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Globular Polyampholytes: Structure and Translocation

  • Nam-Kyung Lee*
    Nam-Kyung Lee
    Department of Physics and Astronomy, Sejong University, Seoul 05006, Korea
    *Email: [email protected]
  • Youngkyun Jung*
    Youngkyun Jung
    Supercomputing Center, Korea Institute of Science and Technology Information, Daejeon 34141, Korea
    *Email: [email protected]
  • Albert Johner*
    Albert Johner
    Institut Charles Sadron CNRS-Unistra, 6 rue Boussingault, Strasbourg Cedex 67083, France
    *Email: [email protected]
  • , and 
  • Jean-François Joanny
    Jean-François Joanny
    Collège de France, 11, place Marcelin-Berthelot, Paris Cedex 05 75231, France
    Physico-chimie Curie, Institut Curie, PSL University, Paris Cedex 05 75248, France
Cite this: Macromolecules 2021, 54, 5, 2394–2411
Publication Date (Web):February 23, 2021
Copyright © 2021 American Chemical Society

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    Abstract Image

    Polyampholytes (PAs) are polymers carrying electrical charges of both signs along their backbone. We consider synthetic PAs with a quenched random charge sequence. At low to moderate salt concentrations, PAs typically adopt pearl-necklace structures with collapsed globules linked by open strands. We study the structure of a PA as a function of its net charge by means of coarse-grained molecular dynamics simulations and analytical theory. It is shown theoretically and evidenced by simulations that the free energy drives quenched random PAs toward states with (very) polydisperse pearls. The translocation of a (partially) globular PA, driven by an electric field through a narrow pore, usually starts from a chain end in a tailed configuration. In our simulations, about half of all the observed PA configurations are tailed. The vast majority of the sequences visits tailed configurations long enough to initiate translocation like for open PAs. A detailed description of the tail size distribution and tail structure is obtained, and the survival statistics of tails is explored. The consequences of the pearl-necklace structures, observed in the simulations, for the translocation are discussed. Translocation itself is not simulated in this contribution.

    We also collected some simulation data for distributions with average charge equal to the target charge, which slightly reduces σ1 without major consequences.

    There are obvious restrictions in the xy space. For example, a globule cannot carry a net charge larger than its number of sites. This constraint reduces the accessible xy space for increasing net charges. For regular PEs (all sites carrying the same charge), only the diagonal is accessible.

    The energy E introduced previously is in fact a free energy where thermal fluctuations enter through the surface tension and the concentration.

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    Cited By

    This article is cited by 10 publications.

    1. Min-Kyung Chae, Nam-Kyung Lee, Youngkyun Jung, Albert Johner. Shape Fluctuations of Random Polyampholyte and Intrinsically Disordered Protein Sequences. Macromolecules 2023, 56 (3) , 785-793.
    2. Min-Kyung Chae, Nam-Kyung Lee, Youngkyun Jung, Jean François Joanny, Albert Johner. Structure of a Hydrophobic Polyelectrolyte Chain with a Random Sequence. Macromolecules 2022, 55 (14) , 6275-6285.
    3. Min-Kyung Chae, Nam-Kyung Lee, Youngkyun Jung, Albert Johner, Jean-Francois Joanny. Partially Globular Conformations from Random Charge Sequences. ACS Macro Letters 2022, 11 (3) , 382-386.
    4. Artem M. Rumyantsev, Albert Johner, Juan J. de Pablo. Sequence Blockiness Controls the Structure of Polyampholyte Necklaces. ACS Macro Letters 2021, 10 (8) , 1048-1054.
    5. Zening Liu, Jong K Keum, Tianyu Li, Jihua Chen, Kunlun Hong, Yangyang Wang, Bobby G Sumpter, Rigoberto Advincula, Rajeev Kumar, . Anti-polyelectrolyte and polyelectrolyte effects on conformations of polyzwitterionic chains in dilute aqueous solutions. PNAS Nexus 2023, 2 (7)
    6. Seowon Kim, Nam-Kyung Lee, Min-Kyung Chae, Albert Johner, Jeong-Man Park. Translocation of Hydrophobic Polyelectrolytes under Electrical Field: Molecular Dynamics Study. Polymers 2023, 15 (11) , 2550.
    7. Chen‐Gang Wang, Nayli Erdeanna Binte Surat'man, Jun Jie Chang, Zhi Lin Ong, Bofan Li, Xiaotong Fan, Xian Jun Loh, Zibiao Li. Polyelectrolyte Hydrogels for Tissue Engineering and Regenerative Medicine. Chemistry – An Asian Journal 2022, 17 (18)
    8. Yang Yang, Bosen Chai, Bin Yang, Peng Li. Conformational Behavior of Polyampholytes Grafted onto Spherical Particles. 2022, 507-510.
    9. Yeong-Beom Kim, Min-Kyung Chae, Jeong-Man Park, Albert Johner, Nam-Kyung Lee. Translocation, Rejection and Trapping of Polyampholytes. Polymers 2022, 14 (4) , 797.
    10. Kevin S. Silmore, Rajeev Kumar. Dynamics of a single polyampholyte chain. The Journal of Chemical Physics 2021, 155 (21)

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