Summary: HrcA protein C terminal domain
HrcA protein C terminal domain Provide feedback
HrcA is found to negatively regulate the transcription of heat shock genes [1,2]. HrcA contains an amino terminal helix-turn-helix domain, however this corresponds to the carboxy terminal domain.
Schulz A, Schumann W; , J Bacteriol 1996;178:1088-1093.: hrcA, the first gene of the Bacillus subtilis dnaK operon encodes a negative regulator of class I heat shock genes. PUBMED:8576042 EPMC:8576042
Roberts RC, Toochinda C, Avedissian M, Baldini RL, Gomes SL, Shapiro L; , J Bacteriol 1996;178:1829-1841.: Identification of a Caulobacter crescentus operon encoding hrcA, involved in negatively regulating heat-inducible transcription, and the chaperone gene grpE. PUBMED:8606155 EPMC:8606155
Internal database links
|SCOOP:||NLE DUF2111 DUF3452 FtsZ_C DUF3926 FOXO_KIX_bdg|
External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR021153
Prokaryotic cells have a defence mechanism against a sudden heat-shock stress. Commonly, they induce a set of proteins that protect cellular proteins from being denatured by heat. Among such proteins are the GroE and DnaK chaperones whose transcription is regulated by a heat-shock repressor protein HrcA. HrcA is a winged helix-turn-helix repressor that negatively regulates the transcription of dnaK and groE operons by binding the upstream CIRCE (controlling inverted repeat of chaperone expression) element. In Bacillus subtilis this element is a perfect 9 base pair inverted repeat separated by a 9 base pair spacer.
The crystal structure of a heat-inducible transcriptional repressor, HrcA, from Thermotoga maritima has been reported at 2.2A resolution. HrcA is composed of three domains: an N-terminal winged helix-turn-helix domain (WHTH), a GAF-like domain, and an inserted dimerizing domain (IDD). The IDD shows a unique structural fold with an anti-parallel beta-sheet composed of three beta-strands sided by four alpha-helices. HrcA crystallises as a dimer, which is formed through hydrophobic contact between the IDDs and a limited contact that involves conserved residues between the GAF-like domains [PUBMED:15979091]. The structural studies suggest that the inactive form of HrcA is the dimer and this is converted to its DNA-binding form by interaction with GroEL, which binds to a conserved C-terminal sequence region [PUBMED:19277496, PUBMED:15979091]. Comparison of the HrcA-CIRCE complexes from B. subtilis and Bacillus thermoglucosidasius (Geobacillus thermoglucosidasius), which grow at vastly different ranges of temperature shows that the thermostability profiles were consistent with the difference in the growth temperatures suggesting that HrcA can function as a thermosensor to detect temperature changes in cells [PUBMED:12486078]. Any increase in temperature causes the dissociation of the HrcA from the CIRCE complex with the concomitant activation of transcription of the groE and dnaK operons.This entry represents the C terminus of HrcA, consisting of the GAF-like domain with the inserted dimerising domain.
The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.
|Molecular function||DNA binding (GO:0003677)|
|Biological process||regulation of transcription, DNA-templated (GO:0006355)|
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Curation and family details
|Seed source:||Pfam-B_1133 (release 4.1)|
|Number in seed:||738|
|Number in full:||12276|
|Average length of the domain:||216.70 aa|
|Average identity of full alignment:||33 %|
|Average coverage of the sequence by the domain:||64.35 %|
|HMM build commands:||
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 80369284 -E 1000 --cpu 4 HMM pfamseq
|Family (HMM) version:||17|
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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 HrcA domain has been found. There are 3 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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