中山大学学报(自然科学版)2017，Vol.56Issue(3)：85-92,8.DOI:10.13471/j.cnki.acta.snus.2017.03.013
基于氨基做质子迁移桥梁亮氨酸的手性转变机理及水溶剂化效应
Chiral transition mechanism and water solvation effect of leucine molecules based on the amino proton transfer bridge
摘要
Abstract
The title reaction mechanism was explored by using the B3LYP density functional theory,the MP2 method of perturbation theory and smd model method of self consistent reaction field theory.The study of reaction channels showed that there are two channels a,b in the chiral transition reaction,and in the one the proton is transferred from one side to the other of chiral carbon with only the amino as a bridge,in the other with carbonyl and amino N as the bridge successively.The molecular structure analysis showed that the seven-ring structure in the transition state aTS2·2H2O is almost coplanar and each hydrogen bond angles of the seven-ring structure approach straight angle.Calculations of potential energy surface pointed out that the channel a is the dominant reaction channel and the free energy barrier of the rate-determining step is 249.5 kJ·mol-1,which is caused by the transition state with proton migration from chiral carbon to amino nitrogen.Moreover,with consideration of two water molecules as H transfer media and with inclusion of the water solvation effect of the continuous medium model,,the free energy barrier of the rate-determining step is reduced to 113.2 kJ·mol-1 and the reaction rate constant is 5.85×10-8 s-1,and the water solvation effect enables the energy barrier of the amino heterogeneous reaction increased from 13.4 kJ·mol-1 to 19.3 kJ·mol-1.Therefore,water solvation effect can hinder the heterogeneous reaction of non proton transfer,and the interaction of the catalytic action of water molecules and water solvation effect can cooperatively reduce the proton transfer reaction energy barrier to a large degree.关键词
手性/亮氨酸/自洽反应场/密度泛函理论/过渡态/微扰论Key words
chiral/leucine/self consistent reaction field/density functional theory/transition state/perturbation theory.分类
化学引用本文复制引用
赵晓波,李晨洁,王佐成,喻小继,闫红彦,杨晓翠,佟华..基于氨基做质子迁移桥梁亮氨酸的手性转变机理及水溶剂化效应[J].中山大学学报(自然科学版),2017,56(3):85-92,8.基金项目
吉林省科技发展计划资助项目自然科学基金(20130101308JC （）
20160101308JC) （）
