Myosin V executes steps of variable length via structurally constrained diffusion

eLife

D Thirumalai¹  Riina Tehver²  Michael Hinczewski³  David Hathcock⁴ 

[1] Department of Chemistry, University of Texas, Austin, United States;Department of Physics and Astronomy, Denison University, Granville, United States;Department of Physics, Case Western Reserve University, Cleveland, United States;Department of Physics, Cornell University, Ithaca, United States;

关键词: myosin V;    motor protein;    lever arm;    actin;    diffusion;   

DOI  :  10.7554/eLife.51569

来源: DOAJ

【 摘 要 】

The molecular motor myosin V transports cargo by stepping on actin filaments, executing a random diffusive search for actin binding sites at each step. A recent experiment suggests that the joint between the myosin lever arms may not rotate freely, as assumed in earlier studies, but instead has a preferred angle giving rise to structurally constrained diffusion. We address this controversy through comprehensive analytical and numerical modeling of myosin V diffusion and stepping. When the joint is constrained, our model reproduces the experimentally observed diffusion, allowing us to estimate bounds on the constraint energy. We also test the consistency between the constrained diffusion model and previous measurements of step size distributions and the load dependence of various observable quantities. The theory lets us address the biological significance of the constrained joint and provides testable predictions of new myosin behaviors, including the stomp distribution and the run length under off-axis force.

【 授权许可】

Unknown