FIG 6.

The mosaic collar complex changes conformation to accommodate the inner membrane curvature in B. burgdorferi. (A) Surface rendering of a representative WT cell tip. Ten motors embed in the IM and distribute along the cell tip. The diameter of the IM at different positions at the cell tip is indicated. Note that the IM is more curved (has a smaller diameter) at the positions closer to the cell tip. (B and C) The flagellar motor embeds on the IM and is distorted due to the IM curvature. The periplasmic collar complex surrounds the stator units and can change conformation to fit the IM curvature, facilitating the assembly and function of spirochetal motors in highly curved membrane environments. PG, peptidoglycan.