title: Dynamics of myosin-V processivity.
abstract: Myosin-V is an actin-associated processive molecular motor. Single molecule experiments revealed that myosin-V walks in a stepwise fashion with occasional backward steps. By combining the mechanical structure of the motor with the ATP hydrolysis kinetics, we construct a dynamical model that accounts for the stepwise processivity. The molecular properties of the protein chains connecting the myosin heads are important. A simple elastic model demonstrates that the stress transmitted from the leading head to the trailing head leads to net forward motion. The step-sizes are non-uniform. We also predict there are several substeps. The translational speed and step-size distributions are computed for several different conditions. The computed force-versus-velocity curve shows that under an external load, myosin-V slows down. However, the sizes of the steps remain the same.
authors.affiliation: Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland, USA.
authors.forename: Ganhui
authors.initials: G
authors.lastname: Lan
authors.forename: Sean X
authors.initials: SX
authors.lastname: Sun
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry*; D003198:Computer Simulation; D004548:Elasticity; D004735:Energy Transfer; D004789:Enzyme Activation; D004795:Enzyme Stability; D007700:Kinetics; D008956:Models, Chemical; D008958:Models, Molecular; D020409:Molecular Motor Proteins / Q000737:chemistry* / Q000648:ultrastructure*; D009068:Movement; D024701:Myosin Type V / Q000032:analysis / Q000737:chemistry* / Q000648:ultrastructure*; D011487:Protein Conformation; D013314:Stress, Mechanical; D013329:Structure-Activity Relationship
chemical_list: D020409:Molecular Motor Proteins; D000255:Adenosine Triphosphate; D024701:Myosin Type V