Efficiently driving F${}_1$ molecular motor in experiment by suppressing nonequilibrium variation

Abstract

F${}_1$-ATPase (F${}_1$) is central to cellular energy transduction. Forcibly rotated by another motor F${}_{\mathrm{o}}$, F${}_1$ catalyzes ATP synthesis by converting mechanical work into chemical free energy stored in the molecule ATP. The details of how F${}_{\mathrm{o}}$ drives F${}_1$ are not fully understood; however, evaluating efficient ways to rotate F${}_1$ could provide fruitful insights into this driving since there is a selective pressure to improve efficiency. Here, we show that rotating F${}_1$ with an angle clamp is significantly more efficient than a constant torque. Our experiments, combined with theory and simulation, indicate that the angle clamp significantly suppresses the nonequilibrium variation that contributes to the futile dissipation of input work.

5 pages, 4 figures for the main manuscript. 9 pages, 5 figures for the supplemental material