Regensburg 2010 – scientific programme

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BP: Fachverband Biologische Physik

BP 35: Posters: Statistical Physics, Evolution, and Networks

BP 35.9: Poster

Thursday, March 25, 2010, 17:15–20:00, Poster B2

Role of hydrodynamic anisotropy for protein-protein encounter — •Jakob Schluttig, Christian Korn, and Ulrich Schwarz — Institut für Theoretische Physik, Universität Heidelberg, 69120 Deutschland

Protein-protein interactions in cells comprise both transport and reaction steps. Although both single proteins and intermediate complexes are usually not spherical, the role of anisotropy for protein-protein encounter has not been systematically studied before. Using a Langevin equation approach, we quantify the influence of anisotropy on the encounter rate of model particles. We consider a purely geometric definition of the encounter complex by introducing spherical encounter patches located on the surface of ellipsoidal particles. We investigate the encounter rate k at various aspect ratios ξ for different locations of the encounter patches and different concentrations. We show that the dependence of k on ξ can be mainly attributed to steric effects while the altered diffusion behaviour has a rather small effect. In general one expects that rotational diffusion crosses over to isotropic behaviour for sufficiently long times. We analytically calculate the three-dimensional crossover time and show that it is much smaller than typical protein encounter times, in good agreement with our simulation results.