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9  structures 6908  species 2  interactions 8270  sequences 14  architectures

Family: FliG_C (PF01706)

Summary: FliG C-terminal domain

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This is the Wikipedia entry entitled "Flagellar motor switch". More...

Flagellar motor switch Edit Wikipedia article

FliG C-terminal domain
PDB 1lkv EBI.jpg
crystal structure of the middle and c-terminal domains of the flagellar rotor protein flig
Symbol FliG_C
Pfam PF01706
Pfam clan CL0436
InterPro IPR000090
SCOP 1qc7
Flagellar motor switch protein FliM
Symbol FliM
Pfam PF02154
Pfam clan CL0355
InterPro IPR001689

In molecular biology, the flagellar motor switch is a protein complex. In Escherichia coli and Salmonella typhimurium it regulates the direction of flagellar rotation and hence controls swimming behaviour.[1] The switch is a complex apparatus that responds to signals transduced by the chemotaxis sensory signalling system during chemotactic behaviour.[1] CheY, the chemotaxis response regulator, is believed to act directly on the switch to induce tumbles in the swimming pattern, but no physical interactions of CheY and switch proteins have yet been demonstrated.

The switch complex comprises at least three proteins - FliG, FliM and FliN. It has been shown that FliG interacts with FliM, FliM interacts with itself, and FliM interacts with FliN.[2] Several amino acids within the middle third of FliG appear to be strongly involved in the FliG-FliM interaction, with residues near the N- or C-termini being less important.[2] Such clustering suggests that FliG-FliM interaction plays a central role in switching.

Analysis of the FliG, FliM and FliN sequences shows that none are especially hydrophobic or appear to be integral membrane proteins.[3] This result is consistent with other evidence suggesting that the proteins may be peripheral to the membrane, possibly mounted on the basal body M ring.[3][4] FliG is present in about 25 copies per flagellum. The structure of the C-terminal domain of FliG is known, this domain functions specifically in motor rotation.[5]


  1. ^ a b Roman SJ, Frantz BB, Matsumura P (October 1993). "Gene sequence, overproduction, purification and determination of the wild-type level of the Escherichia coli flagellar switch protein FliG". Gene 133 (1): 103–8. doi:10.1016/0378-1119(93)90232-R. PMID 8224881. 
  2. ^ a b Marykwas DL, Berg HC (March 1996). "A mutational analysis of the interaction between FliG and FliM, two components of the flagellar motor of Escherichia coli". J. Bacteriol. 178 (5): 1289–94. PMC 177801. PMID 8631704. 
  3. ^ a b Kihara M, Homma M, Kutsukake K, Macnab RM (June 1989). "Flagellar switch of Salmonella typhimurium: gene sequences and deduced protein sequences". J. Bacteriol. 171 (6): 3247–57. PMC 210043. PMID 2656645. 
  4. ^ Francis NR, Irikura VM, Yamaguchi S, DeRosier DJ, Macnab RM (July 1992). "Localization of the Salmonella typhimurium flagellar switch protein FliG to the cytoplasmic M-ring face of the basal body". Proc. Natl. Acad. Sci. U.S.A. 89 (14): 6304–8. doi:10.1073/pnas.89.14.6304. PMC 49489. PMID 1631122. 
  5. ^ Lloyd SA, Whitby FG, Blair DF, Hill CP (July 1999). "Structure of the C-terminal domain of FliG, a component of the rotor in the bacterial flagellar motor". Nature 400 (6743): 472–5. doi:10.1038/22794. PMID 10440379. 

This article incorporates text from the public domain Pfam and InterPro IPR001689

This article incorporates text from the public domain Pfam and InterPro IPR000090

This page is based on a Wikipedia article. The text is available under the Creative Commons Attribution/Share-Alike License.

This tab holds the annotation information that is stored in the Pfam database. As we move to using Wikipedia as our main source of annotation, the contents of this tab will be gradually replaced by the Wikipedia tab.

FliG C-terminal domain Provide feedback

FliG is a component of the flageller rotor, present in about 25 copies per flagellum. This domain functions specifically in motor rotation.

Literature references

  1. Lloyd SA, Whitby FG, Blair DF, Hill CP; , Nature 1999;400:472-475.: Structure of the C-terminal domain of FliG, a component of the rotor in the bacterial flagellar motor [In Process Citation] PUBMED:10440379 EPMC:10440379

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External database links

This tab holds annotation information from the InterPro database.

No InterPro data for this Pfam family.

Domain organisation

Below is a listing of the unique domain organisations or architectures in which this domain is found. More...

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Pfam Clan

This family is a member of clan FliG (CL0436), which has the following description:

This superfamily is characterised by a fragmented superhelix consisting of 3-4 helical motifs and connecting helices. Memebers include the direct flagellar motor as well as the MG2+ families.

The clan contains the following 4 members:

FliG_C FliG_M FliG_N MgtE_N


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Curation and family details

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Seed source: [1]
Previous IDs: FliG-C;
Type: Domain
Author: Bateman A
Number in seed: 358
Number in full: 8270
Average length of the domain: 107.80 aa
Average identity of full alignment: 45 %
Average coverage of the sequence by the domain: 32.47 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 80369284 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 23.0 23.0
Trusted cut-off 23.0 23.1
Noise cut-off 22.9 22.8
Model length: 108
Family (HMM) version: 12
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Species distribution

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Archea Archea Eukaryota Eukaryota
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Viroids Viroids Unclassified sequence Unclassified sequence


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There are 2 interactions for this family. More...

FliG_M FliG_C


For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the FliG_C domain has been found. There are 9 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein seqence.

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