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Title | Structural basis for assembly and function of the Salmonella flagellar MS-ring with three different symmetries. |
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Journal, issue, pages | Commun Biol, Vol. 8, Issue 1, Page 61, Year 2025 |
Publish date | Jan 16, 2025 |
![]() | Miki Kinoshita / Fumiaki Makino / Tomoko Miyata / Katsumi Imada / Keiichi Namba / Tohru Minamino / ![]() |
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 ...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. |
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Methods | EM (single particle) |
Resolution | 2.4 - 4.2 Å |
Structure data | EMDB-60007, PDB-8zds: EMDB-60008, PDB-8zdt: EMDB-60009, PDB-8zdu: ![]() EMDB-62210: Structure of the 34-mer RBM3 ring of Salmonella flagellar MS-ring protein FliF with C1 symmetry applied ![]() EMDB-62211: Structure of the 33-mer RBM3 ring of Salmonella flagellar MS-ring protein FliF with C1 symmetry applied |
Source |
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![]() | MOTOR PROTEIN / Bacterial flagellum / flagellar assembly / electron Cryomicroscopy / MS-ring / type III secretion system / Salmonella |