Dual stator dynamics in the Shewanella oneidensis MR‐1 flagellar motor. Issue 5 (31st March 2015)

• Record Type: Journal Article
• Authors: Paulick, Anja; Delalez, Nicolas J.; Brenzinger, Susanne; Steel, Bradley C.; Berry, Richard M.; Armitage, Judith P.; Thormann, Kai M.
• Is Part Of: Molecular microbiology. Volume 96:Issue 5(2015)
• Page Start: 993
• Page End: 1001
• Publication Date: 2015-03-31
• Subjects: Molecular microbiology -- Periodicals; 572.829
• DOI: 10.1111/mmi.12984
• Languages: English
• ISSNs: 0950-382X

Abstract

<abstract abstract-type="main"> <title>Summary</title> <p>The bacterial flagellar motor is an intricate nanomachine which converts ion gradients into rotational movement. Torque is created by ion‐dependent stator complexes which surround the rotor in a ring. <italic>S</italic><italic>hewanella oneidensis</italic> MR‐1 expresses two distinct types of stator units: the Na<sup>+</sup>‐dependent PomA<sub>4</sub>B<sub>2</sub> and the H<sup>+</sup>‐dependent MotA<sub>4</sub>B<sub>2</sub>. Here, we have explored the stator unit dynamics in the MR‐1 flagellar system by using mCherry‐labeled PomAB and MotAB units. We observed a total of between 7 and 11 stator units in each flagellar motor. Both types of stator units exchanged between motors and a pool of stator complexes in the membrane, and the exchange rate of MotAB, but not of PomAB, units was dependent on the environmental Na<sup>+</sup>‐levels. In 200 mM Na<sup>+</sup>, the numbers of PomAB and MotAB units in wild‐type motors was determined to be about 7:2 (PomAB:MotAB), shifting to about 6:5 without Na<sup>+</sup>. Significantly, the average swimming speed of MR‐1 cells at low Na<sup>+</sup> conditions was increased in the presence of MotAB. These data strongly indicate that the <italic>S</italic><italic>. oneidensis</italic> flagellar motors simultaneously use H<sup>+</sup> and Na<sup>+</sup> driven stators in a configuration governed by MotAB incorporation efficiency in response to environmental Na<sup>+</sup> levels.</p> </abstract>