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Studies on sea snake venom.

Tamiya N, Yagi T - Proc. Jpn. Acad., Ser. B, Phys. Biol. Sci. (2011)

Bottom Line: Erabutoxins a and b are neurotoxins isolated from venom of a sea snake Laticauda semifasciata (erabu-umihebi).The sequence comparison and the location of essential residues on the protein suggested the mechanism of binding of the toxin to the acetylcholine receptor.Classification of snakes by means of sequence comparison and that based on different morphological features were inconsistent, which led the authors to propose a hypothesis "Evolution without divergence."

View Article: PubMed Central - PubMed

Affiliation: Tohoku University, Miyagi, Japan.

ABSTRACT
Erabutoxins a and b are neurotoxins isolated from venom of a sea snake Laticauda semifasciata (erabu-umihebi). Amino acid sequences of the toxins indicated that the toxins are members of a superfamily consisting of short and long neurotoxins and cytotoxins found in sea snakes and terrestrial snakes. The short neurotoxins to which erabutoxins belong act by blocking the nicotinic acetylcholine receptor on the post synaptic membrane in a manner similar to that of curare. X-ray crystallography and NMR analyses showed that the toxins have a three-finger structure, in which three fingers made of three loops emerging from a dense core make a gently concave surface of the protein. The sequence comparison and the location of essential residues on the protein suggested the mechanism of binding of the toxin to the acetylcholine receptor. Classification of snakes by means of sequence comparison and that based on different morphological features were inconsistent, which led the authors to propose a hypothesis "Evolution without divergence."

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Related in: MedlinePlus

Stereopairs of the best fit superposition of 14 final converged structures of Eb [PDBid: 1FRA] viewed similarly to that in Fig. 6a.
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Related In: Results  -  Collection


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fig07: Stereopairs of the best fit superposition of 14 final converged structures of Eb [PDBid: 1FRA] viewed similarly to that in Fig. 6a.

Mentions: The solution structure of Eb in D2O (Fig. 7) elucidated by proton-NMR in collaboration with late Miyazawa and Inagaki38,39) was in good agreement with that observed by X-ray crystallography (Fig. 6a).


Studies on sea snake venom.

Tamiya N, Yagi T - Proc. Jpn. Acad., Ser. B, Phys. Biol. Sci. (2011)

Stereopairs of the best fit superposition of 14 final converged structures of Eb [PDBid: 1FRA] viewed similarly to that in Fig. 6a.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3066545&req=5

fig07: Stereopairs of the best fit superposition of 14 final converged structures of Eb [PDBid: 1FRA] viewed similarly to that in Fig. 6a.
Mentions: The solution structure of Eb in D2O (Fig. 7) elucidated by proton-NMR in collaboration with late Miyazawa and Inagaki38,39) was in good agreement with that observed by X-ray crystallography (Fig. 6a).

Bottom Line: Erabutoxins a and b are neurotoxins isolated from venom of a sea snake Laticauda semifasciata (erabu-umihebi).The sequence comparison and the location of essential residues on the protein suggested the mechanism of binding of the toxin to the acetylcholine receptor.Classification of snakes by means of sequence comparison and that based on different morphological features were inconsistent, which led the authors to propose a hypothesis "Evolution without divergence."

View Article: PubMed Central - PubMed

Affiliation: Tohoku University, Miyagi, Japan.

ABSTRACT
Erabutoxins a and b are neurotoxins isolated from venom of a sea snake Laticauda semifasciata (erabu-umihebi). Amino acid sequences of the toxins indicated that the toxins are members of a superfamily consisting of short and long neurotoxins and cytotoxins found in sea snakes and terrestrial snakes. The short neurotoxins to which erabutoxins belong act by blocking the nicotinic acetylcholine receptor on the post synaptic membrane in a manner similar to that of curare. X-ray crystallography and NMR analyses showed that the toxins have a three-finger structure, in which three fingers made of three loops emerging from a dense core make a gently concave surface of the protein. The sequence comparison and the location of essential residues on the protein suggested the mechanism of binding of the toxin to the acetylcholine receptor. Classification of snakes by means of sequence comparison and that based on different morphological features were inconsistent, which led the authors to propose a hypothesis "Evolution without divergence."

Show MeSH
Related in: MedlinePlus