No abstract

PostprintThis is the accepted version of a paper published in Journal of Molecular Biology. This paper has been peer-reviewed but does not include the final publisher proof-corrections or journal pagination. Citation for the original published paper (version of record):Ericsson, D., Kasrayan, A., Johansson, P., Bergfors, T., Sandström, A. et al. (2008) X-ray structure of Candida antarctica lipase A shows a novel lid structure and a likely mode of interfacial activation. Abstract: Directed evolution of enzymes as enantioselective catalysts in organic chemistry is an alternative to traditional asymmetric catalysis using chiral transition metal complexes or organocatalysts, the different approaches often being complementary. Moreover, directed evolution studies allow us to learn more about how enzymes perform mechanistically. The present study concerns a previously evolved highly enantioselective mutant of the epoxide hydrolase from Aspergillus niger in the hydrolytic kinetic resolution of racemic glycidyl phenyl ether. Kinetic data, molecular dynamics calculations, molecular modeling, inhibition experiments and X-ray structural work for the wild-type (WT) enzyme and the best mutant reveal the basis of the large increase in enantioselectivity (E = 4.6 versus E = 115). The overall structures of the WT and the mutant are essentially identical, but dramatic differences are observed in the active site as revealed by the X-ray structures. All of the experimental and computational results support a model in which productive positioning of the preferred (S)-glycidyl phenyl ether, but not the (R)-enantiomer, forms the basis of enhanced enantioselectivity. Predictions regarding substrate scope and enantioselectivity of the best mutant are shown to be possible. Journal of Molecular

No abstract

Here we report that an engineered microbial cytochrome P450 BM-3 (CYP102A subfamily) efficiently catalyzes the alpha-hydroxylation of phenylacetic acid esters. This P450 BM-3 variant also produces the authentic human metabolite of buspirone, R-6-hydroxybuspirone, with 99.5% ee.