Engineered Ammonia Lyases for the Production of Challenging Electron-Rich l-Phenylalanines

Engineered variants of phenylalanine ammonia lyase from Planctomyces brasiliensis were developed through rational design efforts focusing on the aryl binding pocket of the active site, guided by structural and phylogenetic inference. Inherent problems traditionally associated with the biocatalytic hydroamination of acrylic acids, such as low conversion and poor regioselectivity with alkyl and methoxy derivatives, could be overcome. The PbPAL variants described here represent a valuable addition to the biocatalytic toolbox, allowing previously inaccessible amino acid building blocks to be obtained regio- and enantioselectively on preparative scale.