An overall perspective of X-ray damage to a DNA oligomer mediated by reactive oxygen species.

The products produced by X irradiation of an oxygenated aqueous solution containing d(CpApTpG) were analyzed by NMR spectroscopy and mass spectrometry. Thirteen different base modifications were detected, including a novel product formed by the addition of oxygen to guanine. Seven different strand break products were identified, including strands having 5'-phosphoryl groups, 3'-phosphoryl groups and groups having 3'-phosphoglycolates as termini. The products produced in largest yield contained base modifications: Pyrimidine bases degraded to a formamido moiety, the 8-oxo-7,8-dihydroguanine (8-oxoguanine) lesion, and double base lesions in which both the 8-oxo-7,8-dihydroguanine lesion and a formamido remnant are present.