Work

Synthesis of β-Branched Tryptophan Analogues Using an Engineered Subunit of Tryptophan Synthase

Year: 2016

Type: article

Abstract: We report that l-threonine may substitute for l-serine in the β-substitution reaction of an engineered subunit of tryptophan synthase from Pyrococcus furiosus, yielding (2S,3S)-β-methyltryptophan (β-MeTrp) in a single step. The trace activity of the wild-type β-subunit on this substrate was enhanced more than 1000-fold by directed evolution. Structural and spectroscopic data indicate that this increase is correlated with stabilization of the electrophilic aminoacrylate intermediate. The engineered biocatalyst also reacts with a variety of indole analogues and thiophenol for diastereoselective C-C, C-N, and C-S bond-forming reactions. This new activity circumvents the 3-enzyme pathway that produces β-MeTrp in nature and offers a simple and expandable route to preparing derivatives of this valuable building block.

Source: Journal of the American Chemical Society

DOI: 10.1021/jacs.6b04836

Authors: Michael Herger, Paul van Roye, David K. Romney, Sabine Brinkmann-Chen, Andrew R. Buller, Frances H. Arnold

Institution: California Institute of Technology

Language: English

Topic: Enzyme Catalysis and Immobilization

Subfield: Molecular Biology

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

Open Access status: green

Funders: Gordon and Betty Moore Foundation, California Institute of Technology, National Institute of General Medical Sciences, Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana-Champaign

Awards: Synthesis of Biologically Active Molecular Scaffolds via Enzyme-Catalyzed Asymmetric Carbene Transfer, Radical SAM enzyme engineering to produce improved thiopeptide antibiotics