Optimal rectification without forward-current suppression by biological molecular motor

TL;DR

This study experimentally demonstrates that the biological motor F$_1$-ATPase achieves an optimal rectification mechanism, allowing ATP synthesis without hindering ATP hydrolysis, contrasting with simple ratchet models.

Contribution

It reveals a novel rectification mechanism in F$_1$-ATPase involving parallel landscapes and asymmetric transition rates, advancing understanding of molecular motor function.

Findings

F$_1$-ATPase efficiently synthesizes ATP without suppressing hydrolysis.

The rectification mechanism involves parallel energy landscapes and asymmetric transition rates.

This mechanism differs from simple ratchet models, indicating a unique biological optimization.

Abstract

We experimentally showed that biological molecular motor F$_1$-ATPase (F$_1$) implements an optimal rectification mechanism. F$_1$ hardly suppresses adenosine triphosphate (ATP) synthesis, which is the F$_1$'s physiological role while inhibiting unfavorable hydrolysis of ATP. This optimal rectification is a high contrast to a simple ratchet model, where the inhibition of the backward current is inevitably accompanied by the suppression of the forward current. The detailed analysis of single-molecule trajectories demonstrated a novel but simple rectification mechanism of F$_1$ with parallel landscapes and asymmetric transition rates.