OxyR, a positive regulator of hydrogen peroxide-inducible genes in Escherichia coli and Salmonella typhimurium, is homologous to a family of bacterial regulatory proteins.
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Christman MF, Storz G, Ames BN
OxyR, a positive regulator of hydrogen peroxide-inducible genes in Escherichia coli and Salmonella typhimurium, is homologous to a family of bacterial regulatory proteins.
Proc Natl Acad Sci U S A. 1989 May;86(10):3484-8.
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- 2471187 [ View in PubMed]
- Abstract
The oxyR gene is required for the induction of a regulon of hydrogen peroxide-inducible genes in Escherichia coli and Salmonella typhimurium. The E. coli oxyR gene has been cloned and sequenced, revealing an open reading frame (305 amino acids) that encodes a 34.4-kDa protein, which is produced in maxicells carrying the oxyR clone. The OxyR protein shows homology to a family of positive regulatory proteins including LysR in E. coli and NodD in Rhizobium. Like them, oxyR appears to be negatively autoregulated: an oxyR::lacZ gene fusion produced 5-fold higher levels of beta-galactosidase activity in oxyR null mutants compared to oxyR+ controls, and extracts from an OxyR-overproducing strain were able to protect regions (-27 to +21) of the oxyR promoter from DNase I digestion. DNA sequence analysis of the oxyR2 mutation, which causes overexpression of oxyR-regulated proteins in the absence of oxidative stress, showed that the oxyR2 phenotype is due to a missense mutation (C.G to T.A transition) that changes alanine to valine at amino acid position 234 of OxyR.