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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 17: Transport and Confinement I

CPP 17.3: Vortrag

Dienstag, 1. April 2014, 10:15–10:30, ZEU 260

Anomalous Diffusion of Proteins in a Membrane due to Crowding and Trapping — •Mislav Cvitković¹, Timo Bihr^1,2, and Ana-Sunčana Smith¹ — ¹Institute for Theoretical Physics I and Cluster of Excellence: Engineering of Advanced Materials, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Germany — ²II Institute for Theoretical Physics, University of Stuttgart, Germany

The transport of lipids and proteins in biological membranes is one of the most fundamental processes in living cells. Despite a wealth of experiments on related biological processes, the general biophysical principles underlying the complex diffusion in a membrane are still not well understood. Here we model anomalous diffusion in the crowded and multicomponent membrane environment where proteins acting as tracers bind and unbind from immobilised counter–partners (traps), the latter representing a functionalized scaffold. Using a self–developed Monte–Carlo simulation scheme that accounts for length scales from 1 nm to 1 mm in the time domain from 1 µs to 10 s, we explore the full parameter space spanned by the densities of the diffusing molecules and the traps, as well as the binding and unbinding rates. We find several regimes of diffusion and types of anomalous transport. We determine the effective diffusion constant within an analytical model based on scaling arguments that account for trapping, self–avoidance and cooperative effects in the long–time limits of all regimes. We find that this approach reproduces well the results of analogous single–particle–tracking experiments in supported scaffolding membranes.