Superoxide accelerates DNA damage by elevating free-iron levels

摘要

Superoxide promotes hydroxyl-radical for- mation and consequent DNA damage in cells of all types. The long-standing hypothesis that it primarily does so by deliver- ing electrons to adventitious iron on DNA was refuted by recent studies in Escherichia coli. Alternative proposals have suggested that superoxide may accelerate oxidative DNA damage by leaching iron from storage proteins or enzymic [4Fe-4S] clusters. The released iron might then deposit on the surface of the DNA, where it could catalyze the formation of DNA oxidants using other electron donors.