Creation of (R)-Amine Transaminase Activity within an α-Amino Acid Transaminase Scaffold

ACS Chem Biol. 2020 Feb 21;15(2):416-424. doi: 10.1021/acschembio.9b00888. Epub 2020 Feb 11.

Abstract

The enzymatic transamination of ketones into (R)-amines represents an important route for accessing a range of pharmaceuticals or building blocks. Although many publications have dealt with enzyme discovery, protein engineering, and the application of (R)-selective amine transaminases [(R)-ATA] in biocatalysis, little is known about the actual in vivo role and how these enzymes have evolved from the ubiquitous α-amino acid transaminases (α-AATs). Here, we show the successful introduction of an (R)-transaminase activity in an α-amino acid aminotransferase with one to six amino acid substitutions in the enzyme's active site. Bioinformatic analysis combined with computational redesign of the d-amino acid aminotransferase (DATA) led to the identification of a sextuple variant having a specific activity of 326 milliunits mg-1 in the conversion of (R)-phenylethylamine and pyruvate to acetophenone and d-alanine. This value is similar to those of natural (R)-ATAs, which typically are in the range of 250 milliunits mg-1. These results demonstrate that (R)-ATAs can evolve from α-AAT as shown here for the DATA scaffold.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacillus subtilis / enzymology
  • Escherichia coli / enzymology
  • Escherichia coli Proteins / genetics
  • Escherichia coli Proteins / metabolism*
  • Mutagenesis, Site-Directed
  • Mutation
  • Phenethylamines / chemistry
  • Phenethylamines / metabolism
  • Protein Binding
  • Stereoisomerism
  • Substrate Specificity
  • Transaminases / genetics
  • Transaminases / metabolism*

Substances

  • Escherichia coli Proteins
  • Phenethylamines
  • Transaminases
  • branched-chain-amino-acid transaminase
  • 1-phenethylamine