4ufo

Publication Abstract from PubMed

Engineered enzyme variants of potato epoxide hydrolase (StEH1) display varying degrees of enrichment of (2R)-3-phenylpropane-1,2-diol from racemic benzyloxirane. Curiously, the observed increase in the enantiomeric excess of the (R)-diol is not only due to changes in enantioselectivity for the preferred epoxide enantiomer, but also to changes in the regioselectivity of the epoxide ring opening of (S)-benzyloxirane. To probe the structural origin of these differences in substrate selectivities and catalytic regiopreferences, we have solved the crystal structures for the in-vitro evolved StEH1 variants. We have additionally used these structures as a starting point for docking the epoxide enantiomers into the respective active sites. Interestingly, despite the simplicity of our docking calculations, the apparent preferred binding modes obtained from the docking appears to rationalize the experimentally determined regioselectivities. These calculations could also identify an active site residue (F33) as a putatively important interaction partner, a role that could explain the high degree of conservation of this residue during evolution. Overall, our combined experimental, structural and computational studies of this system provide snapshots into the evolution of enantioconvergence in StEH1 catalyzed epoxide hydrolysis.

Laboratory Evolved Enzymes Provide Snapshots of the Development of Enantioconvergence in Enzyme-Catalyzed Epoxide Hydrolysis.,Janfalk Carlsson A, Bauer P, Dobritzsch D, Nilsson M, Kamerlin SC, Widersten M Chembiochem. 2016 Jul 7. doi: 10.1002/cbic.201600330. PMID:27383542^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.