title: Hydrodynamic collective effects of active protein machines in solution and lipid bilayers.
abstract: The cytoplasm and biomembranes in biological cells contain large numbers of proteins that cyclically change their shapes. They are molecular machines that can function as molecular motors or carry out various other tasks in the cell. Many enzymes also undergo conformational changes within their turnover cycles. We analyze the advection effects that nonthermal fluctuating hydrodynamic flows induced by active proteins have on other passive molecules in solution or membranes. We show that the diffusion constants of passive particles are enhanced substantially. Furthermore, when gradients of active proteins are present, a chemotaxis-like drift of passive particles takes place. In lipid bilayers, the effects are strongly nonlocal, so that active inclusions in the entire membrane contribute to local diffusion enhancement and the drift. All active proteins in a biological cell or in a membrane contribute to such effects and all passive particles, and the proteins themselves, will be subject to them.
authors.affiliation: Abteilung Physikalische Chemie, Fritz-Haber-Institut der Max-Planck-Gesellschaft, 14195 Berlin, Germany; Department of Mathematical and Life Sciences, Hiroshima University, Hiroshima 739-8526, Japan;
authors.forename: Alexander S
authors.initials: AS
authors.lastname: Mikhailov
authors.affiliation: Chemical Physics Theory Group, Department of Chemistry, University of Toronto, Toronto, ON M5S 3H6, Canada; Institut für Theoretische Physik, Technische Universität Berlin, D-10623 Berlin, Germany rkapral@chem.utoronto.ca.
authors.forename: Raymond
authors.initials: R
authors.lastname: Kapral
mesh_terms: D004058:Diffusion; D057446:Hydrodynamics; D008051:Lipid Bilayers; D011506:Proteins / Q000737:chemistry*
chemical_list: D008051:Lipid Bilayers; D011506:Proteins
keywords: active proteins; collective hydrodynamic effects; enhanced passive particle diffusion; nonthermal fluctuation effects