Abstract
Maurotoxin (MTX) is a scorpion toxin acting on several K(+) channel subtypes. It is a 34-residue peptide cross-linked by four disulfide bridges that are in an "uncommon" arrangement of the type C1-C5, C2-C6, C3-C4, and C7-C8 (versus C1-C5, C2-C6, C3-C7, and C4-C8 for Pi1 or HsTx1, two MTX-related scorpion toxins). We report here that a single mutation in MTX, in either position 15 or 33, resulted in a shift from the MTX toward the Pi1/HsTx1 disulfide bridge pattern. This shift is accompanied by structural and pharmacological changes of the peptide without altering the general alpha/beta scaffold of scorpion toxins.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Animals
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Brain / metabolism
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Chromatography, High Pressure Liquid
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Cysteine / chemistry
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Disulfides*
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Dose-Response Relationship, Drug
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Electrophysiology
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Kinetics
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Lethal Dose 50
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Ligands
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Magnetic Resonance Spectroscopy
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Mice
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Mice, Inbred C57BL
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Models, Molecular
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Molecular Sequence Data
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Mutation
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Oocytes / metabolism
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Peptide Biosynthesis
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Point Mutation
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Potassium Channels / chemistry
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Protein Conformation
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Protein Structure, Secondary
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Rats
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Scorpion Venoms / chemistry*
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Scorpion Venoms / genetics
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Sequence Homology, Amino Acid
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Synaptosomes / metabolism
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Time Factors
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Xenopus
Substances
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Disulfides
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Ligands
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Pi1 toxin
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Potassium Channels
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Scorpion Venoms
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TX1 toxin, Heterometrus spinnifer
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maurotoxin
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Cysteine