Li Dejie, Han Ying, Li Huijuan, Zhang Ping, Kang Qi, Li Zhihua, Shen Dazhong
College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, Shandong Normal University Jinan 250014 P. R. China.
National Engineering Research Center for Colloidal Materials, School of Chemistry and Chemical Engineering, Shandong University Jinan 250100 P. R. China.
RSC Adv. 2018 Mar 20;8(20):11021-11026. doi: 10.1039/c7ra13750h. eCollection 2018 Mar 16.
Zinc cation (Zn) plays an important role in the chemistry of DNA base pairs. In this work, the influence of isolated and penta-hydrated Zn on some of the intramolecular proton-transfer processes of thymine (T) is investigated by the density functional theory method. It is shown that the calculated binding energies between Zn and T are exothermic in vacuum. Compared to T, Zn increases the stability of tautomer T' by 28.7 kcal mol, promoting the intramolecular proton transfer of T. But in a micro-water environment, the attachment processes of Zn to T hydrates, penta-hydrated Zn to T, and penta-hydrated Zn to T hydrates lead to the rearrangement of molecules and the redistribution of charges. The conventional T is still the most stable form and the influence of Zn is much reduced and the proton transfer is thermodynamically unfavored. The detailed characterization is helpful to understand the genotoxicity of zinc ions.
锌阳离子（Zn）在DNA碱基对的化学过程中起着重要作用。在这项工作中，采用密度泛函理论方法研究了孤立的和五水合锌对胸腺嘧啶（T）一些分子内质子转移过程的影响。结果表明，在真空中计算得到的锌与胸腺嘧啶之间的结合能是放热的。与胸腺嘧啶相比，锌使互变异构体T'的稳定性增加了28.7千卡/摩尔，促进了胸腺嘧啶的分子内质子转移。但在微水环境中，锌与胸腺嘧啶水合物的结合过程、五水合锌与胸腺嘧啶的结合过程以及五水合锌与胸腺嘧啶水合物的结合过程会导致分子重排和电荷重新分布。传统的胸腺嘧啶仍然是最稳定的形式，锌的影响大大降低，质子转移在热力学上是不利的。详细的表征有助于理解锌离子的遗传毒性。
