Dresden 2009 – scientific programme

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BP: Fachverband Biologische Physik

BP 7: Poster I

BP 7.4: Poster

Monday, March 23, 2009, 17:45–20:00, P3

Curvature-coupled protein diffusion in a fluctuating model membrane — •Stefan Leitenberger, Ellen Reister-Gottfried, and Udo Seifert — II. Institut für Theoretische Physik, Universität Stuttgart

The influence of an interaction between a protein and a fluctuating membrane on the dynamics of the system is analyzed. The energy is given by the Helfrich Hamiltonian in Monge-representation with a correction for the inserted protein. We derive coupled equations of motion for the membrane dynamics and the projected diffusion of the inclusion that are nummerically integrated in our simulation scheme.

In our model the influence of the protein-membrane interaction on the membrane dynamics modifies the height correlation function of the membrane. Two time regimes reflect the different time scale of membrane fluctuations and that of protein diffusion.

The effective lateral diffusion coefficient of the protein is also affected by the curvature-coupling. The resulting coefficient determined by our simulations is smaller than the free diffusion coefficient of the protein. This is in contrast to a previous result that neglects the influence of the particle on membrane fluctuations and shows enhanced diffusion. The analysis of the correlation functions contributing to the mean squared displacement of the protein reveals that the decrease is caused by a strong correlation between the stochastic force on the protein and the response of the membrane to the motion of the protein.