Toxin III from Leiurus quinquestriatus quinquestriatus: a specific probe for receptor site 3 on insect sodium channels.
Scorpion toxin Lqq III binds to a single class of high affinity (Kd = 72 +/- 19 pM) and low capacity (Bmax = 2.5 +/- 0.2 pmol/mg) binding sites in cockroach neuronal membranes. Its binding was inhibited by Lqh alpha IT (IC50 = 80 +/- 30 pM) and sea-anemone toxin ATX II (IC50 = 2.5 +/- 0.3 nM), suggesting that Lqq III is a specific probe for receptor site 3 on cockroach sodium channels. This was confirmed by competitive binding experiments between 125I-Lqq III and scorpion alpha-toxins which have less toxicity in insects.
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Laboratoire de Biochimie, Impénierie des Protéines UNR6560, Université de la Méditeranneé CNRS IFR Jean Roche, Faculté de Médecine Nord Bd Pierre Dramard, Marseille, France. sandrine@u.washington.edu
Gordon
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Kopeyan
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Rochat
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D000595:Amino Acid Sequence; D000818:Animals; D003058:Cockroaches; D036341:Intercellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D010455:Peptides / Q000378:metabolism*; D012604:Scorpion Venoms / Q000378:metabolism*; D012605:Scorpions; D015222:Sodium Channels / Q000378:metabolism*
D036341:Intercellular Signaling Peptides and Proteins; D010455:Peptides; D012604:Scorpion Venoms; D015222:Sodium Channels; C077585:leiurutoxin III; C029574:scorpion toxin receptor