Duty-ratio of cooperative molecular motors

TL;DR

This paper uses statistical mechanics to analyze how cooperation among molecular motors affects their duty ratio, revealing that collective behavior can lower the effective duty ratio due to elastic tension effects.

Contribution

It introduces a model that calculates the duty ratio of cooperative molecular motors, highlighting the impact of elastic tension on motor attachment dynamics.

Findings

Effective duty ratio of cooperative motors is lower than individual motors.

Elastic tension in the filament influences motor attachment and detachment.

Cooperative behavior affects the overall motor performance and efficiency.

Abstract

Molecular motors are found throughout the cells of the human body, and have many different and important roles. These micro-machines move along filament tracks, and have the ability to convert chemical energy into mechanical work that powers cellular motility. Different types of motors are characterized by different duty-ratios, which is the fraction of time that a motor is attached to its filament. In the case of myosin II - a non-processive molecular machine with a low duty ratio - cooperativity between several motors is essential to induce motion along its actin filament track. In this work we use statistical mechanical tools to calculate the duty ratio of cooperative molecular motors. The model suggests that the effective duty ratio of non-processive motors that work in cooperation is lower than the duty ratio of the individual motors. The origin of this effect is the elastic tension that develops in the filament which is relieved when motors detach from the track.