R.; Lin, J.; Ijzerman, A. P.; Yeager, M.; Kufareva, I.; Stevens, R. C.; Abagyan, R. Structure-Based Discovery of Novel Chemotypes for Adenosine a(2a) Receptor Antagonists J. Med. Chem. 2010, 53, 1799– 1809Google Scholar39https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXptlKqsw%253D%253D&md5=5a54df43f6edd20d83e7e5942e2f9811Structure-Based Discovery of Novel Chemotypes for Adenosine A2A Receptor AntagonistsKatritch, Vsevolod; Jaakola, Veli-Pekka; Lane, J. Robert; Lin, Judy; IJzerman, Adriaan P.; Yeager, Mark; Kufareva, Irina; Stevens, Raymond C.; Abagyan, RubenJournal of Medicinal Chemistry (2010), 53 (4), 1799-1809CODEN: JMCMAR; ISSN:0022-2623. (American Chemical Society)The recent progress in crystallog. of G-protein coupled receptors opens an unprecedented venue for structure-based GPCR drug discovery. To test efficiency of the structure-based approach, we performed mol. docking and virtual ligand screening (VLS) of more than 4 million com. available "drug-like" and "lead-like" compds. against the A2AAR 2.6 Å resoln. crystal structure. Out of 56 high ranking compds. tested in A2AAR binding assays, 23 showed affinities under 10 μM, 11 of those had sub-μM affinities and two compds. had affinities under 60 nM. The identified hits represent at least 9 different chem. scaffolds and are characterized by very high ligand efficiency (0.3-0.5 kcal/mol per heavy atom). Significant A2AAR antagonist activities were confirmed for 10 out of 13 ligands tested in functional assays. High success rate, novelty, and diversity of the chem. scaffolds and strong ligand efficiency of the A2AAR antagonists identified in this study suggest practical applicability of receptor-based VLS in GPCR drug discovery.
- 40Kolb, P.; Rosenbaum, D. M.; Irwin, J. J.; Fung, J. J.; Kobilka, B. K.; Shoichet, B. K. Structure-Based Discovery of Beta2-Adrenergic Receptor Ligands Proc. Natl. Acad. Sci. U.S.A. 2009, 106, 6843– 6848Google Scholar40https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXlsV2qsro%253D&md5=4d1a4cb2aa3925aa4c99c6b0496417a7Structure-based discovery of β2-adrenergic receptor ligandsKolb, Peter; Rosenbaum, Daniel M.; Irwin, John J.; Fung, Juan Jose; Kobilka, Brian K.; Shoichet, Brian K.Proceedings of the National Academy of Sciences of the United States of America (2009), 106 (16), 6843-6848CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)Aminergic G protein-coupled receptors (GPCRs) have been a major focus of pharmaceutical research for many years. Due partly to the lack of reliable receptor structures, drug discovery efforts have been largely ligand-based. The recently detd. X-ray structure of the β2-adrenergic receptor offers an opportunity to investigate the advantages and limitations inherent in a structure-based approach to ligand discovery against this and related GPCR targets. Approx. 1 million com. available, "lead-like" mols. were docked against the β2-adrenergic receptor structure. On testing of 25 high-ranking mols., 6 were active with binding affinities <4 μM, with the best mol. binding with a Ki of 9 nM (95% confidence interval 7-10 nM). Five of these mols. were inverse agonists. The high hit rate, the high affinity of the most potent mol., the discovery of unprecedented chemotypes among the new inhibitors, and the apparent bias toward inverse agonists among the docking hits, have implications for structure-based approaches against GPCRs that recognize small org. mols.
- 41Mysinger, M. M.; Weiss, D. R.; Ziarek, J. J.; Gravel, S.; Doak, A. K.; Karpiak, J.; Heveker, N.; Shoichet, B. K.; Volkman, B. F. Structure-Based Ligand Discovery for the Protein-Protein Interface of Chemokine Receptor Cxcr4 Proc. Natl. Acad. Sci. U.S.A. 2012, 109, 5517– 5522Google ScholarThere is no corresponding record for this reference.
- 42de Graaf, C.; Rognan, D. Customizing G Protein-Coupled Receptor Models for Structure-Based Virtual Screening Curr. Pharm. Des. 2009, 15, 4026– 4048Google Scholar42https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtlKlu7Y%253D&md5=e3aefb5a191d0507cca6766ce191e82cCustomizing G protein-coupled receptor models for structure-based virtual screeningde Graaf, Chris; Rognan, DidierCurrent Pharmaceutical Design (2009), 15 (35), 4026-4048CODEN: CPDEFP; ISSN:1381-6128. (Bentham Science Publishers Ltd.)This review will focus on the construction, refinement, and validation of G Protein-coupled receptor models for the purpose of structure-based virtual screening. Practical tips and tricks derived from concrete modeling and virtual screening exercises to overcome the problems and pitfalls assocd. with the different steps of the receptor modeling workflow will be presented. These examples will not only include rhodopsin-like (class A), but also secretine-like (class B), and glutamate-like (class C) receptors. In addn., the review will present a careful comparative anal. of current crystal structures and their implication on homol. modeling. The following themes will be discussed: (i) the use of exptl. anchors in guiding the modeling procedure; (ii) amino acid sequence alignments; (iii) ligand binding mode accommodation and binding cavity expansion; (iv) proline-induced kinks in transmembrane helixes; (v) binding mode prediction and virtual screening by receptor-ligand interaction fingerprint scoring; (vi) extracellular loop modeling; (vii) virtual filtering schemes. Finally, an overview of several successful structure-based screening shows that receptor models, despite structural inaccuracies, can be efficiently used to find novel ligands.
- 43Kooistra, A. J.; Roumen, L.; Leurs, R.; de Esch, I. J.; de Graaf, C. From Heptahelical Bundle to Hits from the Haystack: Structure-Based Virtual Screening for GPCR Ligands. Methods Enzymol. 2013, 522, 279– 336.Google ScholarThere is no corresponding record for this reference.
- 44Palczewski, K.; Kumasaka, T.; Hori, T.; Behnke, C. A.; Motoshima, H.; Fox, B. A.; Le Trong, I.; Teller, D. C.; Okada, T.; Stenkamp, R. E.; Yamamoto, M.; Miyano, M. Crystal Structure of Rhodopsin: A G Protein-Coupled Receptor Science 2000, 289, 739– 745Google Scholar44https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXlslOqs78%253D&md5=b3d229fc696247ec0f4a6efa10490922Crystal structure of rhodopsin: A G protein-coupled receptorPalczewski, Krzysztof; Kumasaka, Takashi; Hori, Tetsuya; Behnke, Craig A.; Motoshima, Hiroyuki; Fox, Brian A.; Le Trong, Isolde; Teller, David C.; Okada, Tetsuji; Stenkamp, Ronald E.; Yamamoto, Masaki; Miyano, MasashiScience (Washington, D. C.) (2000), 289 (5480), 739-745CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)Heterotrimeric guanine nucleotide-binding protein (G protein)-coupled receptors (GPCRs) respond to a variety of different external stimuli and activate G proteins. GPCRs share many structural features, including a bundle of seven transmembrane α-helixes connected by six loops of varying lengths. We detd. the structure of rhodopsin from diffraction data extending to 2.8 angstroms resoln. The highly organized structure in the extracellular region, including a conserved disulfide bridge, forms a basis for the arrangement of the seven-helix transmembrane motif. The ground-state chromophore, 11-cis-retinal, holds the transmembrane region of the protein in the inactive conformation. Interactions of the chromophore with a cluster of key residues det. the wavelength of the max. absorption. Changes in these interactions among rhodopsins facilitate color discrimination. Identification of a set of residues that mediate interactions between the transmembrane helixes and the cytoplasmic surface, where G-protein activation occurs, also suggests a possible structural change upon photoactivation.
- 45de Graaf, C.; Rein, C.; Piwnica, D.; Giordanetto, F.; Rognan, D. Structure-Based Discovery of Allosteric Modulators of Two Related Class B G-Protein-Coupled Receptors ChemMedChem 2011, 6, 2159– 2169Google ScholarThere is no corresponding record for this reference.
- 46Kellenberger, E.; Springael, J. Y.; Parmentier, M.; Hachet-Haas, M.; Galzi, J. L.; Rognan, D. Identification of Nonpeptide Ccr5 Receptor Agonists by Structure-Based Virtual Screening J. Med. Chem. 2007, 50, 1294– 1303Google Scholar46https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhvFKrur4%253D&md5=67ef5036ec130b7fb77980a76b79decbIdentification of Nonpeptide CCR5 Receptor Agonists by Structure-based Virtual ScreeningKellenberger, Esther; Springael, Jean-Yves; Parmentier, Marc; Hachet-Haas, Muriel; Galzi, Jean-Luc; Rognan, DidierJournal of Medicinal Chemistry (2007), 50 (6), 1294-1303CODEN: JMCMAR; ISSN:0022-2623. (American Chemical Society)A three-dimensional model of the chemokine receptor CCR5 has been built to fulfill structural peculiarities of its α-helix bundle and to distinguish known CCR5 antagonists from randomly chosen drug-like decoys. In silico screening of a library of 1.6 million com. available compds. against the CCR5 model by sequential filters (drug-likeness, 2-D pharmacophore, 3-D docking, scaffold clustering) yielded a hit list of 59 compds., out of which 10 exhibited a detectable binding affinity to the CCR5 receptor. Unexpectedly, most binders tested in a functional assay were shown to be agonists of the CCR5 receptor. A follow-up database query based on similarity to the most potent binders identified three new CCR5 agonists. Despite a moderate affinity of all nonpeptide ligands for the CCR5 receptor, one of the agonists was shown to promote efficient receptor internalization, which is a process therapeutically favorable for protection against HIV-1 infection.
- 47Kiss, R.; Kiss, B.; Konczol, A.; Szalai, F.; Jelinek, I.; Laszlo, V.; Noszal, B.; Falus, A.; Keseru, G. M. Discovery of Novel Human Histamine H4 Receptor Ligands by Large-Scale Structure-Based Virtual Screening J. Med. Chem. 2008, 51, 3145– 3153Google Scholar47https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXlslamsr0%253D&md5=adf561bdcae37e2e7898812c83e0e7b5Discovery of Novel Human Histamine H4 Receptor Ligands by Large-Scale Structure-Based Virtual ScreeningKiss, Robert; Kiss, Bela; Konczol, Arpad; Szalai, Ferenc; Jelinek, Ivett; Laszlo, Valeria; Noszal, Bela; Falus, Andras; Keseru, Gyorgy M.Journal of Medicinal Chemistry (2008), 51 (11), 3145-3153CODEN: JMCMAR; ISSN:0022-2623. (American Chemical Society)A structure-based virtual screening (SBVS) was conducted on a ligand-supported homol. model of the human histamine H4 receptor (hH4R). More than 8.7 million 3D structures derived from different vendor databases were investigated by docking to the hH4R binding site using FlexX. A total of 255 selected compds. were tested by radioligand binding assay and 16 of them possessed significant [3H]histamine displacement. Several novel scaffolds were identified that can be used to develop selective H4 ligands in the future. As far as we know, this is the first SBVS reported on H4R, representing one of the largest virtual screens validated by the biol. evaluation of the virtual hits.
- 48Salo, O. M.; Raitio, K. H.; Savinainen, J. R.; Nevalainen, T.; Lahtela-Kakkonen, M.; Laitinen, J. T.; Jarvinen, T.; Poso, A. Virtual Screening of Novel Cb2 Ligands Using a Comparative Model of the Human Cannabinoid Cb2 Receptor J. Med. Chem. 2005, 48, 7166– 7171Google Scholar48https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhtFWku7bM&md5=58c0fef5e385196c9e21da4c5bd3fe32Virtual Screening of Novel CB2 Ligands Using a Comparative Model of the Human Cannabinoid CB2 ReceptorSalo, Outi M. H.; Raitio, Katri H.; Savinainen, Juha R.; Nevalainen, Tapio; Lahtela-Kakkonen, Maija; Laitinen, Jarmo T.; Jaervinen, Tomi; Poso, AnttiJournal of Medicinal Chemistry (2005), 48 (23), 7166-7171CODEN: JMCMAR; ISSN:0022-2623. (American Chemical Society)To identify novel selective CB2 lead compds., a comparative model of the CB2 receptor was constructed using the high-resoln. bovine rhodopsin X-ray structure as a template. The CB2 model was utilized both in building the database queries and in filtering the hit compds. by a docking and scoring method. In G-protein activation assays, 1-isoquinolyl[3-(trifluoromethyl)phenyl]methanone (40, NRB 04079) was found to act as a selective agonist at the human CB2 receptor.
- 49Tikhonova, I. G.; Sum, C. S.; Neumann, S.; Engel, S.; Raaka, B. M.; Costanzi, S.; Gershengorn, M. C. Discovery of Novel Agonists and Antagonists of the Free Fatty Acid Receptor 1 (Ffar1) Using Virtual Screening J. Med. Chem. 2008, 51, 625– 633Google Scholar49https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXmtFylsg%253D%253D&md5=99001918ff4dab865830c39e659dabb3Discovery of novel agonists and antagonists of the free fatty acid receptor 1 (FFAR1) using virtual screeningTikhonova, Irina G.; Sum, Chi Shing; Neumann, Susanne; Engel, Stanislav; Raaka, Bruce M.; Costanzi, Stefano; Gershengorn, Marvin C.Journal of Medicinal Chemistry (2008), 51 (3), 625-633CODEN: JMCMAR; ISSN:0022-2623. (American Chemical Society)The G-protein-coupled receptor free fatty acid receptor 1 (FFAR1), previously named GPR40, is a possible novel target for the treatment of type 2 diabetes. In an attempt to identify new ligands for this receptor, we performed virtual screening (VS) based on 2-dimensional (2D) similarity, 3-dimensional (3D) pharmacophore searches, and docking studies by the structure of known agonists and our model of the ligand binding site, which was validated by mutagenesis. VS of a database of 2.6 million compds. followed by extn. of structural neighbors of functionally confirmed hits resulted in identification of 15 compds. active at FFAR1 either as full agonists, partial agonists, or pure antagonists. Site-directed mutagenesis and docking studies revealed different patterns of ligand-receptor interactions and provided important information on the role of specific amino acids in binding and activation of FFAR1.
- 50Varady, J.; Wu, X.; Fang, X.; Min, J.; Hu, Z.; Levant, B.; Wang, S. Molecular Modeling of the Three-Dimensional Structure of Dopamine 3 (D3) Subtype Receptor: Discovery of Novel and Potent D3 Ligands through a Hybrid Pharmacophore- and Structure-Based Database Searching Approach J. Med. Chem. 2003, 46, 4377– 4392Google Scholar50https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXmvVGhu7s%253D&md5=758611e234bf6b517e3e91a6dfd895b7Molecular Modeling of the Three-Dimensional Structure of Dopamine 3 (D3) Subtype Receptor: Discovery of Novel and Potent D3 Ligands through a Hybrid Pharmacophore- and Structure-Based Database Searching ApproachVarady, Judith; Wu, Xihan; Fang, Xueliang; Min, Ji; Hu, Zengjian; Levant, Beth; Wang, ShaomengJournal of Medicinal Chemistry (2003), 46 (21), 4377-4392CODEN: JMCMAR; ISSN:0022-2623. (American Chemical Society)The dopamine 3 (D3) subtype receptor has been implicated in several neurol. conditions, and potent and selective D3 ligands may have therapeutic potential for the treatment of drug addiction, Parkinson's disease, and schizophrenia. In this paper, we report computational homol. modeling of the D3 receptor based upon the high-resoln. x-ray structure of rhodopsin, extensive structural refinement in the presence of explicit lipid bilayer and water environment, and validation of the refined D3 structural models using exptl. data. We further describe the development, validation, and application of a hybrid computational screening approach for the discovery of several classes of novel and potent D3 ligands. This computational approach employs stepwise pharmacophore and structure-based searching of a large three-dimensional chem. database for the identification of potential D3 ligands. The obtained hits are then subjected to structural novelty screening, and the most promising compds. are tested in a D3 binding assay. Using this approach we identified four compds. with Ki values better than 100 nM and eight compds. with Ki values better than 1 μM out of 20 compds. selected for testing in the D3 receptor binding assay. Our results suggest that the D3 structural models obtained from this study may be useful for the discovery and design of novel and potent D3 ligands. Furthermore, the employed hybrid approach may be more effective for lead discovery from a large chem. database than either pharmacophore-based or structure-based database screening alone.
- 51Kooistra, A. J.; Leurs, R.; de Esch, I. J.; de Graaf, C. From Three-Dimensional GPCR Structure to Rational Ligand Discovery. Adv. Exp. Med. Biol. 2014, 796, 129– 157Google ScholarThere is no corresponding record for this reference.
- 52Weiss, D. R.; Ahn, S.; Sassano, M. F.; Kleist, A.; Zhu, X.; Strachan, R.; Roth, B. L.; Lefkowitz, R. J.; Shoichet, B. K. Conformation Guides Molecular Efficacy in Docking Screens of Activated Beta-2 Adrenergic G Protein Coupled Receptor ACS Chem. Biol. 2013, 8, 1018– 1026Google ScholarThere is no corresponding record for this reference.
- 53Moitessier, N.; Englebienne, P.; Lee, D.; Lawandi, J.; Corbeil, C. R. Towards the Development of Universal, Fast and Highly Accurate Docking/Scoring Methods: A Long Way to Go Br. J. Pharmacol. 2008, 153 (Suppl 1) S7– 26Google Scholar53https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXislSjt7w%253D&md5=4f6b8d64743100c0c58240c9874a1e65Towards the development of universal, fast and highly accurate docking/scoring methods: a long way to goMoitessier, N.; Englebienne, P.; Lee, D.; Lawandi, J.; Corbeil, C. R.British Journal of Pharmacology (2008), 153 (Suppl. 1), S7-S26CODEN: BJPCBM; ISSN:0007-1188. (Nature Publishing Group)A review. Accelerating the drug discovery process requires predictive computational protocols capable of reducing or simplifying the synthetic and/or combinatorial challenge. Docking-based virtual screening methods have been developed and successfully applied to a no. of pharmaceutical targets. In this review, we first present the current status of docking and scoring methods, with exhaustive lists of these. We next discuss reported comparative studies, outlining criteria for their interpretation. In the final section, we describe some of the remaining developments that would potentially lead to a universally applicable docking/scoring method. Published online 26 Nov. 2007.
- 54Sabio, M.; Jones, K.; Topiol, S. Use of the X-Ray Structure of the Beta2-Adrenergic Receptor for Drug Discovery. Part 2: Identification of Active Compounds Bioorg. Med. Chem. Lett. 2008, 18, 5391– 5395Google Scholar54https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXht1CqsrfP&md5=e91ea267e0851bc0e08b310b3f8966eeUse of the X-ray structure of the β2-adrenergic receptor for drug discovery. Part 2: Identification of active compoundsSabio, Michael; Jones, Kenneth; Topiol, SidBioorganic & Medicinal Chemistry Letters (2008), 18 (20), 5391-5395CODEN: BMCLE8; ISSN:0960-894X. (Elsevier Ltd.)The recently published X-ray structures of the β2-adrenergic receptor are the first examples of ligand-mediated GPCR crystal structures. We have previously performed computational studies that examine the potential viability of these structures for use in drug design, exploiting known ligand activities. Our previous study and a newly reported β2/Timolol X-ray complex provide validation of the computational approaches. In the present work, we use the X-ray structures to ext., via in silico high-throughput docking, compds. from proprietary and com. databases and demonstrate the successful identification of active compds. by radioligand binding.
- 55de Graaf, C.; Rognan, D. Selective Structure-Based Virtual Screening for Full and Partial Agonists of the Beta2 Adrenergic Receptor J. Med. Chem. 2008, 51, 4978– 4985Google Scholar55https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXptl2gtr8%253D&md5=e4c2d724a9356d1223b53334c6357327Selective Structure-Based Virtual Screening for Full and Partial Agonists of the β2 Adrenergic Receptorde Graaf, Chris; Rognan, DidierJournal of Medicinal Chemistry (2008), 51 (16), 4978-4985CODEN: JMCMAR; ISSN:0022-2623. (American Chemical Society)The recently solved high-resoln. X-ray structure of the β2 adrenergic receptor has been challenged for its ability to discriminate inverse agonists/antagonists from partial/full agonists. Whereas the X-ray structure of the ground state receptor was unsuitable to distinguish true ligands with different functional effects, modifying this structure to reflect early conformational events in receptor activation led to a receptor model able to selectively retrieve full and partial agonists by structure-based virtual screening. The use of a topol. scoring function based on mol. interaction fingerprints was shown to be mandatory to properly rank docking poses and achieve acceptable enrichments for partial and full agonists only.
- 56Katritch, V.; Reynolds, K. A.; Cherezov, V.; Hanson, M. A.; Roth, C. B.; Yeager, M.; Abagyan, R. Analysis of Full and Partial Agonists Binding to Beta2-Adrenergic Receptor Suggests a Role of Transmembrane Helix V in Agonist-Specific Conformational Changes J. Mol. Recognit. 2009, 22, 307– 318Google Scholar56https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXnslGis7k%253D&md5=01e2c841b200697382e551b3cf104451Analysis of full and partial agonists binding to β2-adrenergic receptor suggests a role of transmembrane helix V in agonist-specific conformational changesKatritch, Vsevolod; Reynolds, Kimberly A.; Cherezov, Vadim; Hanson, Michael A.; Roth, Christopher B.; Yeager, Mark; Abagyan, RubenJournal of Molecular Recognition (2009), 22 (4), 307-318CODEN: JMORE4; ISSN:0952-3499. (John Wiley & Sons Ltd.)The 2.4 Å crystal structure of the β2-adrenergic receptor (β2AR) in complex with the high-affinity inverse agonist (-)-carazolol provides a detailed structural framework for the anal. of ligand recognition by adrenergic receptors. Insights into agonist binding and the corresponding conformational changes triggering G-protein coupled receptor (GPCR) activation mechanism are of special interest. While the carazolol pocket captured in the β2AR crystal structure accommodates (-)-isoproterenol and other agonists without steric clashes, a finite movement of the flexible extracellular part of TM-V helix (TM-Ve) obtained by receptor optimization in the presence of docked ligand can further improve the calcd. binding affinities for agonist compds. Tilting of TM-Ve towards the receptor axis provides a more complete description of polar receptor-ligand interactions for full and partial agonists, by enabling optimal engagement of agonists with two exptl. identified anchor sites, formed by Asp 113/Asn 312 and Ser 203/Ser 204/Ser 207 side chains. Further, receptor models incorporating a flexible TM-V backbone allow reliable prediction of binding affinities for a set of diverse ligands, suggesting potential utility of this approach to design of effective and subtype-specific agonists for adrenergic receptors. Systematic differences in capacity of partial, full and inverse agonists to induce TM-V helix tilt in the β2AR model suggest potential role of TM-V as a conformational "rheostat" involved in the whole spectrum of β2AR responses to small mol. signals.
- 57Reynolds, K. A.; Katritch, V.; Abagyan, R. Identifying Conformational Changes of the Beta(2) Adrenoceptor That Enable Accurate Prediction of Ligand/Receptor Interactions and Screening for Gpcr Modulators J. Comput. Aided Mol. Des. 2009, 23, 273– 288Google Scholar57https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXkt1yitLw%253D&md5=48e809569368d89fb9ba2c36bddc3f3bIdentifying conformational changes of the β2 adrenoceptor that enable accurate prediction of ligand/receptor interactions and screening for GPCR modulatorsReynolds, Kimberly A.; Katritch, Vsevolod; Abagyan, RubenJournal of Computer-Aided Molecular Design (2009), 23 (5), 273-288CODEN: JCADEQ; ISSN:0920-654X. (Springer)The new β2 Adrenoceptor (β2AR) crystal structures provide a high-resoln. snapshot of receptor interactions with two particular partial inverse agonists, (-)-carazolol and timolol. However, both exptl. and computational studies of GPCR structure are significantly complicated by the existence of multiple conformational states coupled to ligand type and receptor activity. Agonists and antagonists induce or stabilize distinct changes in receptor structure that mediate a range of pharmacol. activities. In this work, the authors (1) established that the existing β2AR crystallog. conformers can be extended to describe ligand/receptor interactions for addnl. antagonist types, (2) generated agonist-bound receptor conformations, and (3) validated these models for agonist and antagonist virtual ligand screening (VLS). Using a ligand directed refinement protocol, the authors derived a single agonist-bound receptor conformation that selectively retrieved a diverse set of full and partial β2AR agonists in VLS trials. Addnl., the impact of extracellular loop two conformation on VLS was assessed by docking studies with rhodopsin-based β2AR homol. models, and loop-deleted receptor models. A general strategy for constructing and selecting agonist-bound receptor pocket conformations is presented, which may prove broadly useful in creating agonist and antagonist bound models for other GPCRs.
- 58Vilar, S.; Karpiak, J.; Berk, B.; Costanzi, S. In Silico Analysis of the Binding of Agonists and Blockers to the Beta2-Adrenergic Receptor J. Mol. Graph. Model. 2011, 29, 809– 817Google Scholar58https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXjvFSlsLY%253D&md5=7401c0929f01c3cf9bf41962f2bdaa7dIn silico analysis of the binding of agonists and blockers to the β2-adrenergic receptorVilar, Santiago; Karpiak, Joel; Berk, Barkin; Costanzi, StefanoJournal of Molecular Graphics & Modelling (2011), 29 (6), 809-817CODEN: JMGMFI; ISSN:1093-3263. (Elsevier Ltd.)Activation of G protein-coupled receptors (GPCRs) is a complex phenomenon. Here, we applied Induced Fit Docking (IFD) in tandem with linear discriminant anal. (LDA) to generate hypotheses on the conformational changes induced to the β2-adrenergic receptor by agonist binding, preliminary to the sequence of events that characterize activation of the receptor. This anal., corroborated by a follow-up mol. dynamics study, suggested that agonists induce subtle movements to the fifth transmembrane domain (TM5) of the receptor. Furthermore, mol. dynamics also highlighted a correlation between movements of TM5 and the second extracellular loop (EL2), suggesting that freedom of motion of EL2 is required for the agonist-induced TM5 displacement. Importantly, we also showed that the IFD/LDA procedure can be used as a computational means to distinguish agonists from blockers on the basis of the differential conformational changes induced to the receptor. In particular, the two most predictive models obtained are based on the RMSD induced to Ser207 and on the counterclockwise rotation induced to TM5.
- 59Kooistra, A. J.; Kuhne, S.; de Esch, I. J.; Leurs, R.; de Graaf, C. A Structural Chemogenomics Analysis of Aminergic Gpcrs: Lessons for Histamine Receptor Ligand Design Br. J. Pharmacol. 2013, 170, 101– 126Google Scholar59https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtlSgtbnE&md5=08ae55b9565885165e76d98e2db1befaA structural chemogenomics analysis of aminergic GPCRs: lessons for histamine receptor ligand designKooistra, A. J.; Kuhne, S.; de Esch, I. J. P.; Leurs, R.; de Graaf, C.British Journal of Pharmacology (2013), 170 (1), 101-126CODEN: BJPCBM; ISSN:1476-5381. (Wiley-Blackwell)Background and Purpose Chemogenomics focuses on the discovery of new connections between chem. and biol. space leading to the discovery of new protein targets and biol. active mols. G-protein coupled receptors (GPCRs) are a particularly interesting protein family for chemogenomics studies because there is an overwhelming amt. of ligand binding affinity data available. The increasing no. of aminergic GPCR crystal structures now for the first time allows the integration of chemogenomics studies with high-resoln. structural analyses of GPCR-ligand complexes. Exptl. Approach In this study, we have combined ligand affinity data, receptor mutagenesis studies, and amino acid sequence analyses to high-resoln. structural analyses of (hist)aminergic GPCR-ligand interactions. This integrated structural chemogenomics anal. is used to more accurately describe the mol. and structural determinants of ligand affinity and selectivity in different key binding regions of the crystd. aminergic GPCRs, and histamine receptors in particular. Key Results Our investigations highlight interesting correlations and differences between ligand similarity and ligand binding site similarity of different aminergic receptors. Apparent discrepancies can be explained by combining detailed anal. of crystd. or predicted protein-ligand binding modes, receptor mutation studies, and ligand structure-selectivity relationships that identify local differences in essential pharmacophore features in the ligand binding sites of different receptors. Conclusions and Implications We have performed structural chemogenomics studies that identify links between (hist)aminergic receptor ligands and their binding sites and binding modes. This knowledge can be used to identify structure-selectivity relationships that increase our understanding of ligand binding to (hist)aminergic receptors and hence can be used in future GPCR ligand discovery and design.
- 60Strader, C. D.; Candelore, M. R.; Hill, W. S.; Sigal, I. S.; Dixon, R. A. Identification of Two Serine Residues Involved in Agonist Activation of the Beta-Adrenergic Receptor J. Biol. Chem. 1989, 264, 13572– 13578Google Scholar60https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL1MXlsVOht78%253D&md5=0e8e69f212b17a3c54a024d7497d79a7Identification of two serine residues involved in agonist activation of the β-adrenergic receptorStrader, Catherine D.; Candelore, Mari Rios; Hill, Wendy S.; Sigal, Irving S.; Dixon, Richard A. F.Journal of Biological Chemistry (1989), 264 (23), 13572-8CODEN: JBCHA3; ISSN:0021-9258.Pharmacophore mapping of the ligand-binding domain of the β-adrenergic receptor has revealed specific mol. interactions which are important for agonist and antagonist binding to the receptor. Previous site-directed mutagenesis expts. have demonstrated that the binding of amine agonists and antagonists to the receptor involves an interaction between the amine group of the ligand and the carboxylate side chain of Asp113 in the 3rd hydrophobic domain of the receptor. Two serine residues, at positions 204 and 207 in the 5th hydrophobic domain of the β-adrenergic receptor, which are crit. for agonist binding and activation of the receptor have now been identified. These serine residues are conserved with G-protein-coupled receptors which bind catecholamine agonists, but not with receptors whose endogenous ligands do not have the catechol moiety. Removal of the OH side chain from either Ser204 or Ser207 by substitution of the serine residue with an alanine attenuates the activity of catecholamine agonists at the receptor. The effects of these mutations on agonist activity are mimicked selectively by the removal of the catechol OH moieties from the arom. ring of the agonist. The data suggest that the interaction of catecholamine agonists with the β-adrenergic receptor involves 2 H bonds, one between the OH side chain of Ser204 and the meta-OH group of the ligand and a second between the OH side chain of Ser207 and the para-OH group of the ligand.
- 61Kikkawa, H.; Kurose, H.; Isogaya, M.; Sato, Y.; Nagao, T. Differential Contribution of Two Serine Residues of Wild Type and Constitutively Active Beta2-Adrenoceptors to the Interaction with Beta2-Selective Agonists Br. J. Pharmacol. 1997, 121, 1059– 1064Google Scholar61https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXkvFeqsrY%253D&md5=c52765a64a652721b71b6f00bc315318Differential contribution of two serine residues of wild type and constitutively active β2-adrenoceptors to the interaction with β2-selective agonistsKikkawa, Hideo; Kurose, Hitoshi; Isogaya, Masafumi; Sato, Yoji; Nagao, TakuBritish Journal of Pharmacology (1997), 121 (6), 1059-1064CODEN: BJPCBM; ISSN:0007-1188. (Stockton)The authors have studied the difference in receptor binding activity between partial and full β2-adrenoceptor agonists and the abilities of the agonists to interact with Ser204 and Ser207 in the fifth transmembrane region of the β2-adrenoceptor, amino acid residues that are important for activation of the β2-adrenoceptor. In the binding study with [125I]-iodocyanopindolol, the Ki values of (±)-salbutamol, (±)-salmeterol, TA-2005 and (-)-isoprenaline for the β2-adrenoceptor expressed in COS-7 cell membranes were 3340, 21.0, 12.0 and 904 nM, resp. The β1/β2 selectively of these agonists was in the order of (±)-salmeterol (332-fold) > A-2005 (52.8) > (±)-salbutamol (6.8) > (-)-isoprenaline (1.1), and the β3-/β2-adrenoceptor selectivity of these agonists was in the order of TA-2005 (150-fold) > (±)-salmeterol (88.6) > (±)-salbutamol (10.4) > (-)-isoprenaline (3.2). The maximal activation of adenylyl cyclase by stimulation of the β1-, β2- and β3-adrenoceptors by TA-2005 was 32, 100 and 100% of that by (-)-isoprenaline, resp., indicating that TA-2005 is a full agonist at the β2- and β3-adrenoceptors and a partial agonist at the β1-adrenoceptor. (±)-Salbutamol and (±)-salmeterol were partial agonists at both β1- (8%) and 9% of (-)-isoprenaline and β2- (83% and 74% of (-)-isoprenaline) adrenoceptors. The affinities of full agonists, TA-2005 and (-)-isoprenaline, were markedly decreased by substitution of Ala for Ser204 (S204A) of the β2-adrenoceptor, whereas this substitution slightly reduced the affinities of partial agonists, (±)-salbutamol and (±)-salmeterol. Although the affinities of full agonists for the S207A-β2-adrenoceptor were decrease, those of partial agonists for the S207A-β2-adrenoceptor were essentially the same as for the wild type receptor. The constitutively active mutant (L266S, L272A) of the β2-adrenoceptor had an increased affinity for all four agonists. The affinities of full agonists were decreased by substitution of Ser204 of the constitutively active mutant, whereas the degree of decrease was smaller than that caused by the substitution of the wild type receptor. Although the affinities of (±)-salbutamol and (±)-salmeterol for the S207A-β2-adrenoceptor were essentially the same as those for the wild type β2-adrenoceptor, the affinities of (±)-salbutamol and (±)-salmeterol for the constitutively active β2-adrenoceptor were decreased by substitution of Ser207. These results suggest that Ser204 and Ser207 of the wild type and constitutively active β2-adrenoceptors differentially interacted with β2-selective agonists.
- 62Liapakis, G.; Ballesteros, J. A.; Papachristou, S.; Chan, W. C.; Chen, X.; Javitch, J. A. The Forgotten Serine. A Critical Role for Ser-2035.42 in Ligand Binding to and Activation of the Beta 2-Adrenergic Receptor J. Biol. Chem. 2000, 275, 37779– 37788Google Scholar62https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXoslWgtLY%253D&md5=5a7eb8b4b3706808b9679e36ad5a59cbThe forgotten serine. A critical role for Ser-2035.42 in ligand binding to and activation of the β2-adrenergic receptorLiapakis, George; Ballesteros, Juan A.; Papachristou, Stavros; Chan, Wai Chi; Chen, Xun; Javitch, Jonathan A.Journal of Biological Chemistry (2000), 275 (48), 37779-37788CODEN: JBCHA3; ISSN:0021-9258. (American Society for Biochemistry and Molecular Biology)Previous work in the β2-adrenergic receptor demonstrated crit. interactions between Ser-204 and Ser-207 in the fifth membrane-spanning segment and the meta-OH and para-OH, resp., of catecholamine agonists. Using the substituted cysteine accessibility method in the β2-adrenergic receptor, we have found that in addn. to Ser-204 and Ser-207, Ser-203 is also accessible on the surface of the binding-site crevice and is occluded by bound agonist. Mutation of Ser-203 to Ala, Val, or Cys reduced the binding affinity and adenylyl cyclase-activating potency of agonists contg. a meta-OH, whereas their affinities and potencies were largely preserved by mutation of Ser-203 to Thr, which maintained an OH at this position. Thus both Ser-203 and Ser-204 appear to interact with the meta-OH of catecholamines, perhaps through a bifurcated H bond. Furthermore, the removal of the OH at position 203 led to a significant loss of affinity of antagonists with nitrogen in their heterocyclic ring structure. The greatest effect was seen with pindolol, a partial agonist, suggesting that a H bond between the heterocyclic ring and Ser-203 may play a role in partial agonism. In contrast, the affinities of antagonists such as propranolol or alprenolol, which have cyclic structures without H-bonding capability, were unaltered after mutation of Ser-203.
- 63Sato, T.; Kobayashi, H.; Nagao, T.; Kurose, H. Ser203 as Well as Ser204 and Ser207 in Fifth Transmembrane Domain of the Human Beta2-Adrenoceptor Contributes to Agonist Binding and Receptor Activation Br. J. Pharmacol. 1999, 128, 272– 274Google Scholar63https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXmsFWhu7k%253D&md5=7acd5d9079efc31a5a197705965777acSer203 as well as Ser204 and Ser207 in fifth transmembrane domain of the human β2-adrenoceptor contributes to agonist binding and receptor activationSato, Takayuki; Kobayashi, Hiroyuki; Nagao, Taku; Kurose, HitoshiBritish Journal of Pharmacology (1999), 128 (2), 272-274CODEN: BJPCBM; ISSN:0007-1188. (Stockton Press)We examd. the contribution of Ser203 of the human β2-adrenoceptor (β2-AR) to the interaction with isoprenaline. The affinity of (-)-isoprenaline was reduced by substitution of an alanine for Ser203, as well as for Ser204 and Ser207. An (-)-isoprenaline deriv. with only one hydroxyl group, at the meta-position, showed reduced affinity for wild-type β2-AR and S207A-β2-AR and even lower affinities for S203A-β2-AR and S204A-β2-AR. By contrast, an (-)-isoprenaline deriv. with only a para-hydroxyl group showed reduced affinity for wild-type β2-AR but the serine to alanine mutations did not cause further decreases. The EC50 value for cAMP generation in response to (-)-isoprenaline was increased, by about 120 fold, for each alanine-substituted β2-AR mutant. These results suggest that Ser203 of the human β2-AR is important for both ligand binding and receptor activation.
- 64Ambrosio, C.; Molinari, P.; Cotecchia, S.; Costa, T. Catechol-Binding Serines of Beta(2)-Adrenergic Receptors Control the Equilibrium between Active and Inactive Receptor States Mol. Pharmacol. 2000, 57, 198– 210Google Scholar64https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXhslCrsg%253D%253D&md5=0b24e04150e47c0c1fcc468a363435a2Catechol-binding serines of β2-adrenergic receptors control the equilibrium between active and inactive receptor statesAmbrosio, Caterina; Molinari, Paola; Cotecchia, Susanna; Costa, TommasoMolecular Pharmacology (2000), 57 (1), 198-210CODEN: MOPMA3; ISSN:0026-895X. (American Society for Pharmacology and Experimental Therapeutics)The binding free energy for the interaction between serines 204 and 207 of the fifth transmembrane helix of the β2-adrenergic receptor (β2-AR) and catecholic hydroxyl (OH) groups of adrenergic agonists was analyzed using double mutant cycles. Binding affinities for catecholic and noncatecholic agonists were measured in wild-type and mutant receptors, carrying alanine replacement of the two serines (S204A, S207A β2-AR), a constitutive activating mutation, or both. The free energy coupling between the losses of binding energy attributable to OH deletion from the ligand and from the receptor indicates a strong interaction (nonadditivity) as expected for a direct binding between the two sets of groups. However, the authors also measured a significant interaction between the deletion of OH groups from the receptor and the constitutive activating mutation. This suggests that a fraction of the decrease in agonist affinity caused by serine mutagenesis may involve a shift in the conformational equil. of the receptor toward the inactive state. Direct measurements using a transient transfection assay confirm this prediction. The constitutive activity of the (S204A, S207A) β2-AR mutant is 50 to 60% lower than that of the wild-type β2-AR. The authors conclude that S204 and S207 do not only provide a docking site for the agonist, but also control the equil. of the receptor between active (R*) and inactive (R) forms.
- 65Marcou, G.; Rognan, D. Optimizing Fragment and Scaffold Docking by Use of Molecular Interaction Fingerprints J. Chem. Inf. Model. 2007, 47, 195– 207Google Scholar65https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28Xht12iurzL&md5=0c9137a39d40fbcc83546aec17b595baOptimizing Fragment and Scaffold Docking by Use of Molecular Interaction FingerprintsMarcou, Gilles; Rognan, DidierJournal of Chemical Information and Modeling (2007), 47 (1), 195-207CODEN: JCISD8; ISSN:1549-9596. (American Chemical Society)Protein-ligand interaction fingerprints have been used to postprocess docking poses of three ligand data sets: a set of 40 low-mol.-wt. compds. from the Protein Data Bank, a collection of 40 scaffolds from pharmaceutically relevant protein ligands, and a database of 19 scaffolds extd. from true cdk2 inhibitors seeded in 2230 scaffold decoys. Four popular docking tools (FlexX, Glide, Gold, and Surflex) were used to generate poses for ligands of the three data sets. In all cases, scoring by the similarity of interaction fingerprints to a given ref. was statistically superior to conventional scoring functions in posing low-mol.-wt. fragments, predicting protein-bound scaffold coordinates according to the known binding mode of related ligands, and screening a scaffold library to enrich a hit list in true cdk2-targeted scaffolds.
- 66Verlinde, C. L.; Hol, W. G. Structure-Based Drug Design: Progress, Results and Challenges Structure 1994, 2, 577– 587Google Scholar66https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2cXmt1SrtLs%253D&md5=024f2fe4d5d0c1d6e74880c889988e9aStructure-based drug design: progress, results and challengesVerlinde, Christophe L. M. J.; Hol, Wim G. J.Structure (Cambridge, MA, United States) (1994), 2 (7), 577-87CODEN: STRUE6; ISSN:0969-2126.A review with 85 refs. Protein structure-based drug design is rapidly gaining momentum. The new opportunities, developments and results in this field are almost unbelievable compared with the situation less than a decade ago.
- 67Jones, G.; Willett, P.; Glen, R. C.; Leach, A. R.; Taylor, R. Development and Validation of a Genetic Algorithm for Flexible Docking J. Mol. Biol. 1997, 267, 727– 748Google Scholar67https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXis1KntLo%253D&md5=476a2b1d8f80f3ba418052fe29d735caDevelopment and validation of a genetic algorithm for flexible dockingJones, Gareth; Willett, Peter; Glen, Robert C.; Leach, Andrew R.; Taylor, RobinJournal of Molecular Biology (1997), 267 (3), 727-748CODEN: JMOBAK; ISSN:0022-2836. (Academic)Prediction of small mol. binding modes to macromols. of known three-dimensional structure is a problem of paramount importance in rational drug design (the "docking" problem). We report the development and validation of the program GOLD (Genetic Optimization for Ligand Docking). GOLD is an automated ligand docking program that uses a genetic algorithm to explore the full range of ligand conformational flexibility with partial flexibility of the protein and satisfies the fundamental requirement that the ligand must displace loosely bound water on binding. Numerous enhancements and modifications have been applied to the original technique resulting in a substantial increase in the reliability and the applicability of the algorithm. The advanced algorithm has been tested on a dataset of 100 complexes extd. from the Brookhaven Protein Data Bank. When used to dock the ligand back into the binding site, GOLD achieved a 71% success rate in identifying the exptl. binding mode.
- 68Evers, A.; Klebe, G. Successful Virtual Screening for a Submicromolar Antagonist of the Neurokinin-1 Receptor Based on a Ligand-Supported Homology Model J. Med. Chem. 2004, 47, 5381– 5392Google Scholar68https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXnvFSrsLo%253D&md5=5bcb463baad85c2eff133c5fd4d7d53bSuccessful virtual screening for a submicromolar antagonist of the neurokinin-1 receptor based on a ligand-supported homology modelEvers, Andreas; Klebe, GerhardJournal of Medicinal Chemistry (2004), 47 (22), 5381-5392CODEN: JMCMAR; ISSN:0022-2623. (American Chemical Society)The neurokinin-1 (NK1) receptor belongs to the family of G-protein-coupled receptors (GPCRs), which represents one of the most relevant target families in small-mol. drug design. In this paper, we describe a homol. modeling of the NK1 receptor based on the high-resoln. X-ray structure of rhodopsin and the successful virtual screening based on this protein model. The NK1 receptor model has been generated using our new MOBILE (modeling binding sites including ligand information explicitly) approach. Starting with preliminary homol. models, it generates improved models of the protein binding pocket together with bound ligands. Ligand information is used as an integral part in the homol. modeling process. For the construction of the NK1 receptor, antagonist CP-96345 was used to restrain the modeling. The quality of the obtained model was validated by probing its ability to accommodate addnl. known NK1 antagonists from structurally diverse classes. On the basis of the generated model and on the anal. of known NK1 antagonists, a pharmacophore model was deduced, which subsequently guided the 2D and 3D database search with UNITY. As a following step, the remaining hits were docked into the modeled binding pocket of the NK1 receptor. Finally, seven compds. were selected for biochem. testing, from which one showed affinity in the submicromolar range. Our results suggest that ligand-supported homol. models of GPCRs may be used as effective platforms for structure-based drug design.
- 69Barril, X.; Morley, S. D. Unveiling the Full Potential of Flexible Receptor Docking Using Multiple Crystallographic Structures J. Med. Chem. 2005, 48, 4432– 4443Google Scholar69https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXktlKisbk%253D&md5=9a5b15df10784020470cd2972d737995Unveiling the Full Potential of Flexible Receptor Docking Using Multiple Crystallographic StructuresBarril, Xavier; Morley, S. DavidJournal of Medicinal Chemistry (2005), 48 (13), 4432-4443CODEN: JMCMAR; ISSN:0022-2623. (American Chemical Society)One of the current challenges in docking studies is the inclusion of receptor flexibility. This is crucial because the binding sites of many therapeutic targets sample a wide range of conformational states, which has major consequences on mol. recognition. In this paper, we make use of very large sets of x-ray structures of cyclin dependent kinase 2 (CDK2) and heat shock protein 90 (HSP90) to assess the performance of flexible receptor docking in binding-mode prediction and virtual screening expts. Flexible receptor docking performs much better than rigid receptor docking in the former application. Regarding the latter, we observe a significant improvement in the prediction of binding affinities, but owing to an increase in the no. of false positives, this is not translated into better hit rates. A simple scoring scheme to correct this limitation is presented. More importantly, pitfalls inherent to flexible receptor docking have been identified and guidelines are presented to avoid them.
- 70Bissantz, C.; Bernard, P.; Hibert, M.; Rognan, D. Protein-Based Virtual Screening of Chemical Databases. Ii. Are Homology Models of G-Protein Coupled Receptors Suitable Targets? Proteins 2003, 50, 5– 25Google ScholarThere is no corresponding record for this reference.
- 71Katritch, V.; Rueda, M.; Abagyan, R. Ligand-Guided Receptor Optimization Methods Mol. Biol. 2012, 857, 189– 205Google Scholar71https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC383itFWmtQ%253D%253D&md5=8401e92ffbc4b6df8acd7f635388e56fLigand-guided receptor optimizationKatritch Vsevolod; Rueda Manuel; Abagyan RubenMethods in molecular biology (Clifton, N.J.) (2012), 857 (), 189-205 ISSN:.Receptor models generated by homology or even obtained by crystallography often have their binding pockets suboptimal for ligand docking and virtual screening applications due to insufficient accuracy or induced fit bias. Knowledge of previously discovered receptor ligands provides key information that can be used for improving docking and screening performance of the receptor. Here, we present a comprehensive ligand-guided receptor optimization (LiBERO) algorithm that exploits ligand information for selecting the best performing protein models from an ensemble. The energetically feasible protein conformers are generated through normal mode analysis and Monte Carlo conformational sampling. The algorithm allows iteration of the conformer generation and selection steps until convergence of a specially developed fitness function which quantifies the conformer's ability to select known ligands from decoys in a small-scale virtual screening test. Because of the requirement for a large number of computationally intensive docking calculations, the automated algorithm has been implemented to use Linux clusters allowing easy parallel scaling. Here, we will discuss the setup of LiBERO calculations, selection of parameters, and a range of possible uses of the algorithm which has already proven itself in several practical applications to binding pocket optimization and prospective virtual ligand screening.
- 72Tehan, B. G.; Bortolato, A.; Blaney, F. E.; Weir, M. P.; Mason, J. S. Unifying Family a Gpcr Theories of Activation Pharmacol. Ther. 2014, 143, 51– 60Google Scholar72https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXjsVKkuro%253D&md5=ed0d1494a2030427df48d1dee6f31a33Unifying Family A GPCR Theories of ActivationTehan, Benjamin G.; Bortolato, Andrea; Blaney, Frank E.; Weir, Malcolm P.; Mason, Jonathan S.Pharmacology & Therapeutics (2014), 143 (1), 51-60CODEN: PHTHDT; ISSN:0163-7258. (Elsevier)A review. Several new pairs of active and inactive GPCR structures have recently been solved enabling detailed structural insight into the activation process, not only of rhodopsin but now also of the β2 adrenergic, M2 muscarinic and adenosine A2A receptors. Combined with structural analyses they have enabled us to examine the different recent theories proposed for GPCR activation and show that they are all indeed parts of the same process, and are intrinsically related through their effect on the central hydrophobic core of GPCRs. This new unifying general process of activation is consistent with the identification of known constitutively active mutants and an in-depth conservational anal. of significant residues implicated in the process.
- 73Meng, X. Y.; Zhang, H. X.; Mezei, M.; Cui, M. Molecular Docking: A Powerful Approach for Structure-Based Drug Discovery Curr. Comput. Aided Drug Des. 2011, 7, 146– 157Google Scholar73https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXnsFyrsLY%253D&md5=b1712e0c9091fae4c71c280b296b61f4Molecular docking: A powerful approach for structure-based drug discoveryMeng, Xuan-Yu; Zhang, Hong-Xing; Mezei, Mihaly; Cui, MengCurrent Computer-Aided Drug Design (2011), 7 (2), 146-157CODEN: CCDDAS; ISSN:1573-4099. (Bentham Science Publishers Ltd.)A review. Mol. docking has become an increasingly important tool for drug discovery. In this review, we present a brief introduction of the available mol. docking methods, and their development and applications in drug discovery. The relevant basic theories, including sampling algorithms and scoring functions, are summarized. The differences in and performance of available docking software are also discussed. Flexible receptor mol. docking approaches, esp. those including backbone flexibility in receptors, are a challenge for available docking methods. A recently developed Local Move Monte Carlo (LMMC) based approach is introduced as a potential soln. to flexible receptor docking problems. Three application examples of mol. docking approaches for drug discovery are provided.
- 74Rognan, D.; Desaphy, J. Molecular Interaction Fingerprints. Scaffold Hopping in Medicinal Chemistry; Wiley-VCH Verlag GmbH & Co. KGaA: Weinheim, 2013; pp 215– 230.Google ScholarThere is no corresponding record for this reference.
- 75Ring, A. M.; Manglik, A.; Kruse, A. C.; Enos, M. D.; Weis, W. I.; Garcia, K. C.; Kobilka, B. K. Adrenaline-Activated Structure of Beta2-Adrenoceptor Stabilized by an Engineered Nanobody Nature 2013, 502, 575– 579Google ScholarThere is no corresponding record for this reference.
- 76Andrews, S. P.; Brown, G. A.; Christopher, J. A. Structure-Based and Fragment-Based Gpcr Drug Discovery ChemMedChem 2014, 9, 256– 275Google ScholarThere is no corresponding record for this reference.
- 77Miller-Gallacher, J. L.; Nehme, R.; Warne, T.; Edwards, P. C.; Schertler, G. F.; Leslie, A. G.; Tate, C. G. The 2.1 a Resolution Structure of Cyanopindolol-Bound Beta1-Adrenoceptor Identifies an Intramembrane Na+ Ion That Stabilises the Ligand-Free Receptor PLoS One 2014, 9e92727Google ScholarThere is no corresponding record for this reference.
- 78Casella, I.; Ambrosio, C.; Gro, M. C.; Molinari, P.; Costa, T. Divergent Agonist Selectivity in Activating Beta1- and Beta2-Adrenoceptors for G-Protein and Arrestin Coupling Biochem. J. 2011, 438, 191– 202Google ScholarThere is no corresponding record for this reference.
- 79Drake, M. T.; Violin, J. D.; Whalen, E. J.; Wisler, J. W.; Shenoy, S. K.; Lefkowitz, R. J. Beta-Arrestin-Biased Agonism at the Beta2-Adrenergic Receptor J. Biol. Chem. 2008, 283, 5669– 5676Google ScholarThere is no corresponding record for this reference.
- 80Kahsai, A. W.; Xiao, K.; Rajagopal, S.; Ahn, S.; Shukla, A. K.; Sun, J.; Oas, T. G.; Lefkowitz, R. J. Multiple Ligand-Specific Conformations of the Beta2-Adrenergic Receptor Nat. Chem. Biol. 2011, 7, 692– 700Google Scholar80https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtVGksrjF&md5=166f9b98dc5dd8625ec831cf3176ca61Multiple ligand-specific conformations of the β2-adrenergic receptorKahsai, Alem W.; Xiao, Kunhong; Rajagopal, Sudarshan; Ahn, Seungkirl; Shukla, Arun K.; Sun, Jinpeng; Oas, Terrence G.; Lefkowitz, Robert J.Nature Chemical Biology (2011), 7 (10), 692-700CODEN: NCBABT; ISSN:1552-4450. (Nature Publishing Group)Seven-transmembrane receptors (7TMRs), also called G protein-coupled receptors (GPCRs), represent the largest class of drug targets, and they can signal through several distinct mechanisms including those mediated by G proteins and the multifunctional adaptor proteins β-arrestins. Moreover, several receptor ligands with differential efficacies toward these distinct signaling pathways have been identified. However, the structural basis and mechanism underlying this 'biased agonism' remains largely unknown. Here, we develop a quant. mass spectrometry strategy that measures specific reactivities of individual side chains to investigate dynamic conformational changes in the β2-adrenergic receptor occupied by nine functionally distinct ligands. Unexpectedly, only a minority of residues showed reactivity patterns consistent with classical agonism, whereas the majority showed distinct patterns of reactivity even between functionally similar ligands. These findings demonstrate, contrary to two-state models for receptor activity, that there is significant variability in receptor conformations induced by different ligands, which has significant implications for the design of new therapeutic agents.
- 81Kaya, A. I.; Onaran, H. O.; Ozcan, G.; Ambrosio, C.; Costa, T.; Balli, S.; Ugur, O. Cell Contact-Dependent Functional Selectivity of Beta2-Adrenergic Receptor Ligands in Stimulating Camp Accumulation and Extracellular Signal-Regulated Kinase Phosphorylation J. Biol. Chem. 2012, 287, 6362– 6374Google ScholarThere is no corresponding record for this reference.
- 82Kim, I. M.; Tilley, D. G.; Chen, J.; Salazar, N. C.; Whalen, E. J.; Violin, J. D.; Rockman, H. A. Beta-Blockers Alprenolol and Carvedilol Stimulate Beta-Arrestin-Mediated Egfr Transactivation Proc. Natl. Acad. Sci. U.S.A. 2008, 105, 14555– 14560Google ScholarThere is no corresponding record for this reference.
- 83Liu, J. J.; Horst, R.; Katritch, V.; Stevens, R. C.; Wuthrich, K. Biased Signaling Pathways in Beta2-Adrenergic Receptor Characterized by 19f-Nmr Science 2012, 335, 1106– 1110Google ScholarThere is no corresponding record for this reference.
- 84Rajagopal, S.; Ahn, S.; Rominger, D. H.; Gowen-MacDonald, W.; Lam, C. M.; Dewire, S. M.; Violin, J. D.; Lefkowitz, R. J. Quantifying Ligand Bias at Seven-Transmembrane Receptors Mol. Pharmacol. 2011, 80, 367– 377Google Scholar84https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhs1ektb7J&md5=3af41d68a6e41d477610338f8e7041f0Quantifying ligand bias at seven-transmembrane receptorsRajagopal, Sudarshan; Ahn, Seungkirl; Rominger, David H.; Gowen-MacDonald, William; Lam, Christopher M.; DeWire, Scott M.; Violin, Jonathan D.; Lefkowitz, Robert J.Molecular Pharmacology (2011), 80 (3), 367-377CODEN: MOPMA3; ISSN:0026-895X. (American Society for Pharmacology and Experimental Therapeutics)Seven transmembrane receptors (7TMRs), commonly referred to as G protein-coupled receptors, form a large part of the "druggable" genome. 7TMRs can signal through parallel pathways simultaneously, such as through heterotrimeric G proteins from different families, or, as more recently appreciated, through the multifunctional adapters, β-arrestins. Biased agonists, which signal with different efficacies to a receptor's multiple downstream pathways, are useful tools for deconvoluting this signaling complexity. These compds. may also be of therapeutic use because they have distinct functional and therapeutic profiles from "balanced agonists.". Although some methods have been proposed to identify biased ligands, no comparison of these methods applied to the same set of data has been performed. Therefore, at this time, there are no generally accepted methods to quantify the relative bias of different ligands, making studies of biased signaling difficult. Here, we use complementary computational approaches for the quantification of ligand bias and demonstrate their application to two well known drug targets, the β2 adrenergic and angiotensin II type 1A receptors. The strategy outlined here allows a quantification of ligand bias and the identification of weakly biased compds. This general method should aid in deciphering complex signaling pathways and may be useful for the development of novel biased therapeutic ligands as drugs.
- 85Baker, J. G. The Selectivity of Beta-Adrenoceptor Agonists at Human Beta1-, Beta2- and Beta3-Adrenoceptors Br. J. Pharmacol. 2010, 160, 1048– 1061Google Scholar85The selectivity of β-adrenoceptor agonists at human β1-, β2- and β3-adrenoceptorsBaker, Jillian G.British Journal of Pharmacology (2010), 160 (5), 1048-1061CODEN: BJPCBM; ISSN:1476-5381. (Wiley-Blackwell)There are two important properties of receptor-ligand interactions: affinity (the ability of the ligand to bind to the receptor) and efficacy (the ability of the receptor-ligand complex to induce a response). Ligands are classified as agonists or antagonists depending on whether or not they have efficacy. In theory, it is possible to develop selective agonists based on selective affinity, selective intrinsic efficacy or both. This study examd. the affinity and intrinsic efficacy of β-adrenoceptor agonists at the three human β-adrenoceptors to det. whether the current agonists are subtype selective because of affinity or intrinsic efficacy. Stable clonal CHO-K1 cell lines, transfected with either the human β1, β2 or β3-adrenoceptor, were used