[Assessment of the number of myosin heads interacting with actin fibers in an artificial, mobile system].

A mathematical model of an actin filament sliding along myosin-coated surface in the in vitro motility assay is considered. The frontal end of the filament is supposed to be affected by a random Brownian force. The relation between the surface density of the myosin heads and average distance between the neighbour heads propelling the filament is calculated and compared with those predicted by earlier simplified models.