Rocking ratchet based on F1-ATPase in the absence of ATP

TL;DR

This study models F1-ATPase as a rocking ratchet driven by oscillating forces, demonstrating directional rotation and reversals in the absence of ATP through molecular dynamics simulations.

Contribution

It applies rocking ratchet theory to F1-ATPase, showing force-driven directional rotation and reversals without ATP, which is a novel approach.

Findings

F1-ATPase exhibits directional rotation under oscillating force

Rotation direction can be reversed by changing oscillation frequency

Directionless Brownian motion occurs without oscillating force

Abstract

Bartussek, Hanggi and Kissner studied a rocking ratchet system, in which a Brownian particle is subject to an asymmetric periodic potential together with an oscillating force, and found that the direction of the macroscopic current can be reversed by changing the parameter values characterizing the model [Europhys. Lett., 28 (1994) 459]. In this letter, we apply their ratchet theory to a rotary motor-protein, F1-ATPase. In this work, we construct a model of a rocking ratchet in which F1-ATPase rotates not as a result of ATP hydrolysis but through the influence of an oscillating force. We then study the motion of F1-ATPase on the basis of molecular dynamics simulations of this coarse-grained protein model. Although in the absence of ATP, F1-ATPase exhibits directionless Brownian motion when there exists no oscillating force, we observe directional motion when we do apply an oscillating force. Furthermore, we observe that the direction of rotation is reversed when we change the oscillation frequency.