title: Energetics of ion transport in a peptide nanotube.
abstract: Ion channels constitute an important family of integral membrane proteins responsible for the regulation of ion transport across the cell membrane. Yet, the underlying energetics of the permeation events and how the latter are modulated by the environment, specifically near the mouth of the pore, remain only partially characterized. Here, a synthetic membrane channel formed by cyclic peptides of alternated d- and l-hydrophobic alpha-amino acids was considered. The free energy delineating the translocation of a sodium ion was measured along the conduction pathway by means of molecular dynamics simulations. The free-energy profiles that underly the permeation of the open-ended tubular structure are shown to not only depend on the characteristics of the latter but also inherently on the location of the mouth of the synthetic channel with respect to the membrane surface.
authors: Equipe de Dynamique des Assemblages Membranaires, Unité Mixte de Recherche CNRS/UHP 7565, Nancy Université, BP 239, 54506 Vandoeuvre-lès-Nancy Cedex, France.
authors: François
authors: F
authors: Dehez
authors: Mounir
authors: M
authors: Tarek
authors: Christophe
authors: C
authors: Chipot
mesh_terms: D003198:Computer Simulation; D057927:Hydrophobic and Hydrophilic Interactions; D017136:Ion Transport; D007477:Ions; D008954:Models, Biological; D043942:Nanotubes / Q000737:chemistry*; D010456:Peptides, Cyclic / Q000737:chemistry*; D055672:Static Electricity; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
chemical_list: D007477:Ions; D010456:Peptides, Cyclic; D014867:Water