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

ABSTRACT: We report that photo-excitation of one-electron-oxidized adenine [A(-H)*] in dAdo and its 2'-deoxyribonucleotides leads to formation of deoxyribose sugar radicals in remarkably high yields. Illumination of A(-H)* in dAdo, 3'-dAMP and 5'-dAMP in aqueous glasses at 143 K leads to 80-100% conversion to sugar radicals at C5' and C3'. The position of the phosphate in 5'- and 3'-dAMP is observed to deactivate radical formation at the site of substitution. In addition, the pH has a crucial influence on the site of sugar radical formation; e.g. at pH approximately 5, photo-excitation of A(-H)* in dAdo at 143 K produces mainly C5'* whereas only C3'* is observed at high pH approximately 12. 13C substitution at C5' in dAdo yields 13C anisotropic couplings of (28, 28, 84) G whose isotropic component 4

SUBMITTER: Adhikary A 

PROVIDER: S-EPMC1401510 | biostudies-literature | 2006

REPOSITORIES: biostudies-literature