Direct Oxidative Damage of Naked DNA Generated upon Absorption of UV Radiation by Nucleobases

M. Gomez-Mendoza (1, 2, 3) , A. Banyasz (4, 5) , Thierry Douki (1) , D. Markovitsi (5, 4) , J.-L. Ravanat (1, 2, 3)

1 SYMMES - SYstèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé
2 LAN - Laboratoire Lésions des Acides Nucléiques
3 SCIB - UMR E3 - Service de Chimie Inorganique et Biologique
4 DICO - Biomolécules Excitées
5 LIDyl - Laboratoire Interactions, Dynamiques et Lasers (ex SPAM)

It has been shown that in addition to formation of pyrimidine dimers, UV irradiation of DNA in the absence of photosensitizer also induces formation of 8-oxo-7,8-dihydro-2′-deoxyguanosine, but the mechanism of formation of that oxidized base has not been clearly established. In the present study, we provide an unambiguous demonstration that absorption of UVC and UVB radiation by the nucleobases induces DNA oxidation via a direct process (one-electron oxidation) and not singlet oxygen. Evidence arose from the fact that polyamine-guanine adducts that are specifically produced through the transient formation of guanine radical cation are generated following UV irradiation of DNA in the presence of a polyamine even in the absence of any photosensitizer.

Domains: Chemical Sciences; Theoretical and/or physical chemistry

M. Gomez-Mendoza, A. Banyasz, Thierry Douki, D. Markovitsi, J.-L. Ravanat. Direct Oxidative Damage of Naked DNA Generated upon Absorption of UV Radiation by Nucleobases. Journal of Physical Chemistry Letters, 2016, 7 (19), pp.3945-3948. ⟨10.1021/acs.jpclett.6b01781⟩. ⟨cea-01426181⟩