title: Discovery and structural characterisation of new fold type IV-transaminases exemplify the diversity of this enzyme fold.
abstract: Transaminases are useful biocatalysts for the production of amino acids and chiral amines as intermediates for a broad range of drugs and fine chemicals. Here, we describe the discovery and characterisation of new transaminases from microorganisms which were enriched in selective media containing (R)-amines as sole nitrogen source. While most of the candidate proteins were clearly assigned to known subgroups of the fold IV family of PLP-dependent enzymes by sequence analysis and characterisation of their substrate specificity, some of them did not fit to any of these groups. The structure of one of these enzymes from Curtobacterium pusillum, which can convert d-amino acids and various (R)-amines with high enantioselectivity, was solved at a resolution of 2.4 Å. It shows significant differences especially in the active site compared to other transaminases of the fold IV family and thus indicates the existence of a new subgroup within this family. Although the discovered transaminases were not able to convert ketones in a reasonable time frame, overall, the enrichment-based approach was successful, as we identified two amine transaminases, which convert (R)-amines with high enantioselectivity, and can be used for a kinetic resolution of 1-phenylethylamine and analogues to obtain the (S)-amines with e.e.s >99%.
authors.affiliation: acib, Austrian Centre of Industrial Biotechnology GmbH, 8010 Graz, Austria.
authors.forename: Tea
authors.initials: T
authors.lastname: Pavkov-Keller
authors.affiliation: acib, Austrian Centre of Industrial Biotechnology GmbH, 8010 Graz, Austria.
authors.forename: Gernot A
authors.initials: GA
authors.lastname: Strohmeier
authors.affiliation: acib, Austrian Centre of Industrial Biotechnology GmbH, 8010 Graz, Austria.
authors.forename: Matthias
authors.initials: M
authors.lastname: Diepold
authors.affiliation: DSM, Ahead R&D - Innovative Synthesis BV, NL-6167 RD Geleen, The Netherlands.
authors.forename: Wilco
authors.initials: W
authors.lastname: Peeters
authors.affiliation: DSM, Ahead R&D - Innovative Synthesis BV, NL-6167 RD Geleen, The Netherlands.
authors.forename: Natascha
authors.initials: N
authors.lastname: Smeets
authors.affiliation: DSM, Ahead R&D - Innovative Synthesis BV, NL-6167 RD Geleen, The Netherlands.
authors.forename: Martin
authors.initials: M
authors.lastname: Schürmann
authors.affiliation: acib, Austrian Centre of Industrial Biotechnology GmbH, 8010 Graz, Austria.|Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria.
authors.forename: Karl
authors.initials: K
authors.lastname: Gruber
authors.affiliation: acib, Austrian Centre of Industrial Biotechnology GmbH, 8010 Graz, Austria.|Institute of Molecular Biotechnology, TU Graz, 8010 Graz, Austria.
authors.forename: Helmut
authors.initials: H
authors.lastname: Schwab
authors.affiliation: acib, Austrian Centre of Industrial Biotechnology GmbH, 8010 Graz, Austria.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Steiner
mesh_terms: D039903:Actinobacteria / Q000201:enzymology*; D001426:Bacterial Proteins / Q000737:chemistry*; D018360:Crystallography, X-Ray; D017510:Protein Folding; D013379:Substrate Specificity; D000637:Transaminases / Q000737:chemistry*
chemical_list: D001426:Bacterial Proteins; D000637:Transaminases