The DNA-binding domain of OmpR: crystal structures of a winged helix transcription factor

摘要: Abstract Background: The differential expression of the ompF and ompC genes is regulated by two proteins that belong to component family signal transduction proteins: histidine kinase, EnvZ, response regulator, OmpR. OmpR belongs a subfamily at least 50 regulators with homologous C-terminal DNA-binding domains approximately 98 amino acids. Sequence homology known structure cannot be detected, lack structural information has prevented understanding many this familys functional properties. Results: We have determined crystal Escherichia coli domain 1.95 A resolution. consists three α helices packed against antiparallel β sheets. Two helices, 2 3, ten residue loop connecting them constitute variation helix-turn-helix (HTH) motif. Helix 3 strands, 6 7, are probable DNA-recognition sites. Previous mutagenesis studies indicate large site interaction subunit RNA polymerase. Conclusions: OmpRc ‘winged helix-turn-helix' proteins. This relationship, results from numerous published studies, helped us interpret functions most elements present in protein domain. could useful helping define positioning polymerase relation transcriptional activators bound DNA.