2003 Volume 79B Issue 1 Pages 9-14
A recent study with single molecule measurements has reported that myosin II, a molecular motor, generates stochastic and multiple steps during the hydrolysis of a single ATP molecule. In order to elucidate the mechanism for the motion of myosin, we traced the movements of individual molecules by simulating the Brownian movements along the potentials created by the interaction between a myosin molecule and an actin filament. We demonstrated that Brownian movement was biased to one direction as observed for myosins by either spatially tilting or temporally fluctuating the height of the potential. We incorporated the biased Brownian movement into an ATP hydrolysis reaction scheme and studied the effects of the load on the movement. The results could successfully explain the movements and mechanical properties of myosin. Thus, it was demonstrated that the movement of myosin is thermally driven and the random motion is biased by the energy released from the ATP hydrolysis.
(Communicated by Fumio OOSAWA, M. J. A., Jan. 14, 2003)