Presentation Information
[P02-204]An Oxoamine Synthase Enables Efficient Biosynthesis of a Symmetrical Pyrazine from Tyrosine
○Riri Totsuka1, Kurumi Usui1, Shunsuke Masuo1, Naoki Takaya1 (1. Institute of Life and Environmental Sciences, Microbiology Research Center for Sustainability, Tsukuba Institute for Advanced Research, University of Tsukuba (Japan))
Keywords:
Pyrazine,Oxoamine synthase,Amino acid,Tyrosine,Bioproduction
Pyrazines are nitrogen-containing heterocyclic compounds with broad applications as flavoring agents, pharmaceuticals, and precursors for high-performance polymers. Given their diverse applications, expanding the structural diversity of pyrazines is also important. However, conventional chemical synthesis often imposes a substantial environmental burden. Therefore, there is growing interest in environmentally friendly and structurally versatile production systems for pyrazines. In this context, converting biomass-derived amino acids with diverse side-chain structures into valuable pyrazines while preserving their side-chain functionalities represents a promising strategy for sustainable production and structural diversification.
We previously elucidated a novel biosynthetic pathway for pyrazine compounds in Pseudomonas species. A key enzyme in this pathway, the oxoamine synthase Pf.PapD, catalyzes the conversion of 4-aminophenylalanine into the corresponding aminoketone using acetyl-CoA as the acetyl donor. To investigate the functional diversity of this enzyme family, we constructed a phylogenetic tree based on Pf.PapD and its homologs and selected 29 Pf.PapD-like enzymes representing distinct clades. These recombinant enzymes were expressed, purified, and evaluated for specific activities toward various amino acids.
Enzymes exhibiting activity toward several amino acids, including alanine, glycine, leucine, isoleucine, lysine, valine, phenylalanine, and tyrosine, were newly identified. Among them, St.PapD from a Streptomyces species showed high activity toward tyrosine. Resting-cell reactions using tyrosine as the substrate were then performed with three enzymes, including St.PapD and Pf.PapD, and the resulting supernatants were analyzed by LC–MS. These analyses revealed that St.PapD produced a symmetrical pyrazine bearing hydroxybenzyl groups at both termini, derived from tyrosine. Notably, the production level of this compound was 2.2-fold higher than that observed with Pf.PapD. These results highlight the functional diversity of the Pf.PapD enzyme family and identify St.PapD as a promising biocatalyst for efficient pyrazine biosynthesis from tyrosine, providing a basis for sustainable and versatile pyrazine bioproduction through enzyme selection.
We previously elucidated a novel biosynthetic pathway for pyrazine compounds in Pseudomonas species. A key enzyme in this pathway, the oxoamine synthase Pf.PapD, catalyzes the conversion of 4-aminophenylalanine into the corresponding aminoketone using acetyl-CoA as the acetyl donor. To investigate the functional diversity of this enzyme family, we constructed a phylogenetic tree based on Pf.PapD and its homologs and selected 29 Pf.PapD-like enzymes representing distinct clades. These recombinant enzymes were expressed, purified, and evaluated for specific activities toward various amino acids.
Enzymes exhibiting activity toward several amino acids, including alanine, glycine, leucine, isoleucine, lysine, valine, phenylalanine, and tyrosine, were newly identified. Among them, St.PapD from a Streptomyces species showed high activity toward tyrosine. Resting-cell reactions using tyrosine as the substrate were then performed with three enzymes, including St.PapD and Pf.PapD, and the resulting supernatants were analyzed by LC–MS. These analyses revealed that St.PapD produced a symmetrical pyrazine bearing hydroxybenzyl groups at both termini, derived from tyrosine. Notably, the production level of this compound was 2.2-fold higher than that observed with Pf.PapD. These results highlight the functional diversity of the Pf.PapD enzyme family and identify St.PapD as a promising biocatalyst for efficient pyrazine biosynthesis from tyrosine, providing a basis for sustainable and versatile pyrazine bioproduction through enzyme selection.
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