Highly efficient synthesis of pharmaceutically relevant chiral 3-N-substituted-azacyclic alcohols using two enantiocomplementary short chain dehydrogenases

Bioreductions catalyzed by alcohol dehydrogenases (ADHs) play an important role in the synthesis of chiral alcohols. In this study, we reported two stereocomplementary alcohol dehydrogenases from Flavobacterium psychrophilum (FpADH) and Flavobacterium sp. (FsADH), which showed the potential industrial application in highly efficient synthesis of a series of enantiomerically pure 3-N-substituted-azacyclic alochols. Both the enzymes showed high catalytic activity toward the model substrate N-Boc-4-piperidone (NBPO) and presented a strict enantioselectivity for the corresponding alcohol products. In addition, both enzymes showed broad substrate scope, including ketoesters, acryl ketones, and heterocyclic ketones. Using glucose dehydrogenase coexpressed with each of the enzymes to realize the efficient coenzyme recycling, various pharmaceutically relevant chiral 3-N-Boc azacyclic alcohols were asymmetrically synthesized at high substrate concentrations (343.7–643.8 g/L) and low equilvelent of NADP+ (0.1 mM) with excellent enantioselectivity (> 99.5% e.e), which have met the requirements of biocatalytic processes in the industry, and demonstrated the feasibility of FpADH and FsADH for industrial application in the biotransformation of chiral 3-N-substituted-azacyclic alcohols. The molecular basis of the enantioselectivity and catalytic efficiency of both enzymes were revealed the by molecular docking and MD simulation analysis.