鸟嘌呤四链体中K^+移动路径的预测  

Prediction of the Exchanging Route of K^+ in Guanine-Quadruplex

作　　者：王华荣[1] 刘翠[1] 杨忠志[1] 

机构地区：[1]辽宁师范大学化学化工学院,大连116029

出　　处：《化学学报》2010年第8期753-759,共7页Acta Chimica Sinica

基　　金：国家自然科学基金(No.20633050);辽宁省教育厅基金(Nos.2008S133;2009T057和LNETRC0503)资助项目

摘　　要：结合鸟嘌呤四链体(G4)的结构特点,取G4中的一个K+与一片g-tetrad(g-tetrad-K+)为研究对象,和一个K+与两片g-tetrad(1,2-g-tetrads-K+和2,3-g-tetrads-K+)为研究对象.为g-tetrad-K+,1,2-g-tetrads-K+和2,3-g-tetrads-K+三体系中的K+设计了几种移动路径,来探讨G4中K+与g-tetrad的作用.首先分别应用从头计算MP2/6-31G(d,p)和ABEEMσπ/MM(σπ水平的原子键电负性均衡原理融入到分子力学)方法,对g-tetrad-K+中K+移动过程中体系的结构和能量变化进行了详细研究.结果表明ABEEMσπ/MM方法能够准确地描述g-tetrad-K+体系的结构、结合能等性质.为了更接近实际体系,进而用ABEEMσπ/MM方法预测了更大的体系:一个K+和两片g-tetrad.由于体系较大,MP2方法无法计算其结合能.ABEEMσπ/MM方法对g-tetrad-K+,1,2-g-tetrads-K+和2,3-g-tetrads-K+体系中K+移动而产生的结合能变化表明:如果吸收足够的能量,G4中K+最容易沿α方向移出.Considering the configuration characteristic,this paper takes K^＋ and one g-tetrad （g-tetrad-K^＋） as studied object,together with K^＋ and two g-tetrads （1,2-g-tetrads-K^＋ and 2,3-g-tetrads-K^＋） in guanine-quadruplex structure （G4） as studied object.We have designed several moving routes for K^＋ in g-tetrad-K^＋,1,2-g-tetrads-K^＋ and 2,3-g-tetrads-K^＋ three systems to explore the interaction between g-tetrad and K^＋.First,ab initio [MP2/6-31G（d,p）] and ABEEMσπ/MM （Atom Bond Electronegativity Equalization Method at σπ level fused into Molecular Mechanics） methods have been used to investigate the changes of structure and energy,when K^＋ moves in g-tetrad-K^＋.The results indicate that ABEEMσπ/MM can accurately describe the properties of the g-tetrad-K^＋ system structure and energy.To approaching the practical system,ABEEMσπ/MM has been used to explore the bigger system K^＋ and two g-tetrads,which is too big to calculate the interaction energy using MP2.The changes of the interaction energy from ABEEMσπ/MM,when K^＋ moves in g-tetrad-K^＋,1,2-g-tetrads-K^＋ and 2,3-g-tetrads-K^＋ systems indicate that if absorb enough energy,it is easiest for the K^＋ in G4 moves out of the cavity along the α direction.

关 键 词：平面G-四方结构 钾离子 从头计算 ABEEMΣΠ/MM 

分 类 号：Q52[生物学—生物化学]