Regulators of Oxidative Stress Response Genes in Escherichia Coli and Their Conservation in Bacteria

Bacterial responses to oxidative stress are complex, and they include both factors that prevent the accumulation of reactive oxygen species that are a normal by‐product of metabolism and factors that repair damage caused by oxidative stress. An important biological imperative in bacteria is reducing the flux of reactive oxygen species within the cell by increasing levels of enzymes, including superoxide dismutase, catalase, and hydroperoxidase, in addition to sequestering transition metals, particularly iron that can exacerbate oxidative stress through the production of hydroxyl radicals. Regulation of protective factors is mediated by conserved regulators, including OxyR, controlling catalase and peroxidases; the SoxRS system, controlling superoxide dismutase; and RpoS, the general stress response regulator that potentiates expression of key protective enzymes in the stationary phase. Other regulators that maintain intracellular iron levels are also key conserved components of the oxidative stress response.