Sugar radical formation by a proton coupled hole transfer in 2'-deoxyguanosine radical cation (2'-dG*+): a theoretical treatment.

ABSTRACT: Previous experimental and theoretical work has established that electronic excitation of a guanine cation radical in nucleosides or in DNA itself leads to sugar radical formation by deprotonation from the dexoxyribose sugar. In this work, we investigate a ground electronic state pathway for such sugar radical formation in a hydrated one electron oxidized 2'-deoxyguanosine (dG(*+) + 7H(2)O), using density functional theory (DFT) with the B3LYP functional and the 6-31G* basis set. We follow the stretching of the C(5')-H bond in dG(*+) to gain an understanding of the energy requirements to transfer the hole from the base to sugar ring and then to deprotonate to proton acceptor sites in solution and on the guanine ring. The geometries of reactant (dG(*+) + 7H(2)O), transition state (TS) for de

SUBMITTER: Kumar A 

PROVIDER: S-EPMC2765868 | biostudies-literature | 2009 Oct

REPOSITORIES: biostudies-literature