1
|
Shakeel K, Olamendi-Portugal T, Naseem MU, Becerril B, Zamudio FZ, Delgado-Prudencio G, Possani LD, Panyi G. Of Seven New K + Channel Inhibitor Peptides of Centruroides bonito, α-KTx 2.24 Has a Picomolar Affinity for Kv1.2. Toxins (Basel) 2023; 15:506. [PMID: 37624263 PMCID: PMC10467108 DOI: 10.3390/toxins15080506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 08/07/2023] [Accepted: 08/11/2023] [Indexed: 08/26/2023] Open
Abstract
Seven new peptides denominated CboK1 to CboK7 were isolated from the venom of the Mexican scorpion Centruroides bonito and their primary structures were determined. The molecular weights ranged between 3760.4 Da and 4357.9 Da, containing 32 to 39 amino acid residues with three putative disulfide bridges. The comparison of amino acid sequences with known potassium scorpion toxins (KTx) and phylogenetic analysis revealed that CboK1 (α-KTx 10.5) and CboK2 (α-KTx 10.6) belong to the α-KTx 10.x subfamily, whereas CboK3 (α-KTx 2.22), CboK4 (α-KTx 2.23), CboK6 (α-KTx 2.21), and CboK7 (α-KTx 2.24) bear > 95% amino acid similarity with members of the α-KTx 2.x subfamily, and CboK5 is identical to Ce3 toxin (α-KTx 2.10). Electrophysiological assays demonstrated that except CboK1, all six other peptides blocked the Kv1.2 channel with Kd values in the picomolar range (24-763 pM) and inhibited the Kv1.3 channel with comparatively less potency (Kd values between 20-171 nM). CboK3 and CboK4 inhibited less than 10% and CboK7 inhibited about 42% of Kv1.1 currents at 100 nM concentration. Among all, CboK7 showed out-standing affinity for Kv1.2 (Kd = 24 pM), as well as high selectivity over Kv1.3 (850-fold) and Kv1.1 (~6000-fold). These characteristics of CboK7 may provide a framework for developing tools to treat Kv1.2-related channelopathies.
Collapse
Affiliation(s)
- Kashmala Shakeel
- Department of Biophysics and Cell Biology, Faculty of Medicine, Research Center for Molecular Medicine, University of Debrecen, Egyetem ter. 1, 4032 Debrecen, Hungary; (K.S.); (M.U.N.)
| | - Timoteo Olamendi-Portugal
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologia, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca 62210, Mexico; (T.O.-P.); (B.B.); (F.Z.Z.); (G.D.-P.)
| | - Muhammad Umair Naseem
- Department of Biophysics and Cell Biology, Faculty of Medicine, Research Center for Molecular Medicine, University of Debrecen, Egyetem ter. 1, 4032 Debrecen, Hungary; (K.S.); (M.U.N.)
| | - Baltazar Becerril
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologia, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca 62210, Mexico; (T.O.-P.); (B.B.); (F.Z.Z.); (G.D.-P.)
| | - Fernando Z. Zamudio
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologia, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca 62210, Mexico; (T.O.-P.); (B.B.); (F.Z.Z.); (G.D.-P.)
| | - Gustavo Delgado-Prudencio
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologia, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca 62210, Mexico; (T.O.-P.); (B.B.); (F.Z.Z.); (G.D.-P.)
| | - Lourival Domingos Possani
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologia, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca 62210, Mexico; (T.O.-P.); (B.B.); (F.Z.Z.); (G.D.-P.)
| | - Gyorgy Panyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, Research Center for Molecular Medicine, University of Debrecen, Egyetem ter. 1, 4032 Debrecen, Hungary; (K.S.); (M.U.N.)
| |
Collapse
|
2
|
Yamashita T, Rhoads DD, Pummill J. A robust genome and assembly with transcriptomic data from the striped scorpion, Centruroides vittatus. bioRxiv 2023:2023.08.04.551372. [PMID: 37609349 PMCID: PMC10441356 DOI: 10.1101/2023.08.04.551372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
AbstractScorpions, a seemingly primitive, stinging arthropod taxa, are known to exhibit marked diversity in their venom components. These venoms are known for their human pathology, but also important as models for therapeutic and drug development applications. We report a high quality genome assembly and annotation of the striped bark scorpion,Centruroides vittatus, created with several shotgun libraries. The final assembly is 760 Mb in size, with a BUSCO score of 97.8%, a 30.85% GC, and a N50 of 2.35 Mb. We estimated 36,189 proteins with 37.32% assigned to GO terms in our GOanna analysis. We were able to map 2011 and 60 venom toxin genes to contigs and scaffolds, respectively. We were also able to identify expression differences between venom gland (telson) and body tissue (carapace) with 19 Sodium toxin and 14 Potassium toxin genes to 18 contigs and two scaffolds. This assembly along with our transcriptomic data, provides further data to investigate scorpion venom genomics.
Collapse
Affiliation(s)
- Tsunemi Yamashita
- Department of Biological Sciences, Arkansas Tech University, Russellville, AR 72801, USA
| | - Douglas D. Rhoads
- Department of Biological Sciences, University of Arkansas-Fayetteville, Fayetteville, AR 72701, USA
| | - Jeff Pummill
- High Performance Computing Center, University of Arkansas-Fayetteville, Fayetteville, AR 72701, USA
| |
Collapse
|
3
|
Naseem MU, Gurrola-Briones G, Romero-Imbachi MR, Borrego J, Carcamo-Noriega E, Beltrán-Vidal J, Zamudio FZ, Shakeel K, Possani LD, Panyi G. Characterization and Chemical Synthesis of Cm39 (α-KTx 4.8): A Scorpion Toxin That Inhibits Voltage-Gated K + Channel K V1.2 and Small- and Intermediate-Conductance Ca 2+-Activated K + Channels K Ca2.2 and K Ca3.1. Toxins (Basel) 2023; 15:41. [PMID: 36668861 PMCID: PMC9866218 DOI: 10.3390/toxins15010041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 12/22/2022] [Accepted: 12/27/2022] [Indexed: 01/06/2023] Open
Abstract
A novel peptide, Cm39, was identified in the venom of the scorpion Centruroides margaritatus. Its primary structure was determined. It consists of 37 amino acid residues with a MW of 3980.2 Da. The full chemical synthesis and proper folding of Cm39 was obtained. Based on amino acid sequence alignment with different K+ channel inhibitor scorpion toxin (KTx) families and phylogenetic analysis, Cm39 belongs to the α-KTx 4 family and was registered with the systematic number of α-KTx 4.8. Synthetic Cm39 inhibits the voltage-gated K+ channel hKV1.2 with high affinity (Kd = 65 nM). The conductance-voltage relationship of KV1.2 was not altered in the presence of Cm39, and the analysis of the toxin binding kinetics was consistent with a bimolecular interaction between the peptide and the channel; therefore, the pore blocking mechanism is proposed for the toxin-channel interaction. Cm39 also inhibits the Ca2+-activated KCa2.2 and KCa3.1 channels, with Kd = 502 nM, and Kd = 58 nM, respectively. However, the peptide does not inhibit hKV1.1, hKV1.3, hKV1.4, hKV1.5, hKV1.6, hKV11.1, mKCa1.1 K+ channels or the hNaV1.5 and hNaV1.4 Na+ channels at 1 μM concentrations. Understanding the unusual selectivity profile of Cm39 motivates further experiments to reveal novel interactions with the vestibule of toxin-sensitive channels.
Collapse
Affiliation(s)
- Muhammad Umair Naseem
- Department of Biophysics and Cell Biology, Faculty of Medicine, Research Center for Molecular Medicine, University of Debrecen, Egyetem ter. 1, 4032 Debrecen, Hungary
| | - Georgina Gurrola-Briones
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologia, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca 62210, Morelos, Mexico
| | - Margarita R. Romero-Imbachi
- Grupo de Investigaciones Herpetológicas y Toxinológicas, Centro de Investigaciones Biomédicas, Departamento de Biología, Facultad de Ciencias Naturales, Exactas y de la Educación, Universidad del Cauca, Sector Tulcan, Calle 2 N 3N-100, Popayán 190002, Cauca, Colombia
| | - Jesus Borrego
- Department of Biophysics and Cell Biology, Faculty of Medicine, Research Center for Molecular Medicine, University of Debrecen, Egyetem ter. 1, 4032 Debrecen, Hungary
| | - Edson Carcamo-Noriega
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologia, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca 62210, Morelos, Mexico
| | - José Beltrán-Vidal
- Grupo de Investigaciones Herpetológicas y Toxinológicas, Centro de Investigaciones Biomédicas, Departamento de Biología, Facultad de Ciencias Naturales, Exactas y de la Educación, Universidad del Cauca, Sector Tulcan, Calle 2 N 3N-100, Popayán 190002, Cauca, Colombia
| | - Fernando Z. Zamudio
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologia, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca 62210, Morelos, Mexico
| | - Kashmala Shakeel
- Department of Biophysics and Cell Biology, Faculty of Medicine, Research Center for Molecular Medicine, University of Debrecen, Egyetem ter. 1, 4032 Debrecen, Hungary
| | - Lourival Domingos Possani
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologia, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca 62210, Morelos, Mexico
| | - Gyorgy Panyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, Research Center for Molecular Medicine, University of Debrecen, Egyetem ter. 1, 4032 Debrecen, Hungary
| |
Collapse
|
4
|
Ben Abderrazek R, Ksouri A, Idoudi F, Dhaouadi S, Hamdi E, Vincke C, Farah A, Benlasfar Z, Majdoub H, El Ayeb M, Muyldermans S, Bouhaouala-Zahar B. Neutralizing Dromedary-Derived Nanobodies Against BotI-Like Toxin From the Most Hazardous Scorpion Venom in the Middle East and North Africa Region. Front Immunol 2022; 13:863012. [PMID: 35514999 PMCID: PMC9063451 DOI: 10.3389/fimmu.2022.863012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 03/16/2022] [Indexed: 01/18/2023] Open
Abstract
Scorpion envenoming is a severe health problem in many regions causing significant clinical toxic effects and fatalities. In the Middle East/North Africa (MENA) region, Buthidae scorpion stings are responsible for devastating toxic outcomes in human. The only available specific immunotherapeutic treatment is based on IgG fragments of animal origin. To overcome the limitations of classical immunotherapy, we have demonstrated the in vivo efficacy of NbF12-10 bispecific nanobody at preclinical level. Nanobodies were developed against BotI analogues belonging to a distinct structural and antigenic group of scorpion toxins, occurring in the MENA region. From Buthus occitanus tunetanus venom, BotI-like toxin was purified. The 41 N-terminal amino acid residues were sequenced, and the LD50 was estimated at 40 ng/mouse. The BotI-like toxin was used for dromedary immunization. An immune VHH library was constructed, and after screening, two nanobodies were selected with nanomolar and sub-nanomolar affinity and recognizing an overlapping epitope. NbBotI-01 was able to neutralize 50% of the lethal effect of 13 LD50 BotI-like toxins in mice when injected by i.c.v route, whereas NbBotI-17 neutralized 50% of the lethal effect of 7 LD50. Interestingly, NbBotI-01 completely reduced the lethal effect of the 2 LD50 of BotG50 when injected at 1:4 molar ratio excess. More interestingly, an equimolar mixture of NbBotI-01 with NbF12-10 neutralized completely the lethal effect of 7 and 5 LD50 of BotG50 or AahG50, at 1:4 and 1:2 molar ratio, respectively. Hence, NbBotI-01 and NbF12-10 display synergic effects, leading to a novel therapeutic candidate for treating Buthus occitanus scorpion stings in the MENA region.
Collapse
Affiliation(s)
- Rahma Ben Abderrazek
- Laboratoire des Biomolécules, Venins et Applications Théranostiques, Institut Pasteur Tunis, University Tunis El Manar, Tunis, Tunisia
| | - Ayoub Ksouri
- Laboratoire des Biomolécules, Venins et Applications Théranostiques, Institut Pasteur Tunis, University Tunis El Manar, Tunis, Tunisia
| | - Faten Idoudi
- Laboratoire des Biomolécules, Venins et Applications Théranostiques, Institut Pasteur Tunis, University Tunis El Manar, Tunis, Tunisia
| | - Sayda Dhaouadi
- Laboratoire des Biomolécules, Venins et Applications Théranostiques, Institut Pasteur Tunis, University Tunis El Manar, Tunis, Tunisia
| | - Emna Hamdi
- Laboratoire des Biomolécules, Venins et Applications Théranostiques, Institut Pasteur Tunis, University Tunis El Manar, Tunis, Tunisia
| | - Cécile Vincke
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium.,Myeloid Cell Immunology Lab, Vlaams Interuniversitair Instituut voor Biotechnologie (VIB) Center for Inflammation Research, Brussels, Belgium
| | - Azer Farah
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium
| | - Zakaria Benlasfar
- Laboratoire des Biomolécules, Venins et Applications Théranostiques, Institut Pasteur Tunis, University Tunis El Manar, Tunis, Tunisia
| | - Hafedh Majdoub
- Unité des Services Communs de Recherche (USCR) Séquenceur de Protéines, Faculté des Sciences de Sfax, Sfax, Tunisia
| | - Mohamed El Ayeb
- Laboratoire des Biomolécules, Venins et Applications Théranostiques, Institut Pasteur Tunis, University Tunis El Manar, Tunis, Tunisia
| | - Serge Muyldermans
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium
| | - Balkiss Bouhaouala-Zahar
- Laboratoire des Biomolécules, Venins et Applications Théranostiques, Institut Pasteur Tunis, University Tunis El Manar, Tunis, Tunisia.,Unité des Services Communs de Recherche (USCR) Séquenceur de Protéines, Faculté des Sciences de Sfax, Sfax, Tunisia.,Faculté de Médecine de Tunis, Université Tunis El Manar, Tunis, Tunisia
| |
Collapse
|
5
|
Cui Y, Wang T, Hao Z, Zhang J, Zhao Y. Methionine 58 is a key residue in the modulation of BmK scorpion toxin AGP-SYPU2 activity through in silico and in vivo studies. J Biomol Struct Dyn 2022; 40:2955-2962. [PMID: 33228478 DOI: 10.1080/07391102.2020.1848626] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Protein dynamic networks play an important role in the regulation of many protein systems. Some residues that are far away from the interface between proteins and their targets have a critical role in modulating the activity of some scorpion toxins. Here, conservation analysis combined with an in vivo experiment has reveals that Met58 is a key residue of BmK scorpion toxin AGP-SYPU2 in the modulation of analgesic activity. Molecular dynamics simulations clearly reveal the conformational changes that allow the loop between the β2 and β3 sheets to be exposed on the toxin surface to interact with its targets. Our results emphasize specific roles for the residue Met58 in the NC domain and our work gives valuable information for further modification of scorpion toxins to obtain new analgesic peptides with enhanced activity. Communicated by Ramaswamy H. Sarma.
Collapse
Affiliation(s)
- Yong Cui
- School of Medical Devices, Shenyang Pharmaceutical University, Benxi, Liaoning Province, PR China
| | - Ting Wang
- School of Life Science and Bio-pharmaceutics, Shenyang Pharmaceutical University, Shenyang, Liaoning Province, PR China
| | - Zhihui Hao
- School of Life Science and Bio-pharmaceutics, Shenyang Pharmaceutical University, Shenyang, Liaoning Province, PR China
| | - Jinghai Zhang
- School of Medical Devices, Shenyang Pharmaceutical University, Benxi, Liaoning Province, PR China
| | - Yongshan Zhao
- School of Life Science and Bio-pharmaceutics, Shenyang Pharmaceutical University, Shenyang, Liaoning Province, PR China
| |
Collapse
|
6
|
Zhao F, Zou X, Li S, He J, Xi C, Tang Q, Wang Y, Cao Z. BmK NSPK, a Potent Potassium Channel Inhibitor from Scorpion Buthus martensii Karsch, Promotes Neurite Outgrowth via NGF/TrkA Signaling Pathway. Toxins (Basel) 2021; 13:33. [PMID: 33466524 DOI: 10.3390/toxins13010033] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 12/30/2020] [Accepted: 12/31/2020] [Indexed: 12/31/2022] Open
Abstract
Scorpion toxins represent a variety of tools to explore molecular mechanisms and cellular signaling pathways of many biological functions. These toxins are also promising lead compounds for developing treatments for many neurological diseases. In the current study, we purified a new scorpion toxin designated as BmK NSPK (Buthus martensii Karsch neurite-stimulating peptide targeting Kv channels) from the BmK venom. The primary structure was determined using Edman degradation. BmK NSPK directly inhibited outward K+ current without affecting sodium channel activities, depolarized membrane, and increased spontaneous calcium oscillation in spinal cord neurons (SCNs) at low nanomolar concentrations. BmK NSPK produced a nonmonotonic increase on the neurite extension that peaked at ~10 nM. Mechanistic studies demonstrated that BmK NSPK increased the release of nerve growth factor (NGF). The tyrosine kinases A (TrkA) receptor inhibitor, GW 441756, eliminated the BmK NSPK-induced neurite outgrowth. BmK NSPK also increased phosphorylation levels of protein kinase B (Akt) that is the downstream regulator of TrkA receptors. These data demonstrate that BmK NSPK is a new voltage-gated potassium (Kv) channel inhibitor that augments neurite extension via NGF/TrkA signaling pathway. Kv channels may represent molecular targets to modulate SCN development and regeneration and to develop the treatments for spinal cord injury.
Collapse
|
7
|
Xu Y, Sun J, Yu Y, Kong X, Meng X, Liu Y, Cui Y, Su Y, Zhao M, Zhang J. Trp: a conserved aromatic residue crucial to the interaction of a scorpion peptide with sodium channels. J Biochem 2020; 168:633-641. [PMID: 32730584 DOI: 10.1093/jb/mvaa088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Accepted: 07/03/2020] [Indexed: 11/14/2022] Open
Abstract
Anti-tumour-analgesic peptide (AGAP), one scorpion toxin purified from Buthus martensii Karsch, was known as its analgesic and anti-tumour activities. Trp38, a conserved aromatic residue of AGAP, might play important roles in its interaction with sodium channels. In this study, a mutant W38F was generated and effects of W38F were examined on hNav1.4, hNav1.5 and hNav1.7 by using whole-cell patch-clamp, which were closely associated to the biotoxicity of skeletal and cardiac muscles and pain signalling. The data showed that W38F decreased the inhibition effects of peak currents of hNav1.7, hNav1.4 and hNav1.5 compared with AGAP, notably, W38F reduced the analgesic activity compared with AGAP. The results suggested that Trp38 be a crucial amino acid involved in the interaction with these three sodium channels. The decreased analgesic activity of W38F might result from its much less inhibition of hNav1.7. These findings provided more information about the relationship between structure and function of AGAP and may facilitate the modification of other scorpion toxins with pharmacological effects.
Collapse
Affiliation(s)
- Yijia Xu
- School of Life Sciences and Biopharmaceutical Science, Shenyang Pharmaceutical University, 103 Wenhua road, Shenyang, Liaoning 110016, China
| | - Jianfang Sun
- College of Life and Health Sciences, Northeastern University, 195 Chuangxin road, Shenyang, Liaoning 110004, China
| | - Yue Yu
- College of Traditional Chinese Medicine, Shenyang Pharmaceutical University, 103 Wenhua road, Shenyang, Liaoning 110016, China
| | - Xiaohua Kong
- School of Life Sciences and Biopharmaceutical Science, Shenyang Pharmaceutical University, 103 Wenhua road, Shenyang, Liaoning 110016, China
| | - Xiangxue Meng
- School of Life Sciences and Biopharmaceutical Science, Shenyang Pharmaceutical University, 103 Wenhua road, Shenyang, Liaoning 110016, China
| | - Yanfeng Liu
- School of Life Sciences and Biopharmaceutical Science, Shenyang Pharmaceutical University, 103 Wenhua road, Shenyang, Liaoning 110016, China
| | - Yong Cui
- School of Medical Devices, Shenyang Pharmaceutical University, 103 Wenhua road, Shenyang, Liaoning 110016, China
| | - Yang Su
- Department of General Surgery, Shengjing Hospital of China Medical University, 36 Sanhao street, Shenyang, Liaoning 110004, China
| | - Mingyi Zhao
- School of Life Sciences and Biopharmaceutical Science, Shenyang Pharmaceutical University, 103 Wenhua road, Shenyang, Liaoning 110016, China
| | - Jinghai Zhang
- School of Medical Devices, Shenyang Pharmaceutical University, 103 Wenhua road, Shenyang, Liaoning 110016, China
| |
Collapse
|
8
|
Lai MC, Wu SN, Huang CW. The Specific Effects of OD-1, a Peptide Activator, on Voltage-Gated Sodium Current and Seizure Susceptibility. Int J Mol Sci 2020; 21:E8254. [PMID: 33158049 DOI: 10.3390/ijms21218254] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Revised: 10/24/2020] [Accepted: 10/29/2020] [Indexed: 12/12/2022] Open
Abstract
OD-1, a scorpion toxin, has been previously recognized as an activator of voltage-gated Na+ currents. To what extent this agent can alter hippocampal neuronal Na+ currents and network excitability and how it can be applied to neuronal hyperexcitability research remains unclear. With the aid of patch-clamp technology, it was revealed that, in mHippoE-14 hippocampal neurons, OD-1 produced a concentration-, time-, and state-dependent rise in the peak amplitude of INa. It shifted the INa inactivation curve to a less negative potential and increased the frequency of spontaneous action currents. Further characterization of neuronal excitability revealed higher excitability in the hippocampal slices treated with OD-1 as compared with the control slices. A stereotaxic intrahippocampal injection of OD-1 generated a significantly higher frequency of spontaneous seizures and epileptiform discharges compared with intraperitoneal injection of lithium-pilocarpine- or kainic acid-induced epilepsy, with comparable pathological changes. Carbamazepine significantly attenuated OD-1 induced seizures and epileptiform discharges. The OD-1-mediated modifications of INa altered the electrical activity of neurons in vivo and OD-1 could potentially serve as a novel seizure and excitotoxicity model.
Collapse
|
9
|
Zhao Y, Chen Z, Cao Z, Li W, Wu Y. Diverse Structural Features of Potassium Channels Characterized by Scorpion Toxins as Molecular Probes. Molecules 2019; 24:molecules24112045. [PMID: 31146335 PMCID: PMC6600638 DOI: 10.3390/molecules24112045] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 05/15/2019] [Accepted: 05/26/2019] [Indexed: 12/21/2022] Open
Abstract
Scorpion toxins are well-known as the largest potassium channel peptide blocker family. They have been successfully proven to be valuable molecular probes for structural research on diverse potassium channels. The potassium channel pore region, including the turret and filter regions, is the binding interface for scorpion toxins, and structural features from different potassium channels have been identified using different scorpion toxins. According to the spatial orientation of channel turrets with differential sequence lengths and identities, conformational changes and molecular surface properties, the potassium channel turrets can be divided into the following three states: open state with less hindering effects on toxin binding, half-open state or half-closed state with certain effects on toxin binding, and closed state with remarkable effects on toxin binding. In this review, we summarized the diverse structural features of potassium channels explored using scorpion toxin tools and discuss future work in the field of scorpion toxin-potassium channel interactions.
Collapse
Affiliation(s)
- Yonghui Zhao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Zongyun Chen
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
- Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, College of Basic Medicine, Hubei University of Medicine, Shiyan 442000, China.
| | - Zhijian Cao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
- Biodrug Research Center, Wuhan University, Wuhan 430072, China.
| | - Wenxin Li
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
- Biodrug Research Center, Wuhan University, Wuhan 430072, China.
| | - Yingliang Wu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
- Biodrug Research Center, Wuhan University, Wuhan 430072, China.
| |
Collapse
|
10
|
Gilchrist J, Bosmans F. Using voltage-sensor toxins and their molecular targets to investigate Na V 1.8 gating. J Physiol 2018; 596:1863-1872. [PMID: 29193176 DOI: 10.1113/jp275102] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 11/16/2017] [Indexed: 01/10/2023] Open
Abstract
Voltage-gated sodium (NaV ) channel gating is a complex phenomenon which involves a distinct contribution of four integral voltage-sensing domains (VSDI, VSDII, VSDIII and VSDIV). Utilizing accrued pharmacological and structural insights, we build on an established chimera approach to introduce animal toxin sensitivity in each VSD of an acceptor channel by transferring in portable S3b-S4 motifs from the four VSDs of a toxin-susceptible donor channel (NaV 1.2). By doing so, we observe that in NaV 1.8, a relatively unexplored channel subtype with distinctly slow gating kinetics, VSDI-III participate in channel opening whereas VSDIV can regulate opening as well as fast inactivation. These results illustrate the effectiveness of a pharmacological approach to investigate the mechanism underlying gating of a mammalian NaV channel complex.
Collapse
Affiliation(s)
- John Gilchrist
- Department of Physiology, Johns Hopkins University, School of Medicine, Baltimore, MD, 21205, USA
| | - Frank Bosmans
- Department of Physiology, Johns Hopkins University, School of Medicine, Baltimore, MD, 21205, USA.,Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD, 21205, USA
| |
Collapse
|
11
|
Yuan S, Gao B, Zhu S. Molecular Dynamics Simulation Reveals Specific Interaction Sites between Scorpion Toxins and K v1.2 Channel: Implications for Design of Highly Selective Drugs. Toxins (Basel) 2017; 9:toxins9110354. [PMID: 29104247 PMCID: PMC5705969 DOI: 10.3390/toxins9110354] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 10/15/2017] [Accepted: 10/19/2017] [Indexed: 01/06/2023] Open
Abstract
The Kv1.2 channel plays an important role in the maintenance of resting membrane potential and the regulation of the cellular excitability of neurons, whose silencing or mutations can elicit neuropathic pain or neurological diseases (e.g., epilepsy and ataxia). Scorpion venom contains a variety of peptide toxins targeting the pore region of this channel. Despite a large amount of structural and functional data currently available, their detailed interaction modes are poorly understood. In this work, we choose four Kv1.2-targeted scorpion toxins (Margatoxin, Agitoxin-2, OsK-1, and Mesomartoxin) to construct their complexes with Kv1.2 based on the experimental structure of ChTx-Kv1.2. Molecular dynamics simulation of these complexes lead to the identification of hydrophobic patches, hydrogen-bonds, and salt bridges as three essential forces mediating the interactions between this channel and the toxins, in which four Kv1.2-specific interacting amino acids (D353, Q358, V381, and T383) are identified for the first time. This discovery might help design highly selective Kv1.2-channel inhibitors by altering amino acids of these toxins binding to the four channel residues. Finally, our results provide new evidence in favor of an induced fit model between scorpion toxins and K+ channel interactions.
Collapse
Affiliation(s)
- Shouli Yuan
- Group of Peptide Biology and Evolution, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Bin Gao
- Group of Peptide Biology and Evolution, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
| | - Shunyi Zhu
- Group of Peptide Biology and Evolution, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
| |
Collapse
|
12
|
Geron M, Hazan A, Priel A. Animal Toxins Providing Insights into TRPV1 Activation Mechanism. Toxins (Basel) 2017; 9:toxins9100326. [PMID: 29035314 PMCID: PMC5666373 DOI: 10.3390/toxins9100326] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 10/13/2017] [Accepted: 10/13/2017] [Indexed: 02/06/2023] Open
Abstract
Beyond providing evolutionary advantages, venoms offer unique research tools, as they were developed to target functionally important proteins and pathways. As a key pain receptor in the nociceptive pathway, transient receptor potential vanilloid 1 (TRPV1) of the TRP superfamily has been shown to be a target for several toxins, as a way of producing pain to deter predators. Importantly, TRPV1 is involved in thermoregulation, inflammation, and acute nociception. As such, toxins provide tools to understand TRPV1 activation and modulation, a critical step in advancing pain research and the development of novel analgesics. Indeed, the phytotoxin capsaicin, which is the spicy chemical in chili peppers, was invaluable in the original cloning and characterization of TRPV1. The unique properties of each subsequently characterized toxin have continued to advance our understanding of functional, structural, and biophysical characteristics of TRPV1. By building on previous reviews, this work aims to provide a comprehensive summary of the advancements made in TRPV1 research in recent years by employing animal toxins, in particular DkTx, RhTx, BmP01, Echis coloratus toxins, APHCs and HCRG21. We examine each toxin’s functional aspects, behavioral effects, and structural features, all of which have contributed to our current knowledge of TRPV1. We additionally discuss the key features of TRPV1’s outer pore domain, which proves to be the target of the currently discussed toxins.
Collapse
Affiliation(s)
- Matan Geron
- The Institute for Drug Research (IDR), School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel.
| | - Adina Hazan
- The Institute for Drug Research (IDR), School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel.
| | - Avi Priel
- The Institute for Drug Research (IDR), School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel.
| |
Collapse
|
13
|
Cremonez CM, Maiti M, Peigneur S, Cassoli JS, Dutra AAA, Waelkens E, Lescrinier E, Herdewijn P, de Lima ME, Pimenta AMC, Arantes EC, Tytgat J. Structural and Functional Elucidation of Peptide Ts11 Shows Evidence of a Novel Subfamily of Scorpion Venom Toxins. Toxins (Basel) 2016; 8:toxins8100288. [PMID: 27706049 PMCID: PMC5086648 DOI: 10.3390/toxins8100288] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 09/25/2016] [Accepted: 09/26/2016] [Indexed: 12/31/2022] Open
Abstract
To date, several families of peptide toxins specifically interacting with ion channels in scorpion venom have been described. One of these families comprise peptide toxins (called KTxs), known to modulate potassium channels. Thus far, 202 KTxs have been reported, belonging to several subfamilies of KTxs (called α, β, γ, κ, δ, and λ-KTxs). Here we report on a previously described orphan toxin from Tityus serrulatus venom, named Ts11. We carried out an in-depth structure-function analysis combining 3D structure elucidation of Ts11 and electrophysiological characterization of the toxin. The Ts11 structure is highlighted by an Inhibitor Cystine Knot (ICK) type scaffold, completely devoid of the classical secondary structure elements (α-helix and/or β-strand). This has, to the best of our knowledge, never been described before for scorpion toxins and therefore represents a novel, 6th type of structural fold for these scorpion peptides. On the basis of their preferred interaction with voltage-gated K channels, as compared to all the other targets tested, it can be postulated that Ts11 is the first member of a new subfamily, designated as ε-KTx.
Collapse
Affiliation(s)
- Caroline M Cremonez
- Laboratório de Toxinas Animais, Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo (USP), Ribeirão Preto 14040-903, São Paulo, Brasil.
| | - Mohitosh Maiti
- Laboratory for Medicinal Chemistry, Rega Institute for Medical Research, University of Leuven (KU Leuven), P.O. Box 922, Leuven 3000, Belgium.
| | - Steve Peigneur
- Toxicology & Pharmacology, University of Leuven (KU Leuven), Campus Gasthuisberg O&N2, P.O. Box 922, Leuven 3000, Belgium.
| | - Juliana Silva Cassoli
- Laboratório de Venenos e Toxinas Animais, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte 31270-901, Brasil.
| | - Alexandre A A Dutra
- Laboratório de Venenos e Toxinas Animais, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte 31270-901, Brasil.
| | - Etienne Waelkens
- Laboratory of Protein Phosphorylation and Proteomics, University of Leuven (KU Leuven), P.O. Box 922, Leuven 3000, Belgium.
| | - Eveline Lescrinier
- Laboratory for Medicinal Chemistry, Rega Institute for Medical Research, University of Leuven (KU Leuven), P.O. Box 922, Leuven 3000, Belgium.
| | - Piet Herdewijn
- Laboratory for Medicinal Chemistry, Rega Institute for Medical Research, University of Leuven (KU Leuven), P.O. Box 922, Leuven 3000, Belgium.
| | - Maria Elena de Lima
- Laboratório de Venenos e Toxinas Animais, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte 31270-901, Brasil.
| | - Adriano M C Pimenta
- Laboratório de Venenos e Toxinas Animais, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte 31270-901, Brasil.
| | - Eliane C Arantes
- Laboratório de Toxinas Animais, Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo (USP), Ribeirão Preto 14040-903, São Paulo, Brasil.
| | - Jan Tytgat
- Toxicology & Pharmacology, University of Leuven (KU Leuven), Campus Gasthuisberg O&N2, P.O. Box 922, Leuven 3000, Belgium.
| |
Collapse
|
14
|
Wu B, Zhu Y, Shi J, Tao J, Ji Y. BmP02 Atypically Delays Kv4.2 Inactivation: Implication for a Unique Interaction between Scorpion Toxin and Potassium Channel. Toxins (Basel) 2016; 8:toxins8100280. [PMID: 27690098 PMCID: PMC5086640 DOI: 10.3390/toxins8100280] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 09/20/2016] [Indexed: 01/22/2023] Open
Abstract
BmP02, a short-chain peptide with 28 residues from the venom of Chinese scorpion Buthus martensi Karsch, has been reported to inhibit the transient outward potassium currents (Ito) in rat ventricular muscle cells. However, it remains unclear whether BmP02 modulates the Kv4.2 channel, one of the main contributors to Ito. The present study investigated the effects of BmP02 on Kv4.2 kinetics and its underlying molecular mechanism. The electrophysiological recordings showed that the inactivation of Kv4.2 expressed in HEK293T cells was significantly delayed by BmP02 in a dose-response manner with EC50 of ~850 nM while the peak current, activation and voltage-dependent inactivation of Kv4.2 were not affected. Meanwhile, the recovery from inactivation of Kv4.2 was accelerated and the deactivation was slowed after the application of BmP02. The site-directed mutagenesis combined with computational modelling identified that K347 and K353, located in the turret motif of the Kv4.2, and E4/E5, D20/D21 in BmP02 are key residues to interact with BmP02 through electrostatic force. These findings not only reveal a novel interaction between Kv4.2 channel and its peptidyl modulator, but also provide valuable information for design of highly-selective Kv4.2 modulators.
Collapse
Affiliation(s)
- Bin Wu
- Lab of Neuropharmacology and Neurotoxicology, Shanghai University, Nanchen Road 333, Shanghai 200444, China.
| | - Yan Zhu
- Lab of Neuropharmacology and Neurotoxicology, Shanghai University, Nanchen Road 333, Shanghai 200444, China.
| | - Jian Shi
- Lab of Neuropharmacology and Neurotoxicology, Shanghai University, Nanchen Road 333, Shanghai 200444, China.
- Vascular Biology Research Centre, Institute of Cardiovascular and Cell Sciences, St. George's, University of London, Cranmer Terrace, London SW17 0RE, UK.
| | - Jie Tao
- Central Laboratory, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, 164 Lanxi road, Shanghai 200062, China.
| | - Yonghua Ji
- Lab of Neuropharmacology and Neurotoxicology, Shanghai University, Nanchen Road 333, Shanghai 200444, China.
| |
Collapse
|
15
|
Ye F, Hu Y, Yu W, Xie Z, Hu J, Cao Z, Li W, Wu Y. The Scorpion Toxin Analogue BmKTX-D33H as a Potential Kv1.3 Channel-Selective Immunomodulator for Autoimmune Diseases. Toxins (Basel) 2016; 8:115. [PMID: 27104568 PMCID: PMC4848641 DOI: 10.3390/toxins8040115] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Revised: 04/11/2016] [Accepted: 04/12/2016] [Indexed: 01/23/2023] Open
Abstract
The Kv1.3 channel-acting scorpion toxins usually adopt the conserved anti-parallel β-sheet domain as the binding interface, but it remains challenging to discover some highly selective Kv1.3 channel-acting toxins. In this work, we investigated the pharmacological profile of the Kv1.3 channel-acting BmKTX-D33H, a structural analogue of the BmKTX scorpion toxin. Interestingly, BmKTX-D33H, with its conserved anti-parallel β-sheet domain as a Kv1.3 channel-interacting interface, exhibited more than 1000-fold selectivity towards the Kv1.3 channel as compared to other K+ channels (including Kv1.1, Kv1.2, Kv1.7, Kv11.1, KCa2.2, KCa2.3, and KCa3.1). As expected, BmKTX-D33H was found to inhibit the cytokine production and proliferation of both Jurkat cells and human T cells in vitro. It also significantly improved the delayed-type hypersensitivity (DTH) responses, an autoreactive T cell-mediated inflammation in rats. Amino acid sequence alignment and structural analysis strongly suggest that the “evolutionary” Gly11 residue of BmKTX-D33H interacts with the turret domain of Kv1 channels; it appears to be a pivotal amino acid residue with regard to the selectivity of BmKTX-D33H towards the Kv1.3 channel (in comparison with the highly homologous scorpion toxins). Together, our data indicate that BmKTX-D33H is a Kv1.3 channel–specific blocker. Finally, the remarkable selectivity of BmKTX-D33H highlights the great potential of evolutionary-guided peptide drug design in future studies.
Collapse
Affiliation(s)
- Fang Ye
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Youtian Hu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Weiwei Yu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Zili Xie
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Jun Hu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Zhijian Cao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Wenxin Li
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| | - Yingliang Wu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
| |
Collapse
|
16
|
Abstract
Nine different voltage-gated sodium channel isoforms are responsible for inducing and propagating action potentials in the mammalian nervous system. The Nav1.7 channel isoform plays an important role in conducting nociceptive signals. Specific mutations of this isoform may impair gating behavior of the channel resulting in several pain syndromes. In addition to channel mutations, similar or opposite changes in gating may be produced by spider and scorpion toxins binding to different parts of the voltage-gated sodium channel. In the present study, we analyzed the effects of the α-scorpion toxin OD1 and 2 synthetic toxin analogs on the gating properties of the Nav1.7 sodium channel. All toxins potently inhibited channel inactivation, however, both toxin analogs showed substantially increased potency by more than one order of magnitude when compared with that of wild-type OD1. The decay phase of the whole-cell Na(+) current was substantially slower in the presence of toxins than in their absence. Single-channel recordings in the presence of the toxins revealed that Na(+) current inactivation slowed due to prolonged flickering of the channel between open and closed states. Our findings support the voltage-sensor trapping model of α-scorpion toxin action, in which the toxin prevents a conformational change in the domain IV voltage sensor that normally leads to fast channel inactivation.
Collapse
Affiliation(s)
- Leonid Motin
- a Health Innovations Research Institute, RMIT University , Melbourne , Victoria, Australia
| | - Thomas Durek
- b Division of Chemistry & Structural Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane , Queensland, Australia
| | - David J Adams
- a Health Innovations Research Institute, RMIT University , Melbourne , Victoria, Australia
| |
Collapse
|
17
|
Pucca MB, Cerni FA, Peigneur S, Bordon KCF, Tytgat J, Arantes EC. Revealing the Function and the Structural Model of Ts4: Insights into the "Non-Toxic" Toxin from Tityus serrulatus Venom. Toxins (Basel) 2015; 7:2534-50. [PMID: 26153865 PMCID: PMC4516927 DOI: 10.3390/toxins7072534] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 06/20/2015] [Accepted: 06/25/2015] [Indexed: 01/21/2023] Open
Abstract
The toxin, previously described as a "non-toxic" toxin, was isolated from the scorpion venom of Tityus serrulatus (Ts), responsible for the most severe and the highest number of accidents in Brazil. In this study, the subtype specificity and selectivity of Ts4 was investigated using six mammalian Nav channels (Nav1.2→Nav1.6 and Nav1.8) and two insect Nav channels (DmNav1 and BgNav). The electrophysiological assays showed that Ts4 specifically inhibited the fast inactivation of Nav1.6 channels, the most abundant sodium channel expressed in the adult central nervous system, and can no longer be classified as a "non-toxic peptide". Based on the results, we could classify the Ts4 as a classical α-toxin. The Ts4 3D-structural model was built based on the solved X-ray Ts1 3D-structure, the major toxin from Ts venom with which it shares high sequence identity (65.57%). The Ts4 model revealed a flattened triangular shape constituted by three-stranded antiparallel β-sheet and one α-helix stabilized by four disulfide bonds. The absence of a Lys in the first amino acid residue of the N-terminal of Ts4 is probably the main responsible for its low toxicity. Other key amino acid residues important to the toxicity of α- and β-toxins are discussed here.
Collapse
Affiliation(s)
- Manuela B Pucca
- Department of Physics and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Av. do Café, s/n, Ribeirão Preto, SP 14040-903, Brazil.
| | - Felipe A Cerni
- Department of Physics and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Av. do Café, s/n, Ribeirão Preto, SP 14040-903, Brazil.
| | - Steve Peigneur
- Toxicology and Pharmacology, University of Leuven, O&N 2, Herestraat 49, P.O. Box 922, Leuven 3000, Belgium.
| | - Karla C F Bordon
- Department of Physics and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Av. do Café, s/n, Ribeirão Preto, SP 14040-903, Brazil.
| | - Jan Tytgat
- Toxicology and Pharmacology, University of Leuven, O&N 2, Herestraat 49, P.O. Box 922, Leuven 3000, Belgium.
| | - Eliane C Arantes
- Department of Physics and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Av. do Café, s/n, Ribeirão Preto, SP 14040-903, Brazil.
| |
Collapse
|
18
|
Zhu S, Peigneur S, Gao B, Umetsu Y, Ohki S, Tytgat J. Experimental conversion of a defensin into a neurotoxin: implications for origin of toxic function. Mol Biol Evol 2014; 31:546-59. [PMID: 24425781 DOI: 10.1093/molbev/msu038] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Scorpion K(+) channel toxins and insect defensins share a conserved three-dimensional structure and related biological activities (defense against competitors or invasive microbes by disrupting their membrane functions), which provides an ideal system to study how functional evolution occurs in a conserved structural scaffold. Using an experimental approach, we show that the deletion of a small loop of a parasitoid venom defensin possessing the "scorpion toxin signature" (STS) can remove steric hindrance of peptide-channel interactions and result in a neurotoxin selectively inhibiting K(+) channels with high affinities. This insect defensin-derived toxin adopts a hallmark scorpion toxin fold with a common cysteine-stabilized α-helical and β-sheet motif, as determined by nuclear magnetic resonance analysis. Mutations of two key residues located in STS completely diminish or significantly decrease the affinity of the toxin on the channels, demonstrating that this toxin binds to K(+) channels in the same manner as scorpion toxins. Taken together, these results provide new structural and functional evidence supporting the predictability of toxin evolution. The experimental strategy is the first employed to establish an evolutionary relationship of two distantly related protein families.
Collapse
Affiliation(s)
- Shunyi Zhu
- Group of Animal Innate Immunity, State Key Laboratory of Integrated Management of Pest Insects & Rodents, Institute of Zoology, Chinese Academy of Sciences, Chaoyang District, Beijing, China
| | | | | | | | | | | |
Collapse
|
19
|
Abstract
The structure of a complex containing a toxin bound to a potassium ion channel has been solved for the first time, revealing how scorpions have designed toxins that can recognize and target the filter that controls the movement of potassium ions through these channels.
Collapse
Affiliation(s)
- Kenton J Swartz
- is at the Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke , National Institutes of Health , Bethesda , United States
| |
Collapse
|
20
|
Abstract
Ion channels function as multi-protein complexes made up of ion-conducting α-subunits and regulatory β-subunits. To detect, identify, and quantitate the regulatory β-subunits in functioning K(+) channel complexes, we have chemically derivatized peptide-toxins that specifically react with strategically placed cysteine residues in the channel complex. Two protein labeling approaches have been developed to derivatize the peptide-toxin, charybdotoxin, with hydrophilic and hydrophobic bismaleimides, and other molecular probes. Using these cysteine-reactive peptide-toxins, we have specifically targeted KCNQ1-KCNE1 K(+) channel complexes expressed in both Xenopus oocytes and mammalian cells. The modular design of the reagents should permit this approach to be applied to the many ion channel complexes involved in electrical excitability as well as salt and water homoeostasis.
Collapse
|
21
|
Abstract
Many kinds of venomous principles modulate physiological responses of mammalian signal transduction systems, on which they act selectively as enhancers, inhibitors or some other kind of effectors. These toxins become useful tools for physiological research. We have employed and characterized paralyzing toxins from the venom of spiders, insects and scorpions with a limited supply. We have developed rapid and sensitive mass spectrometric technology and applied for the identification of these toxins. Venom profiles are screened by MALDI-TOF fingerprinting analysis prior to purification of venomous components, then marked target toxins of small molecular mass (1000-5000) are characterized directly by means of mass spectrometric techniques such as Frit-FAB MS/MS, CID/PSD-TOF MS, Capil.-HPLC/Q-TOF MS/MS etc.
Collapse
Affiliation(s)
- Terumi Nakajima
- Hoshi University, 2–4–41 Ebara, Shinagawa-ku, Tokyo 142–8501, Japan (e-mail: )
| |
Collapse
|
22
|
Guijarro JI, M'Barek S, Gómez-Lagunas F, Garnier D, Rochat H, Sabatier JM, Possani L, Delepierre M, Possani L. Solution structure of Pi4, a short four-disulfide-bridged scorpion toxin specific of potassium channels. Protein Sci 2003; 12:1844-54. [PMID: 12930984 PMCID: PMC2323982 DOI: 10.1110/ps.03186703] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Pi4 is a short toxin found at very low abundance in the venom of Pandinus imperator scorpions. It is a potent blocker of K(+) channels. Like the other members of the alpha-KTX6 subfamily to which it belongs, it is cross-linked by four disulfide bonds. The synthetic analog (sPi4) and the natural toxin (nPi4) have been obtained by solid-phase synthesis or from scorpion venom, respectively. Analysis of two-dimensional (1)H NMR spectra of nPi4 and sPi4 indicates that both peptides have the same structure. Moreover, electrophysiological recordings of the blocking of Shaker B K(+) channels by sPi4 (K(D) = 8.5 nM) indicate that sPi4 has the same blocking activity of nPi4 (K(D) = 8.0 nM), previously described. The disulfide bonds have been independently determined by NMR and structure calculations, and by Edman-degradation/mass-spectrometry identification of peptides obtained by proteolysis of nPi4. Both approaches indicate that the pairing of the half-cystines is (6)C-(27)C, (12)C-(32)C, (16)C-(34)C, and (22)C-(37)C. The structure of the toxin has been determined by using 705 constraints derived from NMR data on sPi4. The structure, which is well defined, shows the characteristic alpha/beta scaffold of scorpion toxins. It is compared to the structure of the other alpha-KTX6 subfamily members and, in particular, to the structure of maurotoxin, which shows a different pattern of disulfide bridges despite its high degree of sequence identity (76%) with Pi4. The structure of Pi4 and the high amounts of synthetic peptide available, will enable the detailed analysis of the interaction of Pi4 with K(+) channels.
Collapse
Affiliation(s)
- J Iñaki Guijarro
- Unité de RMN des Biomolécules (CNRS URA 2185), Dépt. de Biologie Structurale et Chimie, Institut Pasteur, 75724 Paris Cedex 15, France
| | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Cook WJ, Zell A, Watt DD, Ealick SE. Structure of variant 2 scorpion toxin from Centruroides sculpturatus Ewing. Protein Sci 2002; 11:479-86. [PMID: 11847271 PMCID: PMC2373473 DOI: 10.1110/ps.39202] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2001] [Revised: 11/12/2001] [Accepted: 11/13/2001] [Indexed: 10/17/2022]
Abstract
Centruroides sculpturatus Ewing variant 2 toxin (CsE-v2) is a neurotoxin isolated from the venom of a scorpion native to the Arizona desert. The structure of CsE-v2 was solved in two different crystal forms using a combination of molecular replacement and multiple isomorphous replacement techniques. Crystals of CsE-v2 display a temperature-dependent, reversible-phase transition near room temperature. At lower temperature the space group changes from P3(2)21 to P3(1)21 with an approximate doubling of the C-axis. The small-cell structure, which has one molecule per asymmetric unit, has an R factor of 0.229 at 2.8 A resolution. The large-cell structure has two molecules per asymmetric unit and was refined at 2.2 A resolution to an R factor of 0.255. CsE-v2 is a rigid, compact structure with four intrachain disulfide bonds. The structure is similar to other long-chain beta neurotoxins, and the largest differences occur in the last six residues. The high-resolution structure of CsE-v2 corrects an error in the reported C-terminal sequence; the terminal tripeptide sequence is Ser 64-Cys 65-Ser 66 rather than Ser 64-Ser 65-Cys 66. Comparison of CsE-v2 with long-chain alpha toxins reveals four insertions and one deletion, as well as additional residues at the N and C termini. Structural alignment of alpha and beta toxins suggests that the primary distinguishing feature between the two classes is the length of the loop between the second and third strands in a three-strand beta sheet. The shorter loop in alpha toxins exposes a critical lysine side chain, whereas the longer loop in beta toxins buries the corresponding basic residue (either arginine or lysine).
Collapse
Affiliation(s)
- William J Cook
- Department of Pathology, University of Alabama at Birmingham, 35294, USA
| | | | | | | |
Collapse
|
24
|
Tripathy A, Resch W, Xu L, Valdivia HH, Meissner G. Imperatoxin A induces subconductance states in Ca2+ release channels (ryanodine receptors) of cardiac and skeletal muscle. J Gen Physiol 1998; 111:679-90. [PMID: 9565405 PMCID: PMC2217137 DOI: 10.1085/jgp.111.5.679] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/1997] [Accepted: 03/10/1998] [Indexed: 11/20/2022] Open
Abstract
Single-channel and [3H]ryanodine binding experiments were carried out to examine the effects of imperatoxin activator (IpTxa), a 33 amino acid peptide isolated from the venom of the African scorpion Pandinus imperator, on rabbit skeletal and canine cardiac muscle Ca2+ release channels (CRCs). Single channel currents from purified CRCs incorporated into planar lipid bilayers were recorded in 250 mM KCl media. Addition of IpTxa in nanomolar concentration to the cytosolic (cis) side, but not to the lumenal (trans) side, induced substates in both ryanodine receptor isoforms. The substates displayed a slightly rectifying current-voltage relationship. The chord conductance at -40 mV was approximately 43% of the full conductance, whereas it was approximately 28% at a holding potential of +40 mV. The substate formation by IpTxa was voltage and concentration dependent. Analysis of voltage and concentration dependence and kinetics of substate formation suggested that IpTxa reversibly binds to the CRC at a single site in the voltage drop across the channel. The rate constant for IpTxa binding to the skeletal muscle CRC increased e-fold per +53 mV and the rate constant of dissociation decreased e-fold per +25 mV applied holding potential. The effective valence of the reaction leading to the substate was approximately 1.5. The IpTxa binding site was calculated to be located at approximately 23% of the voltage drop from the cytosolic side. IpTxa induced substates in the ryanodine-modified skeletal CRC and increased or reduced [3H]ryanodine binding to sarcoplasmic reticulum vesicles depending on the level of channel activation. These results suggest that IpTxa induces subconductance states in skeletal and cardiac muscle Ca2+ release channels by binding to a single, cytosolically accessible site different from the ryanodine binding site.
Collapse
Affiliation(s)
- A Tripathy
- Department of Biochemistry and Biophysics, and Department of Physiology, University of North Carolina, Chapel Hill, North Carolina 27599, USA.
| | | | | | | | | |
Collapse
|