1h5o
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SOLUTION STRUCTURE OF CROTAMINE, A NEUROTOXIN FROM CROTALUS DURISSUS TERRIFICUS
OverviewOverview
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.
About this StructureAbout this Structure
1H5O is a Single protein structure of sequence from Crotalus durissus terrificus. Full crystallographic information is available from OCA.
ReferenceReference
Solution structure of crotamine, a Na+ channel affecting toxin from Crotalus durissus terrificus venom., Nicastro G, Franzoni L, de Chiara C, Mancin AC, Giglio JR, Spisni A, Eur J Biochem. 2003 May;270(9):1969-79. PMID:12709056
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