【作者】 谢磊； 张弛； 丁元琪； 孙强； 许维；

【Author】 Lei Xie;Chi Zhang;Yuanqi Ding;Qiang Sun;Wei Xu;College of Materials Science and Engineering, Tongji University;

【机构】 同济大学；

【摘要】 水对生命来说极其重要,如携带遗传信息的DNA在体内就以水化形式存在。理论计算研究证实,水可以通过影响碱基互变异构体间的平衡和降低互变异构反应势垒来诱导一些罕见的碱基互变异构体生成。而互变异构现象可以导致碱基错配、突变甚至基因损伤,因此研究水诱导的互变异构十分必要。我们利用扫描隧道显微镜在超高真空环境下通过精确地引入水,首次在Au(111)表面上实空间观测到了鸟嘌呤的一种罕见互变异构体G/(3H,7H)。密度泛函理论计算表明,水分子在鸟嘌呤上方可能形成"水桥"进而降低了分子内质子转移的势垒,导致罕见互变异构体的生成。更多还原

【Abstract】 Water is vital for life and DNA molecules are hydrated in vivo. Theoretical investigations have revealed that water is responsible for the existence of some non-canonical DNA base tautomers and such tautomerization phenomenon may be responsible for base mismatch, mutagenesis, and further genetic damage. Herein, from the high-resolution scanning tunneling microscopy(STM) imaging we surprisingly find the formation of the rare guanine tautomer, i.e. G/(3H,7H) form, on the Au(111) surface by delicately introducing water into the system. Furthermore, extensive density functional theory(DFT) calculations reveal that the performance of "water bridge" may largely reduce the energy barriers of intramolecular proton-transfer processes. The real-space experimental evidence and the proposed mechanism make a step forward towards the fundamental understanding of water-assisted base tautomerization processes.更多还原