Helicobacter pyloriFlgV forms a flagellar motor ring structure required for optimal motility

Abstract

ABSTRACTThe bacteriumHelicobacter pylorihas a large flagellar motor that generates significantly higher torque than the archetypicalEscherichia colimotor. To understand howH. pylorinavigates the viscous environment of the stomach, it is essential to establish how specific motor components contribute to efficient motility. We show here that the protein FlgV, required for motility inCampylobacter jejuni, forms a novel ring associated with the MS and C rings inH. pylori. Deletion offlgVfromH. pyloriB128 or a highly motile variant ofH. pyloriG27 (G27M) resulted in reduced motility in soft agar medium. Based on comparative analyses ofin-situflagellar motor structures ofH. pyloriwild-type and ΔflgVmutants, the reduced motility of the ΔflgVmutants and the location of the FlgV ring suggest it stabilizes interactions between the MS and C rings and/or plays a role in switching the direction of flagellar rotation. Overall, these results identify a novel motor accessory likely adapted to promote flagellar function for bacterial colonization of high-load environments such as the gastric mucosa.