A Kinetic Model to Describe the Bidirectional Motility of Dimeric Molecular Motors

Abstract

Highly processive molecular motors travel long distances on cytoskeletal filaments by consistently moving in one direction without detaching and frequently dimerize to reduce their rate of dissociation. Gating: the mechanism by which the two heads coordinate stepping can be either biochemical, kinetic differences between the leading and trailing head, or mechanical, increased likelihood of rebinding forward. We present a kinetic model which relates step size, run length, velocity, and fraction of backwards steps to the relevant reaction rates including both biochemical and mechanical gating parameters.