Role of directional fidelity in multiple extreme performance of F1-ATPase motor

TL;DR

This paper introduces a unified theoretical framework based on directional fidelity to analyze the extreme performance limits of the biological F1-ATPase nanomotor, revealing its near-maximum energy conversion and directional fidelity capabilities.

Contribution

It presents a novel theoretical approach centered on directional fidelity to quantitatively analyze nanomotor performance limits, supported by experimental data on F1-ATPase.

Findings

F1-motor nearly exhausts available energy for maximum directional fidelity

Motor performance approaches physical limits in energy conversion and speed

Tight chemomechanical coupling observed up to a stalemate state

Abstract

Quantitative understanding of the best possible performance of nanomotors allowed by physical laws pertains to study of nanomotors from biology as well as nanotechnology. Biological nanomotor F1-ATPase is the best available model system as it is the only nanomotor known for extreme energy conversion near the limit of energy conservation. Using a unified theoretical framework centred on a concept called directional fidelity, we analyze recent experiments in which F1-motor's performance was measured for controlled chemical potentials, and expose from the experiments quantitative evidence for the motor's multiple extreme performance in directional fidelity, speed and catalytic capability close to physical limits. Specifically, the motor nearly exhausts available energy from the fuel to retain the highest possible directional fidelity for arbitrary load, encompassing the motor's extreme energy conversion and beyond. The theory-experiment comparison implies a tight chemomechanical coupling up to stalemate as futile steps occur but unlikely involve fuel consumption. The F1-motor data also helps clarify relation between directional fidelity and experimentally measured stepping ratio.