title: A one-dimensional continuum elastic model for membrane-embedded gramicidin dimer dissociation.
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.
authors.affiliation: Department of Physiology and Biophysics, Institute for Computational Biomedicine, Weill Medical College of Cornell University, New York, New York, United States of America. js1569@nyumc.org
authors.forename: Joseph N
authors.initials: JN
authors.lastname: Stember
authors.forename: Olaf
authors.initials: O
authors.lastname: Andersen
mesh_terms: D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism*; D004548:Elasticity; D004734:Energy Metabolism / Q000502:physiology; D006096:Gramicidin / Q000737:chemistry* / Q000378:metabolism*; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism; D008954:Models, Biological; D011485:Protein Binding; D017510:Protein Folding; D055503:Protein Multimerization / Q000502:physiology*
chemical_list: D008051:Lipid Bilayers; D008565:Membrane Proteins; D006096:Gramicidin