title: Tauropine dehydrogenase from the marine sponge Halichondria japonica is a homolog of ornithine cyclodeaminase/mu-crystallin.
abstract: The partial amino acid sequence including the N- and C-terminal portions of tauropine dehydrogenase (EC 1.5.1.23) from the marine sponge Halichondria japonica was determined by enzymatic cleavages followed by peptide sequencing. This information was used to design degenerate primers for amplification of cDNA encoding the tauropine dehydrogenase. The cDNA included 1231 nucleotides with an open reading frame of 1002 nucleotides that encodes a protein of 334 amino acid residues. From the peptide and nucleotide sequencing, the mature tauropine dehydrogenase was estimated to consist of 333 amino acid residues with an acetylated N-terminal serine residue and no intrachain disulfide bonds. The primary structure of the H. japonica enzyme showed apparent similarity with a homolog of ornithine cyclodeaminase from Rhizobium meliloti and other proteins of the ornithine cyclodeaminase/mu-crystallin family, but it showed no significant similarity with the known sequences of octopine dehydrogenases and tauropine dehydrogenases from marine invertebrates. These findings indicate that opine dehydrogenases in marine invertebrates are not all homologous.
authors.affiliation: Department of Marine Biosciences, School of Fisheries Sciences, Kitasato University Sanriku 160-4, Ohfunato, Iwate 022-0101, Japan. kan-no@kitasato-u.ac.jp
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Kan-No
authors.forename: Hiroto
authors.initials: H
authors.lastname: Matsu-Ura
authors.forename: Shinya
authors.initials: S
authors.lastname: Jikihara
authors.forename: Takayuki
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Endo
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Moriyama
authors.forename: Eizoh
authors.initials: E
authors.lastname: Nagahisa
authors.forename: Minoru
authors.initials: M
authors.lastname: Sato
mesh_terms: D000594:Amino Acid Oxidoreductases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000642:Ammonia-Lyases / Q000737:chemistry*; D000818:Animals; D001483:Base Sequence; D002851:Chromatography, High Pressure Liquid; D003001:Cloning, Molecular; D003459:Crystallins / Q000737:chemistry*; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000378:metabolism; D011161:Porifera / Q000201:enzymology*; D017386:Sequence Homology, Amino Acid; D000090803:mu-Crystallins
chemical_list: D003459:Crystallins; D018076:DNA, Complementary; D010446:Peptide Fragments; D000594:Amino Acid Oxidoreductases; C050564:tauropine dehydrogenase; C021903:D-octopine dehydrogenase; D000090803:mu-Crystallins; D000642:Ammonia-Lyases; C021914:ornithine cyclodeaminase