FliL and its paralog MotF have distinct roles in the stator activity of the Sinorhizobium meliloti flagellar motor.

Autor: Sobe RC; Department of Biological Sciences, Life Sciences I, Virginia Tech, Blacksburg, Virginia, USA., Gilbert C; Department of Biological Sciences, Life Sciences I, Virginia Tech, Blacksburg, Virginia, USA., Vo L; Department of Biochemistry and Cell and Molecular Biology, University of Tennessee at Knoxville, Knoxville, Tennessee, USA., Alexandre G; Department of Biochemistry and Cell and Molecular Biology, University of Tennessee at Knoxville, Knoxville, Tennessee, USA., Scharf BE; Department of Biological Sciences, Life Sciences I, Virginia Tech, Blacksburg, Virginia, USA.
Jazyk: angličtina
Zdroj: Molecular microbiology [Mol Microbiol] 2022 Sep; Vol. 118 (3), pp. 223-243. Date of Electronic Publication: 2022 Jul 28.
DOI: 10.1111/mmi.14964
Abstrakt: The bacterial flagellum is a complex macromolecular machine that drives bacteria through diverse fluid environments. Although many components of the flagellar motor are conserved across species, the roles of FliL are numerous and species-specific. Here, we have characterized an additional player required for flagellar motor function in Sinorhizobium meliloti, MotF, which we have identified as a FliL paralog. We performed a comparative analysis of MotF and FliL, identified interaction partners through bacterial two-hybrid and pull-down assays, and investigated their roles in motility and motor rotation. Both proteins form homooligomers, and interact with each other, and with the stator proteins MotA and MotB. The ∆motF mutant exhibits normal flagellation but its swimming behavior and flagellar motor activity are severely impaired and erratic. In contrast, the ∆fliL mutant is mostly aflagellate and nonmotile. Amino acid substitutions in cytoplasmic regions of MotA or disruption of the proton channel plug of MotB partially restored motor activity to the ∆motF but not the ∆fliL mutant. Altogether, our findings indicate that both, MotF and FliL, are essential for flagellar motor torque generation in S. meliloti. FliL may serve as a scaffold for stator integration into the motor, and MotF is required for proton channel modulation.
(© 2022 The Authors. Molecular Microbiology published by John Wiley & Sons Ltd.)
Databáze: MEDLINE
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