Tauropine dehydrogenase from the marine sponge Halichondria japonica is a homolog of ornithine cyclodeaminase/mu-crystallin

• Published in: Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology 2005-07, Vol.141 (3), p.331-339
• Main Authors: Kan-no, Nobuhiro, Matsu-ura, Hiroto, Jikihara, Shinya, Yamamoto, Takayuki, Endo, Noriyuki, Moriyama, Shunsuke, Nagahisa, Eizoh, Sato, Minoru
• Format: Article
• Language: English
• Subjects: Amino Acid Oxidoreductases - chemistry; Amino Acid Oxidoreductases - genetics; Amino Acid Oxidoreductases - metabolism; Amino Acid Sequence; Ammonia-Lyases - chemistry; Animals; Base Sequence; cDNA; Chromatography, High Pressure Liquid; Cloning, Molecular; Crystallins - chemistry; DNA, Complementary - genetics; DNA, Complementary - metabolism; Halichondria japonica; Marine; Molecular Sequence Data; Mu-crystallin; Opine dehydrogenase; Ornithine cyclodeaminase; Peptide Fragments - metabolism; Porifera - enzymology; Rhizobium meliloti; Sequence Homology, Amino Acid; Sponge; Tauropine dehydrogenase
• ISSN: 1096-4959; 1879-1107
• DOI: 10.1016/j.cbpc.2005.04.003

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.