Chem. J. Chinese Universities ›› 2021, Vol. 42 ›› Issue (7): 2306.doi: 10.7503/cjcu20210125

• Article • Previous Articles    

Theoretical Insights into the Cleavage of β-Hydroxy Ketone Catalyzed by Artificial Retro-aldolase RA95.5-8F

LI Xinyi, LIU Yongjun()   

  1. School of Chemistry and Chemical Engineering,Shandong University,Jinan 250100,China
  • Received:2021-02-26 Online:2021-07-10 Published:2021-07-07
  • Contact: LIU Yongjun E-mail:yongjunliu_1@sdu.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(22073056)

Abstract:

The mechanism of the cleavage of β-hydroxy ketone catalyzed by the artificial retro-aldolase RA95.5-8F was studied by the combined quantum mechanics and molecular mechanics(QM/MM) method. The results show that the cleavage reaction includes the nucleophilic attack of Lys1083 on the substrate, formation of Schiff base intermediate, hydrolysis of enamine, C—N cleavage and so on. The final step of the cleavage of C—N bond to generate acetone is the rate-limiting step with the energy barrier of 106.27 kJ/mol. Lys1083, Tyr1051, Asn1110 and Tyr1180 form a catalytic tetrad, in which Lys1083 and Tyr1051 act as nucleophile and catalytic acid-base, respectively. The hydrogen bond network of the catalytic tetrad stabilizes the reaction transition states and makes it easier for R-configuration substrate to bind to the active site, resul?ting in the high selectivity and reactivity of RA95.5-8F for R-configuration substrate.

Key words: Combined quantum mechanics/molecular mechanics(QM/MM) method, Retro-aldolase, Enzymatic reaction, Reaction mechanism

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