Theoretical investigations on the thiol–thioester exchange steps of different thioesters  

作　　者：Xiao-Hui Sun Hai-Zhu Yu Shu-Qi Pei Zhi-Min Dang 

机构地区：[1]Department of Polymer Science and Engineering, University of Science and Technology Beijing [2]Department of Chemistry and Centre for Atomic Engineering of Advanced Materials, Anhui University

出　　处：《Chinese Chemical Letters》2015年第10期1259-1264,共6页中国化学快报（英文版）

基　　金：NSFC (No. 21202006);FRFCU (No. FRF-TP14-015A2) for financial supports and Super-computer Center of Shanghai and Shenzhen for technical supports

摘　　要：As the rate-determining step in native chemical ligation reactions, the thiol–thioester exchange step is important in determining the efficiency of the ligations of peptides. In the present study, systematic theoretical calculations were carried out on the relationships between the structure of different thioesters and the free energy barriers of the thiol–thioester exchange step. According to the calculation results, the thiol–thioester exchange step is disfavored by the steric hindrance around the carbonyl center, while the electronic effect（i.e. conjugation and hyper-conjugation effects） becomes important when the steric hindrance is insignificant.As the rate-determining step in native chemical ligation reactions, the thiol–thioester exchange step is important in determining the efficiency of the ligations of peptides. In the present study, systematic theoretical calculations were carried out on the relationships between the structure of different thioesters and the free energy barriers of the thiol–thioester exchange step. According to the calculation results, the thiol–thioester exchange step is disfavored by the steric hindrance around the carbonyl center, while the electronic effect（i.e. conjugation and hyper-conjugation effects） becomes important when the steric hindrance is insignificant.

关 键 词：Native chemical ligation Thiol–thioester exchange Density functional theory 

分 类 号：O623.81[理学—有机化学]