Ensemble velocity of non-processive molecular motors with multiple chemical states

TL;DR

This paper analyzes how the ensemble velocity of non-processive molecular motors depends on ATP concentration, revealing complex behaviors including potential velocity reversal due to multiple conformational changes.

Contribution

It introduces a simplified model capturing complex ATP-dependent velocity behaviors, including deviations from Michaelis-Menten kinetics and velocity reversal predictions.

Findings

Velocity dependence on ATP concentration can be non-Michaelis-Menten.

Model predicts possible velocity reversal at specific ATP levels.

Order of conformational events influences velocity behavior.

Abstract

We study the ensemble velocity of non-processive motor proteins, described with multiple chemical states. In particular, we discuss the velocity as a function of ATP concentration. Even a simple model which neglects the strain-dependence of transition rates, reverse transition rates and nonlinearities in the elasticity can show interesting functional dependencies, which deviate significantly from the frequently assumed Michaelis-Menten form. We discuss how the oder of events in the duty cycle can be inferred from the measured dependence. The model also predicts the possibility of velocity reversal at a certain ATP concentration if the duty cycle contains several conformational changes of opposite directionalities.