脂肪族氨基酸二肽与水团簇的理论研究

Theoretical study of aliphatic dipeptide in water clusters

用ABEEMσπ/MM模型和MP2/6-31+G(d)//B3LYP/6-31G(d)方法研究水合效应对脂肪族氨基酸二肽的影响.从结构和能量两方面说明Leu残基在蛋白质中起成旋作用,Val和Ile残基在蛋白质中起解旋作用.同时得出:水分子严重影响了二肽分子的骨架二面角;对于结合相同数目水分子的团簇倾向于形成含有环状氢键的结构,并且含有环状氢键团簇的结合能大于含有链状氢键团簇的结合能.

This paper studies the hydration on aliphatic dipeptides by applying the ABEEMσπ/MM and MP2/6-31 ＋ G（ d）//B3LYP/6-31G（d） methods .Two aspects of structure and energetics indicate that in protein system, Leu facilitates helix formation, whereas Val and lie destabilize helix. Furthemore, we find that water greatly modifies the backbone dihedral angles of dipeptides;the binding energy of the complex contained cyclic hydrogen bond is larger than those contained linear hydrogen bond, for binding the same number water.