@article {Kaloudis2009a,
	title = {{Comparison of Isoelectronic 8-HO-G and 8-NH2-G Derivatives in Redox Processes}},
	journal = {J. Am. Chem. Soc.},
	volume = {131},
	number = {43},
	year = {2009},
	pages = {15895{\textendash}15902},
	publisher = {American Chemical Society},
	abstract = {8-Oxo-7,8-dihydroguanine (8-oxo-G) is the major lesion of oxidatively generated DNA damage. Despite two decades of intense study, several fundamental properties remain to be defined. Its isoelectronic 8-aminoguanine (8-NH2-G) has also received considerable attention from a biological point of view, although its chemistry involving redox processes remains to be discovered. We investigated the one-electron oxidation and one-electron reduction reactions of 8-oxo-G and 8-NH2-G derivatives. The reactions of hydrated electrons (eaq{\quotesinglbase}{\`a}{\'\i}) and azide radicals (N3{\quotesinglbase}{\"A}{\textcent}) with both derivatives were studied by pulse radiolysis techniques, and the transient absorption spectra were assigned to specific tautomers computationally by means of time-dependent DFT (TD-B3LYP/6-311G**//B1B95/6-31+G**) calculations. The protonated electron adducts of 8-NH2-G and 8-oxo-G showed a substantial difference in their absorption spectra, the unpaired electron being mainly delocalized in the imidazolyl ring and in the six-membered ring, respectively. On the other hand, the deprotonated forms of one-electron oxidation of 8-NH2-G and 8-oxo-G showed quite similar spectral characteristics. In a parallel study, the one-electron reduction of 8-azidoguanine (8-N3-G) afforded the same transient of one-electron oxidation of 8-NH2-G, which represents another example of generation of one-electron oxidized guanine derivatives under reducing conditions. Moreover, the fate of transient species was investigated by radiolytic methods coupled with product studies and allowed self- and cross-termination rate constants associated with these reactions to be estimated.},
	isbn = {0002-7863},
	doi = {10.1021/ja9065464},
	url = {http://dx.doi.org/10.1021/ja9065464},
	author = {Kaloudis, Panagiotis and D{\quotesinglbase}{\"A}{\^o}Angelantonio, Mila and Guerra, Maurizio and Spadafora, Marie and Cismas{\~A}{\ss}, Crina and Gimisis, Thanasis and Mulazzani, Quinto G. and Chatgilialoglu, Chryssostomos}
}
