PerR, OxyR, and SoxR regulate bacterial responses to:
Aerobic metabolism inevitably generates reactive oxygen species including superoxide radical anion and hydrogen peroxide via single-electron leakage from respiratory flavoproteins and autoxidation of reduced ferredoxins that damage solvent-exposed iron-sulfur clusters, DNA bases and unsaturated lipids. Bacteria have evolved exquisite sensing transcription factors that regulate defensive regulons. OxyR in Escherichia coli contains highly reactive cysteines C199 and C208 that when oxidized by low micromolar H2O2 form a reversible intramolecular disulfide bond driving conformational change to act
Ref: Storz and Imlay, Oxidative Stress Regulators, Annu Rev Microbiol: OxyR, PerR, SoxR Oxidative Stress Systems.
