Podolyan Yevgeniy, Gorb Leonid, Leszczynski Jerzy
Computational Center for Molecular Structure and Interactions, Department of Chemistry, Jackson State University, Jackson, Mississippi 39217-0510, USA.
J Phys Chem A. 2005 Nov 17;109(45):10445-50. doi: 10.1021/jp0550412.
Density functional theory calculations were applied to the prediction of the tautomeric properties of N-methyl-P (6-methyl-3,4-dihydro-8H-pyrimido[4,5-c][1,2]oxazin-7-one), a base of the nucleoside analogue dP (6-(2-deoxy-beta-D-ribofuranosyl)-3,4-dihydro-8H-pyrimido[4,5-c][1,2]oxazin-7-one), for which water-solution experimental data have become available recently. The calculations have been performed for three tautomers in the gas phase, with various numbers of water molecules, and within the polarizable continuum model (PCM) of solvation. The obtained results correctly predict the presence of two tautomers and reproduce accurately the experimentally obtained ratio of the two most stable tautomeric forms when using a combination of explicit water molecules and the PCM of solvation. This lends additional support to the rare tautomer hypothesis of substitution mutagenesis in DNA replication.
密度泛函理论计算被用于预测N-甲基-P（6-甲基-3,4-二氢-8H-嘧啶并[4,5-c][1,2]恶嗪-7-酮）的互变异构性质，它是核苷类似物dP（6-(2-脱氧-β-D-呋喃核糖基)-3,4-二氢-8H-嘧啶并[4,5-c][1,2]恶嗪-7-酮）的一种碱基，最近已有其水溶液的实验数据。计算针对气相中的三种互变异构体进行，包括不同数量的水分子，并在可极化连续介质溶剂化模型（PCM）中进行。当使用明确的水分子和溶剂化PCM相结合时，所得结果正确预测了两种互变异构体的存在，并准确再现了实验获得的两种最稳定互变异构形式的比例。这为DNA复制中取代诱变的稀有互变异构体假说提供了额外支持。
