C5'- and C3'-sugar radicals produced via photo-excitation of one-electron oxidized adenine in 2'-deoxyadenosine and its derivatives

摘要: We report that photo-excitation of one-electron-oxidized adenine [A(-H)*] in dAdo and its 2'-deoxyribonucleotides leads to formation deoxyribose sugar radicals remarkably high yields. Illumination A(-H)* dAdo, 3'-dAMP 5'-dAMP aqueous glasses at 143 K 80-100% conversion C5' C3'. The position the phosphate 5'- is observed deactivate radical site substitution. In addition, pH has a crucial influence on formation; e.g. approximately 5, produces mainly C5'* whereas only C3'* 12. 13C substitution yields anisotropic couplings (28, 28, 84) G whose isotropic component 46.7 identifies near planar C5'*. A beta-13C 16 coupling from also found. These results are found be accord with theoretically calculated [DFT, B3LYP, 6-31(G) level] for C3'*. Calculations using time-dependent density functional theory [TD-DFT 6-31G(d)] confirm transitions UV visible induce hole transfer base group leading formation.