DOI: 10.1002/bit.28535 ISSN:

Structural‐guided design to improve the catalytic performance of aldo‐keto reductase KdAKR

Chen Dai, Hai‐Xing Cao, Jia‐Xin Tian, Yan‐Chi Gao, Hua‐Tao Liu, Shen‐Yuan Xu, Ya‐Jun Wang, Yu‐Guo Zheng
  • Applied Microbiology and Biotechnology
  • Bioengineering
  • Biotechnology


Aldo‐keto reductases (AKRs) are important biocatalysts that can be used to synthesize chiral pharmaceutical alcohols. In this study, the catalytic activity and stereoselectivity of a NADPH‐dependent AKR from Kluyveromyces dobzhanskii (KdAKR) toward t‐butyl 6‐chloro (5S)‐hydroxy‐3‐oxohexanoate ((5S)‐CHOH) were improved by mutating its residues in the loop regions around the substrate‐binding pocket. And the thermostability of KdAKR was improved by a consensus sequence method targeted on the flexible regions. The best mutant M6 (Y28A/L58I/I63L/G223P/Y296W/W297H) exhibited a 67‐fold higher catalytic efficiency compared to the wild‐type (WT) KdAKR, and improved R‐selectivity toward (5S)‐CHOH (dep value from 47.6% to >99.5%). Moreover, M6 exhibited a 6.3‐fold increase in half‐life (t1/2) at 40°C compared to WT. Under the optimal conditions, M6 completely converted 200 g/L (5S)‐CHOH to diastereomeric pure t‐butyl 6‐chloro‐(3R, 5S)‐dihydroxyhexanoate ((3R, 5S)‐CDHH) within 8.0 h, with a space‐time yield of 300.7 g/L/day. Our results deepen the understandings of the structure−function relationship of AKRs, providing a certain guidance for the modification of other AKRs.

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