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Improved enantioselective conversion of styrene epoxides and meso-epoxides through epoxide hydrolases with a mutated nucleophile-flanking residue

Paper ID Volume ID Publish Year Pages File Format Full-Text
17674 42688 2009 9 PDF Available
Title
Improved enantioselective conversion of styrene epoxides and meso-epoxides through epoxide hydrolases with a mutated nucleophile-flanking residue
Abstract

In epoxide hydrolase from Agrobacterium radiobacter (EchA), phenylalanine 108 flanks the nucleophilic aspartate and forms part of the substrate-binding pocket. The influence of mutations at this position on the activity and enantioselectivity of the enzyme was investigated. Screening for improved enantioselectivity towards para-nitrophenyl glycidyl ether (pNPGE) using spectrophotometric progress curve analysis yielded five different mutants with 3- to 7-fold improved enantioselectivity. The increase in enantioselectivity was in most cases the result of an enhanced catalytic efficiency toward the preferred enantiomer. Several mutations at position F108 resulted in a higher activity toward cis-disubstituted meso-epoxides, which were converted to a single product enantiomer. Mutant F108C converted cis-2,3-epoxybutane to (2R,3R)-2,3-butanediol of >99% ee with a 7-fold improved activity, and mutant F108A hydrolyzed cyclohexene oxide to (1R,2R)-1,2-cyclohexanediol of >99% ee with a more than 150-fold higher activity than wild-type enzyme. It is concluded that single amino acid substitutions in the active site of epoxide hydrolase can result in enzyme variants with catalytic properties that are suitable for preparative scale production of (S)-epoxides and chiral vicinal diols in high yield and with excellent ee.

Keywords
Biocatalysis; Epoxide hydrolase; Enantioselectivity; Mutagenesis; Screening
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Improved enantioselective conversion of styrene epoxides and meso-epoxides through epoxide hydrolases with a mutated nucleophile-flanking residue
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Publisher
Database: Elsevier - ScienceDirect
Journal: Enzyme and Microbial Technology - Volume 44, Issue 3, 5 March 2009, Pages 145–153
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us