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Title | CryoEM structures reveal how the bacterial flagellum rotates and switches direction. |
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Journal, issue, pages | Nat Microbiol, Vol. 9, Issue 5, Page 1271-1281, Year 2024 |
Publish date | Apr 17, 2024 |
![]() | Prashant K Singh / Pankaj Sharma / Oshri Afanzar / Margo H Goldfarb / Elena Maklashina / Michael Eisenbach / Gary Cecchini / T M Iverson / ![]() ![]() |
PubMed Abstract | Bacterial chemotaxis requires bidirectional flagellar rotation at different rates. Rotation is driven by a flagellar motor, which is a supercomplex containing multiple rings. Architectural ...Bacterial chemotaxis requires bidirectional flagellar rotation at different rates. Rotation is driven by a flagellar motor, which is a supercomplex containing multiple rings. Architectural uncertainty regarding the cytoplasmic C-ring, or 'switch', limits our understanding of how the motor transmits torque and direction to the flagellar rod. Here we report cryogenic electron microscopy structures for Salmonella enterica serovar typhimurium inner membrane MS-ring and C-ring in a counterclockwise pose (4.0 Å) and isolated C-ring in a clockwise pose alone (4.6 Å) and bound to a regulator (5.9 Å). Conformational differences between rotational poses include a 180° shift in FliF/FliG domains that rotates the outward-facing MotA/B binding site to inward facing. The regulator has specificity for the clockwise pose by bridging elements unique to this conformation. We used these structures to propose how the switch reverses rotation and transmits torque to the flagellum, which advances the understanding of bacterial chemotaxis and bidirectional motor rotation. |
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Methods | EM (single particle) |
Resolution | 3.4 - 5.9 Å |
Structure data | EMDB-41100, PDB-8t8o: EMDB-41101, PDB-8t8p: EMDB-43256, PDB-8vib: EMDB-43258, PDB-8vid: EMDB-43327, PDB-8vkq: EMDB-43328, PDB-8vkr: |
Source |
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![]() | MOTOR PROTEIN / Domain Swap / Symmetry mismatch / Flagellar component / Switch complex / MS-ring / Membrane protein |