Do cardiotoxins possess a functional site? Structural and chemical modification studies reveal the functional site of the cardiotoxin from Naja nigricollis

A Ménez, E Gatineau, C Roumestand, A L Harvey, L Mouawad, B Gilquin, F Toma

Research output: Contribution to journalArticle

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Abstract

Examination of the literature has revealed that regarding the amino acid sequences, cardiotoxins constitute a family of homogeneous compounds. In contrast, cardiotoxins appear heterogeneous as far as their biological and spectroscopic properties are concerned. As a result, comparison between these molecules with a view to establishing structure-activity correlations is complicated. We have therefore reviewed recent works aiming at identifying the functional site of a defined cardiotoxin, ie toxin gamma from the venom of the spitting cobra Naja nigricollis. The biological and structural properties of toxin gamma are first described. In particular, a model depicting the 3-dimensional structure of the toxin studied by NMR spectroscopy is proposed. The toxin polypeptide chain is folded into 3 adjacent loops rich in beta-sheet structure connected to a small globular core containing the 4 disulfide bonds. A number of derivatives chemically modified at a single aromatic or amino group have been prepared. The structure of each derivative was probed by emission fluorescence, circular dichroism and NMR spectroscopy. Also tested was the ability of the derivatives to kill mice, depolarize excitable cell membranes and lyse epithelial cells. Modification of some residues in the first loop, in particular Lys-12 and at the base of the second loop substantially affected biological properties, with no sign of concomitant structural modifications other than local changes. Modifications in other regions much less affected the biological properties of the toxin. A plausible functional site for toxin gamma involving loop I and the base of loop II is presented. It is stressed that the functional site of other cardiotoxins may be different.
Original languageEnglish
Pages (from-to)575-588
Number of pages14
JournalBiochimie
Volume72
Issue number8
DOIs
Publication statusPublished - Aug 1990

Fingerprint

Cardiotoxins
Elapidae
Chemical modification
Derivatives
Nuclear magnetic resonance spectroscopy
Biological Toxins
Magnetic Resonance Spectroscopy
Circular dichroism spectroscopy
Cobra Venoms
Venoms
Cell membranes
Circular Dichroism
Disulfides
Structural properties
Amino Acid Sequence
Fluorescence
Epithelial Cells
Cell Membrane
Amino Acids
Peptides

Keywords

  • amino acid sequence
  • animals
  • cobra cardiotoxin proteins
  • cobra venoms
  • molecular sequence data
  • protein conformation
  • nucleic acid sequence homology
  • spectrophotometry
  • structure-activity relationship

Cite this

Ménez, A ; Gatineau, E ; Roumestand, C ; Harvey, A L ; Mouawad, L ; Gilquin, B ; Toma, F. / Do cardiotoxins possess a functional site? Structural and chemical modification studies reveal the functional site of the cardiotoxin from Naja nigricollis. In: Biochimie. 1990 ; Vol. 72, No. 8. pp. 575-588.
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Do cardiotoxins possess a functional site? Structural and chemical modification studies reveal the functional site of the cardiotoxin from Naja nigricollis. / Ménez, A; Gatineau, E; Roumestand, C; Harvey, A L; Mouawad, L; Gilquin, B; Toma, F.

In: Biochimie, Vol. 72, No. 8, 08.1990, p. 575-588.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Do cardiotoxins possess a functional site? Structural and chemical modification studies reveal the functional site of the cardiotoxin from Naja nigricollis

AU - Ménez, A

AU - Gatineau, E

AU - Roumestand, C

AU - Harvey, A L

AU - Mouawad, L

AU - Gilquin, B

AU - Toma, F

PY - 1990/8

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N2 - Examination of the literature has revealed that regarding the amino acid sequences, cardiotoxins constitute a family of homogeneous compounds. In contrast, cardiotoxins appear heterogeneous as far as their biological and spectroscopic properties are concerned. As a result, comparison between these molecules with a view to establishing structure-activity correlations is complicated. We have therefore reviewed recent works aiming at identifying the functional site of a defined cardiotoxin, ie toxin gamma from the venom of the spitting cobra Naja nigricollis. The biological and structural properties of toxin gamma are first described. In particular, a model depicting the 3-dimensional structure of the toxin studied by NMR spectroscopy is proposed. The toxin polypeptide chain is folded into 3 adjacent loops rich in beta-sheet structure connected to a small globular core containing the 4 disulfide bonds. A number of derivatives chemically modified at a single aromatic or amino group have been prepared. The structure of each derivative was probed by emission fluorescence, circular dichroism and NMR spectroscopy. Also tested was the ability of the derivatives to kill mice, depolarize excitable cell membranes and lyse epithelial cells. Modification of some residues in the first loop, in particular Lys-12 and at the base of the second loop substantially affected biological properties, with no sign of concomitant structural modifications other than local changes. Modifications in other regions much less affected the biological properties of the toxin. A plausible functional site for toxin gamma involving loop I and the base of loop II is presented. It is stressed that the functional site of other cardiotoxins may be different.

AB - Examination of the literature has revealed that regarding the amino acid sequences, cardiotoxins constitute a family of homogeneous compounds. In contrast, cardiotoxins appear heterogeneous as far as their biological and spectroscopic properties are concerned. As a result, comparison between these molecules with a view to establishing structure-activity correlations is complicated. We have therefore reviewed recent works aiming at identifying the functional site of a defined cardiotoxin, ie toxin gamma from the venom of the spitting cobra Naja nigricollis. The biological and structural properties of toxin gamma are first described. In particular, a model depicting the 3-dimensional structure of the toxin studied by NMR spectroscopy is proposed. The toxin polypeptide chain is folded into 3 adjacent loops rich in beta-sheet structure connected to a small globular core containing the 4 disulfide bonds. A number of derivatives chemically modified at a single aromatic or amino group have been prepared. The structure of each derivative was probed by emission fluorescence, circular dichroism and NMR spectroscopy. Also tested was the ability of the derivatives to kill mice, depolarize excitable cell membranes and lyse epithelial cells. Modification of some residues in the first loop, in particular Lys-12 and at the base of the second loop substantially affected biological properties, with no sign of concomitant structural modifications other than local changes. Modifications in other regions much less affected the biological properties of the toxin. A plausible functional site for toxin gamma involving loop I and the base of loop II is presented. It is stressed that the functional site of other cardiotoxins may be different.

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