title: Evaluation of Brachypodium distachyon L-Tyrosine Decarboxylase Using L-Tyrosine Over-Producing Saccharomyces cerevisiae.
abstract: To demonstrate that herbaceous biomass is a versatile gene resource, we focused on the model plant Brachypodium distachyon, and screened the B. distachyon for homologs of tyrosine decarboxylase (TDC), which is involved in the modification of aromatic compounds. A total of 5 candidate genes were identified in cDNA libraries of B. distachyon and were introduced into Saccharomyces cerevisiae to evaluate TDC expression and tyramine production. It is suggested that two TDCs encoded in the transcripts Bradi2g51120.1 and Bradi2g51170.1 have L-tyrosine decarboxylation activity. Bradi2g51170.1 was introduced into the L-tyrosine over-producing strain of S. cerevisiae that was constructed by the introduction of mutant genes that promote deregulated feedback inhibition. The amount of tyramine produced by the resulting transformant was 6.6-fold higher (approximately 200 mg/L) than the control strain, indicating that B. distachyon TDC effectively converts L-tyrosine to tyramine. Our results suggest that B. distachyon possesses enzymes that are capable of modifying aromatic residues, and that S. cerevisiae is a suitable host for the production of L-tyrosine derivatives.
authors.affiliation: Biomass Engineering Program, RIKEN, Yokohama, Kanagawa, Japan.
authors.forename: Shuhei
authors.initials: S
authors.lastname: Noda
authors.affiliation: Biomass Engineering Program, RIKEN, Yokohama, Kanagawa, Japan.
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Shirai
authors.affiliation: Biomass Engineering Program, RIKEN, Yokohama, Kanagawa, Japan.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Mochida
authors.affiliation: Biomass Engineering Program, RIKEN, Yokohama, Kanagawa, Japan; Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, Suita, Osaka, Japan.
authors.forename: Fumio
authors.initials: F
authors.lastname: Matsuda
authors.affiliation: Biomass Engineering Program, RIKEN, Yokohama, Kanagawa, Japan.
authors.forename: Sachiko
authors.initials: S
authors.lastname: Oyama
authors.affiliation: Biomass Engineering Program, RIKEN, Yokohama, Kanagawa, Japan.
authors.forename: Mami
authors.initials: M
authors.lastname: Okamoto
authors.affiliation: Biomass Engineering Program, RIKEN, Yokohama, Kanagawa, Japan; Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, Kobe, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kondo
mesh_terms: D058431:Brachypodium / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D015870:Gene Expression; D017343:Genes, Plant; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D014439:Tyramine / Q000096:biosynthesis; D014443:Tyrosine / Q000096:biosynthesis*; D014445:Tyrosine Decarboxylase / Q000235:genetics / Q000378:metabolism*
chemical_list: D014443:Tyrosine; D014445:Tyrosine Decarboxylase; D014439:Tyramine