A simple kinetic model describes the processivity of myosin-v.
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 substep of size d(0) approximately 13-14 nm (from the ATP-binding state) that appears to accord with independent observations.
Kolomeisky
Anatoly B
AB
Department of Chemistry, Rice University, Houston, Texas 77005-1892, USA. tolya@rice.edu
Fisher
Michael E
ME
D000244:Adenosine Diphosphate / Q000737:chemistry*; D000255:Adenosine Triphosphate / Q000737:chemistry*; D003198:Computer Simulation; D004305:Dose-Response Relationship, Drug; D007700:Kinetics; D008954:Models, Biological; D008956:Models, Chemical; D008958:Models, Molecular; D015233:Models, Statistical; D020409:Molecular Motor Proteins / Q000737:chemistry* / Q000502:physiology; D009038:Motion; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013269:Stochastic Processes; D013314:Stress, Mechanical; D016474:Weight-Bearing
D020409:Molecular Motor Proteins; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate