...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Physical chemistry chemical physics: PCCP >The coupling of tautomerization to hydration in the transition state on the pyrimidine photohydration reaction path
【24h】

The coupling of tautomerization to hydration in the transition state on the pyrimidine photohydration reaction path

机译：嘧啶光水合反应路径上过渡态互变异构与水合的耦合

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The ground state reaction path for formation of the pyrimidine hydrates was calculated using a nudged elastic band (NEB) approach, combined with a calculation of the transition state, and implemented using a numerical basis set in the density functional theory (DFT) code DMol~3. The model systems used for study consist of 1-methyl pyrimidines with a H2O molecule as the reactant, and the corresponding C5-hydro-C6-hydroxypyrimidine as the product. The barrier to addition of water across the C5-C6 it-bond ranges from 43-48 kcal mol~(-1) in the 1-methylpyrimidines (1-MP) studied. Similar but slightly smaller barriers of 34-45 kcal mol~(-1) were found for the tautomers of the 1-MPs, i.e. the enols of uridine and thymine and imine of cytosine. Comparison of these calculations with previous computational and experimental work suggests that a hot ground state formed by the rapid internal conversion of pyrimidines has sufficient energy to permit crossover from the common form to the tautomeric form of the pyrimidine at the transition state The hot ground state mechanism can account for the experimentally observed yield and thermal reversion of pyrimidine photohydrates, while simultaneously explaining the effect of photohydrates on the mutation rate
机译：使用微带（NEB）方法计算形成嘧啶水合物的基态反应路径，并结合过渡态的计算，并使用在密度泛函理论（DFT）代码DMol〜中设置的数值基础来实现3。用于研究的模型系统由带有H2O分子作为反应物的1-甲基嘧啶和相应的C5-氢-C6-羟基嘧啶产物组成。在所研究的1-甲基嘧啶（1-MP）中，跨C5-C6键的加水障碍为43-48 kcal mol〜（-1）。对于1-MP的互变异构体，即尿苷和胸腺嘧啶的烯醇和胞嘧啶的亚胺，发现了相似但稍小的34-45kcal mol -1的势垒。这些计算与以前的计算和实验工作的比较表明，由嘧啶的快速内部转化形成的热基态具有足够的能量，可以使嘧啶在过渡态从普通形式转变为互变异构形式。可以解释实验观察到的嘧啶光水合物的产率和热转化率，同时可以解释光水合物对突变率的影响

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号