Molecular Dynamics Simulations of a Membrane Protein/Amphipol Complex

Jason D. Perlmutter, Jean Luc Popot, Jonathan N. Sachs

Research output: Contribution to journalArticlepeer-review

23 Scopus citations

Abstract

Amphipathic polymers known as “amphipols” provide a highly stabilizing environment for handling membrane proteins in aqueous solutions. A8-35, an amphipol with a polyacrylate backbone and hydrophobic grafts, has been extensively characterized and widely employed for structural and functional studies of membrane proteins using biochemical and biophysical approaches. Given the sensitivity of membrane proteins to their environment, it is important to examine what effects amphipols may have on the structure and dynamics of the proteins they complex. Here we present the first molecular dynamics study of an amphipol-stabilized membrane protein, using Escherichia coli OmpX as a model. We begin by describing the structure of the complexes formed by supplementing OmpX with increasing amounts of A8-35, in order to determine how the amphipol interacts with the transmembrane and extramembrane surfaces of the protein. We then compare the dynamics of the protein in either A8-35, a detergent, or a lipid bilayer. We find that protein dynamics on all accessible length scales is restrained by A8-35, which provides a basis to understanding some of the stabilizing and functional effects of amphipols that have been experimentally observed.

Original languageEnglish (US)
Pages (from-to)883-895
Number of pages13
JournalJournal of Membrane Biology
Volume247
Issue number9-10
DOIs
StatePublished - Oct 14 2014

Bibliographical note

Funding Information:
Particular thanks are due to L. J. Catoire, M. Tehei, and G. Zaccai for discussions about the manuscript, as well as to a referee for useful comments. Computational resources were provided by the Minnesota Supercomputing Institute (MSI). This work was also supported by the French Centre National de la Recherche Scientifique.

Publisher Copyright:
© 2014, Springer Science+Business Media New York.

Keywords

  • A8-35
  • Dynamics
  • OmpX
  • Surfactants

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