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A Simple Kinetic Model Describes the Processivity of Myosin-V

Anatoly B. Kolomeisky·Michael E. Fisher
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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 $d_{0} \simeq$ 13-14 nm (from the ATP-binding site) that appears to accord with independent observations.

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BibTeXRIS

Anatoly B. Kolomeisky, Michael E. Fisher. 2002-12-18. A Simple Kinetic Model Describes the Processivity of Myosin-V. https://doi.org/10.1016/s0006-3495(03)74973-x

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