The European Physical Journal B (EPJ B)

Eur. Phys. J. B 3, 535-546

Elastically coupled molecular motors

A. Vilfan - E. Frey - F. Schwabl

Institut für Theoretische Physik, Physik-Department der Technischen Universität München,
James-Franck-Straße, 85747 Garching, Germany

Received: 27 November 1997 / Revised: 20 February 1998 / Accepted: 27 March 1998

Abstract
We study the influence of filament elasticity on the motion of collective molecular motors. It is found that for a backbone flexibility exceeding a characteristic value (motor stiffness divided through the mean displacement between attached motors), the ability of motors to produce force reduces as compared to rigidly coupled motors, while the maximum velocity remains unchanged. The force-velocity-relation in two different analytic approximations is calculated and compared with Monte-Carlo simulations. Finally, we extend our model by introducing motors with a strain-dependent detachment rate. A remarkable crossover from the nearly hyperbolic shape of the Hill curve for stiff backbones to a linear force-velocity relation for very elastic backbones is found. With realistic model parameters we show that the backbone flexibility plays no role under physiological conditions in muscles, but it should be observable in certain in vitro assays.

PACS
02.50.Ey Stochastic processes - 05.40.+j Fluctuation phenomena, random processes, and Brownian motion - 87.22.Jb Muscle contraction, nerve conduction, synaptic transmission, memorization, and other neurophysiological processes (excluding perception processes and speech)

Author for correspondance: andrej_vilfan@physik.tu-muenchen.de

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