title: An Engineered Tryptophan Synthase Opens New Enzymatic Pathways to β-Methyltryptophan and Derivatives.
abstract: β-Methyltryptophans (β-mTrp) are precursors in the biosynthesis of bioactive natural products and are used in the synthesis of peptidomimetic-based therapeutics. Currently β-mTrp is produced by inefficient multistep synthetic methods. Here we demonstrate how an engineered variant of tryptophan synthase from Salmonella (StTrpS) can catalyse the efficient condensation of l-threonine and various indoles to generate β-mTrp and derivatives in a single step. Although l-serine is the natural substrate for TrpS, targeted mutagenesis of the StTrpS active site provided a variant (βL166V) that can better accommodate l-Thr as a substrate. The condensation of l-Thr and indole proceeds with retention of configuration at both α- and β-positions to give (2S,3S)-β-mTrp. The integration of StTrpS (βL166V) with l-amino acid oxidase, halogenase enzymes and palladium chemocatalysts provides access to further d-configured and regioselectively halogenated or arylated β-mTrp derivatives.
authors.affiliation: School of Chemistry, Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK.
authors.forename: Daniel
authors.initials: D
authors.lastname: Francis
authors.affiliation: School of Chemistry, Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Winn
authors.affiliation: School of Chemistry, Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Latham
authors.affiliation: School of Chemistry, Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK.
authors.forename: Michael F
authors.initials: MF
authors.lastname: Greaney
authors.affiliation: School of Chemistry, Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester, M1 7DN, UK.
authors.forename: Jason
authors.initials: J
authors.lastname: Micklefield
mesh_terms: D015394:Molecular Structure; D009154:Mutation; D057786:Peptidomimetics; D015202:Protein Engineering; D012475:Salmonella / Q000201:enzymology / Q000235:genetics; D014364:Tryptophan / Q000737:chemistry / Q000378:metabolism*; D014367:Tryptophan Synthase / Q000138:chemical synthesis* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D057786:Peptidomimetics; D014364:Tryptophan; D014367:Tryptophan Synthase
keywords: biocatalysis; enzyme cascades; methylamino acids; peptidomimetics; tryptophan synthase