Rational mutagenesis of an epoxide hydrolase and its structural mechanism for the enantioselectivity improvement toward chiral ortho-fluorostyrene oxide.

Chiral (S)-o-fluorostyrene oxide (oFSO) and vicinal diol (R)-o-fluorophenylethane-1,2-diol (oFPED) are important intermediates for synthesizing treatments for neuropathic diseases. This study aimed to engineer Aspergillus usamii epoxide hydrolase (AuEH2) through a rational mutagenesis strategy to customize high enantioselectivity mutant for rac-oFSO. Out of 181 single-site mutants screened, six showed elevated enantiomeric ratio (E value) ranging from 32 to 108 according to E value and activity mutability landscapes.

Engineering an Epoxide Hydrolase for Chemoenzymatic Asymmetric Synthesis of Chiral Triazole Fungicide ()- and ()-Flutriafol.

Flutriafol, a globally utilized triazole fungicide in agriculture, is typically applied as a racemic mixture, but its enantiomers differ in bioactivity and environmental impact. The synthesis of flutriafol enantiomers is critically dependent on chiral precursors: 2,2-bisaryl-substituted oxirane [(2-fluorophenyl)-2-(4-fluorophenyl)oxirane, ] and 1,2-diol [1-(2-fluorophenyl)-1-(4-fluorophenyl)ethane-1,2-diol, ]. Here, we engineered a epoxide hydrolase (EH), obtaining mutant / with a 6.

Chemoenzymatic Asymmetric Synthesis of Chiral Triazole Fungicide ()-Tebuconazole in High Optical Purity Mediated by an Epoxide Hydrolase from .

Tebuconazole is a chiral triazole fungicide used globally in agriculture as a racemic mixture, but its enantiomers exhibit significant enantioselective dissimilarities in bioactivity and environmental behaviors. The steric hindrance caused by the -butyl group makes it a great challenge to synthesize tebuconazole enantiomers. Here, we designed a simple chemoenzymatic approach for the asymmetric synthesis of ()-tebuconazole, which includes the biocatalytic resolution of racemic epoxy-precursor (2--butyl-2-[2-(4-chlorophenyl)ethyl] oxirane, -) by / whole cells expressed epoxide hydrolase from (EH), followed by a one-step chemocatalytic synthesis of ()-tebuconazole.

Improving Biotransformation Efficiency of by Enhancement of Cell Stress Tolerance and Enzyme Activity.

exhibits excellent Δ-dehydrogenation ability, but the acquisition of the desirable strain is limited due to lacking of comprehensive genetic manipulation. Herein, a promoter collection for fine-tuning gene expression was achieved. Next, the expression level was enhanced and directed evolution of the global transcriptional factor (IrrE) was applied to enhance cell viability in systems containing more substrate and ethanol, thus contributing to higher production.