The presence and absence of periplasmic rings in bacterial flagellar motors correlates with stator type

Kaplan, M.; Ghosal, D.; Subramanian, P.; Oikonomou, C.M.; Kjaer, A.; Pirbadian, S.; ... ; Jensen, G.J. (2019)

Article / Letter to editor

The bacterial flagellar motor, a cell-envelope-embedded macromolecular machine that functions as a cellular propeller, exhibits significant structural variability between species. Different torque-generating stator modules allow motors to operate in different pH, salt or viscosity levels. How such diversity evolved is unknown. Here, we use electron cryo-tomography to determine the in situ macromolecular structures of three Gammaproteobacteria motors: Legionella pneumophila, Pseudomonas aeruginosa, and Shewanella oneidensis, providing the first views of intact motors with dual stator systems. Complementing our imaging with bioinformatics analysis, we find a correlation between the motor’s stator system and its structural elaboration. Motors with a single H⁺-driven stator have only the core periplasmic P- and L-rings; those with dual H⁺-driven stators have an elaborated P-ring; and motors with Na⁺ or Na⁺/H⁺-driven stators have both their P- and L-rings embellished. Our results suggest an evolution of structural elaboration that may have enabled pathogenic bacteria to colonize higher-viscosity environments in animal hosts.

• All authors: Kaplan, M.; Ghosal, D.; Subramanian, P.; Oikonomou, C.M.; Kjaer, A.; Pirbadian, S.; Ortega, D.R.; Briegel, A.; El-Naggar, M.Y.; Jensen, G.J.
• Date: 2019-01-16
• Journal: eLife
• Volume: 8
• Pages: e43487
• DOI: doi:10.7554/eLife.43487
• Link: https://elifesciences.org/articles/43487