PUB - Publikationen an der Universität Bielefeld

In this contribution, the unique and unprecedented stereochemical phenomenon of an aldoxime dehydratase-catalyzed enantioselective dehydration of racemic E- and Z-aldoximes with formation of both opposite enantiomeric forms of a chiral nitrile has been rationalized by means of molecular modelling, comprising in silico mutations and docking studies. This theoretical investigation gave a detailed insight why with the same enzyme the use of racemic E- and Z-aldoximes leads to opposite forms of the chiral nitrile. The calculated mutants with an increased and decreased cavity in the active site have then been prepared and used in biotransformations, showed the theoretically predicted decrease and increase of the enantioselectivities in these nitrile syntheses. This validated model also enabled the rational design of mutants with a decreased size of the cavity, which gave superior enantioselectivities compared to the known wild-type enzyme with excellent E-values of up to E>200 when utilizing the mutant OxdRE-Leu145Phe. © 2021 Wiley-VCH GmbH.