Kinetics of deamination and Cu(II)/H2O2/Ascorbate-induced formation of 5-methylcytosine glycol at CpG sites in duplex DNA.

ABSTRACT: Mutation in p53 tumor suppressor gene is a hallmark of human cancers. Six major mutational hotspots in p53 contain methylated CpG (mCpG) sites, and C -->T transition is the most common mutation at these sites. It was hypothesized that the formation of 5-methylcytosine glycol induced by reactive oxygen species, its spontaneous deamination to thymine glycol and the miscoding property of the latter may account, in part, for the ubiquitous C -->T mutation at CpG site. Here, we assessed the kinetics of deamination for two diastereomers of 5-methylcytosine glycol in duplex DNA. Our results revealed that the half-lives for the deamination of the (5S,6S) and (5R,6R) diastereomers of 5-methylcytosine glycol in duplex DNA at 37 degrees C were 37.4 +/- 1.6 and 27.4 +/- 1.0 h, respectively. The deamin

SUBMITTER: Cao H 

PROVIDER: S-EPMC2770644 | biostudies-literature | 2009 Oct

REPOSITORIES: biostudies-literature