A Brownian motor for a Myosin II head sliding along an actin filament is designed. Various models based on an overdamped equation have often been proposed to mimic the myosin head as a Brownian particle subject to the impacts by the surrounding molecules. In this equation appears a periodic potential U = U(x, f(t)) to take in account of the global force arising from all deterministic interactions of myosin head with the actin filament. In Chauwin et. al. (1994) U(t,f(t)) is a single saw-tooth potential, the positions of whose minima change according to a Poisson law. Here, we shall refer to this formulation, by adding the assumptions that the motor step equals the distance L between successive actin monomers (roughly 5.5 nm). Furthermore, we assume that two 2L-periodic potentials, U1(x) and U2(x), alternate according to a Poisson process, each potential being spatially shifted by L with respect to the other.
On Myosin II Dynamics: from a Pulsating Ratchet to a Washboard Potential
CAPUTO, LUIGIA;
2005-01-01
Abstract
A Brownian motor for a Myosin II head sliding along an actin filament is designed. Various models based on an overdamped equation have often been proposed to mimic the myosin head as a Brownian particle subject to the impacts by the surrounding molecules. In this equation appears a periodic potential U = U(x, f(t)) to take in account of the global force arising from all deterministic interactions of myosin head with the actin filament. In Chauwin et. al. (1994) U(t,f(t)) is a single saw-tooth potential, the positions of whose minima change according to a Poisson law. Here, we shall refer to this formulation, by adding the assumptions that the motor step equals the distance L between successive actin monomers (roughly 5.5 nm). Furthermore, we assume that two 2L-periodic potentials, U1(x) and U2(x), alternate according to a Poisson process, each potential being spatially shifted by L with respect to the other.
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