Ketoreductase ChKRED12 from Chryseobacterium sp. CA49 was identified as a highly stereoselective catalyst for the bioreductive production of (2S,3S)-ethyl 3-hydroxy-2-methoxy-3-phenylpropanoate (EMHP) through dynamic kinetic resolution. Its performance was further improved using semi-rational design strategies targeting residues Gln151 and Met191. Mutant M191S displayed enhanced activity (4-fold), producing (2S,3S)-EMHP with >99% ee and > 99/1 dr; two double mutants (Q151F/M191 L and Q151Y/M191 L) displayed reversed stereoselectivity and enhanced activity (~3-fold), producing (2R,3R)-EMHP with >99% ee and 98/2 dr. Models of the mutants docked with the substrate and NAD⁺ revealed possible mechanism of the improved characteristics.

产自Chryseobacterium sp。的酮还原酶Ch KRED12 。CA49被确定为通过动态动力学拆分生物还原生产（2 S，3 S）-乙基3-羟基-2-甲氧基-3-苯基丙酸酯（EMHP）的高度立体选择性催化剂。使用针对残留物Gln151和Met191的半理性设计策略可进一步提高其性能。突变体M191S表现出增强的活性（4倍），产生（2 S，3 S）-EMHP，ee大于99％，dr大于99/1。两个双突变体（Q151F / M191 L和Q151Y / M191 L）显示出反向的立体选择性和增强的活性（〜3倍），产生（2 R，3 R）-EMHP，> 99％ee和98/2 dr。与底物和NAD ⁺对接的突变体模型揭示了改善特性的可能机制。