8T8O

CCW Flagellar Switch Complex - FliF, FliG, FliM, and FliN forming 34-mer C-ring from Salmonella

This is a non-PDB format compatible entry.

Summary for 8T8O

• Entry DOI: 10.2210/pdb8t8o/pdb
• EMDB information: 41100 41101 41102 41103 41104
• Descriptor: Flagellar M-ring protein, Flagellar motor switch protein FliG, FliM,Flagellar motor switch protein FliM, ... (4 entities in total)
• Functional Keywords: domain swap, symmetry mismatch, flagellar component, switch complex, motor protein
• Biological source: Salmonella enterica subsp. enterica serovar Typhimurium; More
• Total number of polymer chains: 204
• Total formula weight: 4103786.06

Authors

Singh, P.K.,Iverson, T.M. (deposition date: 2023-06-22, release date: 2024-02-28, Last modification date: 2024-08-21)

Primary citation

Singh, P.K.,Sharma, P.,Afanzar, O.,Goldfarb, M.H.,Maklashina, E.,Eisenbach, M.,Cecchini, G.,Iverson, T.M.
CryoEM structures reveal how the bacterial flagellum rotates and switches direction.
Nat Microbiol, 9:1271-1281, 2024

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 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.

PubMed: 38632342
DOI: 10.1038/s41564-024-01674-1

Experimental method

ELECTRON MICROSCOPY (4 Å)