RESUMEN
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.
Asunto(s)
Daño del ADN , ADN/efectos de la radiación , Oligodesoxirribonucleótidos/efectos de la radiación , Especies Reactivas de Oxígeno , Resonancia Magnética Nuclear Biomolecular , Conformación de Ácido Nucleico , Oligodesoxirribonucleótidos/química , Oxidación-Reducción , Soluciones , Espectrometría de Masa Bombardeada por Átomos Veloces , Rayos XRESUMEN
An improved method for separating the products of DNA oligomers irradiated in aqueous solution has been devised. Altogether 39 products were isolated from the tetramer d(CpGpTpA) X-irradiated in dilute anoxic solution. Of these, 16, including most of the major products, were identified through the use of proton nmr spectroscopy. The identified products fall into four categories: (1) base products, (2) strand scission products, (3) base modifications and (4) tandem lesion. A tandem lesion in which the methyl carbon atom of thymine is covalently linked to the guanine C8 carbon atom was produced in larger yield than any of the simple base modifications.