Berlin 2008 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 27: Membrane Morphology and Adhesion

BP 27.7: Vortrag

Freitag, 29. Februar 2008, 12:15–12:30, C 243

Curvature induced interaction between a membrane protein and a fluctuating model membrane: the influence on membrane dynamics and protein diffusion — •Stefan Leitenberger, Ellen Reister-Gottfried, and Udo Seifert — II. Institut für Theoretische Physik, Universität Stuttgart

In our work the influence of an interaction between a curved protein and a fluctuating membrane whose energy is given by the Helfrich Hamiltonian on the dynamics of the system is analyzed. We derive coupled equations of motion for the membrane dynamics and the lateral protein diffusion. In a first step, the influence of the protein on the membrane dynamics is neglected. Within this approximation we calculate the curvature-coupled diffusion coefficient, which is enhanced compared to free diffusion. This increase is caused by the additional force acting on the protein. To probe our results and overcome other approximations of the calculations, we set up simulations that also neglect the changed membrane dynamics. Comparing the results we find qualitative agreement, however, the diffusion coefficients achieved in the simulations are smaller since the particle tries to follow energetically favorable positions. Correlations between protein position and local membrane shape are not accounted for correctly in the analytical calculations. In a second step, the influence of the curvature-coupling on the membrane dynamics is taken into account. Using an extension of our simulation scheme we study the changed height correlations of the membrane and the effect on the lateral protein diffusion as a function of the protein’s spontaneous curvature and bending rigidity.