Long-range oxidative damage to cytosines in duplex DNA.

ABSTRACT: Charge transport (CT) through DNA has been found to occur over long molecular distances in a reaction that is sensitive to intervening structure. The process has been described mechanistically as involving diffusive charge-hopping among low-energy guanine sites. Using a kinetically fast electron hole trap, N(4)-cyclopropylcytosine ((CP)C), here we show that hole migration must involve also the higher-energy pyrimidine bases. In DNA assemblies containing either [Rh(phi)(2)(bpy')](3+) or an anthraquinone derivative, two high-energy photooxidants, appreciable oxidative damage at a distant (CP)C is observed. The damage yield is modulated by lower-energy guanine sites on the same or complementary strand. Significantly, the efficiency in trapping at (CP)C is equivalent to that at N(2)-cyclopropy

SUBMITTER: Shao F 

PROVIDER: S-EPMC539793 | biostudies-literature | 2004 Dec

REPOSITORIES: biostudies-literature