PMID:7868602
| Citation |
Kullik, I, Toledano, MB, Tartaglia, LA and Storz, G (1995) Mutational analysis of the redox-sensitive transcriptional regulator OxyR: regions important for oxidation and transcriptional activation. J. Bacteriol. 177:1275-84 |
|---|---|
| Abstract |
OxyR is a redox-sensitive transcriptional regulator of the LysR family which activates the expression of genes important for the defense against hydrogen peroxide in Escherichia coli and Samonella typhimurium. OxyR is sensitive to oxidation and reduction, and only oxidized OxyR is able to activate transcription of its target genes. Using site-directed mutagenesis, we found that one cysteine residue (C-199) is critical for the redox sensitivity of OxyR, and a C-199-->S mutation appears to lock the OxyR protein in the reduced form. We also used a random mutagenesis approach to isolate eight constitutively active mutants. All of the mutations are located in the C-terminal half of the protein, and four of the mutations map near the critical C-199 residue. In vivo as well as in vitro transcription experiments showed that the constitutive mutant proteins were able to activate transcription under both oxidizing and reducing conditions, and DNase I footprints showed that this activation is due to the ability of the mutant proteins to induce cooperative binding of RNA polymerase. Unexpectedly, RNA polymerase was also found to reciprocally affect OxyR binding. |
| Links | |
| Keywords |
Amino Acid Sequence; Bacterial Proteins/genetics; Base Sequence; Binding Sites/genetics; Cysteine/genetics; DNA Mutational Analysis; DNA-Binding Proteins; DNA-Directed RNA Polymerases/metabolism; Drug Resistance, Microbial/genetics; Escherichia coli/genetics; Escherichia coli Proteins; Hydrogen Peroxide/pharmacology; Molecular Sequence Data; Mutagenesis, Site-Directed; Oxidation-Reduction; Oxidative Stress/genetics; Protein Binding; Repressor Proteins; Selection, Genetic; Sequence Homology, Amino Acid; Signal Transduction/genetics; Structure-Activity Relationship; Transcription Factors/genetics; Transcription, Genetic |
| edit table |
Notes
This paper has an error in it. pAQ5 is described as being CmR and AmpR. It is, in fact, only CmR.
Significance
You can help EcoliWiki by summarizing why this paper is useful
Useful Materials and Methods
You can help Ecoliwiki by describing the useful materials (strains, plasmids, antibodies, etc) described in this paper.
Annotations
<annotationlinks/>
EcoliWiki Links
Add links to pages that link here (e.g. gene, product, method pages)
References
See Help:References for how to manage references in EcoliWiki.