title: Mechanosensitive channel activation by diffusio-osmotic force.
abstract: For ion channel gating, the appearance of two distinct conformational states and the discrete transitions between them are essential, and therefore of crucial importance to all living organisms. We show that the physical interplay between two structural elements that are commonly present in bacterial mechanosensitive channels--namely, a charged vestibule and a hydrophobic constriction--creates two distinct conformational states, open and closed, as well as the gating between them. We solve the nonequilibrium Stokes-Poisson-Nernst-Planck equations, extended to include a molecular potential of mean force, and show that a first order transition between the closed and open states arises naturally from the diffusio-osmotic stress caused by the ions and the water inside the channel and the elastic restoring force from the membrane.
authors.affiliation: Rudolf Peierls Centre for Theoretical Physics, University of Oxford, Oxford OX1 3NP, United Kingdom.
authors.forename: Douwe Jan
authors.initials: DJ
authors.lastname: Bonthuis
authors.affiliation: Rudolf Peierls Centre for Theoretical Physics, University of Oxford, Oxford OX1 3NP, United Kingdom.
authors.forename: Ramin
authors.initials: R
authors.lastname: Golestanian
mesh_terms: D004058:Diffusion; D004926:Escherichia coli / Q000737:chemistry / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism; D057927:Hydrophobic and Hydrophilic Interactions; D015640:Ion Channel Gating; D007473:Ion Channels / Q000737:chemistry* / Q000378:metabolism*; D040542:Mechanotransduction, Cellular; D008954:Models, Biological; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D009995:Osmosis; D011487:Protein Conformation; D013816:Thermodynamics
chemical_list: D029968:Escherichia coli Proteins; D007473:Ion Channels; C086596:MscL protein, E coli; C469542:MscS protein, E coli