Summary: Type III secretion chaperone domain
Type III secretion chaperone domain Provide feedback
Type III secretion chaperones are involved in delivering virulence effector proteins from bacterial pathogens directly into eukaryotic cells. The chaperones may prevent aggregation and degradation of their substrates, may target the effector to the secretion apparatus, and may ensure a secretion-component unfolded confirmation of their specific substrate. One member of this family, SigE (O30917) forms homodimers in crystal. The monomers have a novel fold with an alpha-beta(3)-alpha-beta(2)-alpha topology .
Luo Y, Bertero MG, Frey EA, Pfuetzner RA, Wenk MR, Creagh L, Marcus SL, Lim D, Sicheri F, Kay C, Haynes C, Finlay BB, Strynadka NC; , Nat Struct Biol 2001;8:1031-1036.: Structural and biochemical characterization of the type III secretion chaperones CesT and SigE. PUBMED:11685226 EPMC:11685226
External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR013095
Type III secretion chaperones are involved in delivering virulence effector proteins from bacterial pathogens directly into eukaryotic cells. The chaperones may prevent aggregation and degradation of their substrates, may target the effector to the secretion apparatus, and may ensure a secretion-component unfolded conformation of their specific substrate. One member of this family, SigE (SWISSPROT) forms homodimers in crystal. The monomers have a novel fold with an alpha-beta(3)-alpha-beta(2)-alpha topology [PUBMED:11685226].
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The translocation of pathogenic proteins into a host cell is mediated by the type III secretory system. A component of this system is a chaperone, which binds to the protein which is going to be secreted in the bacterial cytosol and is involved in translocation of the secreted protein, although the chaperone is not translocated itself. An individual chaperone associates with one or two specific proteins . There are a large number of type III secretory system chaperones, which are small acidic proteins and exhibit significant sequence divergence. This clan groups type III secretory system chaperones. Members with a known structure form small compact globular domains with an alpha-beta(3)- alpha-beta(2)-alpha like organisation .
The clan contains the following 3 members:CesT Chaperone_III YbjN
We make a range of alignments for each Pfam-A family:
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Curation and family details
|Seed source:||Pfam-B_32938 (release 14.0)|
|Number in seed:||4|
|Number in full:||132|
|Average length of the domain:||106.40 aa|
|Average identity of full alignment:||88 %|
|Average coverage of the sequence by the domain:||98.71 %|
|HMM build commands:||
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
|Family (HMM) version:||7|
|Download:||download the raw HMM for this family|
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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 Chaperone_III domain has been found. There are 2 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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