Redox-operated genetic switches: the SoxR and OxyR transcription factors

Two redox-responsive transcription regulators have been well defined in Escherichia coli and serve as paradigms of redox-operated genetic switches. SoxR contains iron-sulfur centers that activate the protein when they are one-electron oxidized, or nitrosylated by nitric oxide. OxyR contains a pair of redox-active cysteine residues that activate the protein when they are oxidized to form a disulfide bond.