a one-dimensional continuum elastic model for membrane-embedded gramicidin dimer dissociation一维连续介质弹性模型种短杆菌肽二聚体分离.pdfVIP

A One-Dimensional Continuum Elastic Model for Membrane-Embedded Gramicidin Dimer Dissociation Joseph N. Stember*, Olaf Andersen Department of Physiology and Biophysics, Institute for Computational Biomedicine, Weill Medical College of Cornell University, New York, New York, United States of America Abstract Membrane elastic properties, which are subject to alteration by compounds such as cholesterol, lipid metabolites and other amphiphiles, as well as pharmaceuticals, can have important effects on membrane proteins. A useful tool for measuring some of these effects is the gramicidin A channels, which are formed by transmembrane dimerization of non-conducting subunits that reside in each bilayer leaflet. The length of the conducting channels is less than the bilayer thickness, meaning that channel formation is associated with a local bilayer deformation. Electrophysiological studies have shown that the dimer becomes increasingly destabilized as the hydrophobic mismatch between the channel and the host bilayer increases. That is, the bilayer imposes a disjoining force on the channel, which grows larger with increasing hydrophobic mismatch. The energetic analysis of the channel-bilayer coupling is usually pursued assuming that each subunit, as well as the subunit- subunit interface, is rigid. Here we relax the latter assumption and explore how the bilayer junction responds to changes in this disjoining force using a simple one-dimensional energetic model, which reproduces key features of the bilayer regulation of gramicidin channel lifetimes. Citation: Stember JN, Andersen O (2011) A One-Dimensional Continuum Elastic Model for Membrane-Embedded Gramicidin Dimer Dissociation. PLoS ONE 6(2): e15563. doi:10.1371/journal.pone.0015563 Editor: Bard Ermentrout, University of Pittsburgh, United States of America Received August 3, 201