甘氨酸-α-二肽构象稳定性的理论研究  

A Theoretical Study on the Conformation Stability of Glycine α-dipeptide

作　　者：齐学洁[1] 王长生[1] 

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）》2004年第1期41-44,共4页Journal of Liaoning Normal University:Natural Science Edition

基　　金：国家自然科学基金资助项目(20173025);辽宁省教育厅基金资助项目(202122026)

摘　　要：二肽分子CH3CO[NHCH2CO]NHCH3中的结构基元[NHCH2CO]是甘氨酸 α 多肽的基本重复单元.其中二面角φ和ψ的不同取值决定了多肽的不同构象.使用B3LYP/6 311G(d,p)方法对二肽分子CH3CO[NHCH2CO]NHCH3的所有可能稳定构象进行了研究,分析了二肽分子CH3CO[NHCH2CO]NHCH3的不同稳定构象的相对稳定性,从分子内氢键作用、大基团间的空间位阻以及库仑作用角度探讨了影响二肽构象稳定性的因素.结果表明:甘氨酸 α 二肽中构象的相对稳定性主要取决于分子内氢键作用和φ角的空间位阻.ψ角的空间位阻不起决定作用.因此在多肽分子的分子模拟中,如何准确合理地描述φ角的空间位阻是今后分子模拟工作者要解决的重点课题.The motif in dipeptide molecule CH_3CONHCH_3 is the basic repeated unit of glycine polypeptide molecule. The glycine polypeptide conformations are determined by the dihedral angles φ andψ corresponding to the rotations of N-C bond and C-C bond in the repeated unit . In this paper, B3LYP/6-311G(d,p) method was applied to study the conformation stabilities of dipeptide molecule CH_3CONHCH_3. Conformation analysis was carried out from the point of view of intramolecule hydrogen bond interaction, steric interaction, and Coulomb interactions. It was shown that the intramolecular hydrogen bond as well as the steric interaction about the angle φ play a very important role in the conformation stability of glycine dipeptide molecule, whereas the steric interaction about the angle ψ doesn't. This also suggests a strategy for the development of more consistent molecular modeling methods.

关 键 词：甘氨酸-α-二肽 a-多肽 重复单元 密度泛函理论 构象稳定性 空间位阻 量子化学 

分 类 号：Q516[生物学—生物化学]