Ab initio research on DNA base alkylation by the beta-position metabolite of methylethylnitrosamine

摘要

Ab initio calculation is carried out to study the different supposed mechanisms of DNA base alkylation by beta-sulphate-nitrosamines at RHF/6-31G(d) and MP2/6-31G(d) levels. Full geometric structure optimization is done for all reactants, intermediates, products and transition states. The activation energy and IRC are obtained. The results show that the anchimeric assistant effect promotes the alkylation of DNA base by beta-sulphate-nitrosamines. Solvent calculation is carried out with Onsager model of SCRF method at the same level. The results indicate that the activation energy is decreased obviously in water.