NMR solution structures of delta-conotoxin EVIA from Conus ermineus that selectively acts on vertebrate neuronal Na+ channels. - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Biological Chemistry Année : 2004

NMR solution structures of delta-conotoxin EVIA from Conus ermineus that selectively acts on vertebrate neuronal Na+ channels.

Résumé

Delta-conotoxin EVIA, from Conus ermineus, is a 32-residue polypeptide cross-linked by three disulfide bonds forming a four-loop framework. delta-Conotoxin EVIA is the first conotoxin known to inhibit sodium channel inactivation in neuronal membranes from amphibians and mammals (subtypes rNa(v)1.2a, rNa(v)1.3, and rNa(v)1.6), without affecting rat skeletal muscle (subtype rNa(v)1.4) and human cardiac muscle (subtype hNa(v)1.5) sodium channel (Barbier, J., Lamthanh, H., Le Gall, F., Favreau, P., Benoit, E., Chen, H., Gilles, N., Ilan, N., Heinemann, S. F., Gordon, D., M?z, A., and Molg?. (2004) J. Biol. Chem. 279, 4680-4685). Its structure was solved by NMR and is characterized by a 1:1 cis/trans isomerism of the Leu(12)-Pro(13) peptide bond in slow exchange on the NMR time scale. The structure of both cis and trans isomers could be calculated separately. The isomerism occurs within a specific long disordered loop 2, including residues 11-19. These contribute to an important hydrophobic patch on the surface of the toxin. The rest of the structure matches the "inhibitor cystine-knot motif" of conotoxins from the "O superfamily" with a high structural order. To probe a possible functional role of the Leu(12)-Pro(13) cis/trans isomerism, a Pro(13) --> Ala delta-conotoxin EVIA was synthesized and shown to exist only as a trans isomer. P13A delta-conotoxin EVIA was estimated only two times less active than the wild-type EVIA in binding competition to rat brain synaptosomes and when injected intracerebroventricularly into mice.

Dates et versions

hal-00136554 , version 1 (14-03-2007)

Identifiants

Citer

Laurent Volpon, Hung Lamthanh, Julien Barbier, Nicolas Gilles, Jordi Molgó, et al.. NMR solution structures of delta-conotoxin EVIA from Conus ermineus that selectively acts on vertebrate neuronal Na+ channels.. Journal of Biological Chemistry, 2004, 279 (20), pp.21356-21366. ⟨10.1074/jbc.M309594200⟩. ⟨hal-00136554⟩
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