Phosphoinositide-Containing Polymerized Liposomes: Stable Membrane-Mimetic Vesicles for Protein-Lipid Binding Analysis

Bioconjugate Chem., 16 (6), 1475 -1483, 2005. 10.1021/bc050197q S1043-1802(05)00197-7
Web Release Date: October 22, 2005

Phosphoinositide-Containing Polymerized Liposomes: Stable Membrane-Mimetic Vesicles for Protein-Lipid Binding Analysis

Colin G. Ferguson,* Robyn D. James, Cleve S. Bigman, Donnie A. Shepard, Yasmina Abdiche, Phinikoula S. Katsamba, David G. Myszka, and Glenn D. Prestwich

Echelon Biosciences Inc., 675 Arapeen Drive, Suite 302, Salt Lake City, Utah 84108, Center for Biomolecular Interaction Analysis, University of Utah, 50 North Medical Drive, Salt Lake City, Utah 84132, and Department of Medicinal Chemistry, University of Utah, 419 Wakara Way, Suite 205, Salt Lake City, Utah 84108

Received July 6, 2005

Revised September 2, 2005

Abstract:

Stable phosphoinositide (PIP_n)-containing liposomes were prepared using polydiacetylene photochemistry. Tethered pentacosadiynyl inositol polyphosphate (InsP_n) analogues of Ins(1,3,4)P₃, Ins(1,4,5)P₃, and Ins(1,3,4,5)P₄ were synthesized, incorporated into vesicles made up of diyne-phosphatidylcholine and -phosphatidylethanolamine, and polymerized by UV irradiation. The polymerized liposome nanoparticles showed markedly increased stability over conventional PIP_n-containing vesicles as a result of the covalent conjugated ene-yne network in the acyl chains. The polymerized liposomes were specifically recognized by PIP_n binding PH domains in liposome overlay assays and amplified luminescent proximity homogeneous assays. Moreover, the biotin moiety allowed attachment of the nanoparticles to a streptavidin-coated sensor chips in surface plasmon resonance (SPR) sensor. The PIP_n headgroups displayed on SPR sensors showed higher affinities for PH domains and PIP_n monoclonal antibodies than did monomeric PIP_n-analogues with biotinylated acyl chains.

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