A Reevaluation of the Ambident Reactivity of Guanine Moiety Towards Hydroxyl Radicals

Radically different: Contrary to previous proposals, the main reaction of the HO. radical with guanosine or 2?-deoxyguanosine is the hydrogen abstraction from the NH2 moiety to give a guanyl radical. This radical, characterized by a broad band in the visible region (around 610 nm), undergoes tautomerization to the most stable isomer. This research was supported in part by the European Community's Marie Curie Research Training Network under contract MRTN-CT-2003-505086 (CLUSTOXDNA).