8ZDS

Structure of the Salmonella flagellar MS-ring with C11 symmetry applied

Summary for 8ZDS

• Entry DOI: 10.2210/pdb8zds/pdb
• EMDB information: 60007
• Descriptor: Flagellar M-ring protein (1 entity in total)
• Functional Keywords: bacterial flagellum, flagellar assembly, electron cryomicroscopy, ms-ring, type iii secretion system, salmonella, motor protein
• Biological source: Salmonella enterica subsp. enterica serovar Typhimurium
• Total number of polymer chains: 33
• Total formula weight: 2022756.28

Authors

Kinoshita, M.,Makino, F.,Miyata, T.,Imada, K.,Minamino, T.,Namba, K. (deposition date: 2024-05-03, release date: 2025-01-01, Last modification date: 2025-04-23)

Primary citation

Kinoshita, M.,Makino, F.,Miyata, T.,Imada, K.,Namba, K.,Minamino, T.
Structural basis for assembly and function of the Salmonella flagellar MS-ring with three different symmetries.
Commun Biol, 8:61-61, 2025

PubMed Abstract: The flagellar MS-ring is the initial template for flagellar assembly and houses the flagellar protein export complex. The MS-ring has three parts of different symmetries within the ring structure by assembly of FliF subunits in two different conformations with distinct arrangements of three ring-building motifs, RBM1, RBM2, and RBM3. However, it remains unknown how these symmetries are generated. A combination of cryoEM structure and structure-based mutational analyses demonstrates that the well-conserved DQxGxxL motif in the RBM2-RBM3 hinge loop allows RBM2 to take two different orientations relative to RBM3. Of 34 FliF subunits of the MS-ring in the basal body, 23 RBM2 domains form an inner ring with a central pore that accommodates the flagellar protein export complex, and the remaining 11 RBM2 domains form 11 cog-like structures together with RBM1 domains just outside the inner RBM2-ring. We propose that a dimer of FliF with two different conformations initiates MS-ring assembly.

PubMed: 39820129
DOI: 10.1038/s42003-025-07485-2

Experimental method

ELECTRON MICROSCOPY (3.1 Å)