Tailored mutants of phenylalanine ammonia‐lyase from Petroselinum crispum for the synthesis of bulky L‐ and D‐arylalanines

Alina Filip; Emma Zsofia Aletta Nagy; Diana Tork Souad; Gergely Bánóczi; Monica Ioana Toşa; Florin Dan Irimie; Laszlo Poppe; Csaba Paizs; Laszlo Csaba Bencze

Index: 10.1002/cctc.201800258

Full Text: HTML

Abstract

Tailored mutants of phenylalanine ammonia‐lyase from Petroselinum crispum (PcPAL) were created and tested in ammonia elimination from various sterically demanding, non‐natural analogues of phenylalanine and in ammonia addition reactions onto the corresponding (E)‐arylacrylates. The wild‐type PcPAL was inert or exhibited quite poor conversion in both reactions with all members of the substrate panel. Proper single mutations of residue F137 and the highly conserved residue I460 resulted in PcPAL variants being active in ammonia elimination but having still poor activity in ammonia additions onto bulky substrates. However, combined mutations involving I460 besides the well‐studied F137 led to mutants exhibiting activity in ammonia addition as well. The synergistic multiple mutations resulted in substantial substrate scope extension of PcPAL and opened up novel biocatalytic routes for the synthesis of both enantiomers of valuable phenylalanine analogues, such as (4‐methoxyphenyl)‐, (napthalen‐2‐yl)‐, ([1,1'‐biphenyl]‐4‐yl)‐, (4'‐fluoro‐[1,1'‐biphenyl]‐4‐yl)‐, and (5‐phenylthiophene‐2‐yl)alanines