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Mlayah-Bellalouna S, Aissaoui-Zid D, Chantome A, Jebali J, Souid S, Ayedi E, Mejdoub H, Belghazi M, Marrakchi N, Essafi-Benkhadir K, Vandier C, Srairi-Abid N. Insights into the mechanisms governing P01 scorpion toxin effect against U87 glioblastoma cells oncogenesis. Front Pharmacol 2023; 14:1203247. [PMID: 37426811 PMCID: PMC10326281 DOI: 10.3389/fphar.2023.1203247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 06/12/2023] [Indexed: 07/11/2023] Open
Abstract
The emerging concept of small conductance Ca2+-activated potassium channels (SKCa) as pharmacological target for cancer treatment has significantly increased in recent years. In this study, we isolated the P01 toxin from Androctonus australis (Aa) scorpion venom and investigated its effect on biological properties of glioblastoma U87, breast MDA-MB231 and colon adenocarcinoma LS174 cancer cell lines. Our results showed that P01 was active only on U87 glioblastoma cells. It inhibited their proliferation, adhesion and migration with IC50 values in the micromolar range. We have also shown that P01 reduced the amplitude of the currents recorded in HEK293 cells expressing SK2 channels with an IC50 value of 3 pM, while it had no effect on those expressing SK3 channels. The investigation of the SKCa channels expression pattern showed that SK2 transcripts were expressed differently in the three cancer cell lines. Particularly, we highlighted the presence of SK2 isoforms in U87 cells, which could explain and rely on the specific activity of P01 on this cell line. These experimental data highlighted the usefulness of scorpion peptides to decipher the role of SKCa channels in the tumorigenesis process, and develop potential therapeutic molecules targeting glioblastoma with high selectivity.
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Affiliation(s)
- Saoussen Mlayah-Bellalouna
- LR20IPT01 Biomolécules, Venins et Application Théranostique, Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis, Tunisia
| | - Dorra Aissaoui-Zid
- LR20IPT01 Biomolécules, Venins et Application Théranostique, Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis, Tunisia
| | - Aurelie Chantome
- N2C UMR 1069, Institut national de la santé et de la recherche médicale, University of Tours, Tours, France
| | - Jed Jebali
- LR20IPT01 Biomolécules, Venins et Application Théranostique, Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis, Tunisia
| | - Soumaya Souid
- LR16IPT04 Laboratoire d’Epidémiologie Moléculaire et Pathologie Expérimentale, Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis, Tunisia
| | - Emna Ayedi
- LR20IPT01 Biomolécules, Venins et Application Théranostique, Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis, Tunisia
| | - Hafedh Mejdoub
- USCR Séquenceur de Protéines, Faculté des Sciences de Sfax, Route de Soukra, Sfax, Tunisia
| | - Maya Belghazi
- Aix Marseille Université, CNRS, Plateforme Protéomique, IMM FR3479, Marseille Protéomique (MaP), Marseille, France
| | - Naziha Marrakchi
- LR20IPT01 Biomolécules, Venins et Application Théranostique, Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis, Tunisia
| | - Khadija Essafi-Benkhadir
- LR16IPT04 Laboratoire d’Epidémiologie Moléculaire et Pathologie Expérimentale, Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis, Tunisia
| | - Christophe Vandier
- N2C UMR 1069, Institut national de la santé et de la recherche médicale, University of Tours, Tours, France
| | - Najet Srairi-Abid
- LR20IPT01 Biomolécules, Venins et Application Théranostique, Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis, Tunisia
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2
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ElFessi R, Khamessi O, Srairi-Abid N, Sabatier JM, Tytgat J, Peigneur S, Kharrat R. Purification and Characterization of Bot33: A Non-Toxic Peptide from the Venom of Buthus occitanus tunetanus Scorpion. Molecules 2022; 27:molecules27217278. [PMID: 36364113 PMCID: PMC9657394 DOI: 10.3390/molecules27217278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 10/14/2022] [Accepted: 10/17/2022] [Indexed: 11/30/2022] Open
Abstract
Scorpion venom is a rich source of promising therapeutic compounds, such as highly selective ion channel ligands with potent pharmacological effects. Bot33 is a new short polypeptide of 38 amino acid residues with six cysteines purified from the venom of the Buthus occitanus tunetanus scorpion. Bot33 has revealed less than 40% identity with other known alpha-KTx families. This peptide displayed a neutral amino acid (Leucine), in the position equivalent to lysine 27, described as essential for the interaction with Kv channels. Bot33 did not show any toxicity following i.c.v. injection until 2 µg/kg mouse body weight. Due to its very low venom concentration (0.24%), Bot33 was chemically synthesized. Unexpectedly, this peptide has been subjected to a screening on ion channels expressed in Xenopus laevis oocytes, and it was found that Bot33 has no effect on seven Kv channel subtypes. Interestingly, an in silico molecular docking study shows that the Leu27 prevents the interaction of Bot33 with the Kv1.3 channel. All our results indicate that Bot33 may have a different mode of action from other scorpion toxins, which will be interesting to elucidate.
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Affiliation(s)
- Rym ElFessi
- Laboratoire des Venins et Biomolécules Thérapeutiques, Institut Pasteur de Tunis, Université de Tunis El Manar, 13 Place Pasteur BP74, Tunis 1002, Tunisia
| | - Oussema Khamessi
- Laboratoire des Venins et Biomolécules Thérapeutiques, Institut Pasteur de Tunis, Université de Tunis El Manar, 13 Place Pasteur BP74, Tunis 1002, Tunisia
| | - Najet Srairi-Abid
- Laboratoire Biomolécules, Venins et Applications Théranostiques (LR20IPT01), Institut Pasteur de Tunis, Tunis El Manar, 13 Place Pasteur BP74, Tunis 1002, Tunisia
| | - Jean-Marc Sabatier
- Institut de Neurophysiopathologie (INP), Université Aix-Marseille, UMR 7051, 13005 Marseille, France
| | - Jan Tytgat
- Toxicology and Pharmacology, Campus Gasthuisberg, University of Leuven (KU Leuven), 3000 Leuven, Belgium
| | - Steve Peigneur
- Toxicology and Pharmacology, Campus Gasthuisberg, University of Leuven (KU Leuven), 3000 Leuven, Belgium
- Correspondence: (S.P.); (R.K.)
| | - Riadh Kharrat
- Laboratoire des Venins et Biomolécules Thérapeutiques, Institut Pasteur de Tunis, Université de Tunis El Manar, 13 Place Pasteur BP74, Tunis 1002, Tunisia
- Correspondence: (S.P.); (R.K.)
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3
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Maatoug S, Cheikh A, Khamessi O, Tabka H, Landoulsi Z, Guigonis JM, Diochot S, Bendahhou S, Benkhalifa R. Cross Pharmacological, Biochemical and Computational Studies of a Human Kv3.1b Inhibitor from Androctonus australis Venom. Int J Mol Sci 2021; 22:ijms222212290. [PMID: 34830172 PMCID: PMC8618407 DOI: 10.3390/ijms222212290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 11/05/2021] [Accepted: 11/11/2021] [Indexed: 11/23/2022] Open
Abstract
The voltage-gated K+ channels Kv3.1 display fast activation and deactivation kinetics and are known to have a crucial contribution to the fast-spiking phenotype of certain neurons. AahG50, as a natural product extracted from Androctonus australis hector venom, inhibits selectively Kv3.1 channels. In the present study, we focused on the biochemical and pharmacological characterization of the component in AahG50 scorpion venom that potently and selectively blocks the Kv3.1 channels. We used a combined optimization through advanced biochemical purification and patch-clamp screening steps to characterize the peptide in AahG50 active on Kv3.1 channels. We described the inhibitory effect of a toxin on Kv3.1 unitary current in black lipid bilayers. In silico, docking experiments are used to study the molecular details of the binding. We identified the first scorpion venom peptide inhibiting Kv3.1 current at 170 nM. This toxin is the alpha-KTx 15.1, which occludes the Kv3.1 channel pore by means of the lysine 27 lateral chain. This study highlights, for the first time, the modulation of the Kv3.1 by alpha-KTx 15.1, which could be an interesting starting compound for developing therapeutic biomolecules against Kv3.1-associated diseases.
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Affiliation(s)
- Sonia Maatoug
- Laboratoire Biomolécules, Venins et Applications Théranostiques (LR20IPT01), Institut Pasteur de Tunis, Université Tunis El Manar, 13 Place Pasteur BP74, Tunis 1002, Tunisia; (A.C.); (H.T.); (Z.L.)
- Correspondence: (S.M.); (R.B.); Tel.: +216-98-81-27-32 (R.B.)
| | - Amani Cheikh
- Laboratoire Biomolécules, Venins et Applications Théranostiques (LR20IPT01), Institut Pasteur de Tunis, Université Tunis El Manar, 13 Place Pasteur BP74, Tunis 1002, Tunisia; (A.C.); (H.T.); (Z.L.)
| | - Oussema Khamessi
- Laboratoire des Biomolécules Thérapeutiques, Institut Pasteur de Tunis, Université de Tunis El Manar, 13 Place Pasteur BP74, Tunis 1002, Tunisia;
| | - Hager Tabka
- Laboratoire Biomolécules, Venins et Applications Théranostiques (LR20IPT01), Institut Pasteur de Tunis, Université Tunis El Manar, 13 Place Pasteur BP74, Tunis 1002, Tunisia; (A.C.); (H.T.); (Z.L.)
- Faculté des Sciences de Bizerte, Université de Carthage, Bizerte 7021, Tunisia
| | - Zied Landoulsi
- Laboratoire Biomolécules, Venins et Applications Théranostiques (LR20IPT01), Institut Pasteur de Tunis, Université Tunis El Manar, 13 Place Pasteur BP74, Tunis 1002, Tunisia; (A.C.); (H.T.); (Z.L.)
| | - Jean-Marie Guigonis
- Laboratory Transporter in Imaging and Radiotherapy in Oncology (TIRO), Direction de la Recherche Fondamentale (DRF), Institut des Sciences du Vivant Fréderic Joliot, Commissariat à l′Energie Atomique et aux Énergies Alternatives (CEA), Université Côte d’Azur, F-06107 Nice, France;
| | - Sylvie Diochot
- Institut de Pharmacologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique, Université Côte d’Azur, 660 Route des Lucioles, Sophia-Antipolis, 06560 Valbonne, France;
| | - Saïd Bendahhou
- UMR7370 CNRS, LP2M, Université Côte d’Azur, Labex ICST, Nice, France;
| | - Rym Benkhalifa
- Laboratoire Biomolécules, Venins et Applications Théranostiques (LR20IPT01), Institut Pasteur de Tunis, Université Tunis El Manar, 13 Place Pasteur BP74, Tunis 1002, Tunisia; (A.C.); (H.T.); (Z.L.)
- Correspondence: (S.M.); (R.B.); Tel.: +216-98-81-27-32 (R.B.)
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4
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BenAissa R, Othman H, Villard C, Peigneur S, Mlayah-Bellalouna S, Abdelkafi-Koubaa Z, Marrakchi N, Essafi-Benkhadir K, Tytgat J, Luis J, Srairi-Abid N. AaHIV a sodium channel scorpion toxin inhibits the proliferation of DU145 prostate cancer cells. Biochem Biophys Res Commun 2020; 521:340-346. [DOI: 10.1016/j.bbrc.2019.10.115] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 10/13/2019] [Indexed: 10/25/2022]
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5
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ElFessi-Magouri R, Peigneur S, Khamessi O, Srairi-Abid N, ElAyeb M, Mille BG, Cuypers E, Tytgat J, Kharrat R. Kbot55, purified from Buthus occitanus tunetanus venom, represents the first member of a novel α-KTx subfamily. Peptides 2016; 80:4-8. [PMID: 26079392 DOI: 10.1016/j.peptides.2015.05.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 05/26/2015] [Accepted: 05/28/2015] [Indexed: 01/13/2023]
Abstract
Kbot55 is a 39 amino acid peptide isolated from the venom of the Tunisian scorpion Buthus occitanus tunetanus. This peptide is cross-linked by 3 disulfide bridges and has a molecular mass of 4128.65Da. Kbot55 is very low represented in the venom and thus represents a challenge for biochemical characterization. In this study, Kbot55 has been subjected to a screening on ion channels expressed in Xenopus laevis oocytes. It was found that Kbot55 targets voltage-gated potassium channels with high affinity. Kbot55 shows very low amino acid identity with other scorpion potassium toxins and therefore was considered a bona fide novel type of scorpion toxin. Sequence alignment analysis indicated that Kbot55 is the first representative of the new α-Ktx31 subfamily and therefore was classified as α-Ktx31.1.
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Affiliation(s)
- Rym ElFessi-Magouri
- Laboratoire des Venins et Molécules Thérapeutiques, Institut Pasteur de Tunis, 13 Place Pasteur, BP-74, 1002 Tunis, Tunisia
| | - Steve Peigneur
- Toxicology & Pharmacology, University of Leuven (K.U. Leuven), Campus Gasthuisberg O&N2, Herestraat 49, P.O. Box 922, B-3000 Leuven, Belgium
| | - Oussema Khamessi
- Laboratoire des Venins et Molécules Thérapeutiques, Institut Pasteur de Tunis, 13 Place Pasteur, BP-74, 1002 Tunis, Tunisia
| | - Najet Srairi-Abid
- Laboratoire des Venins et Molécules Thérapeutiques, Institut Pasteur de Tunis, 13 Place Pasteur, BP-74, 1002 Tunis, Tunisia
| | - Mohamed ElAyeb
- Laboratoire des Venins et Molécules Thérapeutiques, Institut Pasteur de Tunis, 13 Place Pasteur, BP-74, 1002 Tunis, Tunisia
| | - Bea Garcia Mille
- Toxicology & Pharmacology, University of Leuven (K.U. Leuven), Campus Gasthuisberg O&N2, Herestraat 49, P.O. Box 922, B-3000 Leuven, Belgium
| | - Eva Cuypers
- Toxicology & Pharmacology, University of Leuven (K.U. Leuven), Campus Gasthuisberg O&N2, Herestraat 49, P.O. Box 922, B-3000 Leuven, Belgium
| | - Jan Tytgat
- Toxicology & Pharmacology, University of Leuven (K.U. Leuven), Campus Gasthuisberg O&N2, Herestraat 49, P.O. Box 922, B-3000 Leuven, Belgium
| | - Riadh Kharrat
- Laboratoire des Venins et Molécules Thérapeutiques, Institut Pasteur de Tunis, 13 Place Pasteur, BP-74, 1002 Tunis, Tunisia.
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6
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ElFessi-Magouri R, Peigneur S, Othman H, Srairi-Abid N, ElAyeb M, Tytgat J, Kharrat R. Characterization of Kbot21 Reveals Novel Side Chain Interactions of Scorpion Toxins Inhibiting Voltage-Gated Potassium Channels. PLoS One 2015; 10:e0137611. [PMID: 26398235 PMCID: PMC4580410 DOI: 10.1371/journal.pone.0137611] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 08/19/2015] [Indexed: 11/18/2022] Open
Abstract
Scorpion toxins are important pharmacological tools for probing the physiological roles of ion channels which are involved in many physiological processes and as such have significant therapeutic potential. The discovery of new scorpion toxins with different specificities and affinities is needed to further characterize the physiology of ion channels. In this regard, a new short polypeptide called Kbot21 has been purified to homogeneity from the venom of Buthus occitanus tunetanus scorpion. Kbot21 is structurally related to BmBKTx1 from the venom of the Asian scorpion Buthus martensii Karsch. These two toxins differ by only two residues at position 13 (R /V) and 24 (D/N).Despite their very similar sequences, Kbot21 and BmBKTx1 differ in their electrophysiological activities. Kbot21 targets KV channel subtypes whereas BmBKTx1 is active on both big conductance (BK) and small conductance (SK) Ca2+-activated K+ channel subtypes, but has no effects on Kv channel subtypes. The docking model of Kbot21 with the Kv1.2 channel shows that the D24 and R13 side-chain of Kbot21 are critical for its interaction with KV channels.
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Affiliation(s)
- Rym ElFessi-Magouri
- Laboratoire des Venins et Molécules Thérapeutiques, Institut Pasteur de Tunis,13 Place Pasteur, BP-74, 1002, Tunis, Tunisie
| | - Steve Peigneur
- Laboratory of Toxicology & Pharmacology, University of Leuven (K.U. Leuven), Campus Gasthuisberg O&N2, Herestraat 49, P.O. Box 922, B-3000, Leuven, Belgium
| | - Houcemeddine Othman
- Laboratoire des Venins et Molécules Thérapeutiques, Institut Pasteur de Tunis,13 Place Pasteur, BP-74, 1002, Tunis, Tunisie
| | - Najet Srairi-Abid
- Laboratoire des Venins et Molécules Thérapeutiques, Institut Pasteur de Tunis,13 Place Pasteur, BP-74, 1002, Tunis, Tunisie
| | - Mohamed ElAyeb
- Laboratoire des Venins et Molécules Thérapeutiques, Institut Pasteur de Tunis,13 Place Pasteur, BP-74, 1002, Tunis, Tunisie
| | - Jan Tytgat
- Laboratory of Toxicology & Pharmacology, University of Leuven (K.U. Leuven), Campus Gasthuisberg O&N2, Herestraat 49, P.O. Box 922, B-3000, Leuven, Belgium
| | - Riadh Kharrat
- Laboratoire des Venins et Molécules Thérapeutiques, Institut Pasteur de Tunis,13 Place Pasteur, BP-74, 1002, Tunis, Tunisie
- * E-mail:
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7
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Mlayah-Bellalouna S, Dufour M, Mabrouk K, Mejdoub H, Carlier E, Othman H, Belghazi M, Tarbe M, Goaillard JM, Gigmes D, Seagar M, El Ayeb M, Debanne D, Srairi-Abid N. AaTX1, from Androctonus australis scorpion venom: purification, synthesis and characterization in dopaminergic neurons. Toxicon 2014; 92:14-23. [PMID: 25240295 DOI: 10.1016/j.toxicon.2014.09.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Revised: 07/21/2014] [Accepted: 09/09/2014] [Indexed: 10/24/2022]
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.
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Affiliation(s)
- Saoussen Mlayah-Bellalouna
- Institut Pasteur de Tunis, Laboratoire des Venins et biomolécules thérapeutiques LR11IPT08, Tunis 1002, Tunisia
| | - Martial Dufour
- 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
| | - Kamel Mabrouk
- 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
| | - Hafedh Mejdoub
- USCR séquenceur de protéines, faculté des sciences de Sfax, Route de Soukra, Km 3.5, BP 1171, 3000 Sfax, Tunisia
| | - Edmond Carlier
- 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
| | - Houcemeddine Othman
- Institut Pasteur de Tunis, Laboratoire des Venins et biomolécules thérapeutiques LR11IPT08, Tunis 1002, Tunisia
| | - Maya Belghazi
- 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
| | - Marion Tarbe
- 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
| | - Jean Marc Goaillard
- 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
| | - Didier Gigmes
- 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
| | - Michael Seagar
- 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
| | - Mohamed El Ayeb
- Institut Pasteur de Tunis, Laboratoire des Venins et biomolécules thérapeutiques LR11IPT08, Tunis 1002, Tunisia
| | - Dominique Debanne
- 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
| | - Najet Srairi-Abid
- Institut Pasteur de Tunis, Laboratoire des Venins et biomolécules thérapeutiques LR11IPT08, Tunis 1002, Tunisia.
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8
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Zhu L, Peigneur S, Gao B, Tytgat J, Zhu S. Two recombinant α-like scorpion toxins from Mesobuthus eupeus with differential affinity toward insect and mammalian Na(+) channels. Biochimie 2013; 95:1732-40. [PMID: 23743216 DOI: 10.1016/j.biochi.2013.05.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2012] [Accepted: 05/23/2013] [Indexed: 11/30/2022]
Abstract
α-Scorpion toxins are modulators of voltage-gated Na(+) channels (Navs), which bind to the receptor site 3 to inhibit the fast inactivation of the channels. MeuNaTxα-12 and MeuNaTxα-13 are two new α-scorpion toxin-like peptides identified by cDNA cloning from the scorpion Mesobuthus eupeus with unknown functions. Here, we report their recombinant production, oxidative refolding, structural and functional features. By in vitro renaturation from bacterial inclusion bodies and further purification through reverse phase high-performance liquid chromatography, we obtained high purity recombinant products with a native-like conformation identified by circular dichroism analysis. Two-electrode voltage clamp recordings on five cloned mammalian Nav subtypes (rNav1.1, rNav1.2, rNav1.4, rNav1.5, and mNav1.6) and the insect counterpart DmNav1, all expressed in Xenopus laevis oocytes, showed that these two peptides inhibited rapid inactivation of the sensitive Na(+) channels with significant preference for DmNav1. The half maximal effective concentrations (EC50) of MeuNaTxα-12 and MeuNaTxα-13 for this channel are 19.95 ± 2.99 nM and 65.50 ± 7.28 nM, respectively, showing 45 and 38 folds higher affinities than for rNav1.1, the most sensitive mammalian channel among the five isoforms. Our functional data confirms that these two peptides belong to the α-like scorpion toxin group. A combined analysis of the site 3 sequences and the pharmacological data illuminates the importance of the loop LD4:S5-S6 of the channel in interacting with the toxins whereas affinity variations between MeuNaTxα-12 and MeuNaTxα-13 highlight a key functional role of a cationic side chain at position 28 of MeuNaTxα-12. Successful expression together with structural and functional characterization of these two new α-like scorpion toxins lays basis for further studies of their structure-function relationship.
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Affiliation(s)
- Limei Zhu
- Group of Animal Innate Immunity, State Key Laboratory of Integrated Management of Pest, Insects & Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
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9
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Rjeibi I, Mabrouk K, Mosrati H, Berenguer C, Mejdoub H, Villard C, Laffitte D, Bertin D, Ouafik L, Luis J, Elayeb M, Srairi-Abid N. Purification, synthesis and characterization of AaCtx, the first chlorotoxin-like peptide from Androctonus australis scorpion venom. Peptides 2011; 32:656-63. [PMID: 21262299 DOI: 10.1016/j.peptides.2011.01.015] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Revised: 01/11/2011] [Accepted: 01/11/2011] [Indexed: 01/18/2023]
Abstract
AaCtx is the first chlorotoxin-like peptide isolated from Androctonus australis scorpion venom. Its amino acid sequence shares 70% similarity with chlorotoxin from Leiurus quinquestriatus scorpion venom, from which it differs by twelve amino acids. Due to its very low concentration in venom (0.05%), AaCtx was chemically synthesized. Both native and synthetic AaCtx were active on invasion and migration of human glioma cells. However, their activity was found to be lower than that of chlorotoxin. The molecular model of AaCtx shows that most of amino acids differing between AaCtx and chlorotoxin are localized on the N-terminal loop and the α-helix. Based on known compounds that block chloride channels, we suggest that the absence of negative charged amino acids on AaCtx structure may be responsible for its weak activity on glioma cells migration and invasion. This finding serves as a starting point for structure-function relationship studies leading to design high specific anti-glioma drugs.
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Affiliation(s)
- Ilhem Rjeibi
- Laboratoire des Venins et Toxines, Institut Pasteur de Tunis, 13, Place Pasteur, BP 74, 1002 Belvédère, Universités Tunis-El Manar, Tunisia
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10
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Duarte CG, Alvarenga LM, Dias-Lopes C, Machado-de-Avila RA, Nguyen C, Molina F, Granier C, Chávez-Olórtegui C. In vivo protection against Tityus serrulatus scorpion venom by antibodies raised against a discontinuous synthetic epitope. Vaccine 2009; 28:1168-76. [PMID: 19948263 DOI: 10.1016/j.vaccine.2009.11.039] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2007] [Revised: 11/06/2009] [Accepted: 11/11/2009] [Indexed: 11/16/2022]
Abstract
Scorpion stings cause human fatalities in numerous countries. Serotherapy is the only specific means to try to circumvent the noxious effects of venom toxins. TsNTxP is a natural anatoxin from the venom of the scorpion Tityus serrulatus that may be useful to raise therapeutic anti-venom sera. Linear epitopes recognized by anti-TsNTxP antibodies have previously been mapped. Here, we attempted to identify discontinuous epitopes in TsNTxP since neutralizing epitopes are often associated with such complex entities. One hundred and fifty-three octadecapeptides with the general formula (P1)-(Gly-Gly)-(P2) were synthesized by the Spot method on cellulose membranes. P1 and P2 were octapeptides from the TsNTxP N-terminal and C-terminal sections, respectively. Each sequence of eight amino acids was frameshifted in turn by three residues, in order to cover TsNTxP entire sequence. Binding of neutralizing anti-TsNTxP rabbit antibodies to spotted peptides revealed GREGYPADGGGLPDSVKI as the more reactive peptide sequence. This epitope was made from the first eight residues of the protein (GREGYPAD) and from residues 47 to 54 (GLPDSVKI) of the C-terminal part of TsNTxP. BALB/c mice were immunized with synthetic GREGYPADGGGLPDSVKI peptide conjugated to ovalbumin. One week after the last immunization, in vivo protection assays showed that immunized mice could resist a challenge by an amount of T.serrulatus whole venom equivalent to 1.75 LD(100), a dose that killed all control non-immune mice. Based on molecular models of TsNTxP and related Tityus toxins, we found that the above peptide matches with a discontinuous epitope, well exposed at the toxin molecular surface which contains residues known to be important for the bioactivity of toxins.
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Affiliation(s)
- Clara Guerra Duarte
- Departamentos de Bioquímica-Imunologia, ICB, Universidade Federal de Minas Gerais, Av. Antonio Carlos 6627, Pampulha, CP 486, CEP 31270901, Belo Horizonte-MG, Brazil
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11
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Felicori L, Fernandes PB, Giusta MS, Duarte CG, Kalapothakis E, Nguyen C, Molina F, Granier C, Chávez-Olórtegui C. An in vivo protective response against toxic effects of the dermonecrotic protein from Loxosceles intermedia spider venom elicited by synthetic epitopes. Vaccine 2009; 27:4201-8. [PMID: 19389441 DOI: 10.1016/j.vaccine.2009.04.038] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2009] [Revised: 04/08/2009] [Accepted: 04/13/2009] [Indexed: 11/19/2022]
Abstract
Loxoscelism is a necrotic-hemolytic syndrome caused by bites of brown spiders belonging to the genus Loxosceles. Many approaches for the treatment of Loxosceles poisoning have already been proposed, among which administration of specific antivenom is thought to be the more specific. We have evaluated the use of peptides as immunogen to raise in rabbits an antibody response that could protect animals from a challenge by the Loxtox isoform LiD1, one of the main toxic component of Loxosceles intermedia venom. Six antigenic regions of LiD1 were mapped by using the SPOT method. The corresponding peptides were further chemically synthesized, mixed, and used as immunogens in rabbits. Control animal received recombinant LiD1 alone or together with peptides. We found that the rabbit antibody response to peptides was cross-reactive with LiD1, although only one peptide from the mix of six was immunogenic. The dermonecrotic, hemorrhagic and oedema forming activities induced by LiD1 in naïve rabbits were inhibited by 82%, 35% and 35% respectively, by preincubation of LiD1 with anti-peptide antibodies prepared from immunized rabbits. Animals that were immunized with peptides or LiD1r, were found to be protected from the dermonecrotic, hemorrhagic and oedema forming activities induced by a challenge with LiD1. The protection conferred by peptides was, however, lower than that provided by the peptide protein combination or by the full-length protein. These results encourage us in the utilization of synthetic peptides for therapeutic serum development or vaccination approaches.
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Affiliation(s)
- Liza Felicori
- Departamento de Bioquímica-Imunologia, ICB, Universidade Federal de Minas Gerais, Brazil.
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12
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Soli R, Kaabi B, Barhoumi M, El-Ayeb M, Srairi-Abid N. Bioinformatic characterizations and prediction of K+ and Na+ ion channels effector toxins. BMC Pharmacol 2009; 9:4. [PMID: 19284552 PMCID: PMC2660317 DOI: 10.1186/1471-2210-9-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2008] [Accepted: 03/10/2009] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND K+ and Na+ channel toxins constitute a large set of polypeptides, which interact with their ion channel targets. These polypeptides are classified in two different structural groups. Recently a new structural group called birtoxin-like appeared to contain both types of toxins has been described. We hypothesized that peptides of this group may contain two conserved structural motifs in K+ and/or Na+ channels scorpion toxins, allowing these birtoxin-like peptides to be active on K+ and/or Na+ channels. RESULTS Four multilevel motifs, overrepresented and specific to each group of K+ and/or Na+ ion channel toxins have been identified, using GIBBS and MEME and based on a training dataset of 79 sequences judged as representative of K+ and Na+ toxins.Unexpectedly birtoxin-like peptides appeared to present a new structural motif distinct from those present in K+ and Na+ channels Toxins. This result, supported by previous experimental data, suggests that birtoxin-like peptides may exert their activity on different sites than those targeted by classic K+ or Na+ toxins.Searching, the nr database with these newly identified motifs using MAST, retrieved several sequences (116 with e-value < 1) from various scorpion species (test dataset). The filtering process left 30 new and highly likely ion channel effectors.Phylogenetic analysis was used to classify the newly found sequences. Alternatively, classification tree analysis, using CART algorithm adjusted with the training dataset, using the motifs and their 2D structure as explanatory variables, provided a model for prediction of the activity of the new sequences. CONCLUSION The phylogenetic results were in perfect agreement with those obtained by the CART algorithm.Our results may be used as criteria for a new classification of scorpion toxins based on functional motifs.
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Affiliation(s)
- Rima Soli
- Laboratory of Epidemiology and Ecology of Parasites, Institut Pasteur de Tunis, Tunis, Tunisia
| | - Belhassen Kaabi
- Laboratory of Epidemiology and Ecology of Parasites, Institut Pasteur de Tunis, Tunis, Tunisia
- Research and Teaching Building, Institut Pasteur de Tunis, 13 Place Pasteur, BP 74, 1002 Belvedere-Tunis, Tunisia
| | - Mourad Barhoumi
- Laboratory of Epidemiology and Ecology of Parasites, Institut Pasteur de Tunis, Tunis, Tunisia
| | - Mohamed El-Ayeb
- Laboratory of Venom and Toxins, Institut Pasteur de Tunis, Tunis, Tunisia
| | - Najet Srairi-Abid
- Laboratory of Venom and Toxins, Institut Pasteur de Tunis, Tunis, Tunisia
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13
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Srairi-Abid N, Shahbazzadeh D, Chatti I, Mlayah-Bellalouna S, Mejdoub H, Borchani L, Benkhalifa R, Akbari A, El Ayeb M. Hemitoxin, the first potassium channel toxin from the venom of the Iranian scorpion Hemiscorpius lepturus. FEBS J 2008; 275:4641-50. [DOI: 10.1111/j.1742-4658.2008.06607.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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14
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Shahbazzadeh D, Srairi-Abid N, Feng W, Ram N, Borchani L, Ronjat M, Akbari A, Pessah I, De Waard M, El Ayeb M. Hemicalcin, a new toxin from the Iranian scorpion Hemiscorpius lepturus which is active on ryanodine-sensitive Ca2+ channels. Biochem J 2007; 404:89-96. [PMID: 17291197 PMCID: PMC1868827 DOI: 10.1042/bj20061404] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In the present work, we purified and characterized a novel toxin named hemicalcin from the venom of the Iranian chactoid scorpion Hemiscorpius lepturus where it represents 0.6% of the total protein content. It is a 33-mer basic peptide reticulated by three disulfide bridges, and that shares between 85 and 91% sequence identity with four other toxins, all known or supposed to be active on ryanodine-sensitive calcium channels. Hemicalcin differs from these other toxins by seven amino acids at positions 9 (leucine/arginine), 12 (alanine/glutamic acid), 13 (aspartic acid/asparagine), 14 (lysine/asparagine), 18 (serine/glycine), 26 (threonine/alanine) and 28 (proline/isoleucine/alanine). In spite of these differences, hemicalcin remains active on ryanodine-sensitive Ca2+ channels, since it increases [3H]ryanodine binding on RyR1 (ryanodine receptor type 1) and triggers Ca2+ release from sarcoplasmic vesicles. Bilayer lipid membrane experiments, in which the RyR1 channel is reconstituted and its gating properties are analysed, indicate that hemicalcin promotes an increase in the opening probability at intermediate concentration and induces a long-lasting subconductance level of 38% of the original amplitude at higher concentrations. Mice intracerebroventricular inoculation of 300 ng of hemicalcin induces neurotoxic symptoms in vivo, followed by death. Overall, these data identify a new biologically active toxin that belongs to a family of peptides active on the ryanodine-sensitive channel.
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Affiliation(s)
- Delavar Shahbazzadeh
- *Laboratoire des Venins et Toxines, Institut Pasteur de Tunis, 13 place Pasteur, Tunis, BP-74, 1002 Tunisia
- †Biotechnology Department, Institute Pasteur of Iran, P.O. Box 13164, Tehran, Iran
| | - Najet Srairi-Abid
- *Laboratoire des Venins et Toxines, Institut Pasteur de Tunis, 13 place Pasteur, Tunis, BP-74, 1002 Tunisia
- To whom correspondence should be addressed (email )
| | - Wei Feng
- ‡Department of Veterinary Medicine-Molecular Biosciences and Center for Children's Environmental Health, University of California Davis, One Shields Avenue, Davis, CA 95616, U.S.A
| | - Narendra Ram
- §INSERM U607, Canaux Calciques, Fonctions et Pathologies, Département Réponse et Dynamique Cellulaire, Commissariat à l'Energie Atomique, 17 rue des Martyrs, 38054 Grenoble Cedex 09, France
| | - Lamia Borchani
- *Laboratoire des Venins et Toxines, Institut Pasteur de Tunis, 13 place Pasteur, Tunis, BP-74, 1002 Tunisia
| | - Michel Ronjat
- §INSERM U607, Canaux Calciques, Fonctions et Pathologies, Département Réponse et Dynamique Cellulaire, Commissariat à l'Energie Atomique, 17 rue des Martyrs, 38054 Grenoble Cedex 09, France
| | - Abolfazl Akbari
- ∥Razi Vaccine & Serum Research Institute, 31975/148 Karaj, Iran
| | - Isaac N. Pessah
- ‡Department of Veterinary Medicine-Molecular Biosciences and Center for Children's Environmental Health, University of California Davis, One Shields Avenue, Davis, CA 95616, U.S.A
| | - Michel De Waard
- §INSERM U607, Canaux Calciques, Fonctions et Pathologies, Département Réponse et Dynamique Cellulaire, Commissariat à l'Energie Atomique, 17 rue des Martyrs, 38054 Grenoble Cedex 09, France
| | - Mohamed El Ayeb
- *Laboratoire des Venins et Toxines, Institut Pasteur de Tunis, 13 place Pasteur, Tunis, BP-74, 1002 Tunisia
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15
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Srairi-Abid N, Guijarro JI, Benkhalifa R, Mantegazza M, Cheikh A, Ben Aissa M, Haumont PY, Delepierre M, El Ayeb M. A new type of scorpion Na+-channel-toxin-like polypeptide active on K+ channels. Biochem J 2005; 388:455-64. [PMID: 15656785 PMCID: PMC1138952 DOI: 10.1042/bj20041407] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We have purified and characterized two peptides, named KAaH1 and KAaH2 (AaH polypeptides 1 and 2 active on K+ channels, where AaH stands for Androctonus australis Hector), from the venom of A. australis Hector scorpions. Their sequences contain 58 amino acids including six half-cysteines and differ only at positions 26 (Phe/Ser) and 29 (Lys/Gln). Although KAaH1 and KAaH2 show important sequence similarity with anti-mammal beta toxins specific for voltage-gated Na+ channels, only weak beta-like effects were observed when KAaH1 or KAaH2 (1 microM) were tested on brain Nav1.2 channels. In contrast, KAaH1 blocks Kv1.1 and Kv1.3 channels expressed in Xenopus oocytes with IC50 values of 5 and 50 nM respectively, whereas KAaH2 blocks only 20% of the current on Kv1.1 and is not active on Kv1.3 channels at a 100 nM concentration. KAaH1 is thus the first member of a new subfamily of long-chain toxins mainly active on voltage-gated K+ channels. NMR spectra of KAaH1 and KAaH2 show good dispersion of signals but broad lines and poor quality. Self-diffusion NMR experiments indicate that lines are broadened due to a conformational exchange on the millisecond time scale. NMR and CD indicate that both polypeptides adopt a similar fold with alpha-helical and b-sheet structures. Homology-based molecular models generated for KAaH1 and KAaH2 are in accordance with CD and NMR data. In the model of KAaH1, the functionally important residues Phe26 and Lys29 are close to each other and are located in the alpha-helix. These residues may constitute the so-called functional dyad observed for short alpha-KTx scorpion toxins in the beta-sheet.
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Affiliation(s)
- Najet Srairi-Abid
- Laboratoire des Venins et Toxines, Institut Pasteur de Tunis, 13, place Pasteur, BP-74 Tunis 1002, Tunisia.
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16
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Mahjoubi-Boubaker B, Crest M, Khalifa RB, El Ayeb M, Kharrat R. Kbot1, a three disulfide bridges toxin from Buthus occitanus tunetanus venom highly active on both SK and Kv channels. Peptides 2004; 25:637-45. [PMID: 15165720 DOI: 10.1016/j.peptides.2004.02.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2004] [Revised: 02/23/2004] [Accepted: 02/25/2004] [Indexed: 10/26/2022]
Abstract
On attempts to identify toxins showing original profile of activity among K+ channels, we purified Kbot1, a scorpion toxin that blocks Kv1 and SK potassium channels. With 28 amino-acid residues, Kbot1 is the shortest toxin sequenced in Buthus occitanus scorpion. It is linked by three disulfide bridges and its primary structure is 93% identical to that of BmP02 isolated from the venom of the Chinese scorpion Buthus martensi Karsch [Eur. J. Biochem. 245 (1996) 457]. Kbot1 exhibited a low neurotoxicity in mice after intracerebroventricular injection (LD50 approximately or = 0.8 microg per mouse). It competes with iodinated apamin for its rat brain synaptosomal membrane-binding site (IC50 of 20 nM). Despite 30% sequence identity between Kbot1 and ChTX, competitive experiments on the [125I] charybdotoxin, show that Kbot1 inhibits its binding to its rat brain synaptosomes with IC50 of 10 nM. This result was supported by electrophysiological experiments on cloned voltage-dependent K+ channels from rat brain, expressed in Xenopus oocytes. Kbot1 blocks Kv1.1, Kv1.2 and Kv1.3 currents with IC50 of 145, 2.5 and 15 nM, respectively. Based on these data, Kbot1 may be considered as the first member of subfamily 9 of scorpion toxins [Trends Pharmacol. Sci. 20 (1999) 444], highly active on both Kv and SK channels.
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Affiliation(s)
- Basma Mahjoubi-Boubaker
- Laboratoire des Venins et Toxines, Institut Pasteur de Tunis, 13 Place Pasteur, B.P. 74, 1002 Tunis-Belvédère, Tunisia
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17
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Alami M, Vacher H, Bosmans F, Devaux C, Rosso JP, Bougis PE, Tytgat J, Darbon H, Martin-Eauclaire MF. Characterization of Amm VIII from Androctonus mauretanicus mauretanicus: a new scorpion toxin that discriminates between neuronal and skeletal sodium channels. Biochem J 2003; 375:551-60. [PMID: 12911331 PMCID: PMC1223727 DOI: 10.1042/bj20030688] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2003] [Revised: 08/01/2003] [Accepted: 08/11/2003] [Indexed: 11/17/2022]
Abstract
The venom of the scorpion Androctonus mauretanicus mauretanicus was screened by use of a specific serum directed against AaH II, the scorpion alpha-toxin of reference, with the aim of identifying new analogues. This led to the isolation of Amm VIII (7382.57 Da), which gave a highly positive response in ELISA, but was totally devoid of toxicity when injected subcutaneously into mice. In voltage-clamp experiments with rat brain type II Na+ channel rNa(v)1.2 or rat skeletal muscle Na+ channel rNa(v)1.4, expressed in Xenopus oocytes, the EC50 values of the toxin-induced slowing of inactivation were: 29+/-5 and 416+/-14 nM respectively for AmmVIII and 2.6+/-0.3 nM and 2.2+/-0.2 nM, respectively, for AaH II interactions. Accordingly, Amm VIII clearly discriminates neuronal versus muscular Na+ channel. The Amm VIII cDNA was amplified from a venom gland cDNA library and its oligonucleotide sequence determined. It shows 87% sequence homology with AaH II, but carries an unusual extension at its C-terminal end, consisting of an additional Asp due to a point mutation in the cDNA penultimate codon. We hypothesized that this extra amino acid residue could induce steric hindrance and dramatically reduce recognition of the target by Amm VIII. We constructed a model of Amm VIII based on the X-ray structure of AaH II to clarify this point. Molecular modelling showed that this C-terminal extension does not lead to an overall conformational change in Amm VIII, but drastically modifies the charge repartition and, consequently, the electrostatic dipole moment of the molecule. At last, liquid-phase radioimmunassays with poly- and monoclonal anti-(AaH II) antibodies showed the loss of conformational epitopes between AaH II and Amm VIII.
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MESH Headings
- Amino Acid Sequence
- Animals
- Base Sequence
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- DNA, Complementary/isolation & purification
- Dose-Response Relationship, Drug
- Female
- Injections, Intraventricular
- Injections, Subcutaneous
- Lethal Dose 50
- Membrane Potentials/drug effects
- Mice
- Molecular Sequence Data
- Muscle, Skeletal/metabolism
- Neurons/metabolism
- Oocytes/drug effects
- Oocytes/physiology
- Scorpion Venoms/chemistry
- Scorpion Venoms/genetics
- Scorpion Venoms/pharmacology
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Sodium Channels/drug effects
- Sodium Channels/genetics
- Sodium Channels/physiology
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
- Xenopus laevis
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Affiliation(s)
- Meriem Alami
- CNRS UMR 6560, Ingénierie des Protéines, Faculté de Médecine secteur Nord, Institut Jean Roche, Université de la Méditerranée, Bd Pierre Dramard, 13916, Marseille, Cedex 20, France
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18
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Mejri T, Borchani L, Srairi-Abid N, Benkhalifa R, Cestele S, Regaya I, Karoui H, Pelhate M, Rochat H, El Ayeb M. BotIT6: a potent depressant insect toxin from Buthus occitanus tunetanus venom. Toxicon 2003; 41:163-71. [PMID: 12565735 DOI: 10.1016/s0041-0101(02)00246-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A new depressant insect toxin Buthus occitanus tunetanus insect-toxin 6 (BotIT6) was purified by high-performance liquid chromatography from Buthus occitanus tunetanus (Bot) venom. BotIT6 is very active against Blatella germanica (LD50=10ng/100mg body mass) thus being one of the most potent anti-insect toxin so far characterised. When compared to other insect toxin sequences, BotIT6 present high similarities with depressant insect toxins with an additional arginine residue at the C-terminus and a methionine at position 27. The calculated net charge of BotIT6 is positive (+3) whereas it is negative for classical depressant toxins: this might be associated with its high toxicity. Voltage current clump studies show that BotIT6 is not a very potent depressant insect toxin despite its high toxicity in vivo. BotIT6 is able to fully inhibit the specific binding of 125I AaHIT and 125I-BotIT2 on Periplaneta americana synaptosomal membrane vesicles with high affinities. Despite its higher toxicity BotIT6 is a weaker competitor with 125I AaHIT and 125I BotIT2 as compared to the other beta toxins.Altogether, these results may suggest that BotIT6 probably defines a novel sub-group of depressant anti-insect toxins for which the receptor site can be overlapping, but not identical to that for classical depressant insect toxins.
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Affiliation(s)
- Thouraya Mejri
- Laboratoire des Venins et Toxines, Institut Pasteur de Tunis, BP 74-1002, Tunis, Tunisia.
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19
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Zhu S, Li W. Precursors of three unique cysteine-rich peptides from the scorpion Buthus martensii Karsch. Comp Biochem Physiol B Biochem Mol Biol 2002; 131:749-56. [PMID: 11923087 DOI: 10.1016/s1096-4959(02)00020-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Scorpion venoms contain a large number of small peptides with diverse primary structures and unique pharmacological functions. From a cDNA library prepared from venom glands of the Chinese scorpion Buthus martensii Karsch, clones encoding precursors of three unique cysteine-rich peptides named BmTXKS3, BmTXLP2 and BmAP1 have been isolated and sequenced. These precursors are composed of 54, 94 and 89 amino acids, respectively, containing a signal peptide in their N-termini. Sequence analysis shows that BmTXKS3 and BmTXLP2 are two novel members of a scorpion toxin family sharing cysteine-stabilized alpha-helical folds. BmAP1 possesses a distinctive cystine framework, which is similar to some serine protease inhibitors and the segments of several extracellular proteins.
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Affiliation(s)
- Shunyi Zhu
- Department of Biotechnology, College of Life Sciences, Wuhan University, Wuhan 430072, Hubei Province, PR China.
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