水液相环境下半胱氨酸分子的手性对映体转变机理  

Mechanism of Chiral Enantiomer Transition of Cysteine in Water/Liquid Phase Environment

作　　者：乔朝阳 潘宇[2] 马宏源[2] 姜春旭 杨晓翠[2] 王佐成[2] QIAO Chaoyang;PAN Yu;MA Hongyuan;JIANG Chunxu;YANG Xiaocui;WANG Zuocheng(Computer Science Collge,Baicheng Normal University,Baicheng 137000.Jilin.China;College of Physics,Baicheng Normal University,Baicheng 137000.Jilin,China)

机构地区：[1]白城师范学院计算机科学学院,吉林白城137000 [2]白城师范学院物理学院,吉林白城137000

出　　处：《武汉大学学报（理学版）》2020年第4期338-344,共7页Journal of Wuhan University:Natural Science Edition

基　　金：吉林省科技发展计划自然科学基金(20130101308JC,20160101308JC)。

摘　　要：在MP2/SMD/6-311++G(3df,2pd)//ωB97X-D/SMD/6-311++G(d,p)双理论水平,研究了水液相环境下半胱氨酸(Cys)分子以氨基氮为质子转移桥梁的手性对映体转变及水分子簇的催化作用。反应历程研究发现,半胱氨酸分子经过6个基元反应实现了手性对映体转变。反应历程的势能面计算显示:半胱氨酸分子手性对映体转变反应的速控步骤是第2基元反应,速控步骤的内禀能垒为242. 7 kJ·mol^-1;2个水分子簇的催化使速控步骤的内禀能垒降至104. 0 kJ·mol^-1。结果表明,水环境下半胱氨酸分子可以实现手性对映体转变。The chiral enantiomer transition of cysteine molecules with amino nitrogen as a proton transfer bridge and the catalysis of water molecules(clusters) in water/liquid phase environment were studied by using the combined MP2/SMD/6-311++G(3 df, 2 pd) and ωB97 X-D/SMD/6-311++G(d,p) methods based on density functional theory. The reaction mechanism shows that the cysteine molecule undergoes six elementary reactions to realize chiral enantiomer transition. The calculation of the potential energy surface shows that the second elementary reaction is the rate-limiting step with high energy barriers of 242.7 kJ·mol^-1,and that the rate-limiting step was reduced to 104.0 kJ·mol^-1 by the catalysis of two water clusters. Our results show that the catalysis of water molecules clusters in water/liquid phase environment can enable cysteine to realize chiral enantiomer transition slowly.

关 键 词：半胱氨酸 手性对映体 密度泛函理论 过渡态 多体微扰理论 能垒 自洽反应场理论 

分 类 号：O641.12[理学—物理化学]