PROSITE documentation PDOC51118HxlR-type HTH domain profile
The hxlR-type HTH domain is a domain of ~90-100 amino acids present in putative transcription regulators with a winged helix-turn-helix (wHTH) structure. The domain is named after Bacillus subtilis hxlR, a transcription activator of the hxlAB operon involved in the detoxification of formaldehyde [1]. The hxlR-type domain forms the core of putative transcription regulators and of hypothetical proteins occurring in eubacteria as well as in archaea. The sequence and structure of hxlR-type proteins show similarities with the marR-type wHTH (see <PDOC00861>) [2].
The crystal structure of ytfH resembles the DNA-binding domains of winged helix proteins (see <PDB:1YYV>), containing a three helix (H) bundle and a three-stranded antiparallel β-sheet (B) in the topology: H1-H2-B1-H3-H4-B2-B3-H5-H6. This topology corresponds with that of the marR-type DNA-binding domain, wherein helices 3 and 4 comprise the helix-turn-helix motif and the β-sheet is called the wing.
Some proteins known to contain a hxlR-type HTH domain:
- Bacillus subtilis hxlR, a transcription activator for enzymes of the ribulose monophosphate pathway, which can be induced by formaldehyde.
- Escherichia coli and Salmonella typhimurium ytfH, a hypothetical protein.
- Fusobacterium mortiferum malR, a potential regulator of the malBH operon involved in the metabolism of sucrose isomers [3].
The profile we developed covers the entire hxlR-type HTH domain.
Last update:April 2005 / First entry.
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PROSITE method (with tools and information) covered by this documentation:
1 | Authors | Yasueda H. Kawahara Y. Sugimoto S. |
Title | Bacillus subtilis yckG and yckF encode two key enzymes of the ribulose monophosphate pathway used by methylotrophs, and yckH is required for their expression. | |
Source | J. Bacteriol. 181:7154-7160(1999). | |
PubMed ID | 10572115 |
2 | Authors | Huffman J.L. Brennan R.G. |
Title | Prokaryotic transcription regulators: more than just the helix-turn-helix motif. | |
Source | Curr. Opin. Struct. Biol. 12:98-106(2002). | |
PubMed ID | 11839496 |
3 | Authors | Pikis A. Immel S. Robrish S.A. Thompson J. |
Title | Metabolism of sucrose and its five isomers by Fusobacterium mortiferum. | |
Source | Microbiology 148:843-852(2002). | |
PubMed ID | 11882720 |
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