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Publication Abstract from PubMed

ChKRED20 is a robust NADH-dependent ketoreductase identified from the genome of Chryseobacterium sp. CA49 that can use 2-propanol as the ultimate reducing agent. The wild-type can reduce over 100 g/l ketones for some pharmaceutical relevant substrates, exhibiting a remarkable potential for industrial application. In this work, to overcome the limitation of ChKRED20 to aryl ketoesters, we first refined the X-ray crystal structure of ChKRED20/NAD(+) complex at a resolution of 1.6 A, and then performed three rounds of iterative saturation mutagenesis at critical amino acid sites to reshape the active cavity of the enzyme. For methyl 2-oxo-2-phenylacetate and ethyl 3-oxo-3-phenylpropanoate, several gain-of-activity mutants were achieved, and for ethyl 2-oxo-4-phenylbutanoate, improved mutants were achieved with kcat/Km increasing to 196-fold of the wild-type. All three substrates were completely reduced at 100 g/l loading catalyzed with selected ChKRED20 mutants, and deliver the corresponding chiral alcohols with >90% isolated yield and 97 - >99%ee.

Structure-guided engineering of ChKRED20 from Chryseobacterium sp. CA49 for asymmetric reduction of aryl ketoesters.,Li TB, Zhao FJ, Liu Z, Jin Y, Liu Y, Pei XQ, Zhang ZG, Wang G, Wu ZL Enzyme Microb Technol. 2019 Jun;125:29-36. doi: 10.1016/j.enzmictec.2019.03.001. , Epub 2019 Mar 4. PMID:30885322^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.