7DM9 image
Entry Detail
PDB ID:
7DM9
Keywords:
Title:
Crystal structure of FliM middle domain (51-229) from Vibro alginolyticus
Biological Source:
Source Organism:
PDB Version:
Deposition Date:
2020-12-02
Release Date:
2021-07-07
Method Details:
Experimental Method:
Resolution:
1.71 Å
R-Value Free:
0.20
R-Value Work:
0.17
R-Value Observed:
0.17
Space Group:
P 21 21 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Flagellar motor switch protein FliM
Chain IDs:A
Chain Length:194
Number of Molecules:1
Biological Source:Vibrio alginolyticus
Primary Citation
A slight bending of an alpha-helix in FliM creates a counterclockwise-locked structure of the flagellar motor in Vibrio.
J.Biochem. 170 531 538 (2021)
PMID: 34143212 DOI: 10.1093/jb/mvab074

Abstact

Many bacteria swim by rotating flagella. The chemotaxis system controls the direction of flagellar rotation. Vibrio alginolyticus, which has a single polar flagellum, swims smoothly by rotating the flagellar motor counterclockwise (CCW) in response to attractants. In response to repellents, the motor frequently switches its rotational direction between CCW and clockwise (CW). We isolated a mutant strain that swims with a CW-locked rotation of the flagellum, which pulls rather than pushes the cell. This CW phenotype arises from a R49P substitution in FliM, which is the component in the C-ring of the motor that binds the chemotaxis signalling protein, phosphorylated CheY. However, this phenotype is independent of CheY, indicating that the mutation produces a CW conformation of the C-ring in the absence of CheY. The crystal structure of FliM with the R49P substitution showed a conformational change in the N-terminal α-helix of the middle domain of FliM (FliMM). This helix should mediates FliM-FliM interaction. The structural models of wild type and mutant C-ring showed that the relatively small conformational change in FliMM induces a drastic rearrangement of the conformation of the FliMM domain that generates a CW conformation of the C-ring.

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Primary Citation of related structures