InterPro : IPR005104

Name  Winged helix-turn-helix transcription repressor, HrcA DNA-binding domain Short Name  WHTH_HrcA_DNA-bd
Type  Domain 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. This domain represents the winged helix-turn-helix DNA-binding domain which is located close to the N terminus of HrcA. This domain is also found at the N terminus of a set of uncharacterised proteins that have two C-terminal CBS domains.

Sequence Features

GO Displayer


InterPro protein domain ID --> Contigs



0 Child Features

0 Contains

2 Found In

Id Name Short Name Type
IPR016436 Uncharacterised conserved protein UCP005063, CBS-type UCP005063_CBS Family
IPR002571 Heat-inducible transcription repressor HrcA HrcA Family

1 Parent Features

Id Name Short Name Type
IPR011991 Winged helix-turn-helix DNA-binding domain WHTH_DNA-bd_dom Domain

3 Publications

First Author Title Year Journal Volume Pages
Liu J Crystal structure of a heat-inducible transcriptional repressor HrcA from Thermotoga maritima: structural insight into DNA binding and dimerization. 2005 J Mol Biol 350 987-96
Kwon HY Reduction-sensitive and cysteine residue-mediated Streptococcus pneumoniae HrcA oligomerization in vitro. 2009 Mol Cells 27 149-57
Hitomi M Identification of a helix-turn-helix motif of Bacillus thermoglucosidasius HrcA essential for binding to the CIRCE element and thermostability of the HrcA-CIRCE complex, indicating a role as a thermosensor. 2003 J Bacteriol 185 381-5

To cite PlanMine, please refer to the following publication:

Rozanski, A., Moon, H., Brandl, H., Martín-Durán, J. M., Grohme, M., Hüttner, K., Bartscherer, K., Henry, I., & Rink, J. C.
PlanMine 3.0—improvements to a mineable resource of flatworm biology and biodiversity
Nucleic Acids Research, gky1070. doi:10.1093/nar/gky1070 (2018)