Non-equilibrium fluctuations and mechanochemical couplings of a molecular motor

TL;DR

This paper theoretically examines violations of classical thermodynamic relations and efficiency in a single molecular motor operating far from equilibrium, linking these to mechanochemical couplings and providing predictions for kinesin behavior.

Contribution

It extends a two-state model to analyze non-equilibrium fluctuations, violations of Einstein and Onsager relations, and motor efficiency, offering new insights into mechanochemical couplings.

Findings

Violations of Einstein and Onsager relations are analyzed using the Fluctuation Theorem.

The model predicts specific behaviors of kinesin that can guide future experiments.

Efficiency and violations are linked to mechanochemical couplings in molecular motors.

Abstract

We investigate theoretically the violations of Einstein and Onsager relations, and the efficiency for a single processive motor operating far from equilibrium using an extension of the two-state model introduced by Kafri {\em et al.} [Biophys. J. {\bf 86}, 3373 (2004)]. With the aid of the Fluctuation Theorem, we analyze the general features of these violations and this efficiency and link them to mechanochemical couplings of motors. In particular, an analysis of the experimental data of kinesin using our framework leads to interesting predictions that may serve as a guide for future experiments.