Structure-Guided Regulation in the Enantioselectivity of an Epoxide Hydrolase to Produce Enantiomeric Monosubstituted Epoxides and Vicinal Diols via Kinetic Resolution
Structure-guided microtuning of an Aspergillus usamii epoxide hydrolase was executed. One mutant, A214C/A250I, displayed a 12.6-fold enhanced enantiomeric ratio (E = 202) toward rac-styrene oxide, achieving its nearly perfect kinetic resolution at 0.8 M in pure water or 1.6 M in n-hexanol/water. Several other beneficial mutants also displayed significantly improved E values, offering promising biocatalysts
对Aspergillus usamii环氧水解酶进行了结构引导的微调。一种突变体 A214C/A250I对消旋-氧化苯乙烯的对映体比 ( E = 202)提高了 12.6 倍,在纯水中 0.8 M 或正己醇/水中 1.6 M 时实现了近乎完美的动力学分辨率。其他一些有益的突变体也显示出显着提高的E值,为获得 19 种结构多样的手性单取代环氧化物(97.1 – ≥ 99% ee s)和邻二醇(56.2–98.0% ee p)提供了有希望的生物催化剂,并且产率很高。
“Cassette” In Situ Enzymatic Screening Identifies Complementary Chiral Scaffolds for Hydrolytic Kinetic Resolution Across a Range of Epoxides
作者:Sangeeta Dey、Douglas R. Powell、Chunhua Hu、David B. Berkowitz
DOI:10.1002/anie.200701280
日期:2007.9.17
‘Cassette’-ISES (In Situ Enzymatic Screening) Identifies Complementary Chiral Scaffolds for Hydrolytic Kinetic Resolution Across a Range of Epoxides A new ‘Cassette’-In Situ Enzymatic Screen (ISES) for combinatorial catalysis is introduced. This allows the experimentalist to obtain an information-rich readout, in real time, providing an estimate of the sense and magnitude of enantioselectivity across more than one substrate. In its first iteration, the screen identified CoIII-salen catalysts with β-pinene- and α-naphthylalanine-derived chiral scaffolds with broad, yet complementary, substrate specificities.
Enantioselectivities of yeast epoxide hydrolases for 1,2-epoxides
作者:Adriana L. Botes、Carel A.G.M. Weijers、Piet J. Botes、Martie S. van Dyk
DOI:10.1016/s0957-4166(99)00355-9
日期:1999.8
Kinetic resolution of homologous series of unbranched 1,2-epoxyalkanes (C-4 to C-12), 1,2-epoxyalkenes (C-4, C-6 and C-8), a 2,2-dialkylsubstituted epoxide (2-methyl-1,2-epoxyheptane) and a benzyloxy-substituted epoxide (benzyl glycidyl ether) was investigated using resting cells of 10 different yeast strains. Biocatalysts with excellent enantioselectivity (E>100) and high initial reaction rates (>300 nmol/min/mg dry weight) were found for the 2-monosubstituted aliphatic epoxides C-6 to C-8. Yeast strains belonging to the genera Rhodotorula, Rhodosporidium and Trichosporon all preferentially hydrolyzed (R)-1,2-epoxides with retention of configuration. The epoxide hydrolases of all the yeast strains are membrane-associated. (C) 1999 Elsevier Science Ltd. All rights reserved.