The coupled chemomechanics of the F1-ATPase molecular motor

The enzyme F1-ATPase is a rotary nanomotor in which the central γ subunit rotates inside the cavity made of α3β3 subunits. The experiments showed that the rotation proceeds in steps of 120° and each 120° step consists of 80° and 40° substeps. Here the Author proposes a stochastic wave mechanics of the F1-ATPase motor and combines it with the structure-based kinetics of the F1-ATPase to form a chemomechanic coupled model. The model can reproduce quantitatively and explain the experimental observations about the F1 motor. Using the model, several rate-limited situations about γ subunit rotation are proposed, the effects of the friction and the load on the substeps are investigated and the chemomechanic coupled time during ATP hydrolysis cycle is determined.