Comparison of motor structures from E. coli, Vibrio, H. pylori, and Borrelia. (A) A central section of an E. coli flagellar motor. (B) A central section from a nonsheathed Vibrio flagellar motor. (C) A central section from a sheathed Vibrio flagellar motor. (D) A central section from a sheathed flagellar motor of H. pylori. (E) A central section from a Borrelia flagellar motor. (F to J) Schematic models derived from the central sections shown in panels A to E, respectively. Adapted from prior publications (16, 50, 51), with permission.