TY - JOUR TI - The presence and absence of periplasmic rings in bacterial flagellar motors correlates with stator type AU - Kaplan, Mohammed AU - Ghosal, Debnath AU - Subramanian, Poorna AU - Oikonomou, Catherine M AU - Kjaer, Andreas AU - Pirbadian, Sahand AU - Ortega, Davi R AU - Briegel, Ariane AU - El-Naggar, Mohamed Y AU - Jensen, Grant J A2 - Egelman, Edward H A2 - Storz, Gisela A2 - Egelman, Edward H A2 - Ito, Masahiro A2 - Stahlberg, Henning VL - 8 PY - 2019 DA - 2019/01/16 SP - e43487 C1 - eLife 2019;8:e43487 DO - 10.7554/eLife.43487 UR - https://doi.org/10.7554/eLife.43487 AB - 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. KW - Shewanella oneidensis MR-1 KW - Pseudomonas aeruginosa KW - Legionella pneumophila KW - electron cryo-tomography KW - bacterial flagellar motor KW - evolution JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -