.alpha.-Cobratoxin: proton NMR assignment and solution structure

Goas, Remi Le; LaPlante, Steven R.; Mikou, Afaf; Delsuc, Marc-André; Guittet, Éric; Robin, Michel; Charpentier, Isabelle; Lallemand, J. Y.

doi:10.1021/bi00135a018

Cited by 42 publications

(34 citation statements)

References 32 publications

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“…A, the HSQC of the ␣18-mer mixed with an equimolar amount of Ea; B, the HSQC of the ␣18-mer mixed with an equimolar amount of Eb; C, the HSQC of the ␣18-mer mixed with an equimolar amount of LSIII; D, the HSQC of the ␣18-mer mixed with an equimolar amount of Cbtx. (6). However, those NOEs and accompanying slow-exchanging amide protons were not seen in the spectra of the Cbtx⅐␣18-mer complex.…”

Section: Hsqc Screen and Titration-as Described Previouslymentioning

confidence: 94%

“…X-ray crystal structures and NMR solution structures of several different ␣-neurotoxins reveal a conserved structural pattern consisting of a core of disulfides with three fingers or loops (3)(4)(5)(6)(7)(8)(9)(10)(11)(12). Short ␣-neurotoxins have four core disulfide bonds, whereas the long ␣-neurotoxins have, in addition, a fifth disulfide in the tip of loop II.…”

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confidence: 99%

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NMR-based Binding Screen and Structural Analysis of the Complex Formed between α-Cobratoxin and an 18-Mer Cognate Peptide Derived from the α1 Subunit of the Nicotinic Acetylcholine Receptor fromTorpedo californica

Zeng¹,

Hawrot

2002

Journal of Biological Chemistry

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The ␣18-mer peptide, spanning residues 181-198 of the Torpedo nicotinic acetylcholine receptor ␣1 subunit, contains key binding determinants for agonists and competitive antagonists. To investigate whether the ␣18-mer can bind other ␣-neurotoxins besides ␣-bungarotoxin, we designed a two-dimensional 1 H-15 N heteronuclear single quantum correlation experiment to screen four related neurotoxins for their binding ability to the peptide. Of the four toxins tested (erabutoxin a, erabutoxin b, LSIII, and ␣-cobratoxin), only ␣-cobratoxin binds the ␣18-mer to form a 1:1 complex. The NMR solution structure of the ␣-cobratoxin⅐␣18-mer complex was determined with a backbone root mean square deviation of 1.46 Å. In the structure, ␣-cobratoxin contacts the ␣18-mer at the tips of loop I and II and through C-terminal cationic residues. The contact zone derived from the intermolecular nuclear Overhauser effects is in agreement with recent biochemical data. Furthermore, the structural models support the involvement of cation-interactions in stabilizing the complex. In addition, the binding screen results suggest that C-terminal cationic residues of ␣-bungarotoxin and ␣-cobratoxin contribute significantly to binding of the ␣18-mer. Finally, we present a structural model for nicotinic acetylcholine receptor-␣-cobratoxin interaction by superimposing the ␣-cobratoxin⅐␣18-mer complex onto the crystal structure of the acetylcholine-binding protein (Protein Data Bank code 1I9B).

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Section: Hsqc Screen and Titration-as Described Previouslymentioning

confidence: 94%

mentioning

confidence: 99%

NMR-based Binding Screen and Structural Analysis of the Complex Formed between α-Cobratoxin and an 18-Mer Cognate Peptide Derived from the α1 Subunit of the Nicotinic Acetylcholine Receptor fromTorpedo californica

Zeng¹,

Hawrot

2002

Journal of Biological Chemistry

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“…The selected toxin was ␣-cobratoxin (␣-Cbtx) from venom of the cobra N. kaouthia. It is a typical long chain curaremimetic toxin whose structural properties have been largely elucidated by x-ray diffraction (5,22) and NMR spectroscopy (34) and whose functional properties have also been analyzed (35,36).…”

Section: Table I Dissociation Constants Of Toxin Wild Types and Mutanmentioning

confidence: 99%

Variability among the Sites by Which Curaremimetic Toxins Bind to Torpedo Acetylcholine Receptor, as Revealed by Identification of the Functional Residues of α-Cobratoxin

Antil

Servent

Ménèz

1999

Journal of Biological Chemistry

107

104

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␣-Cobratoxin, a long chain curaremimetic toxin from Naja kaouthia venom, was produced recombinantly (r␣-Cbtx) from Escherichia coli. It was indistinguishable from the snake toxin. Mutations at 8 of the 29 explored toxin positions resulted in affinity decreases for Torpedo receptor with ⌬⌬G higher than 1.1 kcal/mol. These are R33E > K49E > D27R > K23E > F29A > W25A > R36A > F65A. These positions cover a homogeneous surface of approximately 880 Å 2 and mostly belong to the second toxin loop, except Lys-49 and Phe-65 which are, respectively, on the third loop and C-terminal tail. The mutations K23E and K49E, and perhaps R33E, induced discriminative interactions at the two toxin-binding sites. When compared with the short toxin erabutoxin a (Ea), a number of structurally equivalent residues are commonly implicated in binding to muscular-type nicotinic acetylcholine receptor. These are Lys-23/Lys-27, Asp-27/Asp-31, Arg-33/Arg-33, Lys-49/Lys-47, and to a lesser and variable extent Trp-25/Trp-29 and Phe-29/ Phe-32. In addition, however, the short and long toxins display three major differences. First, Asp-38 is important in Ea in contrast to the homologous Glu-38 in ␣-Cbtx. Second, all of the first loop is insensitive to mutation in ␣-Cbtx, whereas its tip is functionally critical in Ea. Third, the C-terminal tail may be specifically critical in ␣-Cbtx. Therefore, the functional sites of long and short curaremimetic toxins are not identical, but they share common features and marked differences that might reflect an evolutionary pressure associated with a great diversity of prey receptors.

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“…The NMR data showed the presence of a triple-stranded beta-sheet (residues 19-25, 36-41, and 52-57), a short helix, and turns. These were applied as distance constraints in a molecular modeling comprised of distance geometry and dynamical simulated annealing calculations [9].…”

Section: Introductionmentioning

confidence: 99%

Homology Modeling and Prediction of Catalytic Amino Acid in the Neurotoxin from Indian Cobra (Naja naja)

Somvanshi¹,

Singh²

2008

TOBIOIJ

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Abstract:The neurotoxin secreted by Indian cobra (Naja naja) binds to acetylcholine receptor of nerve cells, which leads to a lump in the nerve impulse, ceases breathing, thereby causing the death of a person due to suffocation. These neurotoxins are small peptide with approximately 7 kDa. Homology modeling was performed to generate the 3D structure of neurotoxins (A, B, C and D) of N. naja, using the known protein template crystal structure (PDB: 2CTX). The validation of 3D structure was done using PROCHECK. Furthermore, the prediction of catalytic amino acid residues in the active site domain of the 3-D structure of neurotoxin was identified. The 3-D structures of neurotoxin and catalytic amino acid residue may be used to target and design the antivenom drugs against the Indian cobra.

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.alpha.-Cobratoxin: proton NMR assignment and solution structure

Cited by 42 publications

References 32 publications

NMR-based Binding Screen and Structural Analysis of the Complex Formed between α-Cobratoxin and an 18-Mer Cognate Peptide Derived from the α1 Subunit of the Nicotinic Acetylcholine Receptor fromTorpedo californica

NMR-based Binding Screen and Structural Analysis of the Complex Formed between α-Cobratoxin and an 18-Mer Cognate Peptide Derived from the α1 Subunit of the Nicotinic Acetylcholine Receptor fromTorpedo californica

Variability among the Sites by Which Curaremimetic Toxins Bind to Torpedo Acetylcholine Receptor, as Revealed by Identification of the Functional Residues of α-Cobratoxin

Homology Modeling and Prediction of Catalytic Amino Acid in the Neurotoxin from Indian Cobra (Naja naja)

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