Repair of hydrogen peroxide-induced single-strand breaks in Escherichia coli deoxyribonucleic acid

Abstract
Near-UV (300-400 nm) irradiation of L-tryptophan yielded H2O2 (a toxic photoproduct) that was selectively lethal for rec and polA1 E. coli mutants. H2O2 treatment of cells resulted in the induction of single-strdnd DNA breaks. These breaks were repaired to only a small extent in polA1, recA recB and recA mutants, but were efficiently repaired in wild-type strains. H2O2 induced DNA lesions apparently require the polA+ and recA+ pathways for repair.