Conformational dynamics of capping protein and interaction partners: Simulation studies

Authors

  • Suryani Lukman,

    1. Bioinformatics Institute, Agency for Science, Technology and Research, 30 Biopolis Street, Matrix, Singapore 138671
    2. Department of Chemistry, University of Cambridge, Lensfield Rd, Cambridge CB2 1EW, United Kingdom
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  • Robert C. Robinson,

    1. Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, 61 Biopolis Drive, Proleos, Singapore 138673
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  • David Wales,

    1. Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543
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  • Chandra S. Verma

    Corresponding author
    1. Bioinformatics Institute, Agency for Science, Technology and Research, 30 Biopolis Street, Matrix, Singapore 138671
    2. Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543
    3. School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551
    • 30 Biopolis Street, #07-01 Matrix, Singapore 138671
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Errata

This article is corrected by:

  1. Errata: Erratum: Conformational dynamics of capping protein and interaction partners: Simulation studies Volume 80, Issue 5, 1500, Article first published online: 5 April 2012

Abstract

Capping protein (CP) is important for the regulation of actin polymerization. CP binds to the barbed end of the actin filament and prevents actin polymerization. This interaction is modulated through competitive binding by regulatory proteins such as myotrophin (V-1) and the capping protein interacting (CPI) motif from CARMIL. The binding site of myotrophin overlaps with the region of CP that binds to the barbed end of actin filament, whereas CPI binds at a distant site. The binding of CPI to the myotrophin-CP complex dissociates myotrophin from CP. Detailed multicopy molecular dynamics simulations suggest that the binding of CPI shifts the conformational equilibria of CP away from states that favor myotrophin binding. This shift is underpinned by allosteric effects where CPI inhibits CP through suppression of flexibility and disruption of concerted motions that appear to mediate myotrophin binding. Accompanying these effects are changes in electrostatic interactions, notably those involving residue K142β, which appears to play a critical role in regulating flexibility. In addition, accessibility of the site on CP for binding the key hydrophobic residue W8 of myotrophin is modulated by CPI. These results provide insights into the modulation of CP by CPI and myotrophin and indicate the mechanism by which CPI drives the dissociation of the myotrophin-CP complex. Proteins 2012;. © 2011 Wiley Periodicals, Inc.

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