title: AaTX1, from Androctonus australis scorpion venom: purification, synthesis and characterization in dopaminergic neurons.
abstract: We have purified the AaTX1 peptide from the Androctonus australis (Aa) scorpion venom, previously cloned and sequenced by Legros and collaborators in a venom gland cDNA library from Aa scorpion. AaTX1 belongs to the α-Ktx15 scorpion toxins family (αKTx15-4). Characterized members of this family share high sequence similarity and were found to block preferentially IA-type voltage-dependent K(+) currents in rat cerebellum granular cells in an irreversible way. In the current work, we studied the effects of native AaTX1 (nAaTX1) using whole-cell patch-clamp recordings of IA current in substantia nigra pars compacta dopaminergic neurons. At 250 nM, AaTX1 induces 90% decrease in IA current amplitude. Its activity was found to be comparable to that of rAmmTX3 (αKTx15-3), which differs by only one conserved (R/K) amino acid in the 19th position suggesting that the difference between R19 and K19 in AaTX1 and AmmTX3, respectively, may not be critical for the toxins' effects. Molecular docking of both toxins with Kv4.3 channel is in agreement with experimental data and suggests the implication of the functional dyade K27-Y36 in toxin-channel interactions. Since AaTX1 is not highly abundant in Aa venom, it was synthesized as well as AmmTX3. Synthetic peptides, native AaTX1 and rAmmTX3 peptides showed qualitatively the same pharmacological activity. Overall, these data identify a new biologically active toxin that belongs to a family of peptides active on Kv4.3 channel.
authors.affiliation: Institut Pasteur de Tunis, Laboratoire des Venins et biomolécules thérapeutiques LR11IPT08, Tunis 1002, Tunisia.
authors.forename: Saoussen
authors.initials: S
authors.lastname: Mlayah-Bellalouna
authors.affiliation: INSERM UMR_S 1072, Unité de Neurobiologie des canaux Ioniques et de la Synapse (UNIS), Faculté de Médecine - Secteur Nord, Aix Marseille Université, 51, Bd Pierre Dramard, 13015 Marseille, France.
authors.forename: Martial
authors.initials: M
authors.lastname: Dufour
authors.affiliation: Aix Marseille Université, Institut de Chimie Radicalaire ICR, UMR 7273, Equipe CROPS, Site St Jérôme, Avenue Escadrille Normandie Niémen, Case 542, 13397 Marseille Cedex 20, France.
authors.forename: Kamel
authors.initials: K
authors.lastname: Mabrouk
authors.affiliation: USCR séquenceur de protéines, faculté des sciences de Sfax, Route de Soukra, Km 3.5, BP 1171, 3000 Sfax, Tunisia.
authors.forename: Hafedh
authors.initials: H
authors.lastname: Mejdoub
authors.affiliation: INSERM UMR_S 1072, Unité de Neurobiologie des canaux Ioniques et de la Synapse (UNIS), Faculté de Médecine - Secteur Nord, Aix Marseille Université, 51, Bd Pierre Dramard, 13015 Marseille, France.
authors.forename: Edmond
authors.initials: E
authors.lastname: Carlier
authors.affiliation: Institut Pasteur de Tunis, Laboratoire des Venins et biomolécules thérapeutiques LR11IPT08, Tunis 1002, Tunisia.
authors.forename: Houcemeddine
authors.initials: H
authors.lastname: Othman
authors.affiliation: CRN2M UMR 7286, Plate Forme de Recherche en Neurosciences - CAPM, Faculté de Médecine-secteur Nord Aix Marseille Université, 51 bd Pierre Dramard, 13015 Marseille, France.
authors.forename: Maya
authors.initials: M
authors.lastname: Belghazi
authors.affiliation: Aix Marseille Université, Institut de Chimie Radicalaire ICR, UMR 7273, Equipe CROPS, Site St Jérôme, Avenue Escadrille Normandie Niémen, Case 542, 13397 Marseille Cedex 20, France.
authors.forename: Marion
authors.initials: M
authors.lastname: Tarbe
authors.affiliation: INSERM UMR_S 1072, Unité de Neurobiologie des canaux Ioniques et de la Synapse (UNIS), Faculté de Médecine - Secteur Nord, Aix Marseille Université, 51, Bd Pierre Dramard, 13015 Marseille, France.
authors.forename: Jean Marc
authors.initials: JM
authors.lastname: Goaillard
authors.affiliation: Aix Marseille Université, Institut de Chimie Radicalaire ICR, UMR 7273, Equipe CROPS, Site St Jérôme, Avenue Escadrille Normandie Niémen, Case 542, 13397 Marseille Cedex 20, France.
authors.forename: Didier
authors.initials: D
authors.lastname: Gigmes
authors.affiliation: INSERM UMR_S 1072, Unité de Neurobiologie des canaux Ioniques et de la Synapse (UNIS), Faculté de Médecine - Secteur Nord, Aix Marseille Université, 51, Bd Pierre Dramard, 13015 Marseille, France.
authors.forename: Michael
authors.initials: M
authors.lastname: Seagar
authors.affiliation: Institut Pasteur de Tunis, Laboratoire des Venins et biomolécules thérapeutiques LR11IPT08, Tunis 1002, Tunisia.
authors.forename: Mohamed
authors.initials: M
authors.lastname: El Ayeb
authors.affiliation: INSERM UMR_S 1072, Unité de Neurobiologie des canaux Ioniques et de la Synapse (UNIS), Faculté de Médecine - Secteur Nord, Aix Marseille Université, 51, Bd Pierre Dramard, 13015 Marseille, France.
authors.forename: Dominique
authors.initials: D
authors.lastname: Debanne
authors.affiliation: Institut Pasteur de Tunis, Laboratoire des Venins et biomolécules thérapeutiques LR11IPT08, Tunis 1002, Tunisia. Electronic address: najet.abid@pasteur.rns.tn.
authors.forename: Najet
authors.initials: N
authors.lastname: Srairi-Abid
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D059290:Dopaminergic Neurons / Q000187:drug effects*; D015723:Gene Library; D013058:Mass Spectrometry; D051379:Mice; D008810:Mice, Inbred C57BL; D062105:Molecular Docking Simulation; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics* / Q000633:toxicity*; D018408:Patch-Clamp Techniques; D012604:Scorpion Venoms / Q000737:chemistry*; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D051672:Shal Potassium Channels / Q000378:metabolism*; D013378:Substantia Nigra / Q000166:cytology
chemical_list: D009479:Neuropeptides; D012604:Scorpion Venoms; D051672:Shal Potassium Channels; C064022:Tx1 neurotoxin; C098736:Tx3 neurotoxin
keywords: Alpha-KTx15 toxins family; Androctonus australis scorpion; Kv4 potassium channel