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- Title
Solution structure of crotamine, a Na+ channel affecting toxin from Crotalus durissus terrificus venom.
- Authors
Nicastro, Giuseppe; Franzoni, Lorella; de Chiara, Cesira; Mancin, Adriana C; Giglio, Josè R; Spisni, Alberto
- Abstract
Crotamine is a component of the venom of the snake Crotalus durissus terrificus and it belongs to the myotoxin protein family. It is a 42 amino acid toxin cross-linked by three disulfide bridges and characterized by a mild toxicity (LD50 = 820 micro g per 25 g body weight, i.p. injection) when compared to other members of the same family. Nonetheless, it possesses a wide spectrum of biological functions. In fact, besides being able to specifically modify voltage-sensitive Na+ channel, it has been suggested to exhibit analgesic activity and to be myonecrotic. Here we report its solution structure determined by proton NMR spectroscopy. The secondary structure comprises a short N-terminal alpha-helix and a small antiparallel triple-stranded beta-sheet arranged in an alphabeta1beta2beta3 topology never found among toxins active on ion channels. Interestingly, some scorpion toxins characterized by a biological activity on Na+ channels similar to the one reported for crotamine, exhibit an alpha/beta fold, though with a beta1alphabeta2beta3 topology. In addition, as the antibacterial beta-defensins, crotamine interacts with lipid membranes. A comparison of crotamine with human beta-defensins shows a similar fold and a comparable net positive potential surface. To the best of our knowledge, this is the first report on the structure of a toxin from snake venom active on Na+ channel.
- Publication
European journal of biochemistry, 2003, Vol 270, Issue 9, p1969
- ISSN
0014-2956
- Publication type
Journal Article
- DOI
10.1046/j.1432-1033.2003.03563.x