水液相下两性α-丙氨酸Mg^2+配合物旋光异构的理论研究  

Theoretical Study on the Optical Isomerization of Amphotericα-alanine·Mg^2+Complex in Water-liquid Phase Environment

作　　者：钱研 张雪娇 刘芳[2] 陈静思 丛建民[4] 马宏源[2] 王佐成[2] QIAN Yan;ZHANG Xuejiao;LIU Fang;CHEN Jingsi;CONG Jianmin;MA Hongyuan;WANG Zuocheng(School of Communication, Baicheng Normal University, Baicheng, Jilin 137000, China;College of Physics, Baicheng Normal University, Baicheng, Jilin 137000, China;Department of Clinical Medicine, Baicheng Medical College, Baicheng, Jilin 137000, China;College of Life Science, Baicheng Normal University, Baicheng, Jilin 137000, China)

机构地区：[1]白城师范学院传媒学院,吉林白城137000 [2]白城师范学院物理学院,吉林白城137000 [3]白城医学高等专科学校临床医学系,吉林白城137000 [4]白城师范学院生命科学学院,吉林白城137000

出　　处：《复旦学报（自然科学版）》2020年第6期769-778,共10页Journal of Fudan University：Natural Science

基　　金：吉林省教育厅科学研究规划项目(JJKH20200002KJ);吉林省科技发展计划自然科学基金(20160101308JC)。

摘　　要：采用密度泛函理论的M06-2X方法结合自洽反应场理论的SMD模型方法,研究了水液相下两性α-Ala(丙氨酸)与Mg^2+配合物的旋光异构.研究发现:α-Ala·Mg^2+的旋光异构反应有3个通道a、b和c,a是质子分别以羰基氧和氨基氮为桥迁移;b是质子只以羰基氧为桥迁移;c是质子从质子化氨基迁移到羰基氧后,再以氨基氮为桥迁移.势能面计算表明:隐性水溶剂效应作用下α-Ala·Mg^2+旋光异构的c通道具有优势,决速步能垒是218.1kJ·mol^-1,a和b通道处于劣势,具有共同的决速步能垒297.1kJ·mol^-1.水分子(簇)的作用使c通道的决速步能垒降到143.0kJ·mol^-1,a和b通道的决速步能垒降到148.7kJ·mol^-1.结果表明:水液相环境下α-Ala·Mg^2+可以较好地保持其手性特征,α-丙氨酸二价镁盐用于生命体镁和丙氨酸同补具有很好的安全性.The optical isomerization of the amphotericα-alanine and Mg^2+complexes in water-liquid phase environment has been studied using the M06-2X method combined with the Slovation Model Density(SMD)model method based on self consistent reaction field theory.The study shows that theα-Ala·Mg^2+optical isomerization reaction has three channels a,b and c.The proton is transferred with carbonyl oxygen and amino nitrogen respectively as the bridge in channel a;and that is only transferred with carbonyl oxygen as the bridge in b.In channel c,the proton is transferred with amino nitrogen as a bridge after the transition that from protonated amino to carbonyl oxygen.The potential energy surface shows that the channel c of theα-Ala·Mg^2+optical isomerization has the most advantage under the effect of recessive solvent and the energy barrier of the rate-determining step is 218.1kJ·mol^-1,channel a and b are at a disadvantage,they have the common energy barrier of the rate-determining step is 297.1kJ·mol^-1.The effect of water molecule(cluster)reduced the energy barrier of rate-determining step of the channel c to 143.0kJ·mol^-1,the energy barrier is reduced to 148.7kJ·mol^-1 in a and b.The results shows thatα-Ala·Mg^2+can retain its chirality well in the water-liquid environment,and it's excellently safe that the supplement of magnesium and alanine for life simultaneously throughα-alanine divalent magnesium salt.

关 键 词：丙氨酸 MG^2+ 旋光异构 密度泛函理论 自洽反应场理论 过渡态 能垒 

分 类 号：O641.12[理学—物理化学]