From Conformational Spread to Allosteric and Cooperative models of E. coli flagellar motor

TL;DR

This paper analytically investigates the conformational spread model of E. coli flagellar motors, simplifying it to a cooperative binding model that accurately captures the motor's switching dynamics.

Contribution

It provides an analytical reduction of the conformational spread model to a simpler cooperative binding model, enhancing understanding of motor switching behavior.

Findings

The simplified model reproduces the motor switch dynamics accurately.

Separation of timescales allows for effective model reduction.

Analytical approach clarifies the relationship between conformational spread and cooperative binding.

Abstract

Escherichia coli swims using flagella activated by rotary motors. The direction of rotation of the motors is indirectly regulated by the binding of a single messenger protein. The conformational spread model has been shown to accurately describe the equilibrium properties as well as the dynamics of the flagellar motor. In this paper we study this model from an analytic point of view. By exploiting the separation of timescales observed in experiments, we show how to reduce the conformational spread model to a coarse-grained, cooperative binding model. We show that this simplified model reproduces very well the dynamics of the motor switch.