Characterization of the products of dinucleoside monophosphates d(GpN) irradiated in aqueous solutions.

The dinucleoside monophosphates d(GpT), d(GpC), and d(GpA) were X-irradiated in oxygenated aqueous solution. The principal products were identified in the intact modified dinucleoside monophosphates using NMR spectroscopy and FAB mass spectrometry. The 8-hydroxyguanine modification is a major product in each of the d(GpN). The d(GpN), where N is a pyrimidine nucleoside, also yield products in which the pyrimidine base is degraded to a formamido remnant. The most interesting product is one bearing two base damages, 8-hydroxylation of the guanine base and degradation of the pyrimidine base to a formamido remnant. This double lesion was observed in both d(GpN) where N is a pyrimidine base.