摘要
基于密度泛函理论B3LYP,在6-311+G(d,p)基组水平上研究非限域单体和水环境下亮氨酸(Leu)分子的手性转变机制.通过寻找反应过程中各极值点的结构,绘制水环境下Leu分子的手性转变路径反应势能面,并分析各极值点的几何和电子结构特性.结果表明:水环境下S型Leu分子手性C原子上的H原子以羧基上的O原子为桥梁,转移至手性C原子的另一侧,实现了从S型到R型Leu分子的手性转变;水环境下该路径有4个中间体和5个过渡态,来源于第一个过渡态TS1-S-Leu&1H_2O-1的最大反应能垒为57.235 9kJ/mol,单体Leu分子手性转变第一个过渡态TS1-S-Leu的最大反应能垒为145.452 7kJ/mol.即单个水分子作为H转移桥梁可降低反应能垒.
Using density functional theory B3LYP,we investigated the chiral transition mechanism of the leucine（Leu）molecule in the non-confined monomer and water at the level of 6-311＋G（d,p）basis sets.We drawed a Leu molecule chiral transition path reaction potential energy surface by finding structures of the extreme value points including the transition states and intermediates,and analyzed the geometric and electronic structure properties of extreme value points.The results show that the hydrogen atom on the chiral carbon atom of S-Leu molecule can transfer to the other side of the carbon atom via the oxygen atoms of carboxyl atoms as a bridge,and achieve the chiral transition of Leu molecule fromS-type to R-type.On this path there are four intermediates and five transition states.The maximum reaction energy barrier is 57.235 9 kJ/mol,which comes from the first transition state TS1-S-Leu1H_2O-1.The maximum reaction energy barrier of the first transition state TS1-S-Leu of monomer Leu molecule is 145.452 7kJ/mol.As a result,a single water molecule as the H transfer bridge can reduce the reaction barrier.
作者
陈洪斌
王艳玲
CHEN Hongbin WANG Yanling(College of Biomedical Engineering, Jilin Medical University, Jilin 132013, Jilin Province, China)
出处
《吉林大学学报（理学版）》
CAS
CSCD
北大核心
2017年第2期424-429,共6页
Journal of Jilin University:Science Edition
基金
吉林省自然科学基金(批准号:20130101131JC)
关键词
水分子
手性
亮氨酸
过渡态
water molecule
chirality
leucine
transition state
