A Simple Kinetic Model Describes the Processivity of Myosin-V
Abstract
Myosin-V is a motor protein responsible for organelle and vesicle transport in cells. Recent single-molecule experiments have shown that it is an efficient processive motor that walks along actin filaments taking steps of mean size close to 36 nm. A theoretical study of myosin-V motility is presented following an approach used successfully to analyze the dynamics of conventional kinesin but also taking some account of step-size variations. Much of the present experimental data for myosin-V can be well described by a two-state chemical kinetic model with three load-dependent rates. In addition, the analysis predicts the variation of the mean velocity and of the randomness -- a quantitative measure of the stochastic deviations from uniform, constant-speed motion -- with ATP concentration under both resisting and assisting loads, and indicates a {\it sub}step of size 13-14 nm (from the ATP-binding site) that appears to accord with independent observations.
Cite
@article{arxiv.cond-mat/0212452,
title = {A Simple Kinetic Model Describes the Processivity of Myosin-V},
author = {Anatoly B. Kolomeisky and Michael E. Fisher},
journal= {arXiv preprint arXiv:cond-mat/0212452},
year = {2009}
}
Comments
20 pages, 7 figures, to be published in Biophys. J. in 2003