系列小分子与碱基尿嘧啶间氢键相互作用的理论研究  

Theoretical studies on the hydrogen binding between uracil and a series of micromolecules

作　　者：王长生[1] 汪宇嘉[1] 王红娟 

机构地区：[1]辽宁师范大学化学化工学院,辽宁大连116029

出　　处：《辽宁师范大学学报（自然科学版）》2013年第1期54-61,共8页Journal of Liaoning Normal University:Natural Science Edition

基　　金：国家自然科学基金项目(20973088;21173109);教育部高等学校博士点基金项目(20102136110001)

摘　　要：核酸碱基尿嘧啶分子可以使用3个不同位点与其他分子形成多种类型的分子间氢键.笔者使用密度泛函理论B3LYP/6-31+G(d,p)方法优化得到了系列小分子与尿嘧啶分子形成的31个氢键复合物的稳定结构,进而使用MP2/aug-cc-pVTZ方法计算了这些氢键复合物的结合能.研究结果表明,尿嘧啶分子更倾向作为氢键给体与小分子形成氢键.尿嘧啶分子最易使用1号位点与小分子形成氢键复合物,最不易使用2号位点形成氢键复合物.甲基取代小分子氢键受体上的氢原子会使氢键强度变强.为了深入理解这些氢键复合物体系中氢键作用的本质,还使用B3LYP/6-31G(d,p)方法进行了自然键轨道(NBO)分析计算.自然键轨道(NBO)分析表明,大部分氢键复合物满足二阶相互作用稳定化能之和越大,结合能绝对值越大,结合得越稳定的原则,说明共价作用在这些氢键作用中起重要作用.Nucleic acid base uracil contains three alternating proton donor and acceptor sites（Site 1, Site 2 ,and Site 3） which can be used to hydrogen bond with other molecules. In this article,total thir- ty-one hydrogen-bonded complexes composed of Uracil and micromlecule were optimized using the density functional theory B3LYP method with the 6-31-FG（d, p） basis set. The binding energies for these complexes were then obtained using MP2/aug-cc-pVTZ methods including the basis set super- position error corrections（BSSE）. The calculation results shown that the hydrogen-bond in which U- racil is the proton donor is usually much stronger than the one in which Uracil is the proton acceptor. The hydrogen-bonded complex in which Uracil hydrogen bonds to micromolecule through Site 1 pos- sesses the most negative binding energy while the hydrogen-bonded complex in which Uracil hydro- gen bonds to micromolecule through Site 2 has the least negative binding energy ~ demonstrating that Uracil would hydrogen bond to micromolecule most likely through Site 1 and least likely through Site 2. Our calculation also shows that replacing a hydrogen atom connected directly to the hydrogen bond acceptor atom of the micromolecule with a methyl group strengthens the corresponding hydrogen bond. Natural bond orbital analysis calculations were carried out to explore the hydrogen bond nature in these complexes using B3LYP/6-31G（d,p） method. The results of the natural bond orbital analy- sis suggest that the covalent interactions or orbital overlap interactions play a significant role in most of the hydrogen-bonds.

关 键 词：尿嘧啶 氢键作用 氢键复合物 结合能 自然键轨道分析 

分 类 号：O641.121[理学—物理化学]