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Your search keyword '"Tamiya, Toru"' showing total 105 results
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105 results on '"Tamiya, Toru"'

4. Experimentally based model of a complex between a snake toxin and the [alpha]7 nicotinic receptor

Author

Fruchart-Gaillard, Carole, Gilquin, Bernard, Antil-Delbeke, Stephanie, Le Novere, Nicolas, Tamiya, Toru, Corringer, Pierre-Jean, Changeux, Jean-Pierre, Menez, Andre, and Servent, Denis

Subjects
Poisonous snakes -- Venom, Nicotinic receptors -- Physiological aspects, Structure-activity relationships (Biochemistry) -- Analysis, Binding sites (Biochemistry) -- Analysis, Science and technology
Abstract

To understand how snake neurotoxins interact with nicotinic acetylcholine receptors, we have elaborated an experimentally based model of the [alpha]-cobratoxin-[alpha]7 receptor complex. This model was achieved by using (i) a three-dimensional model of the [alpha]7 extracellular domain derived from the crystallographic structure of the homologous acetylcholine-binding protein, (ii) the previously solved x-ray structure of the toxin, and (iii) nine pairs of residues identified by cycle-mutant experiments to make contacts between the [alpha]-cobratoxin and [alpha]7 receptor. Because the receptor loop F occludes entrance of the toxin binding pocket, we submitted this loop to a dynamics simulation and selected a conformation that allowed the toxin to reach its binding site. The three-dimensional structure of the toxin-receptor complex model was validated a posteriori by an additional double-mutant experiment. The model shows that the toxin interacts perpendicularly to the receptor axis, in an equatorial position of the extracellular domain. The tip of the toxin central loop plugs into the receptor between two subunits, just below the functional receptor loop C, the C-terminal tail of the toxin making adjacent additional interactions at the receptor surface. The receptor establishes major contacts with the toxin by its loop C, which is assisted by principal (loops A and B) and complementary (loops D, F, and 1) functional regions. This model explains the antagonistic properties of the toxin toward the neuronal receptor and opens the way to the design of new antagonists.

Published
2002

9. Alpha-helical structure of fish actomyosin: changes during setting

Author

Ogawa, Masahiro, Kanamura, Jun, Miyashita, Hiroki, Tamiya, Toru, and Tsuchiya, Takahide

Subjects
Circular dichroism -- Methods, Protein folding -- Observations, Fish as food -- Research, Business, Food/cooking/nutrition
Abstract

The setting response of fish meat paste starts with unfolding of the alpha-helix of actomyosin (AM) in fish. Analysis of circular dichroism of AM from eight different species of fish indicates that the amount of aplha-helicity differs among various species. Setting involves transformation from solution to gel of salted fish meat paste when kept at low temperatures. The alpha-helicity of the AM decreases during incubation at 30 degrees or 40 degrees Centigrade.

Published
1995

38. Purification and Characterization of a Novel Isoform of Myosinase from Spear Squid Liver1.

Author

Tamori, Jun, Kanzawa, Nobuyuki, Tajima, Takaho, Tamiya, Toru, and Tsuchiya, Takahide

Subjects
MYOSIN, HYDROXYAPATITE, COLLOIDS, MUSCLE proteins, GLOBULINS
Abstract

A novel isoform of myosinase was purified to homogeneity from liver of spear squid by sequential chromatographies using SP Sephadex, hydroxylapatite, Zn/Co chelating affini-ty, and TSK-gel G2000SW columns. Myosinase activity was detected as a single peak of 45-kDa protein by gel filtration. The novel isoform of myosinase specifically hydrolyzed a rabbit skeletal muscle myosin heavy chain into products of 120 and 100 kDa in the presence of Co2+ ions, and the cleavage site in the myosin heavy chain was quite different from those of two known myosinase isoforms, I and II. Therefore, we named the novel isoform myosinase III. Myosinase III was also distinguishable from myosinase I by its amino-ter-minal sequence. The sequence showed similarity to an internal sequence of the astacin family. [ABSTRACT FROM AUTHOR]

Published
1999
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40. Molecular cloning of the antibacterial protein of the giant African snail, <em>Achatina fulica</em> Férussac.

Author

Obara, Kuniaki, Otsuka-Fuchino, Hisako, Sattayasai, Nison, Nonomura, Yoshiaki, Tsuchiya, Takahide, and Tamiya, Toru

Subjects
MOLECULAR cloning, GIANT African snail, PROTEINS, ANTIBACTERIAL agents, RNA, DNA, BIOCHEMISTRY
Abstract

An expression cDNA library was constructed with poly(A)-rich RNA extracted from the collar of the giant African snail, Achatina fulica Férussac. A 1.9-kbp cDNA clone encoding a precursor of antibacterial glycoprotein of the snail, achacin, was isolated from the cDNA expression library. The cDNA sequence contains an open reading frame with 1593-nucleotide residues. The deduced amino acid sequence of this achacin precursor starts with a 29-residue leader peptide followed by a 502- residue mature peptide (56 kDa) with four possible N-glycosylation sites, Asn-Xaa-Ser or Asn-Xaa-Thr. The Northern-blot analysis proved that the achacin precursor was specifically expressed in the tissue of snail collar and processed to mature achacin, cDNA inserts encoding achacin precursor were subcloned into expression plasmids. Three kinds of expressed polypeptides were cross-reacted with rabbit antiserum raised against achacin. The largest polypeptide (Mr 63000) should be the achacin precursor. [ABSTRACT FROM AUTHOR]

Published
1992
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