Engineering of Candida glabrata Ketoreductase 1 for Asymmetric Reduction of α-Halo Ketones

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• 作者：Fengyu Qin ; Bin Qin ; Takahiro Mori ; Yan Wang ; Lingxin Meng ; Xin Zhang ; Xian Jia ; Ikuro Abe ; Song You
• 刊名：ACS Catalysis
• 出版年：2016
• 出版时间：September 2, 2016
• 年：2016
• 卷：6
• 期：9
• 页码：6135-6140
• 全文大小：409K
• 年卷期：0
• ISSN：2155-5435

文摘

Enantiopure halohydrins, which are important building blocks for pharmaceutical agents, could be synthesized by biocatalytic reduction of α-halo ketones using ketoreductases. In this study, Candida glabrata ketoreductase 1 (CgKR1) variants with >99% stereoselectivity toward α-halo ketones, such as 2-chloroacetophenone, 2-chloro-4′-fluoroacetophenone, and 2-bromoacetophenone, were obtained through engineering of CgKR1 at residues Phe92 and Tyr208. Interestingly, asymmetric reduction of these α-halo ketones by all the variants of CgKR1 followed anti-Prelog’s rule, which is rarely found in natural ketoreductases. Moreover, the biocatalytic processes for reduction of these aromatic α-halo ketones with high substrate loading were achieved by coexpression of glucose dehydrogenase (GDH) for NADPH regeneration, indicating the potential of practical applications of these variants.