Formation of cross-linked adducts between guanine and thymine mediated by hydroxyl radical and one-electron oxidation: a theoretical study

Abstract

The role of local geometric and stereo-electronic effects in tuning the preference for different cross-linked adducts between thymine and purinic bases has been analyzed by a computational approach rooted in density functional theory. Our study points out that G⁁T and T^⁁G tandem lesions are produced according to the same mechanism as A⁁T and T⁁A intrastrand adducts, and in both cases purine⁁T adducts are preferred rather than the opposite sequences. Moreover, use of conceptual DFT tools allows the rationalization of the preferential occurrence of G⁁T and T⁁G tandem lesions in place of their A⁁T and T⁁A counterparts.