单电子还原的胞嘧啶被水质子化的理论研究

Theoretical study of the protonation of the one-electron-reduced cytosine by water

选取胞嘧啶C为研究对象,利用密度泛函理论以C-·…8H2O为模型从理论上研究了C-·的质子化反应.计算结果表明C-·质子化的位点为N(3)位,是一个双质子转移过程. C-·周围第一层及第二层的水分子通过稳定生成的OH-起到了关键作用,溶剂化水进一步降低了反应的能垒.

In the present study, the protonation of C-· has been investigated by density functional theory(DFT) calculations using C-·…8 H2O as calculation model. The results show that the protonation site is N(3) of the C-·, and the protonation is achieved by a mechanism of concerted double proton transfer. The first and the second hydration shell around C-· play an important role in the protonation reaction through stabilizing the generated OH-. And the bulk hydration further reduced the reaction barrier.