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DY: Fachverband Dynamik und Statistische Physik
DY 11: Invited Talk
DY 11.1: Hauptvortrag
Montag, 16. März 2020, 15:00–15:30, HÜL 186
A hydrodynamic view on the diffusion in membranes and dense solutions of proteins — •Gerhard Hummer1,2, Sören von Bülow1, Martin Vögele1,3, Lisa Pietrek1, Marc Siggel1, Max Linke1, Jürgen Köfinger1, and Lukas Stelzl1 — 1Department of Theoretical Biophysics, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany — 2Institute for Biophysics, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany — 3Computer Science Department, Stanford University, Stanford, CA 94305-9025, USA
Molecular dynamics simulations of the diffusion of proteins and other macromolecules in dense solutions and in lipid membranes revealed unexpected complexities. In systems mimicking the interior of a living cell, with densely packed proteins, the translational and rotational diffusion of proteins slow down dramatically at high protein concentrations, and the Stokes-Einstein relation appears to break down. In membranes, the apparent diffusion coefficient appears to grow without bound as the box size is increased. We resolve these issues by showing, first, that transient clustering of proteins explains quantitatively the increase in the apparent Stokes radius and the rise in the viscosity. Second, we show that the divergence of membrane diffusion is the result of the unusual hydrodynamics under periodic boundary conditions. Hydrodynamics also plays a central role in rotational diffusion, both in the bulk and within membranes. Accounting for hydrodynamics, we obtain diffusion coefficients that can be interpreted meaningfully and compared to experiment.