First chemical synthesis of a scorpion α-toxin affecting sodium channels: The Aah I toxin of Androctonus australis hector

• Published in: Journal of peptide science 2004-11, Vol.10 (11), p.666-677
• Main Authors: M'Barek, Sarrah, Fajloun, Ziad, Cestèle, Sandrine, Devaux, Christiane, Mansuelle, Pascal, Mosbah, Amor, Jouirou, Besma, Mantegazza, Massimo, van Rietschoten, Jurphaas, Ayeb, Mohamed El, Rochat, Hervé, Sabatier, Jean-Marc, Sampieri, Franc̨ois
• Format: Article
• Language: English
• Subjects: Aah I; Animals; Antibodies, Monoclonal; Antibody Affinity; Biochemistry; Biochemistry, Molecular Biology; Electrophysiology; Life Sciences; Mice; Neurotoxins; Neurotoxins - chemical synthesis; Neurotoxins - pharmacology; oxidation/refolding; Protein Renaturation; Scorpion Venoms; Scorpion Venoms - chemical synthesis; Scorpion Venoms - pharmacology; scorpion α-toxin; Scorpions; Scorpions - pathogenicity; sodium channel; Sodium Channel Blockers; Sodium Channels; Sodium Channels - drug effects; solid-phase peptide synthesis; Survival Rate; Type C Phospholipases; Type C Phospholipases - chemical synthesis; Type C Phospholipases - immunology; Type C Phospholipases - pharmacology
• ISSN: 1075-2617; 1099-1387
• DOI: 10.1002/psc.582

Aah I is a 63‐residue α‐toxin isolated from the venom of the Buthidae scorpion Androctonus australis hector, which is considered to be the most dangerous species. We report here the first chemical synthesis of Aah I by the solid‐phase method, using a Fmoc strategy. The synthetic toxin I (sAah I) was renatured in DMSO‐Tris buffer, purified and subjected to thorough analysis and comparison with the natural toxin. The sAah I showed physico‐chemical (CD spectrum, molecular mass, HPLC elution), biochemical (amino‐acid composition, sequence), immunochemical and pharmacological properties similar to those of the natural toxin. The synthetic toxin was recognized by a conformation‐dependent monoclonal anti‐Aah I antibody, with an IC50 value close to that for the natural toxin. Following intracerebroventricular injection, the synthetic and the natural toxins were similarly lethal to mice. In voltage‐clamp experiments, Nav1.2 sodium channel inactivation was inhibited by the application of sAah I or of the natural toxin in a similar way. This work describes a simple protocol for the chemical synthesis of a scorpion α‐toxin, making it possible to produce structural analogues in time. Copyright © 2004 European Peptide Society and John Wiley & Sons, Ltd.