Transaminases are an industrially important class of enzyme, due to their ability to catalyse amination reactions for production of chiral amines, and are key building blocks of small molecule pharmaceuticals. We analysed the genome of strain GS115 of the methylotrophic yeast Komagataella phaffii, formerly known as Pichia pastoris, to identify the transaminase genes and propose a systematic nomenclature based on both phylogeny and structuro-functional features. K. phaffii is an increasingly attractive industrial host cell due to its ability to grow to high biomass, up to 60% wet cell weight by volume, using methanol as carbon source and inducer of transgene expression. Thirty-nine UniProt database hits were reduced to 19 on the basis of sequence similarity and hidden Markov model. Of the 19 genes, the open-reading frames of three (KpTam I-II.1b, KpTam I-II.7 and KpTam V.2) had strong homology with no characterized proteinand four (KpTam III.1a, KpTam III.1b, KpTam III.2a and KpTam III.2b) had relatively high sequence similarity to x-type transaminases, a subtype that typically accepts the broadest range of substrates. Comparison with Saccharomyces cerevisiae S288C suggested functions for KpTam I-II.1b and KpTam I-II.7. K. phaffii GS115 was originally generated by mutagenesis of K. phaffii CBS7435 and comparison revealed that one transaminase gene may have been deleted during this mutagenesis. These insights can advance fundamental understanding of yeast biology and can inform industrial screening and engineering of yeast transaminases.
Volume 99, 2020
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