Conformational Spread in the Flagellar Motor Switch: A Model Study

Rao, Christopher V., Ma, Qi, Nicolau, Dan V., Maini, Philip K., Berry, Richard M., & Bai, Fan (2012) Conformational Spread in the Flagellar Motor Switch: A Model Study. PLoS Computational Biology, 8(5), e1002523-e1002523.

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Abstract

The reliable response to weak biological signals requires that they be amplified with fidelity. In E. coli, the flagellar motors that control swimming can switch direction in response to very small changes in the concentration of the signaling protein CheY-P, but how this works is not well understood. A recently proposed allosteric model based on cooperative conformational spread in a ring of identical protomers seems promising as it is able to qualitatively reproduce switching, locked state behavior and Hill coefficient values measured for the rotary motor. In this paper we undertook a comprehensive simulation study to analyze the behavior of this model in detail and made predictions on three experimentally observable quantities: switch time distribution, locked state interval distribution, Hill coefficient of the switch response. We parameterized the model using experimental measurements, finding excellent agreement with published data on motor behavior. Analysis of the simulated switching dynamics revealed a mechanism for chemotactic ultrasensitivity, in which cooperativity is indispensable for realizing both coherent switching and effective amplification. These results showed how cells can combine elements of analog and digital control to produce switches that are simultaneously sensitive and reliable. © 2012 Ma et al.

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ID Code: 80288
Item Type: Journal Article
Refereed: Yes
DOI: 10.1371/journal.pcbi.1002523
ISSN: 1553-7358
Divisions: Current > Schools > School of Mathematical Sciences
Current > QUT Faculties and Divisions > Science & Engineering Faculty
Copyright Owner: The authors
Deposited On: 19 Jan 2015 05:59
Last Modified: 20 Jan 2015 03:20

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