|PROSITE documentation PDOC00043|
The lysR-type HTH domain is a DNA-binding, winged helix-turn-helix (wHTH) domain of about 60 residues present in lysR-type transcriptional regulators (LTTR), one of the most common regulator families in prokaryotes. The family is named after the Escherichia coli regulator lysR . LysR proteins are present in diverse bacterial genera, archaea and algal chloroplasts. All LTTRs contain the DNA-binding lysR-type HTH domain, usually in the N-terminal part. Most LTTRs require a small compound that acts as co-inducer. The C-terminal part of lysR proteins can contain a regulatory domain with two subdomains involved in (1) co-inducer recognition/response and (2) DNA binding and response. LTTRs activate the transcription of operons and regulons involved in very diverse functions, such as amino acid biosynthesis, CO2 fixation, antibiotic resistance, regulation of virulence factors, nodulation for nitrogen fixing bacteria, oxidative stress response or aromatic compounds catabolism.
Most LTTRs act as a transcriptional activator of the target genes and also as a repressor of their own expression. Typical LTTRs bind to a sequence of about 50-60 bp, which contains two distinct sites, (1) a recognition-binding site (RBS) centered near -65 of the target transcription start site and with an inverted repeat motif including the T-N(11)-A motif and (2) an activation-binding site (ABS) which overlaps the -35 region of the transcription start site of the regulated gene. LysR proteins are mainly cytoplasmic, but some seem membrane-bound .
The crystal structure of the lysR DNA-binding domain of CbnR shows three α helices and two anti-parallel β strands (see <PDB:1IXC>), with the helix-turn-helix motif comprising the second and third helices and the strands being called the wing. Most LTTRs are likely tetramers .
Some proteins known to contain a lysR domain:
The profile we developed covers the entire lysR-type HTH domain.
October 2003 / Pattern removed, profile added and text revised.
PROSITE method (with tools and information) covered by this documentation:
|HTH_LYSR, PS50931; LysR-type HTH domain profile (MATRIX)|
|Matching PDB structures: 3ISP 3K1M 3K1N 3K1P ... [ALL]|
|1||Authors||Henikoff S., Haughn G.W., Calvo J.M., Wallace J.C.|
|Title||A large family of bacterial activator proteins.|
|Source||Proc. Natl. Acad. Sci. U.S.A. 85:6602-6606(1988).|
|Title||Molecular biology of the LysR family of transcriptional regulators.|
|Source||Annu. Rev. Microbiol. 47:597-626(1993).|
|3||Authors||Muraoka S., Okumura R., Ogawa N., Nonaka T., Miyashita K., Senda T.|
|Title||Crystal structure of a full-length LysR-type transcriptional regulator, CbnR: unusual combination of two subunit forms and molecular bases for causing and changing DNA bend.|
|Source||J. Mol. Biol. 328:555-566(2003).|