About this Neuroscience article
Structural Implications on the Interaction of Scorpion α-like Toxins with the Sodium Channel Receptor Site Inferred from Toxin Iodination and pH-Dependent Binding by Nicolas Gilles; Isabelle Krimm; Francoise Bouet; Oren Froy; Michael Gurevitz; Jean-Marc Lancelin; Dalia Gordon is a Neuroscience article available to read on EtoBox.
**Abstract:** The α‐like toxin from the venom of the scorpion __Leiurus quinquestriatus hebraeus__ (Lqh III) binds with high affinity to receptor site 3 on insect sodium channels but does not bind to rat brain synaptosomes. The binding affinity of Lqh III to cockroach neuronal membranes was fivefold higher at pH 6.5 than at pH 7.5. This correlated with an increase in the electropositive charge on the toxin surface resulting from protonation of its four histidines. Radioiodination of Tyr^14^ of Lqh III abolished its binding to locust but not cockroach sodium channels, whereas the noniodinated toxin bound equally well to both neuronal preparations. Radioiodination of Tyr^10^ or Tyr^21^ of the structurally similar α‐toxin from __L. quinquestriatus hebraeus__ (LqhαIT), as well as their substitution by phenylalanine, had only minor effects on binding to cockroach neuronal membranes. However, substitution of Tyr^21^, but not Tyr^14^, by leucine decreased the binding affinity of LqhαIT ∼87‐fold. Thus, Tyr^14^ is involved in the bioactivity of Lqh III to locust receptor site 3 and is not crucial for the binding of LqhαIT to this site. In turn, the aromatic ring of Tyr^21^ takes part in the
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- Author
- Nicolas Gilles; Isabelle Krimm; Francoise Bouet; Oren Froy; Michael Gurevitz; Jean-Marc Lancelin; Dalia Gordon
- Publisher
- John Wiley and Sons; Wiley (Blackwell Publishing); Blackwell Publishing Inc.; Wiley (ISSN 0022-3042)
- Published
- 2002
- Language
- EN
- Field
- Neuroscience (Life Sciences)