Radical-mediated cytosine and 5-methylcytosine hydrolytic deamination reactions

摘要

The mechanisms of cytosine and 5-methylcytosine hydrolytic deamination reactions in the gas phase have been investigated. The rate-determining steps of the reactions are found by density functional theory (DFT). The lower barriers of hydrogen and hydroxyl radical-mediated 5-methylcytosine deamination make the C-5 site of 5-methylcytosine the hot spot for spontaneous mutations. The hydrogen radical inhibits cytosine and 5-methylcytosine hydrolytic deamination reactions, while the hydroxyl radical clearly leads to an increased risk of genetic mutagenesis. (c) 2006 Wiley Periodicals, Inc. Int J Quantum Chem 106: 1878-1884, 2006.