Chem. J. Chinese Universities ›› 2020, Vol. 41 ›› Issue (5): 1018.doi: 10.7503/cjcu20190621

• Organic Chemistry • Previous Articles     Next Articles

Improving Catalytic Efficiency of Bacillus Cereus Amine Dehydrogenase for Acetophenone Reduction by Iterative Saturation Mutagenesis

WU Tao1,2,MU Xiaoqing1,2,*(),NIE Yao1,XU Yan1   

  1. 1. Key Laboratory of Industrial Biotechnology of Ministry of Education,Jiangnan University, Wuxi 214122, China
    2. Suqian Jiangnan University Institute of Industrial Technology, Suqian 223800, China
  • Received:2019-12-02 Online:2020-05-10 Published:2020-02-07
  • Contact: Xiaoqing MU E-mail:xqmu@jiangnan.edu.cn
  • Supported by:
    † Supported by the National Natural Science Foundation of China(21336009);† Supported by the National Natural Science Foundation of China(21176103);the National High Technology Research and Development Program of China(2015AA021004);the Overseas Expertise Introduction Project for Discipline Innovation, China(111-2-06)

Abstract:

Based on the 3D structure of Bacillus cereus amine dehydrogenase established by homology modeling, 8 amino acid residues(L42, G43, M67, A115, E116, T136, V293 and V296) around the substrate binding pocket were selected to site-directed saturation mutagenesis. Positive mutants were screened on 3 sites(116, 136, 293) by color-rendering method. The best triple-sites mutant(V293A/E116V/T136S) was obtained by iterative saturation mutation strategy and its catalytic efficiency for acetophenone reached 2.54 L·min -1·mmol-1, which was 719% higher than BcAmDH. Compared with BcAmDH, the substrate concentrations and conversions of asymmetric reduction reaction of acetophenone were increased from 100 mmol/L to 300 mmol/L and from 42.1% to 80.2% at the optimal reaction conditions, respectively. It was suggested that the decrease of steric hindrance in the substrate binding pocket of the mutant and the expansion of the substrate entrance channel were the main reasons for improving catalytic efficiency by molecular docking results.

Key words: Iterative saturation mutagenesis, Amine dehydrogenase, Catalytic efficiency, Acetophenone, (R)-α-Phenethylamine

CLC Number: 

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