Protein Domain : IPR002571

Type:  Family Name:  Heat-inducible transcription repressor HrcA
Description:  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 subtilisthis 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 maritimahas 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 []. 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 [, ]. 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 []. 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. Short Name:  HrcA
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0 Child Features

3 Contains

DB identifier Type Name
IPR011991 Domain Winged helix-turn-helix DNA-binding domain
IPR005104 Domain Winged helix-turn-helix transcription repressor, HrcA DNA-binding domain
IPR021153 Domain Heat-inducible transcription repressor HrcA, C-terminal

3 Cross Referencess

Identifier
PIRSF005485
TIGR00331
MF_00081

0 Found In

2 GO Annotations

GO Term Gene Name
GO:0003677 IPR002571
GO:0006355 IPR002571

2 Ontology Annotations

GO Term Gene Name
GO:0003677 IPR002571
GO:0006355 IPR002571

0 Parent Features

1 Proteins

DB identifier UniProt Accession Secondary Identifier Organism Name Length
33590.m000021 B9TF42 PAC:16825922 Ricinus communis 382  

3 Publications

First Author Title Year Journal Volume Pages PubMed ID
            15979091
            19277496
            12486078