Water radiolysis products and nucleotide damage in γ-irradiated DNA

The radiation chemistry of nucleotide damage introduction into DNA γ-irradiated in dilute aqueous solution has been studied with a damage-specific DNA binding protein. Irradiation in air, N2 or N2O in the presence and absence of free radical scavengers revealed that protein-recognizable lesions were introduced both by the hydrated electron and by the combination of the hydroxyl radical and the superoxide anion radical, but not by the hydroxyl radical alone. In addition, nucleotide damage was introduced into DNA by an enzymatic superoxide-generating system. (author)