title: First chemical synthesis of a scorpion alpha-toxin affecting sodium channels: the Aah I toxin of Androctonus australis hector.
abstract: Aah I is a 63-residue alpha-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, Na(v) 1.2 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 alpha-toxin, making it possible to produce structural analogues in time.
authors.affiliation: FRE 2738 CNRS-Université de la Méditerranée, Laboratoire de Biochimie and Laboratoire International Associé d'lngénierie Biomoleculaire, IFR Jean Roche, Faculté de Médecine Nord, Bd Pierre Dramard, 13916 Marseille, France.
authors.forename: Sarrah
authors.initials: S
authors.lastname: M'Barek
authors.forename: Ziad
authors.initials: Z
authors.lastname: Fajloun
authors.forename: Sandrine
authors.initials: S
authors.lastname: Cestèle
authors.forename: Christiane
authors.initials: C
authors.lastname: Devaux
authors.forename: Pascal
authors.initials: P
authors.lastname: Mansuelle
authors.forename: Amor
authors.initials: A
authors.lastname: Mosbah
authors.forename: Besma
authors.initials: B
authors.lastname: Jouirou
authors.forename: Massimo
authors.initials: M
authors.lastname: Mantegazza
authors.forename: Jurphaas
authors.initials: J
authors.lastname: Van Rietschoten
authors.forename: Mohamed
authors.initials: M
authors.lastname: El Ayeb
authors.forename: Hervé
authors.initials: H
authors.lastname: Rochat
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Sabatier
authors.forename: François
authors.initials: F
authors.lastname: Sampieri
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D000915:Antibody Affinity; D004594:Electrophysiology; D051379:Mice; D009498:Neurotoxins / Q000138:chemical synthesis* / Q000494:pharmacology; D020673:Protein Renaturation; D012604:Scorpion Venoms / Q000138:chemical synthesis* / Q000494:pharmacology; D012605:Scorpions / Q000472:pathogenicity*; D026941:Sodium Channel Blockers; D015222:Sodium Channels / Q000187:drug effects*; D015996:Survival Rate; D010738:Type C Phospholipases / Q000138:chemical synthesis* / Q000276:immunology / Q000494:pharmacology
chemical_list: D000911:Antibodies, Monoclonal; D009498:Neurotoxins; D012604:Scorpion Venoms; D026941:Sodium Channel Blockers; D015222:Sodium Channels; C065314:scorpion toxin I, Androctonus; D010738:Type C Phospholipases