InterPro : IPR018335

Name  Transcription regulator HTH, Crp-type, conserved site Short Name  Tscrpt_reg_HTH_Crp-type_CS
Type  Conserved_site Description  The crp-type HTH domain is a DNA-binding, winged helix-turn-helix (wHTH) domain of about 70-75 amino acids present in transcription regulators of the crp-fnr family, involved in the control of virulence factors, enzymes of aromatic ring degradation, nitrogen fixation, photosynthesis, and various types of respiration. The crp-fnr family is named after the first members identified in Escherichia coli: the well characterised cyclic AMP receptor protein CRP or CAP (catabolite activator protein) and the fumarate and nitrate reductase regulator Fnr. crp-type HTH domain proteins occur in most bacteria and in chloroplasts of red algae. The DNA-binding HTH domain is located in the C-terminal part; the N-terminal part of the proteins of the crp-fnr family contains a nucleotide-binding domain and a dimerisation/linker helix occurs in between. The crp-fnr regulators predominantly act as transcription activators, but can also be important repressors, and respond to diverse intracellular and exogenous signals, such as cAMP, anoxia, redox state, oxidative and nitrosative stress, carbon monoxide, nitric oxide or temperature []. The structure of the crp-type DNA-binding domain shows that the helices (H) forming the helix-turn-helix motif (H2-H3) are flanked by two beta-hairpin (B) wings, in the topology H1-B1-B2-H2-H3-B3-B4. Helix 3 is termed the recognition helix, as in most wHTHs it binds the DNA major groove [, , ]. Some proteins known to contain a Crp-type HTH domain: E. coli crp (also known as cAMP receptor), a protein that complexes with cAMP and regulates the transcription of several catabolite-sensitive operons. E. coli fnr, a protein that activates genes for proteins involved in a variety of anaerobic electron transport systems. Rhizobium leguminosarumfnrN, a transcription regulator of nitrogen fixation. Rhodobacter sphaeroides(Rhodopseudomonas sphaeroides) fnrL, a transcription activator of genes for heme biosynthesis, bacteriochlorophyll synthesis and the light-harvesting complex LHII. Rhizobiacae fixK, a protein that regulates nitrogen fixation genes, both positively and negatively. Lactobacillus caseifnr-like protein flp, a putative regulatory protein linked to the trpDCFBA operon. Cyanobacteria ntcA, a regulator of the expression of genes subject to nitrogen control. Xanthomonas campestrisclp, a protein involved in the regulation of phytopathogenicity. Clp controls the production of extracellular enzymes, xanthan gum and pigment, either positively or negatively.

Sequence Features

GO Displayer


InterPro protein domain ID --> Contigs



0 Child Features

0 Contains

4 Found In

Id Name Short Name Type
IPR011991 Winged helix-turn-helix DNA-binding domain WHTH_DNA-bd_dom Domain
IPR001808 Transcription regulator HTH, Crp Tscrpt_reg_HTH_Crp Domain
IPR012318 Helix-turn-helix motif, Crp-type HTH_CRP_2 Domain
IPR022299 Transcription regulator, NtcA Tscrpt_reg_NtcA Family

0 Parent Features

4 Publications

First Author Title Year Journal Volume Pages
Busby S Transcription activation by catabolite activator protein (CAP). 1999 J Mol Biol 293 199-213
Huffman JL Prokaryotic transcription regulators: more than just the helix-turn-helix motif. 2002 Curr Opin Struct Biol 12 98-106
Irvine AS Lactobacillus casei contains a member of the CRP-FNR family. 1993 Nucleic Acids Res 21 753
Lanzilotta WN Structure of the CO sensing transcription activator CooA. 2000 Nat Struct Biol 7 876-80

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)