An analysis of the hyper-sharp phenomenon of myosin diffusion in an F-actin/ATP solution by computer simulation

The diffusion of myosin molecules was demonstrated using schlieren optics and Rayleigh fringe optics. A hyper-sharp schlieren pattern appeared near the boundary between the upper and lower parts of the diffusion cell at a time when ATP in the lower part had almost been consumed. The mechanism underlying the appearance of the hyper-sharp peak was investigated by means of computer simulations based on random-walk theory. The schlieren pattern with the hyper-sharp peak could be reproduced on the computer with the assumptions that a myosin molecule can be detached from an actin filament only on binding of ATP and that it can then move along actin filaments or diffuse in the aqueous solution. The results of the computer simulations are in good agreement with the experimental data.