1. Mipartoxin-I, a novel three-finger toxin, is the major neurotoxic component in the venom of the redtail coral snake Micrurus mipartitus (Elapidae).
- Author
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Rey-Suárez P, Floriano RS, Rostelato-Ferreira S, Saldarriaga-Córdoba M, Núñez V, Rodrigues-Simioni L, and Lomonte B
- Subjects
- Amino Acid Sequence, Analysis of Variance, Animals, Base Sequence, Bayes Theorem, Chromatography, Colombia, Male, Membrane Potentials drug effects, Mice, Models, Genetic, Molecular Sequence Data, Sequence Alignment, Sequence Analysis, DNA, Sequence Homology, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization, Elapid Venoms chemistry, Elapid Venoms genetics, Models, Molecular, Phylogeny, Protein Conformation
- Abstract
The major venom component of Micrurus mipartitus, a coral snake distributed from Nicaragua to northern South America, was characterized biochemically and functionally. This protein, named mipartoxin-I, is a novel member of the three-finger toxin superfamily, presenting the characteristic cysteine signature and amino acid sequence length of the short-chain, type-I, α-neurotoxins. Nevertheless, it varies considerably from related toxins, with a sequence identity not higher than 70% in a multiple alignment of 67 proteins within this family. Its observed molecular mass (7030.0) matches the value predicted by its amino acid sequence, indicating lack of post-translational modifications. Mipartoxin-I showed a potent lethal effect in mice (intraperitoneal median lethal dose: 0.06 μg/g body weight), and caused a clear neuromuscular blockade on both avian and mouse nerve-muscle preparations, presenting a post-synaptic action through the cholinergic nicotinic receptor. Since mipartoxin-I is the most abundant (28%) protein in M. mipartitus venom, it should play a major role in its toxicity, and therefore represents an important target for developing a therapeutic antivenom, which is very scarce or even unavailable in the regions where this snake inhabits. The structural information here provided might help in the preparation of a synthetic or recombinant immunogen to overcome the limited venom availability., (Copyright © 2012 Elsevier Ltd. All rights reserved.)
- Published
- 2012
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