Engineering an alcohol dehydrogenase with enhanced activity and stereoselectivity toward diaryl ketones: reduction of steric hindrance and change of the stereocontrol element was written by Wu, Kai;Yang, Zhijun;Meng, Xiangguo;Chen, Rong;Huang, Jiankun;Shao, Lei. And the article was included in Catalysis Science & Technology in 2020.SDS of cas: 120121-01-9 This article mentions the following:
Steric hindrance in the binding pocket of an alc. dehydrogenase (ADH) has a great impact on its activity and stereoselectivity simultaneously. Due to the subtle structural difference between two bulky Ph substituents, the asym. synthesis of diaryl alcs. by bioreduction of diaryl ketones is often hindered by the low activity and stereoselectivity of ADHs. To engineer an ADH with practical properties and to investigate the mol. mechanism behind the asym. biocatalysis of diaryl ketones, we engineered an ADH from Lactobacillus kefiri (LkADH) to asym. catalyze the reduction of 4-chlorodiphenylketones (CPPK), which are not catalyzed by the wild type (WT) enzyme. Mutants seq1-seq5 with gradually increased activity and stereoselectivity were obtained through iterative “shrinking mutagenesis.” The final mutant seq5 (Y190P/I144V/L199V/E145C/M206F) demonstrated the highest activity and excellent stereoselectivity of >99% ee. Mol. simulation analyses revealed that mutations may enhance the activity by eliminating steric hindrance, inducing a more open binding loop and constructing more noncovalent interactions. The pro-R pose of CPPK with a halogen bond formed a pre-reaction conformation more easily than the pro-S pose, resulting in the high ee of (R)-CPPO in seq5. Moreover, different halogen bonds formed due to the different positions of chlorine substituents, resulting in opposite substrate binding orientation and stereoselectivity. Therefore, the stereoselectivity of seq5 was inverted toward ortho- rather than para-chlorine substituted ketones. These results indicate that the stereocontrol element of LkADH was changed to recognize diaryl ketones after steric hindrance was eliminated. This study provides novel insights into the role of steric hindrance and noncovalent bonds in the determination of the activity and stereoselectivity of enzymes, and presents an approach producing key intermediates of chiral drugs with practical potential. In the experiment, the researchers used many compounds, for example, (R)-1-(3-Chlorophenyl)ethanol (cas: 120121-01-9SDS of cas: 120121-01-9).
(R)-1-(3-Chlorophenyl)ethanol (cas: 120121-01-9) belongs to alcohols. The oxygen atom of the strongly polarized O―H bond of an alcohol pulls electron density away from the hydrogen atom. This polarized hydrogen, which bears a partial positive charge, can form a hydrogen bond with a pair of nonbonding electrons on another oxygen atom. The most common reactions of alcohols can be classified as oxidation, dehydration, substitution, esterification, and reactions of alkoxides.SDS of cas: 120121-01-9
Referemce:
Alcohol – Wikipedia,
Alcohols – Chemistry LibreTexts