Tuning an Imine Reductase for the Asymmetric Synthesis of Azacycloalkylamines by Concise Structure-Guided Engineering.
Zhang, J., Liao, D., Chen, R., Zhu, F., Ma, Y., Gao, L., Qu, G., Cui, C., Sun, Z., Lei, X., Gao, S.S.(2022) Angew Chem Int Ed Engl 61: e202201908-e202201908
- PubMed: 35322515 
- DOI: https://doi.org/10.1002/anie.202201908
- Primary Citation of Related Structures:  
7WNN, 7WNW - PubMed Abstract: 
Although imine reductases (IREDs) are emerging as attractive reductive aminases (RedAms), their substrate scope is still narrow, and rational engineering is rare. Focusing on hydrogen bond reorganization and cavity expansion, a concise strategy combining rational cavity design, combinatorial active-site saturation test (CAST), and thermostability engineering was designed, that transformed the weakly active IR-G36 into a variant M5 with superior performance for the synthesis of (R)-3-benzylamino-1-Boc-piperidine, with a 4193-fold improvement in catalytic efficiency, a 16.2 °C improvement in T m , and a significant increase in the e.e. value from 78 % (R) to >99 % (R). M5 exhibits broad substrate scope for the synthesis of diverse azacycloalkylamines, and the reaction was demonstrated on a hectogram-scale under industrially relevant conditions. Our study provides a compelling example of the preparation of versatile and efficient IREDs, with exciting opportunities in medicinal and process chemistry as well as synthetic biology.
Organizational Affiliation: 
State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.