Loose mechanochemical coupling of molecular motors

TL;DR

This paper investigates the energy conversion efficiency of molecular motors, revealing that their movement is loosely coupled to their chemical cycle, leading to significant energy dissipation during substeps.

Contribution

It introduces a two-state model showing that molecular motors are loosely coupled to their chemical cycle, explaining partial energy conversion and dissipation.

Findings

Only part of input energy is converted into mechanical work.

Energy is dissipated during substeps without contributing to movement.

Motion is loosely coupled to the chemical cycle.

Abstract

In living cells, molecular motors convert chemical energy into mechanical work. Its thermodynamic energy efficiency, i.e. the ratio of output mechanical work to input chemical energy, is usually high. However, using two-state models, we found the motion of molecular motors is loosely coupled to the chemical cycle. Only part of the input energy can be converted into mechanical work. Others is dissipated into environment during substeps without contributions to the macro scale unidirectional movement.