title: Identification and characterization of a L-tyrosine decarboxylase in Methanocaldococcus jannaschii.
abstract: Methanofuran is the first coenzyme in the methanogenic pathway used by the archaeon Methanocaldococcus jannaschii, as well as other methanogens, to reduce CO2 to methane. The details of the pathway for the biosynthesis of methanofuran and the responsible genes have yet to be established. A clear structural element in all known methanofurans is tyramine, likely produced by the decarboxylation of L-tyrosine. We show here that the mfnA gene at M. jannaschii locus MJ0050 encodes a thermostable pyridoxal phosphate-dependent L-tyrosine decarboxylase that specifically produces tyramine. Homologs of this gene are widely distributed among euryarchaea but are not specifically related to known bacterial or plant tyrosine decarboxylases.
authors.affiliation: Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0308, USA.
authors.forename: Nicole D
authors.initials: ND
authors.lastname: Kezmarsky
authors.forename: Huimin
authors.initials: H
authors.lastname: Xu
authors.forename: David E
authors.initials: DE
authors.lastname: Graham
authors.forename: Robert H
authors.initials: RH
authors.lastname: White
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019843:Archaeal Proteins / Q000302:isolation & purification / Q000378:metabolism; D003001:Cloning, Molecular; D004795:Enzyme Stability; D005663:Furans / Q000378:metabolism; D019848:Gene Expression Regulation, Archaeal; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D007700:Kinetics; D017017:Methanococcus / Q000145:classification / Q000201:enzymology*; D008969:Molecular Sequence Data; D010802:Phylogeny; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013816:Thermodynamics; D014439:Tyramine / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism; D014445:Tyrosine Decarboxylase / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D019843:Archaeal Proteins; D005663:Furans; D014443:Tyrosine; C044289:carbon dioxide reduction factor; D014445:Tyrosine Decarboxylase; D014439:Tyramine