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Relaxation time asymmetry in stator dynamics of the bacterial flagellar motor

Abstract : The bacterial flagellar motor (BFM) is the membrane-embedded rotary molecular motor which turns the flagellum that provides thrust to many bacterial species. This large multimeric complex, composed of a few dozen constituent proteins, has emerged as a hallmark of dynamic subunit exchange. The stator units are inner-membrane ion channels which dynamically bind and unbind to the peptidoglycan at the rotor periphery, consuming the ion motive force (IMF) and applying torque to the rotor when bound. The dynamic exchange is known to be a function of the viscous load on the flagellum, allowing the bacterium to dynamically adapt to its local viscous environment, but the molecular mechanisms of exchange and mechanosensitivity remain to be revealed. Here, by actively perturbing the steady-state stator stoichiometry of individual motors, we reveal a stoichiometry-dependent asymmetry in stator remodeling kinetics. We interrogate the potential effect of next-neighbor interactions and local stator unit depletion and find that neither can explain the observed asymmetry. We then simulate and fit two mechanistically diverse models which recapitulate the asymmetry, finding stator assembly dynamics to be particularly well described by a two-state catch-bond mechanism.
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Preprints, Working Papers, ...
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https://hal.archives-ouvertes.fr/hal-03351194
Contributor : Ashley Nord Connect in order to contact the contributor
Submitted on : Wednesday, September 29, 2021 - 3:03:27 PM
Last modification on : Thursday, November 25, 2021 - 1:08:04 PM

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Ruben Perez-Carrasco, María-José Franco-Oñate, Jean-Charles Walter, Jérôme Dorignac, Fred Geniet, et al.. Relaxation time asymmetry in stator dynamics of the bacterial flagellar motor. 2021. ⟨hal-03351194⟩

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