Oxidation of guanine by carbonate radicals derived from photolysis of carbonatotetramminecobalt(III) complexes and the pH dependence of intrastrand DNA cross-links mediated by guanine radical reactions.

ABSTRACT: The carbonate radical anion CO(3)(*-) is a decomposition product of nitrosoperoxycarbonate derived from the combination of carbon dioxide and peroxynitrite, an important biological byproduct of the inflammatory response. The selective oxidation of guanine in DNA by CO(3)(*-) radicals is known to yield spiroiminodihydantoin (Sp) and guanidinohydantoin (Gh) products, and also a novel intrastrand cross-linked product: 5'-d(CCATCG*CT*ACC), featuring a linkage between guanine C8 (G*) and thymine N3 (T*) atoms in the oligonucleotide (Crean et al., Nucleic Acids Res. 2008, 36, 742-755). Involvement of the T-N3 (pK(a) of N3-H is 9.67) suggests that the formation of 5'-d(CCATCG*CT*ACC) might be pH-dependent. This hypothesis was tested by generating CO(3)(*-) radicals through the photodissociation o

SUBMITTER: Crean C 

PROVIDER: S-EPMC3477471 | biostudies-literature | 2008 Aug

REPOSITORIES: biostudies-literature