Authors: R.F. Fox
Affilation: School of Physics, United States
Pages: 18 - 21
Keywords: rectified Brownian motion, power stroke, ubiquinone, kinesin, Langevin equation
Rectified Brownian motion provides a mechanistic alternative to the power stroke model for the function of motor proteins and other enzyme complexes. ATP is the source of metabolic free energy for motor proteins such as kinesin and myosin V. In the power stroke models, the energy of ATP hydrolysis causes chemo-mechanical energy conversion although the precise manner by which this occurs has yet to be identified. In the rectified Brownian motion model, the energy released by ATP hydrolysis causes an irreversible conformational switch in the ATP binding protein that results in release of the motor protein head from the track along which it moves, and Brownian motion provides the power for the head to move to a new binding site. Asymmetric boundary conditions for this diffusive motion result in a directed motion on the average.