Dresden 2009 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 15: Motor Proteins
BP 15.3: Vortrag
Mittwoch, 25. März 2009, 15:00–15:15, ZEU 260
Buckling of semiflexible filaments under action of molecular motors — •Krzysztof Baczyński1, Melanie Müller1, Reinhard Lipowsky1, and Jan Kierfeld1,2 — 1Max Planck Institute of Colloids and Interfaces, Department of Theory & Bio - Systems, Science Park Golm — 2TU Dortmund University, Faculty of Physics, D - 44221 Dortmund
In this work we present a model for the buckling of semiflexible filaments under the action of molecular motors. We investigate a system in which a group of motors moves along a clamped filament carrying a second filament as a cargo. The cargo-filament is pushed against the wall and eventually buckles. Depending on boundary conditions we observe different buckling behaviors. For a long cargo-filament the critical Euler force for buckling is much smaller than the stall force of a single molecular motor, which leads to buckling of the cargo-filament. We use an analytical linear approximation of the resulting force-extension relation of the buckled filament [1]. Using Bell-theory for unbinding of a motor and a linear velocity-force relation we obtain a stochastic equation for probability pn(t) that n motors link both filaments at time t. Finally, we calculate the mean first passage time needed for unbinding of linking motors which corresponds also to the transition between buckled and unbuckled state of cargo-filament. Our results show that for sufficiently long filaments the movement of kinesin motors is not affected by the load force generated by the cargo filament. Our numerical solution is confirmed by computer simulations.
1) K. Baczyński, R. Lipowsky, J. Kierfeld, PRE 76, 061914, 2007