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Qin C, Yang X, Zhang Y, Deng G, Huang X, Zuo Z, Sun F, Cao Z, Chen Z, Wu Y. Functional Characterization of a New Degradation Peptide BmTX4-P1 from Traditional Chinese Scorpion Medicinal Material. Toxins (Basel) 2023; 15:toxins15050340. [PMID: 37235373 DOI: 10.3390/toxins15050340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 04/28/2023] [Accepted: 04/29/2023] [Indexed: 05/28/2023] Open
Abstract
Thermally processed Buthus martensii Karsch scorpion is an important traditional Chinese medical material that has been widely used to treat various diseases in China for over one thousand years. Our recent work showed that thermally processed Buthus martensii Karsch scorpions contain many degraded peptides; however, the pharmacological activities of these peptides remain to be studied. Here, a new degraded peptide, BmTX4-P1, was identified from processed Buthus martensii Karsch scorpions. Compared with the venom-derived wild-type toxin peptide BmTX4, BmTX4-P1 missed some amino acids at the N-terminal and C-terminal regions, while containing six conserved cysteine residues, which could be used to form disulfide bond-stabilized α-helical and β-sheet motifs. Two methods (chemical synthesis and recombinant expression) were used to obtain the BmTX4-P1 peptide, named sBmTX4-P1 and rBmTX4-P1. Electrophysiological experimental results showed that sBmTX4-P1 and rBmTX4-P1 exhibited similar activities to inhibit the currents of hKv1.2 and hKv1.3 channels. In addition, the experimental electrophysiological results of recombinant mutant peptides of BmTX4-P1 indicated that the two residues of BmTX4-P1 (Lys22 and Tyr31) were the key residues for its potassium channel inhibitory activity. In addition to identifying a new degraded peptide, BmTX4-P1, from traditional Chinese scorpion medicinal material with high inhibitory activities against the hKv1.2 and hKv1.3 channels, this study also provided a useful method to obtain the detailed degraded peptides from processed Buthus martensii Karsch scorpions. Thus, the study laid a solid foundation for further research on the medicinal function of these degraded peptides.
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Affiliation(s)
- Chenhu Qin
- College of Life Sciences, Wuhan University, Wuhan 430072, China
- Department of Biochemistry and Molecular Biology, College of Basic Medicine, Hubei University of Medicine, Shiyan 442000, China
| | - Xuhua Yang
- College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Yuanyuan Zhang
- College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Gang Deng
- College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Xin Huang
- College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Zheng Zuo
- College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Fang Sun
- College of Life Sciences, Wuhan University, Wuhan 430072, China
- Department of Biochemistry and Molecular Biology, College of Basic Medicine, Hubei University of Medicine, Shiyan 442000, China
| | - Zhijian Cao
- College of Life Sciences, Wuhan University, Wuhan 430072, China
- Center for BioDrug Research, Wuhan University, Wuhan 430072, China
| | - Zongyun Chen
- College of Life Sciences, Wuhan University, Wuhan 430072, China
- Department of Biochemistry and Molecular Biology, College of Basic Medicine, Hubei University of Medicine, Shiyan 442000, China
| | - Yingliang Wu
- College of Life Sciences, Wuhan University, Wuhan 430072, China
- Center for BioDrug Research, Wuhan University, Wuhan 430072, China
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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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Naseem MU, Carcamo-Noriega E, Beltrán-Vidal J, Borrego J, Szanto TG, Zamudio FZ, Delgado-Prudencio G, Possani LD, Panyi G. Cm28, a scorpion toxin having a unique primary structure, inhibits KV1.2 and KV1.3 with high affinity. J Gen Physiol 2022; 154:213282. [PMID: 35699659 PMCID: PMC9202693 DOI: 10.1085/jgp.202213146] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 05/23/2022] [Indexed: 02/03/2023] Open
Abstract
The Cm28 in the venom of Centruroides margaritatus is a short peptide consisting of 27 amino acid residues with a mol wt of 2,820 D. Cm28 has <40% similarity with other known α-KTx from scorpions and lacks the typical functional dyad (lysine-tyrosine) required to block KV channels. However, its unique sequence contains the three disulfide-bond traits of the α-KTx scorpion toxin family. We propose that Cm28 is the first example of a new subfamily of α-KTxs, registered with the systematic number α-KTx32.1. Cm28 inhibited voltage-gated K+ channels KV1.2 and KV1.3 with Kd values of 0.96 and 1.3 nM, respectively. There was no significant shift in the conductance-voltage (G-V) relationship for any of the channels in the presence of toxin. Toxin binding kinetics showed that the association and dissociation rates are consistent with a bimolecular interaction between the peptide and the channel. Based on these, we conclude that Cm28 is not a gating modifier but rather a pore blocker. In a selectivity assay, Cm28 at 150 nM concentration (>100× Kd value for KV1.3) did not inhibit KV1.5, KV11.1, KCa1.1, and KCa3.1 K+ channels; NaV1.5 and NaV1.4 Na+ channels; or the hHV1 H+ channel but blocked ∼27% of the KV1.1 current. In a biological functional assay, Cm28 strongly inhibited the expression of the activation markers interleukin-2 receptor and CD40 ligand in anti-CD3-activated human CD4+ effector memory T lymphocytes. Cm28, due to its unique structure, may serve as a template for the generation of novel peptides targeting KV1.3 in autoimmune diseases.
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Affiliation(s)
- Muhammad Umair Naseem
- Department of Biophysics and Cell Biology, Faculty of Medicine, Research Center for Molecular Medicine, University of Debrecen, Debrecen, Hungary
| | - Edson Carcamo-Noriega
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologia, Universidad Nacional Autónoma de México, Cuernavaca, 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, Popayán, Colombia
| | - Jesus Borrego
- Department of Biophysics and Cell Biology, Faculty of Medicine, Research Center for Molecular Medicine, University of Debrecen, Debrecen, Hungary
| | - Tibor G. Szanto
- Department of Biophysics and Cell Biology, Faculty of Medicine, Research Center for Molecular Medicine, University of Debrecen, Debrecen, Hungary
| | - Fernando Z. Zamudio
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologia, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Gustavo Delgado-Prudencio
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologia, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Lourival D. Possani
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologia, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Gyorgy Panyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, Research Center for Molecular Medicine, University of Debrecen, Debrecen, Hungary,Correspondence to Gyorgy Panyi:
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Borrego J, Feher A, Jost N, Panyi G, Varga Z, Papp F. Peptide Inhibitors of Kv1.5: An Option for the Treatment of Atrial Fibrillation. Pharmaceuticals (Basel) 2021; 14:1303. [PMID: 34959701 PMCID: PMC8704205 DOI: 10.3390/ph14121303] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 12/08/2021] [Accepted: 12/09/2021] [Indexed: 12/12/2022] Open
Abstract
The human voltage gated potassium channel Kv1.5 that conducts the IKur current is a key determinant of the atrial action potential. Its mutations have been linked to hereditary forms of atrial fibrillation (AF), and the channel is an attractive target for the management of AF. The development of IKur blockers to treat AF resulted in small molecule Kv1.5 inhibitors. The selectivity of the blocker for the target channel plays an important role in the potential therapeutic application of the drug candidate: the higher the selectivity, the lower the risk of side effects. In this respect, small molecule inhibitors of Kv1.5 are compromised due to their limited selectivity. A wide range of peptide toxins from venomous animals are targeting ion channels, including mammalian channels. These peptides usually have a much larger interacting surface with the ion channel compared to small molecule inhibitors and thus, generally confer higher selectivity to the peptide blockers. We found two peptides in the literature, which inhibited IKur: Ts6 and Osu1. Their affinity and selectivity for Kv1.5 can be improved by rational drug design in which their amino acid sequences could be modified in a targeted way guided by in silico docking experiments.
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Affiliation(s)
- Jesús Borrego
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem ter 1, H-4032 Debrecen, Hungary; (J.B.); (A.F.); (G.P.); (Z.V.)
| | - Adam Feher
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem ter 1, H-4032 Debrecen, Hungary; (J.B.); (A.F.); (G.P.); (Z.V.)
| | - Norbert Jost
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, 6725 Szeged, Hungary;
- Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, 6725 Szeged, Hungary
- ELKH-SZTE Research Group for Cardiovascular Pharmacology, Eötvös Loránd Research Network, 6725 Szeged, Hungary
| | - Gyorgy Panyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem ter 1, H-4032 Debrecen, Hungary; (J.B.); (A.F.); (G.P.); (Z.V.)
| | - Zoltan Varga
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem ter 1, H-4032 Debrecen, Hungary; (J.B.); (A.F.); (G.P.); (Z.V.)
| | - Ferenc Papp
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem ter 1, H-4032 Debrecen, Hungary; (J.B.); (A.F.); (G.P.); (Z.V.)
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Gubič Š, Hendrickx LA, Toplak Ž, Sterle M, Peigneur S, Tomašič T, Pardo LA, Tytgat J, Zega A, Mašič LP. Discovery of K V 1.3 ion channel inhibitors: Medicinal chemistry approaches and challenges. Med Res Rev 2021; 41:2423-2473. [PMID: 33932253 PMCID: PMC8252768 DOI: 10.1002/med.21800] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 03/03/2021] [Accepted: 03/19/2021] [Indexed: 12/12/2022]
Abstract
The KV 1.3 voltage-gated potassium ion channel is involved in many physiological processes both at the plasma membrane and in the mitochondria, chiefly in the immune and nervous systems. Therapeutic targeting KV 1.3 with specific peptides and small molecule inhibitors shows great potential for treating cancers and autoimmune diseases, such as multiple sclerosis, type I diabetes mellitus, psoriasis, contact dermatitis, rheumatoid arthritis, and myasthenia gravis. However, no KV 1.3-targeted compounds have been approved for therapeutic use to date. This review focuses on the presentation of approaches for discovering new KV 1.3 peptide and small-molecule inhibitors, and strategies to improve the selectivity of active compounds toward KV 1.3. Selectivity of dalatazide (ShK-186), a synthetic derivate of the sea anemone toxin ShK, was achieved by chemical modification and has successfully reached clinical trials as a potential therapeutic for treating autoimmune diseases. Other peptides and small-molecule inhibitors are critically evaluated for their lead-like characteristics and potential for progression into clinical development. Some small-molecule inhibitors with well-defined structure-activity relationships have been optimized for selective delivery to mitochondria, and these offer therapeutic potential for the treatment of cancers. This overview of KV 1.3 inhibitors and methodologies is designed to provide a good starting point for drug discovery to identify novel effective KV 1.3 modulators against this target in the future.
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Affiliation(s)
- Špela Gubič
- Faculty of PharmacyUniversity of LjubljanaLjubljanaSlovenia
| | - Louise A. Hendrickx
- Toxicology and PharmacologyUniversity of Leuven, Campus GasthuisbergLeuvenBelgium
| | - Žan Toplak
- Faculty of PharmacyUniversity of LjubljanaLjubljanaSlovenia
| | - Maša Sterle
- Faculty of PharmacyUniversity of LjubljanaLjubljanaSlovenia
| | - Steve Peigneur
- Faculty of PharmacyUniversity of LjubljanaLjubljanaSlovenia
| | | | - Luis A. Pardo
- AG OncophysiologyMax‐Planck Institute for Experimental MedicineGöttingenGermany
| | - Jan Tytgat
- Toxicology and PharmacologyUniversity of Leuven, Campus GasthuisbergLeuvenBelgium
| | - Anamarija Zega
- Faculty of PharmacyUniversity of LjubljanaLjubljanaSlovenia
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Deng Z, Zeng Q, Tang J, Zhang B, Chai J, Andersen JF, Chen X, Xu X. Anti-inflammatory effects of FS48, the first potassium channel inhibitor from the salivary glands of the flea Xenopsylla cheopis. J Biol Chem 2021; 296:100670. [PMID: 33864815 PMCID: PMC8131326 DOI: 10.1016/j.jbc.2021.100670] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 04/07/2021] [Accepted: 04/13/2021] [Indexed: 11/29/2022] Open
Abstract
The voltage-gated potassium (Kv) 1.3 channel plays a crucial role in the immune responsiveness of T-lymphocytes and macrophages, presenting a potential target for treatment of immune- and inflammation related-diseases. FS48, a protein from the rodent flea Xenopsylla cheopis, shares the three disulfide bond feature of scorpion toxins. However, its three-dimensional structure and biological function are still unclear. In the present study, the structure of FS48 was evaluated by circular dichroism and homology modeling. We also described its in vitro ion channel activity using patch clamp recording and investigated its anti-inflammatory activity in LPS-induced Raw 264.7 macrophage cells and carrageenan-induced paw edema in mice. FS48 was found to adopt a common αββ structure and contain an atypical dyad motif. It dose-dependently exhibited the Kv1.3 channel in Raw 264.7 and HEK 293T cells, and its ability to block the channel pore was demonstrated by the kinetics of activation and competition binding with tetraethylammonium. FS48 also downregulated the secretion of proinflammatory molecules NO, IL-1β, TNF-α, and IL-6 by Raw 264.7 cells in a manner dependent on Kv1.3 channel blockage and the subsequent inactivation of the MAPK/NF-κB pathways. Finally, we observed that FS48 inhibited the paw edema formation, tissue myeloperoxidase activity, and inflammatory cell infiltrations in carrageenan-treated mice. We therefore conclude that FS48 identified from the flea saliva is a novel potassium channel inhibitor displaying anti-inflammatory activity. This discovery will promote understanding of the bloodsucking mechanism of the flea and provide a new template molecule for the design of Kv1.3 channel blockers.
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Affiliation(s)
- Zhenhui Deng
- Department of Pulmonary and Critical Care Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, China; Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China
| | - Qingye Zeng
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China
| | - Jie Tang
- Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Bei Zhang
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China
| | - Jinwei Chai
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China
| | - John F Andersen
- Laboratory of Malaria and Vector Research, NIAID, National Intitutes of Health, Bethesda, Maryland, USA
| | - Xin Chen
- Department of Pulmonary and Critical Care Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, China.
| | - Xueqing Xu
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China.
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Saikia C, Dym O, Altman-Gueta H, Gordon D, Reuveny E, Karbat I. A Molecular Lid Mechanism of K + Channel Blocker Action Revealed by a Cone Peptide. J Mol Biol 2021; 433:166957. [PMID: 33771569 DOI: 10.1016/j.jmb.2021.166957] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 03/08/2021] [Accepted: 03/16/2021] [Indexed: 12/15/2022]
Abstract
Many venomous organisms carry in their arsenal short polypeptides that block K+ channels in a highly selective manner. These toxins may compete with the permeating ions directly via a "plug" mechanism or indirectly via a "pore-collapse" mechanism. An alternative "lid" mechanism was proposed but remained poorly defined. Here we study the Drosophila Shaker channel block by Conkunitzin-S1 and Conkunitzin-C3, two highly similar toxins derived from cone venom. Despite their similarity, the two peptides exhibited differences in their binding poses and biophysical assays, implying discrete action modes. We show that while Conkunitzin-S1 binds tightly to the channel turret and acts via a "pore-collapse" mechanism, Conkunitzin-C3 does not contact this region. Instead, Conk-C3 uses a non-conserved Arg to divert the permeant ions and trap them in off-axis cryptic sites above the SF, a mechanism we term a "molecular-lid". Our study provides an atomic description of the "lid" K+ blocking mode and offers valuable insights for the design of therapeutics based on venom peptides.
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Affiliation(s)
- Chandamita Saikia
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Orly Dym
- Structural Proteomic Unit, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Hagit Altman-Gueta
- Department of Plant Molecular Biology and Ecology, Tel-Aviv University, Tel-Aviv 69978, Israel
| | - Dalia Gordon
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Eitan Reuveny
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel.
| | - Izhar Karbat
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel.
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Qin C, Wan X, Li S, Yang F, Yang L, Zuo Z, Cao Z, Chen Z, Wu Y. Different pharmacological properties between scorpion toxin BmKcug2 and its degraded analogs highlight the diversity of K + channel blockers from thermally processed scorpions. Int J Biol Macromol 2021; 178:143-153. [PMID: 33636268 DOI: 10.1016/j.ijbiomac.2021.02.155] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 02/16/2021] [Accepted: 02/20/2021] [Indexed: 11/16/2022]
Abstract
Novel degraded potassium channel-modulatory peptides were recently found in thermally processed scorpions, but their pharmacological properties remain unclear. Here, we identified a full-length scorpion toxin (i.e., BmKcug2) and its four truncated analogs (i.e., BmKcug2-P1, BmKcug2-P2, BmKcug2-P3 and BmKcug2-P4) with three conserved disulfide bonds in processed scorpion medicinal material by mass spectrometry. The pharmacological experiments revealed that the recombinant BmKcug2 and BmKcug2-P1 could selectively inhibit the human Kv1.2 and human Kv1.3 potassium channels, while the other three analogs showed a much weaker inhibitory effect on potassium channels. BmKcug2 inhibited hKv1.2 and hKv1.3 channels, with IC50 values of 45.6 ± 5.8 nM and 215.2 ± 39.7 nM, respectively, and BmKcug2-P1 inhibited hKv1.2 and hKv1.3, with IC50 values of 89.9 ± 9.6 nM and 1142.4 ± 64.5 nM, respectively. The chromatographic analysis and pharmacological properties of BmKcug2 and BmKcug2-P1 boiled in water for different times further strongly supported their good thermal stability. Structural and functional dissection indicated that one amino acid, i.e., Tyr36, determined the differential affinities of BmKcug2 and four BmKcug2 analogs. Altogether, this research investigated the different pharmacological properties of BmKcug2 and its truncated analogs, and the findings highlighted the diversity of K+ channel blockers from various scorpion species through thermal processing.
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Affiliation(s)
- Chenhu Qin
- College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Xiuping Wan
- College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Songryong Li
- College of Life Sciences, Wuhan University, Wuhan 430072, China; Department of Biotechnology, Institute for Life Science, Kim Hyong Jik University of Education, Pyongyang, Democratic People's Republic of Korea
| | - Fan Yang
- College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Liuting Yang
- College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Zheng Zuo
- Center for BioDrug Research, Wuhan University, Wuhan 430072, China
| | - Zhijian Cao
- College of Life Sciences, Wuhan University, Wuhan 430072, China; Center for BioDrug Research, Wuhan University, Wuhan 430072, China
| | - Zongyun Chen
- College of Life Sciences, Wuhan University, Wuhan 430072, China; Department of Biochemistry and Molecular Biology, College of Basic Medicine, Hubei University of Medicine, Shiyan 442000, China
| | - Yingliang Wu
- College of Life Sciences, Wuhan University, Wuhan 430072, China; Center for BioDrug Research, Wuhan University, Wuhan 430072, China.
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Park BG, Peigneur S, Esaki N, Yamaguchi Y, Ryu JH, Tytgat J, Kim JI, Sato K. Solution Structure and Functional Analysis of HelaTx1: The First Toxin Member of the κ-KTx5 Subfamily. BMB Rep 2020. [PMID: 32172732 PMCID: PMC7262511 DOI: 10.5483/bmbrep.2020.53.5.256] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Scorpion venom comprises a cocktail of toxins that have proven to be useful molecular tools for studying the pharmacological properties of membrane ion channels. HelaTx1, a short peptide neurotoxin isolated recently from the venom of the scorpion Heterometrus laoticus, is a 25 amino acid peptide with two disulfide bonds that shares low sequence homology with other scorpion toxins. HelaTx1 effectively decreases the amplitude of the K+ currents of voltage-gated Kv1.1 and Kv1.6 channels expressed in Xenopus oocytes, and was identified as the first toxin member of the κ-KTx5 subfamily, based on a sequence comparison and phylogenetic analysis. In the present study, we report the NMR solution structure of HelaTx1, and the major interaction points for its binding to voltage-gated Kv1.1 channels. The NMR results indicate that HelaTx1 adopts a helix-loop-helix fold linked by two disulfide bonds without any β-sheets, resembling the molecular folding of other cysteine-stabilized helix-loop-helix (Cs α/α) scorpion toxins such as κ-hefutoxin, HeTx, and OmTx, as well as conotoxin pl14a. A series of alanine-scanning analogs revealed a broad surface on the toxin molecule largely comprising positively-charged residues that is crucial for interaction with voltage- gated Kv1.1 channels. Interestingly, the functional dyad, a key molecular determinant for activity against voltage-gated potassium channels in other toxins, is not present in HelaTx1.
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Affiliation(s)
- Bong Gyu Park
- Department of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Steve Peigneur
- Toxicology and Pharmacology, University of Leuven (KU Leuven), Campus Gasthuisberg, O&N2, P.O. Box 922, Leuven 3000, Belgium
| | - Nao Esaki
- Department of Environmental Sciences, Fukuoka Women’s University, Fukuoka 813-8529, Japan
| | - Yoko Yamaguchi
- Department of Environmental Sciences, Fukuoka Women’s University, Fukuoka 813-8529, Japan
| | - Jae Ha Ryu
- Department of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Jan Tytgat
- Toxicology and Pharmacology, University of Leuven (KU Leuven), Campus Gasthuisberg, O&N2, P.O. Box 922, Leuven 3000, Belgium
| | - Jae Il Kim
- Department of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Kazuki Sato
- Department of Environmental Sciences, Fukuoka Women’s University, Fukuoka 813-8529, Japan
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10
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Boldrini-França J, Pinheiro-Junior EL, Peigneur S, Pucca MB, Cerni FA, Borges RJ, Costa TR, Carone SEI, Fontes MRDM, Sampaio SV, Arantes EC, Tytgat J. Beyond hemostasis: a snake venom serine protease with potassium channel blocking and potential antitumor activities. Sci Rep 2020; 10:4476. [PMID: 32161292 PMCID: PMC7066243 DOI: 10.1038/s41598-020-61258-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 02/19/2020] [Indexed: 02/07/2023] Open
Abstract
Snake venom serine proteases (SVSPs) are complex and multifunctional enzymes, acting primarily on hemostasis. In this work, we report the hitherto unknown inhibitory effect of a SVSP, named collinein-1, isolated from the venom of Crotalus durissus collilineatus, on a cancer-relevant voltage-gated potassium channel (hEAG1). Among 12 voltage-gated ion channels tested, collinein-1 selectively inhibited hEAG1 currents, with a mechanism independent of its enzymatic activity. Corroboratively, we demonstrated that collinein-1 reduced the viability of human breast cancer cell line MCF7 (high expression of hEAG1), but does not affect the liver carcinoma and the non-tumorigenic epithelial breast cell lines (HepG2 and MCF10A, respectively), which present low expression of hEAG1. In order to obtain both functional and structural validation of this unexpected discovery, where an unusually large ligand acts as an inhibitor of an ion channel, a recombinant and catalytically inactive mutant of collinein-1 (His43Arg) was produced and found to preserve its capability to inhibit hEAG1. A molecular docking model was proposed in which Arg79 of the SVSP 99-loop interacts directly with the potassium selectivity filter of the hEAG1 channel.
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Affiliation(s)
- Johara Boldrini-França
- School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Av. do Café s/n°, 14040-903, Ribeirão Preto, SP, Brazil.,University of Vila Velha, Av. Comissário José Dantas de Melo, 21, Boa Vista II, 29102-920, Vila Velha, ES, Brazil
| | - Ernesto Lopes Pinheiro-Junior
- School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Av. do Café s/n°, 14040-903, Ribeirão Preto, SP, Brazil.,Toxicology and Pharmacology, KU Leuven, O&N II Herestraat 49, PO 922, 3000, Leuven, Belgium
| | - Steve Peigneur
- Toxicology and Pharmacology, KU Leuven, O&N II Herestraat 49, PO 922, 3000, Leuven, Belgium
| | - Manuela Berto Pucca
- Medical School of Roraima, Federal University of Roraima, Av. Capitão Ene Garcez, 2413, Bairro Aeroporto, 69310-970, Boa Vista, RR, Brazil
| | - Felipe Augusto Cerni
- School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Av. do Café s/n°, 14040-903, Ribeirão Preto, SP, Brazil
| | - Rafael Junqueira Borges
- Institute of Biosciences, São Paulo State University (UNESP), Rua Prof. Dr. Antonio Celso Wagner Zanin, 250, 18618-689, Botucatu, SP, Brazil
| | - Tássia Rafaella Costa
- School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Av. do Café s/n°, 14040-903, Ribeirão Preto, SP, Brazil
| | - Sante Emmanuel Imai Carone
- School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Av. do Café s/n°, 14040-903, Ribeirão Preto, SP, Brazil
| | - Marcos Roberto de Mattos Fontes
- Institute of Biosciences, São Paulo State University (UNESP), Rua Prof. Dr. Antonio Celso Wagner Zanin, 250, 18618-689, Botucatu, SP, Brazil
| | - Suely Vilela Sampaio
- School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Av. do Café s/n°, 14040-903, Ribeirão Preto, SP, Brazil
| | - Eliane Candiani Arantes
- School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Av. do Café s/n°, 14040-903, Ribeirão Preto, SP, Brazil.
| | - Jan Tytgat
- Toxicology and Pharmacology, KU Leuven, O&N II Herestraat 49, PO 922, 3000, Leuven, Belgium.
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11
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Li S, Sunchen S, He D, Qin C, Zuo Z, Shen B, Cao Z, Hong W, Miao L. ImKTx96, a peptide blocker of the Kv1.2 ion channel from the venom of the scorpion Isometrus maculates. Peptides 2020; 123:170172. [PMID: 31626826 DOI: 10.1016/j.peptides.2019.170172] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 10/03/2019] [Accepted: 10/04/2019] [Indexed: 01/13/2023]
Abstract
Scorpion venom contains diverse bioactive peptides that can recognize and interact with membrane proteins such as ion channels. These natural toxins are believed to be useful tools for exploring the structure and function of ion channels. In this study, we characterized a K+-channel toxin gene, ImKTx96, from the venom gland cDNA library of the scorpion Isometrus maculates. The peptide deduced from the ImKTx96 precursor nucleotide sequence contains a signal peptide of 27 amino acid residues and a mature peptide of 29 residues with three disulfide bridges. Multiple sequence alignment indicated that ImKTx96 is similar with the scorpion toxins that typically target K+-channels. The recombined ImKTx96 peptide (rImKTx96) was expressed in the Escherichia coli system, and purified by GST-affinity chromatography and RP-HPLC. Results from whole-cell patch-clamp experiments revealed that rImKTx96 can inhibit the current of the Kv1.2 ion channel expressed in HEK293 cells. The 3D structure of ImKTx96 was constructed by molecular modeling, and the complex formed by ImKTx96 interacting with the Kv1.2 ion channel was obtained by molecular docking. Based on its structural features and pharmacological functions, ImKTx96 was identified as one member of K+-channel scorpion toxin α-KTx10 group and may be useful as a molecular probe for investigating the structure and function of the Kv1.2 ion channel.
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Affiliation(s)
- Sipian Li
- Department of Biochemistry, School of Basic Medical Sciences, Wuhan University, Wuhan 430071, PR China
| | - Shuwen Sunchen
- Department of Biochemistry, School of Basic Medical Sciences, Wuhan University, Wuhan 430071, PR China
| | - Dangui He
- State Key Laboratory of Virology, Renmin Hospital, Wuhan University, Wuhan 430072, PR China
| | - Chenhu Qin
- State Key Laboratory of Virology, Renmin Hospital, Wuhan University, Wuhan 430072, PR China
| | - Zheng Zuo
- State Key Laboratory of Virology, Renmin Hospital, Wuhan University, Wuhan 430072, PR China
| | - Bingzheng Shen
- State Key Laboratory of Virology, Renmin Hospital, Wuhan University, Wuhan 430072, PR China
| | - Zhijian Cao
- State Key Laboratory of Virology, Renmin Hospital, Wuhan University, Wuhan 430072, PR China; Hubei Province Engineering and Technology Research, Center for Fluorinated Pharmaceuticals, Wuhan University, Wuhan 430072, PR China
| | - Wei Hong
- State Key Laboratory of Virology, Renmin Hospital, Wuhan University, Wuhan 430072, PR China.
| | - Lixia Miao
- Department of Biochemistry, School of Basic Medical Sciences, Wuhan University, Wuhan 430071, PR China.
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12
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B Orts DJ, Peigneur S, Silva-Gonçalves LC, Arcisio-Miranda M, P W Bicudo JE, Tytgat J. AbeTx1 Is a Novel Sea Anemone Toxin with a Dual Mechanism of Action on Shaker-Type K⁺ Channels Activation. Mar Drugs 2018; 16:md16100360. [PMID: 30275388 PMCID: PMC6213216 DOI: 10.3390/md16100360] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 09/25/2018] [Accepted: 09/29/2018] [Indexed: 12/19/2022] Open
Abstract
Voltage-gated potassium (KV) channels regulate diverse physiological processes and are an important target for developing novel therapeutic approaches. Sea anemone (Cnidaria, Anthozoa) venoms comprise a highly complex mixture of peptide toxins with diverse and selective pharmacology on KV channels. From the nematocysts of the sea anemone Actinia bermudensis, a peptide that we named AbeTx1 was purified and functionally characterized on 12 different subtypes of KV channels (KV1.1⁻KV1.6; KV2.1; KV3.1; KV4.2; KV4.3; KV11.1; and, Shaker IR), and three voltage-gated sodium channel isoforms (NaV1.2, NaV1.4, and BgNaV). AbeTx1 was selective for Shaker-related K⁺ channels and is capable of inhibiting K⁺ currents, not only by blocking the K⁺ current of KV1.2 subtype, but by altering the energetics of activation of KV1.1 and KV1.6. Moreover, experiments using six synthetic alanine point-mutated analogs further showed that a ring of basic amino acids acts as a multipoint interaction for the binding of the toxin to the channel. The AbeTx1 primary sequence is composed of 17 amino acids with a high proportion of lysines and arginines, including two disulfide bridges (Cys1⁻Cys4 and Cys2⁻Cys3), and it is devoid of aromatic or aliphatic amino acids. Secondary structure analysis reveals that AbeTx1 has a highly flexible, random-coil-like conformation, but with a tendency of structuring in the beta sheet. Its overall structure is similar to open-ended cyclic peptides found on the scorpion κ-KTx toxins family, cone snail venoms, and antimicrobial peptides.
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Affiliation(s)
- Diego J B Orts
- Department of Physiology, Institute of Biosciences, University of São Paulo, 05508-090 São Paulo, Brazil.
| | - Steve Peigneur
- Toxicology and Pharmacology, University of Leuven (KU Leuven), Campus Gasthuisberg O&N2, Herestraat 49, P.O. Box 922, 3000 Leuven, Belgium.
| | - Laíz Costa Silva-Gonçalves
- Laboratório de Neurobiologia Estrutural e Funcional (LaNEF), Departamento de Biofísica, Universidade Federal de São Paulo, 04023-062 São Paulo, Brazil.
| | - Manoel Arcisio-Miranda
- Laboratório de Neurobiologia Estrutural e Funcional (LaNEF), Departamento de Biofísica, Universidade Federal de São Paulo, 04023-062 São Paulo, Brazil.
| | - José Eduardo P W Bicudo
- Department of Physiology, Institute of Biosciences, University of São Paulo, 05508-090 São Paulo, Brazil.
| | - Jan Tytgat
- Toxicology and Pharmacology, University of Leuven (KU Leuven), Campus Gasthuisberg O&N2, Herestraat 49, P.O. Box 922, 3000 Leuven, Belgium.
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Aissaoui D, Mlayah-Bellalouna S, Jebali J, Abdelkafi-Koubaa Z, Souid S, Moslah W, Othman H, Luis J, ElAyeb M, Marrakchi N, Essafi-Benkhadir K, Srairi-Abid N. Functional role of Kv1.1 and Kv1.3 channels in the neoplastic progression steps of three cancer cell lines, elucidated by scorpion peptides. Int J Biol Macromol 2018; 111:1146-1155. [DOI: 10.1016/j.ijbiomac.2018.01.144] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 01/19/2018] [Accepted: 01/20/2018] [Indexed: 12/11/2022]
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14
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Venom-derived peptides inhibiting Kir channels: Past, present, and future. Neuropharmacology 2017; 127:161-172. [PMID: 28716449 DOI: 10.1016/j.neuropharm.2017.07.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 07/05/2017] [Accepted: 07/13/2017] [Indexed: 12/17/2022]
Abstract
Inwardly rectifying K+ (Kir) channels play a significant role in vertebrate and invertebrate biology by regulating the movement of K+ ions involved in membrane transport and excitability. Yet unlike other ion channels including their ancestral K+-selective homologs, there are very few venom toxins known to target and inhibit Kir channels with the potency and selectivity found for the Ca2+-activated and voltage-gated K+ channel families. It is unclear whether this is simply due to a lack of discovery, or instead a consequence of the evolutionary processes that drive the development of venom components towards their targets based on a collective efficacy to 1) elicit pain for defensive purposes, 2) promote paralysis for prey capture, or 3) facilitate delivery of venom components into the circulation. The past two decades of venom screening has yielded three venom peptides with inhibitory activity towards mammalian Kir channels, including the discovery of tertiapin, a high-affinity pore blocker from the venom of the European honey bee Apis mellifera. Venomics and structure-based computational approaches represent exciting new frontiers for venom peptide development, where re-engineering peptide 'scaffolds' such as tertiapin may aid in the quest to expand the palette of potent and selective Kir channel blockers for future research and potentially new therapeutics. This article is part of the Special Issue entitled 'Venom-derived Peptides as Pharmacological Tools.'
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15
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Olamendi-Portugal T, Csoti A, Jimenez-Vargas J, Gomez-Lagunas F, Panyi G, Possani L. Pi5 and Pi6, two undescribed peptides from the venom of the scorpion Pandinus imperator and their effects on K + -channels. Toxicon 2017; 133:136-144. [DOI: 10.1016/j.toxicon.2017.05.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 05/06/2017] [Accepted: 05/09/2017] [Indexed: 01/15/2023]
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16
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Zhang S, Gao B, Zhu S. Independent Origins of Scorpion Toxins Affecting Potassium and Sodium Channels. EVOLUTION OF VENOMOUS ANIMALS AND THEIR TOXINS 2017. [DOI: 10.1007/978-94-007-6458-3_12] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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17
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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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18
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Peigneur S, Yamaguchi Y, Kawano C, Nose T, Nirthanan S, Gopalakrishnakone P, Tytgat J, Sato K. Active Sites of Spinoxin, a Potassium Channel Scorpion Toxin, Elucidated by Systematic Alanine Scanning. Biochemistry 2016; 55:2927-35. [PMID: 27159046 DOI: 10.1021/acs.biochem.6b00139] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Peptide toxins from scorpion venoms constitute the largest group of toxins that target the voltage-gated potassium channel (Kv). Spinoxin (SPX) isolated from the venom of scorpion Heterometrus spinifer is a 34-residue peptide neurotoxin cross-linked by four disulfide bridges. SPX is a potent inhibitor of Kv1.3 potassium channels (IC50 = 63 nM), which are considered to be valid molecular targets in the diagnostics and therapy of various autoimmune disorders and cancers. Here we synthesized 25 analogues of SPX and analyzed the role of each amino acid in SPX using alanine scanning to study its structure-function relationships. All synthetic analogues showed similar disulfide bond pairings and secondary structures as native SPX. Alanine replacements at Lys(23), Asn(26), and Lys(30) resulted in loss of activity against Kv1.3 potassium channels, whereas replacements at Arg(7), Met(14), Lys(27), and Tyr(32) also largely reduced inhibitory activity. These results suggest that the side chains of these amino acids in SPX play an important role in its interaction with Kv1.3 channels. In particular, Lys(23) appears to be a key residue that underpins Kv1.3 channel inhibition. Of these seven amino acid residues, four are basic amino acids, suggesting that the positive electrostatic potential on the surface of SPX is likely required for high affinity interaction with Kv1.3 channels. This study provides insight into the structure-function relationships of SPX with implications for the rational design of new lead compounds targeting potassium channels with high potency.
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Affiliation(s)
- Steve Peigneur
- Toxicology and Pharmacology, University of Leuven , Campus Gasthuisberg O&N2, Herestraat 49, P.O. Box 922, Leuven 3000, Belgium
| | - Yoko Yamaguchi
- Department of Environment Sciences, Fukuoka Women's University , Fukuoka 813-8529, Japan
| | - Chihiro Kawano
- Department of Environment Sciences, Fukuoka Women's University , Fukuoka 813-8529, Japan
| | - Takeru Nose
- Faculty of Arts and Science, Kyushu University , Fukuoka, 819-0395, Japan
| | | | - Ponnampalam Gopalakrishnakone
- Venom and Toxin Research Program, Yong Loo Lin School of Medicine, National University of Singapore , Singapore 117597, Singapore
| | - Jan Tytgat
- Toxicology and Pharmacology, University of Leuven , Campus Gasthuisberg O&N2, Herestraat 49, P.O. Box 922, Leuven 3000, Belgium
| | - Kazuki Sato
- Department of Environment Sciences, Fukuoka Women's University , Fukuoka 813-8529, Japan
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19
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Kuzmenkov AI, Krylov NA, Chugunov AO, Grishin EV, Vassilevski AA. Kalium: a database of potassium channel toxins from scorpion venom. DATABASE-THE JOURNAL OF BIOLOGICAL DATABASES AND CURATION 2016; 2016:baw056. [PMID: 27087309 PMCID: PMC4834203 DOI: 10.1093/database/baw056] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 03/20/2016] [Indexed: 12/16/2022]
Abstract
Kalium (http://kaliumdb.org/) is a manually curated database that accumulates data on potassium channel toxins purified from scorpion venom (KTx). This database is an open-access resource, and provides easy access to pages of other databases of interest, such as UniProt, PDB, NCBI Taxonomy Browser, and PubMed. General achievements of Kalium are a strict and easy regulation of KTx classification based on the unified nomenclature supported by researchers in the field, removal of peptides with partial sequence and entries supported by transcriptomic information only, classification of β-family toxins, and addition of a novel λ-family. Molecules presented in the database can be processed by the Clustal Omega server using a one-click option. Molecular masses of mature peptides are calculated and available activity data are compiled for all KTx. We believe that Kalium is not only of high interest to professional toxinologists, but also of general utility to the scientific community. Database URL: http://kaliumdb.org/
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Affiliation(s)
- Alexey I Kuzmenkov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia
| | - Nikolay A Krylov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia Joint Supercomputer Center, Russian Academy of Sciences, Moscow 119991, Russia
| | - Anton O Chugunov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia
| | - Eugene V Grishin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia
| | - Alexander A Vassilevski
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia
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20
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Novoseletsky VN, Volyntseva AD, Shaitan KV, Kirpichnikov MP, Feofanov AV. Modeling of the Binding of Peptide Blockers to Voltage-Gated Potassium Channels: Approaches and Evidence. Acta Naturae 2016; 8:35-46. [PMID: 27437138 PMCID: PMC4947987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Indexed: 11/13/2022] Open
Abstract
Modeling of the structure of voltage-gated potassium (KV) channels bound to peptide blockers aims to identify the key amino acid residues dictating affinity and provide insights into the toxin-channel interface. Computational approaches open up possibilities for in silico rational design of selective blockers, new molecular tools to study the cellular distribution and functional roles of potassium channels. It is anticipated that optimized blockers will advance the development of drugs that reduce over activation of potassium channels and attenuate the associated malfunction. Starting with an overview of the recent advances in computational simulation strategies to predict the bound state orientations of peptide pore blockers relative to KV-channels, we go on to review algorithms for the analysis of intermolecular interactions, and then take a look at the results of their application.
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Affiliation(s)
- V. N. Novoseletsky
- M.V.Lomonosov Moscow State University, Faculty of Biology, Leninskie Gory 1, bldg. 12, 119992 , Moscow, Russia
| | - A. D. Volyntseva
- M.V.Lomonosov Moscow State University, Faculty of Biology, Leninskie Gory 1, bldg. 12, 119992 , Moscow, Russia
| | - K. V. Shaitan
- M.V.Lomonosov Moscow State University, Faculty of Biology, Leninskie Gory 1, bldg. 12, 119992 , Moscow, Russia
| | - M. P. Kirpichnikov
- M.V.Lomonosov Moscow State University, Faculty of Biology, Leninskie Gory 1, bldg. 12, 119992 , Moscow, Russia
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho- Maklaya str. 16/10, 117997, Moscow, Russia
| | - A. V. Feofanov
- M.V.Lomonosov Moscow State University, Faculty of Biology, Leninskie Gory 1, bldg. 12, 119992 , Moscow, Russia
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho- Maklaya str. 16/10, 117997, Moscow, Russia
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Kuzmenkov AI, Grishin EV, Vassilevski AA. Diversity of Potassium Channel Ligands: Focus on Scorpion Toxins. BIOCHEMISTRY (MOSCOW) 2016; 80:1764-99. [DOI: 10.1134/s0006297915130118] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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22
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Bartok A, Fehér K, Bodor A, Rákosi K, Tóth GK, Kövér KE, Panyi G, Varga Z. An engineered scorpion toxin analogue with improved Kv1.3 selectivity displays reduced conformational flexibility. Sci Rep 2015; 5:18397. [PMID: 26689143 PMCID: PMC4686915 DOI: 10.1038/srep18397] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 11/04/2015] [Indexed: 12/11/2022] Open
Abstract
The voltage-gated Kv1.3 K+ channel plays a key role in the activation of T lymphocytes. Kv1.3 blockers selectively suppress immune responses mediated by effector memory T cells, which indicates the great potential of selective Kv1.3 inhibitors in the therapy of certain autoimmune diseases. Anuroctoxin (AnTx), a 35-amino-acid scorpion toxin is a high affinity blocker of Kv1.3, but also blocks Kv1.2 with similar potency. We designed and produced three AnTx variants: ([F32T]-AnTx, [N17A]-AnTx, [N17A/F32T]-AnTx) using solid-phase synthesis with the goal of improving the selectivity of the toxin for Kv1.3 over Kv1.2 while keeping the high affinity for Kv1.3. We used the patch-clamp technique to determine the blocking potency of the synthetic toxins on hKv1.3, mKv1.1, hKv1.2 and hKCa3.1 channels. Of the three variants [N17A/F32T]-AnTx maintained the high affinity of the natural peptide for Kv1.3 but became more than 16000-fold selective over Kv1.2. NMR data and molecular dynamics simulations suggest that the more rigid structure with restricted conformational space of the double substituted toxin compared to the flexible wild-type one is an important determinant of toxin selectivity. Our results provide the foundation for the possibility of the production and future therapeutic application of additional, even more selective toxins targeting various ion channels.
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Affiliation(s)
- Adam Bartok
- Department of Biophysics and Cell Biology, University of Debrecen, Egyetem tér 1, Debrecen, H-4012, Hungary
| | - Krisztina Fehér
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem tér 1, Debrecen, H-4032, Hungary.,Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, Belgium
| | - Andrea Bodor
- Laboratory of Structural Chemistry and Biology, Institute of Chemistry, Eötvös Loránd University, Pázmány Péter sétány 1/A, Budapest, H-1117, Hungary
| | - Kinga Rákosi
- Department of Medical Chemistry, University of Szeged, Dóm tér 8, Szeged, H-6720, Hungary
| | - Gábor K Tóth
- Department of Medical Chemistry, University of Szeged, Dóm tér 8, Szeged, H-6720, Hungary
| | - Katalin E Kövér
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem tér 1, Debrecen, H-4032, Hungary
| | - Gyorgy Panyi
- Department of Biophysics and Cell Biology, University of Debrecen, Egyetem tér 1, Debrecen, H-4012, Hungary.,MTA-DE Cell Biology and Signaling Research Group, University of Debrecen, Debrecen, Egyetem tér 1, H-4032, Hungary
| | - Zoltan Varga
- MTA-DE-NAP B Ion Channel Structure-Function Research Group, RCMM, University of Debrecen, Debrecen, Egyetem tér 1, H-4032, Hungary.,Department of Biophysics and Cell Biology, University of Debrecen, Egyetem tér 1, Debrecen, H-4012, Hungary
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23
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Nikouee A, Khabiri M, Cwiklik L. Scorpion toxins prefer salt solutions. J Mol Model 2015; 21:287. [PMID: 26475740 DOI: 10.1007/s00894-015-2822-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 09/15/2015] [Indexed: 11/26/2022]
Abstract
There is a wide variety of ion channel types with various types of blockers, making research in this field very complicated. To reduce this complexity, it is essential to study ion channels and their blockers independently. Scorpion toxins, a major class of blockers, are charged short peptides with high affinities for potassium channels. Their high selectivity and inhibitory properties make them an important pharmacological tool for treating autoimmune or nervous system disorders. Scorpion toxins typically have highly charged surfaces and-like other proteins-an intrinsic ability to bind ions (Friedman J Phys Chem B 115(29):9213-9223, 1996; Baldwin Biophys J 71(4):2056-2063, 1996; Vrbka et al. Proc Natl Acad Sci USA 103(42):15440-15444, 2006a; Vrbka et al. J Phys Chem B 110(13):7036-43, 2006b). Thus, their effects on potassium channels are usually investigated in various ionic solutions. In this work, computer simulations of protein structures were performed to analyze the structural properties of the key residues (i.e., those that are presumably involved in contact with the surfaces of the ion channels) of 12 scorpion toxins. The presence of the two most physiologically abundant cations, Na(+) and K(+), was considered. The results indicated that the ion-binding properties of the toxin residues vary. Overall, all of the investigated toxins had more stable structures in ionic solutions than in water. We found that both the number and length of elements in the secondary structure varied depending on the ionic solution used (i.e., in the presence of NaCl or KCl). This study revealed that the ionic solution should be chosen carefully before performing experiments on these toxins. Similarly, the influence of these ions should be taken into consideration in the design of toxin-based pharmaceuticals.
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Affiliation(s)
- Azadeh Nikouee
- Institute of Applied Physiology, Ulm University, Ulm, Germany
| | - Morteza Khabiri
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 16610, Prague 6, Czech Republic.
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA.
| | - Lukasz Cwiklik
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 16610, Prague 6, Czech Republic
- J. Heyrovský Institute of Physical Chemistry Academy of Sciences of the Czech Republic v.v.i., Dolejskova 3, 18223, Prague 8, Czech Republic
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24
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A computational design approach for virtual screening of peptide interactions across K(+) channel families. Comput Struct Biotechnol J 2014; 13:85-94. [PMID: 25709757 PMCID: PMC4334993 DOI: 10.1016/j.csbj.2014.11.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 10/30/2014] [Accepted: 11/03/2014] [Indexed: 11/25/2022] Open
Abstract
Ion channels represent a large family of membrane proteins with many being well established targets in pharmacotherapy. The ‘druggability’ of heteromeric channels comprised of different subunits remains obscure, due largely to a lack of channel-specific probes necessary to delineate their therapeutic potential in vivo. Our initial studies reported here, investigated the family of inwardly rectifying potassium (Kir) channels given the availability of high resolution crystal structures for the eukaryotic constitutively active Kir2.2 channel. We describe a ‘limited’ homology modeling approach that can yield chimeric Kir channels having an outer vestibule structure representing nearly any known vertebrate or invertebrate channel. These computationally-derived channel structures were tested ""in silico for ‘docking’ to NMR structures of tertiapin (TPN), a 21 amino acid peptide found in bee venom. TPN is a highly selective and potent blocker for the epithelial rat Kir1.1 channel, but does not block human or zebrafish Kir1.1 channel isoforms. Our Kir1.1 channel-TPN docking experiments recapitulated published in vitro ""findings for TPN-sensitive and TPN-insensitive channels. Additionally, in silico site-directed mutagenesis identified ‘hot spots’ within the channel outer vestibule that mediate energetically favorable docking scores and correlate with sites previously identified with in vitro thermodynamic mutant-cycle analysis. These ‘proof-of-principle’ results establish a framework for virtual screening of re-engineered peptide toxins for interactions with computationally derived Kir channels that currently lack channel-specific blockers. When coupled with electrophysiological validation, this virtual screening approach may accelerate the drug discovery process, and can be readily applied to other ion channels families where high resolution structures are available.
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25
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Luna-Ramírez K, Bartok A, Restano-Cassulini R, Quintero-Hernández V, Coronas FIV, Christensen J, Wright CE, Panyi G, Possani LD. Structure, Molecular Modeling, and Function of the Novel Potassium Channel Blocker Urotoxin Isolated from the Venom of the Australian Scorpion Urodacus yaschenkoi. Mol Pharmacol 2014; 86:28-41. [DOI: 10.1124/mol.113.090183] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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26
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Berkut AA, Usmanova DR, Peigneur S, Oparin PB, Mineev KS, Odintsova TI, Tytgat J, Arseniev AS, Grishin EV, Vassilevski AA. Structural similarity between defense peptide from wheat and scorpion neurotoxin permits rational functional design. J Biol Chem 2014; 289:14331-40. [PMID: 24671422 DOI: 10.1074/jbc.m113.530477] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
In this study, we present the spatial structure of the wheat antimicrobial peptide (AMP) Tk-AMP-X2 studied using NMR spectroscopy. This peptide was found to adopt a disulfide-stabilized α-helical hairpin fold and therefore belongs to the α-hairpinin family of plant defense peptides. Based on Tk-AMP-X2 structural similarity to cone snail and scorpion potassium channel blockers, a mutant molecule, Tk-hefu, was engineered by incorporating the functionally important residues from κ-hefutoxin 1 onto the Tk-AMP-X2 scaffold. The designed peptide contained the so-called essential dyad of amino acid residues significant for channel-blocking activity. Electrophysiological studies showed that although the parent peptide Tk-AMP-X2 did not present any activity against potassium channels, Tk-hefu blocked Kv1.3 channels with similar potency (IC50 ∼ 35 μm) to κ-hefutoxin 1 (IC50 ∼ 40 μm). We conclude that α-hairpinins are attractive in their simplicity as structural templates, which may be used for functional engineering and drug design.
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Affiliation(s)
- Antonina A Berkut
- From the M. M. Shemyakin and Yu. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia, Moscow Institute of Physics and Technology (State University), Moscow 117303, Russia
| | - Dinara R Usmanova
- From the M. M. Shemyakin and Yu. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia, Moscow Institute of Physics and Technology (State University), Moscow 117303, Russia
| | - Steve Peigneur
- Laboratory of Toxicology and Pharmacology, University of Leuven, Leuven 3000, Belgium, and
| | - Peter B Oparin
- From the M. M. Shemyakin and Yu. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia
| | - Konstantin S Mineev
- From the M. M. Shemyakin and Yu. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia
| | - Tatyana I Odintsova
- N. I. Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow 119991, Russia
| | - Jan Tytgat
- Laboratory of Toxicology and Pharmacology, University of Leuven, Leuven 3000, Belgium, and
| | - Alexander S Arseniev
- From the M. M. Shemyakin and Yu. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia
| | - Eugene V Grishin
- From the M. M. Shemyakin and Yu. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia
| | - Alexander A Vassilevski
- From the M. M. Shemyakin and Yu. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia,
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Electrophysiological characterization of Ts6 and Ts7, K⁺ channel toxins isolated through an improved Tityus serrulatus venom purification procedure. Toxins (Basel) 2014; 6:892-913. [PMID: 24590385 PMCID: PMC3968367 DOI: 10.3390/toxins6030892] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 01/24/2014] [Accepted: 02/17/2014] [Indexed: 01/09/2023] Open
Abstract
In Brazil, Tityus serrulatus (Ts) is the species responsible for most of the scorpion related accidents. Among the Ts toxins, the neurotoxins with action on potassium channels (α-KTx) present high interest, due to their effect in the envenoming process and the ion channel specificity they display. The α-KTx toxins family is the most relevant because its toxins can be used as therapeutic tools for specific target cells. The improved isolation method provided toxins with high resolution, obtaining pure Ts6 and Ts7 in two chromatographic steps. The effects of Ts6 and Ts7 toxins were evaluated in 14 different types of potassium channels using the voltage-clamp technique with two-microelectrodes. Ts6 toxin shows high affinity for Kv1.2, Kv1.3 and Shaker IR, blocking these channels in low concentrations. Moreover, Ts6 blocks the Kv1.3 channel in picomolar concentrations with an IC50 of 0.55 nM and therefore could be of valuable assistance to further designing immunosuppressive therapeutics. Ts7 toxin blocks multiple subtypes channels, showing low selectivity among the channels analyzed. This work also stands out in its attempt to elucidate the residues important for interacting with each channel and, in the near future, to model a desired drug.
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28
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Yang W, Feng J, Wang B, Cao Z, Li W, Wu Y, Chen Z. BF9, the first functionally characterized snake toxin peptide with Kunitz-type protease and potassium channel inhibiting properties. J Biochem Mol Toxicol 2013; 28:76-83. [PMID: 24243656 DOI: 10.1002/jbt.21538] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2013] [Revised: 10/16/2013] [Indexed: 12/14/2022]
Abstract
Although numerous Kunitz-type toxins were isolated from snake venom, no bifunctional Kunitz-type snake toxins with protease and potassium channel inhibiting properties have been reported till now. With the help of bioinformatics analyses and biological experiments, we characterized Kunitz-type snake toxin BF9 as a bifunctional peptide. Enzyme and inhibitor reaction kinetics experiments showed that BF9 inhibited α-chymotrypsin with Ki value of 1.8 × 10⁻⁸ M. Electrophysiological experiments showed that BF9 inhibited the Kv1.3 potassium channel with an IC₅₀ of 120.0 nM, which demonstrated that serine protease inhibitor BF9 could also inhibit potassium channels. In addition, the key amino acids of BF9 responsible for the unique bifunctional mechanism are further investigated. To the best of our knowledge, BF9 is the first Kunitz-type snake peptide with the unique bifunctionality of potassium channel and serine protease inhibiting properties, providing novel insights into divergent evolution and functional applications of snake Kunitz-type peptides.
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Affiliation(s)
- Weishan Yang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, People's Republic of China
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29
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Orts DJB, Moran Y, Cologna CT, Peigneur S, Madio B, Praher D, Quinton L, De Pauw E, Bicudo JEPW, Tytgat J, de Freitas JC. BcsTx3 is a founder of a novel sea anemone toxin family of potassium channel blocker. FEBS J 2013; 280:4839-52. [PMID: 23895459 DOI: 10.1111/febs.12456] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 07/17/2013] [Accepted: 07/24/2013] [Indexed: 12/29/2022]
Abstract
Sea anemone venoms have become a rich source of peptide toxins which are invaluable tools for studying the structure and functions of ion channels. In this work, BcsTx3, a toxin found in the venom of a Bunodosoma caissarum (population captured at the Saint Peter and Saint Paul Archipelago, Brazil) was purified and biochemically and pharmacologically characterized. The pharmacological effects were studied on 12 different subtypes of voltage-gated potassium channels (K(V)1.1-K(V)1.6; K(V)2.1; K(V)3.1; K(V)4.2; K(V)4.3; hERG and Shaker IR) and three cloned voltage-gated sodium channel isoforms (Na(V)1.2, Na(V)1.4 and BgNa(V)1.1) expressed in Xenopus laevis oocytes. BcsTx3 shows a high affinity for Drosophila Shaker IR channels over rKv1.2, hKv1.3 and rKv1.6, and is not active on NaV channels. Biochemical characterization reveals that BcsTx3 is a 50 amino acid peptide crosslinked by four disulfide bridges, and sequence comparison allowed BcsTx3 to be classified as a novel type of sea anemone toxin acting on K(V) channels. Moreover, putative toxins homologous to BcsTx3 from two additional actiniarian species suggest an ancient origin of this newly discovered toxin family.
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Affiliation(s)
- Diego J B Orts
- Department of Physiology, Institute of Biosciences, University of São Paulo, Brazil
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30
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Ali SA, Alam M, Abbasi A, Kalbacher H, Schaechinger TJ, Hu Y, Zhijian C, Li W, Voelter W. Structure–Activity Relationship of a Highly Selective Peptidyl Inhibitor of Kv1.3 Voltage-Gated K+-Channel from Scorpion (B. sindicus) Venom. Int J Pept Res Ther 2013. [DOI: 10.1007/s10989-013-9362-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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31
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Orts DJB, Peigneur S, Madio B, Cassoli JS, Montandon GG, Pimenta AMC, Bicudo JEPW, Freitas JC, Zaharenko AJ, Tytgat J. Biochemical and electrophysiological characterization of two sea anemone type 1 potassium toxins from a geographically distant population of Bunodosoma caissarum. Mar Drugs 2013; 11:655-79. [PMID: 23466933 PMCID: PMC3705364 DOI: 10.3390/md11030655] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 01/23/2013] [Accepted: 02/15/2013] [Indexed: 12/12/2022] Open
Abstract
Sea anemone (Cnidaria, Anthozoa) venom is an important source of bioactive compounds used as tools to study the pharmacology and structure-function of voltage-gated K+ channels (KV). These neurotoxins can be divided into four different types, according to their structure and mode of action. In this work, for the first time, two toxins were purified from the venom of Bunodosoma caissarum population from Saint Peter and Saint Paul Archipelago, Brazil. Sequence alignment and phylogenetic analysis reveals that BcsTx1 and BcsTx2 are the newest members of the sea anemone type 1 potassium channel toxins. Their functional characterization was performed by means of a wide electrophysiological screening on 12 different subtypes of KV channels (KV1.1-KV1.6; KV2.1; KV3.1; KV4.2; KV4.3; hERG and Shaker IR). BcsTx1 shows a high affinity for rKv1.2 over rKv1.6, hKv1.3, Shaker IR and rKv1.1, while Bcstx2 potently blocked rKv1.6 over hKv1.3, rKv1.1, Shaker IR and rKv1.2. Furthermore, we also report for the first time a venom composition and biological activity comparison between two geographically distant populations of sea anemones.
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Affiliation(s)
- Diego J. B. Orts
- Department of Physiology, Institute of Biosciences, University of São Paulo, São Paulo, SP, 05508-090, Brazil; E-Mails: (D.J.B.O.); (B.M.); (J.E.P.W.B.); (J.C.F.)
- Center of Marine Biology, University of São Paulo, São Sebastião, SP, 11600-000, Brazil
| | - Steve Peigneur
- Laboratory of Toxicology, University of Leuven (K.U. Leuven), Campus Gasthuisberg O&N2, Herestraat 49, P.O. Box 922, 3000 Leuven, Belgium; E-Mail:
| | - Bruno Madio
- Department of Physiology, Institute of Biosciences, University of São Paulo, São Paulo, SP, 05508-090, Brazil; E-Mails: (D.J.B.O.); (B.M.); (J.E.P.W.B.); (J.C.F.)
| | - Juliana S. Cassoli
- Laboratory of Venoms and Animals Toxins, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, 31270-901, Brazil; E-Mails: (J.S.C.); (G.G.M.); (A.M.C.P.)
| | - Gabriela G. Montandon
- Laboratory of Venoms and Animals Toxins, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, 31270-901, Brazil; E-Mails: (J.S.C.); (G.G.M.); (A.M.C.P.)
| | - Adriano M. C. Pimenta
- Laboratory of Venoms and Animals Toxins, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, 31270-901, Brazil; E-Mails: (J.S.C.); (G.G.M.); (A.M.C.P.)
| | - José E. P. W. Bicudo
- Department of Physiology, Institute of Biosciences, University of São Paulo, São Paulo, SP, 05508-090, Brazil; E-Mails: (D.J.B.O.); (B.M.); (J.E.P.W.B.); (J.C.F.)
| | - José C. Freitas
- Department of Physiology, Institute of Biosciences, University of São Paulo, São Paulo, SP, 05508-090, Brazil; E-Mails: (D.J.B.O.); (B.M.); (J.E.P.W.B.); (J.C.F.)
| | - André J. Zaharenko
- Laboratorio de Genetica, Instituto Butantan, São Paulo, SP, 05503-900, Brazil
| | - Jan Tytgat
- Laboratory of Toxicology, University of Leuven (K.U. Leuven), Campus Gasthuisberg O&N2, Herestraat 49, P.O. Box 922, 3000 Leuven, Belgium; E-Mail:
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Almeida DD, Torres TM, Barbosa EG, Lima JPMS, de Freitas Fernandes-Pedrosa M. Molecular approaches for structural characterization of a new potassium channel blocker from Tityus stigmurus venom: cDNA cloning, homology modeling, dynamic simulations and docking. Biochem Biophys Res Commun 2012. [PMID: 23200836 DOI: 10.1016/j.bbrc.2012.11.044] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Potassium channels are involved in the maintenance of resting membrane potential, control of cardiac and neuronal excitability, neurotransmitters release, muscle contractility and hormone secretion. The Tityus stigmurus scorpion is widely distributed in Northeastern Brazil and known to cause severe human envenomations, inducing pain, hypoesthesia, edema, erythema, paresthesia, headaches and vomiting. Most potassium channel blocking peptides that have been purified from scorpion venoms contain 30-40 amino acids with three or four disulfide bridges. These peptides belong to α-KTx subfamily. On the other hand, the β-KTx subfamily is poorly characterized, though it is very representative in some scorpion venoms. A transcriptomic approach of T.stigmurus scorpions developed by our group revealed the repertoire of possible molecules present in the venom, including many toxins of the β-KTx subfamily. One of the ESTs found, named TSTI0003C has a cDNA sequence of 538 bp codifying a mature protein with 47 amino acid residues, corresponding to 5299 Da. This β-KTx peptide is a new member of the BmTXKβ-related toxins, and was here named TstKMK. The three-dimensional structure of this potassium channel toxin of the T. stigmurus scorpion was obtained by computational modeling and refined by molecular dynamic simulations. Furthermore, we have made docking simulations using a Shaker kV-1.2 potassium channel from rats as receptor model and proposed which amino acid residues and interactions could be involved in its blockade.
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Affiliation(s)
- Diego Dantas Almeida
- Laboratório de Tecnologia e Biotecnologia Farmacêutica, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil
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Stehling EG, Sforça ML, Zanchin NIT, Oyama S, Pignatelli A, Belluzzi O, Polverini E, Corsini R, Spisni A, Pertinhez TA. Looking over toxin-K(+) channel interactions. Clues from the structural and functional characterization of α-KTx toxin Tc32, a Kv1.3 channel blocker. Biochemistry 2012; 51:1885-94. [PMID: 22332965 DOI: 10.1021/bi201713z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
α-KTx toxin Tc32, from the Amazonian scorpion Tityus cambridgei, lacks the dyad motif, including Lys27, characteristic of the family and generally associated with channel blockage. The toxin has been cloned and expressed for the first time. Electrophysiological experiments, by showing that the recombinant form blocks Kv1.3 channels of olfactory bulb periglomerular cells like the natural Tc32 toxin, when tested on the Kv1.3 channel of human T lymphocytes, confirmed it is in an active fold. The nuclear magnetic resonance-derived structure revealed it exhibits an α/β scaffold typical of the members of the α-KTx family. TdK2 and TdK3, all belonging to the same α-KTx 18 subfamily, share significant sequence identity with Tc32 but diverse selectivity and affinity for Kv1.3 and Kv1.1 channels. To gain insight into the structural features that may justify those differences, we used the recombinant Tc32 nuclear magnetic resonance-derived structure to model the other two toxins, for which no experimental structure is available. Their interaction with Kv1.3 and Kv1.1 has been investigated by means of docking simulations. The results suggest that differences in the electrostatic features of the toxins and channels, in their contact surfaces, and in their total dipole moment orientations govern the affinity and selectivity of toxins. In addition, we found that, regardless of whether the dyad motif is present, it is always a Lys side chain that physically blocks the channels, irrespective of its position in the toxin sequence.
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Affiliation(s)
- Eliana G Stehling
- Department of Toxicological and Bromatologic Clinical Analyses, Faculty of Pharmaceutical Sciences of Ribeirão Preto, USP, Ribeirão Preto, Brazil
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34
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Chen ZY, Hu YT, Yang WS, He YW, Feng J, Wang B, Zhao RM, Ding JP, Cao ZJ, Li WX, Wu YL. Hg1, novel peptide inhibitor specific for Kv1.3 channels from first scorpion Kunitz-type potassium channel toxin family. J Biol Chem 2012; 287:13813-21. [PMID: 22354971 DOI: 10.1074/jbc.m112.343996] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The potassium channel Kv1.3 is an attractive pharmacological target for autoimmune diseases. Specific peptide inhibitors are key prospects for diagnosing and treating these diseases. Here, we identified the first scorpion Kunitz-type potassium channel toxin family with three groups and seven members. In addition to their function as trypsin inhibitors with dissociation constants of 140 nM for recombinant LmKTT-1a, 160 nM for LmKTT-1b, 124 nM for LmKTT-1c, 136 nM for BmKTT-1, 420 nM for BmKTT-2, 760 nM for BmKTT-3, and 107 nM for Hg1, all seven recombinant scorpion Kunitz-type toxins could block the Kv1.3 channel. Electrophysiological experiments showed that six of seven scorpion toxins inhibited ~50-80% of Kv1.3 channel currents at a concentration of 1 μM. The exception was rBmKTT-3, which had weak activity. The IC(50) values of rBmKTT-1, rBmKTT-2, and rHg1 for Kv1.3 channels were ~129.7, 371.3, and 6.2 nM, respectively. Further pharmacological experiments indicated that rHg1 was a highly selective Kv1.3 channel inhibitor with weak affinity for other potassium channels. Different from classical Kunitz-type potassium channel toxins with N-terminal regions as the channel-interacting interfaces, the channel-interacting interface of Hg1 was in the C-terminal region. In conclusion, these findings describe the first scorpion Kunitz-type potassium channel toxin family, of which a novel inhibitor, Hg1, is specific for Kv1.3 channels. Their structural and functional diversity strongly suggest that Kunitz-type toxins are a new source to screen and design potential peptides for diagnosing and treating Kv1.3-mediated autoimmune diseases.
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Affiliation(s)
- Zong-Yun Chen
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan 430072, China
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35
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Zhu L, Gao B, Luo L, Zhu S. Two dyad-free Shaker-type K⁺ channel blockers from scorpion venom. Toxicon 2012; 59:402-7. [PMID: 22239942 DOI: 10.1016/j.toxicon.2011.11.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 11/14/2011] [Accepted: 11/15/2011] [Indexed: 11/27/2022]
Abstract
Most of scorpion toxins affecting voltage-gated K⁺ channels (KTxs) contain a functional dyad composed of a lysine and an aromatic amino acid separated by a suitable distance. By means of two-electrode voltage clamp technique, we describe functional characterization of two Mesobuthus martensii KTxs (BmP02 and BmP03) without the dyad. These two toxins differ by only one single residue at site 16 (K16N) but they display differential affinities on insect and mammalian Shaker-type K⁺ channels expressed in Xenopus oocytes. At 1 μM concentration, BmP02 and BmP03 inhibited currents of rK(v)1.1, rK(v)1.2, rK(v)1.3, and Shaker IR, but lacked detectable activity on rK(v)1.4. The half-inhibitory concentrations (IC₅₀) of BmP02 for rK(v)1.1, rK(v)1.2, rK(v)1.3 and Shaker IR channels are 1.95 μM, 4.40 μM, 7 nM and 20.44 μM, respectively. For BmP03, the corresponding IC₅₀ values for these channels are 5.48 μM, 530 nM, 85.4 nM, and 4.64 μM, respectively. Affinity variation (more than 10-fold) between BmP02 and BmP03 on rK(v)1.3 indicates functional importance of a cationic side chain at site 16. A pH-dependent experiment and a double mutant cycle analysis suggest that the residue K16 resides on the channel-facing surface of the toxin and within 5 Å of rK(v)1.3 position 401. These two toxins block rK(v)1.3 in a weak voltage-dependent manner and both slightly shift the current activation curve to positive potentials. Our work is thus crucial to further understanding structure-function relationship of KTxs without a functional dyad.
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Affiliation(s)
- Limei Zhu
- Group of Animal Innate Immunity, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, Beijing 100101, China
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Peigneur S, Billen B, Derua R, Waelkens E, Debaveye S, Béress L, Tytgat J. A bifunctional sea anemone peptide with Kunitz type protease and potassium channel inhibiting properties. Biochem Pharmacol 2011; 82:81-90. [PMID: 21477583 DOI: 10.1016/j.bcp.2011.03.023] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Revised: 03/24/2011] [Accepted: 03/25/2011] [Indexed: 12/17/2022]
Abstract
Sea anemone venom is a known source of interesting bioactive compounds, including peptide toxins which are invaluable tools for studying structure and function of voltage-gated potassium channels. APEKTx1 is a novel peptide isolated from the sea anemone Anthopleura elegantissima, containing 63 amino acids cross-linked by 3 disulfide bridges. Sequence alignment reveals that APEKTx1 is a new member of the type 2 sea anemone peptides targeting voltage-gated potassium channels (K(V)s), which also include the kalicludines from Anemonia sulcata. Similar to the kalicludines, APEKTx1 shares structural homology with both the basic pancreatic trypsin inhibitor (BPTI), a very potent Kunitz-type protease inhibitor, and dendrotoxins which are powerful blockers of voltage-gated potassium channels. In this study, APEKTx1 has been subjected to a screening on a wide range of 23 ion channels expressed in Xenopus laevis oocytes: 13 cloned voltage-gated potassium channels (K(V)1.1-K(V)1.6, K(V)1.1 triple mutant, K(V)2.1, K(V)3.1, K(V)4.2, K(V)4.3, hERG, the insect channel Shaker IR), 2 cloned hyperpolarization-activated cyclic nucleotide-sensitive cation non-selective channels (HCN1 and HCN2) and 8 cloned voltage-gated sodium channels (Na(V)1.2-Na(V)1.8 and the insect channel DmNa(V)1). Our data show that APEKTx1 selectively blocks K(V)1.1 channels in a very potent manner with an IC(50) value of 0.9nM. Furthermore, we compared the trypsin inhibitory activity of this toxin with BPTI. APEKTx1 inhibits trypsin with a dissociation constant of 124nM. In conclusion, this study demonstrates that APEKTx1 has the unique feature to combine the dual functionality of a potent and selective blocker of K(V)1.1 channels with that of a competitive inhibitor of trypsin.
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Affiliation(s)
- Steve Peigneur
- Laboratory of Toxicology, University of Leuven (K.U. Leuven), Campus Gasthuisberg O&N2, Herestraat, Belgium.
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Gao B, Peigneur S, Tytgat J, Zhu S. A potent potassium channel blocker from Mesobuthus eupeus scorpion venom. Biochimie 2010; 92:1847-53. [DOI: 10.1016/j.biochi.2010.08.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2010] [Revised: 07/24/2010] [Accepted: 08/06/2010] [Indexed: 10/19/2022]
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Peng C, Ye M, Wang Y, Shao X, Yuan D, Liu J, Hawrot E, Wang C, Chi C. A new subfamily of conotoxins belonging to the A-superfamily. Peptides 2010; 31:2009-16. [PMID: 20691232 PMCID: PMC3721517 DOI: 10.1016/j.peptides.2010.07.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Revised: 07/13/2010] [Accepted: 07/22/2010] [Indexed: 11/20/2022]
Abstract
Two novel conotoxins from vermivorous cone snails Conus pulicarius and Conus tessulatus, designated as Pu14.1 and ts14a, were identified by cDNA cloning and peptide purification, respectively. The signal sequence of Pu14.1 is identical to that of α-conotoxins, while its predicted mature peptide, pu14a, shares high sequence similarity with ts14a, with only one residue different in their first intercysteine loop, which contains 10 residues and is rich in proline. Both pu14a and ts14a contain four separate cysteines in framework 14 (C-C-C-C). Peptide pu14a was chemically synthesized, air oxidized, and the connectivity of its two disulfide bonds was determined to be C1-C3, C2-C4, which is the same as found in α-conotoxins. The synthetic pu14a induced a sleeping symptom in mice and was toxic to freshwater goldfish upon intramuscular injection. Using the Xenopus oocyte heterologous expression system, 1μM of pu14a demonstrated to inhibit the rat neuronal α3β2-containing as well as the mouse neuromuscular α1β1γδ subtypes of nicotinic acetylcholine receptors, and then rapidly dissociated from the receptors. However, this toxin had no inhibitory effect on potassium channels in mouse superior cervical ganglion neurons. According to the identical signal sequence to α-conotoxins, the unique cysteine framework and molecular target of pu14a, we propose that pu14a and ts14a may represent a novel subfamily in the A-superfamily, designated as α1-conotoxins.
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Affiliation(s)
- Can Peng
- Institute of Protein Research, Tongji University, Shanghai 200092, China
- Ministry of Education Key Laboratory of Systems Biomedicine, Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240, China
| | - Mingyu Ye
- Institute of Protein Research, Tongji University, Shanghai 200092, China
| | - Yanfang Wang
- Institute of Protein Research, Tongji University, Shanghai 200092, China
| | - Xiaoxia Shao
- Institute of Protein Research, Tongji University, Shanghai 200092, China
| | - Duoduo Yuan
- Institute of Protein Research, Tongji University, Shanghai 200092, China
| | - Jing Liu
- Department of Molecular Pharmacology, Physiology and Biotechnology, Brown Medical School, Providence, Rhode Island 02912, USA
| | - Edward Hawrot
- Department of Molecular Pharmacology, Physiology and Biotechnology, Brown Medical School, Providence, Rhode Island 02912, USA
| | - Chunguang Wang
- Institute of Protein Research, Tongji University, Shanghai 200092, China
- Corresponding author and address: Chengwu Chi, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China. Tel.: +86 21 54921165, Fax: +86 21 54921011, , Chunguang Wang, Institute of Protein Research, College of Life Sciences and Technology, Tongji University, 50 Chifeng Road, Shanghai 200092, China. Tel.: +86 21 65984347, Fax: +86 21 65988403,
| | - Chengwu Chi
- Institute of Protein Research, Tongji University, Shanghai 200092, China
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
- Corresponding author and address: Chengwu Chi, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China. Tel.: +86 21 54921165, Fax: +86 21 54921011, , Chunguang Wang, Institute of Protein Research, College of Life Sciences and Technology, Tongji University, 50 Chifeng Road, Shanghai 200092, China. Tel.: +86 21 65984347, Fax: +86 21 65988403,
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Aguilar MB, Pérez-Reyes LI, López Z, de la Cotera EPH, Falcón A, Ayala C, Galván M, Salvador C, Escobar LI. Peptide sr11a from Conus spurius is a novel peptide blocker for Kv1 potassium channels. Peptides 2010; 31:1287-91. [PMID: 20403399 DOI: 10.1016/j.peptides.2010.04.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2010] [Revised: 04/12/2010] [Accepted: 04/12/2010] [Indexed: 12/22/2022]
Abstract
More than a hundred conotoxins are known today and from them, only seven conopeptides have been identified to target voltage-gated potassium channels (Kv). Conotoxin sr11a belongs to the I(2)-superfamily which is characterized by four disulfide bridges and provokes muscle stiffness when injected intracranially in mice. The aim of this work was to test the biological activity of sr11a on recombinant voltage-gated Kv1 potassium channels expressed in Xenopus laevis oocytes. Peptide sr11a was purified by high-performance liquid chromatography from the venom of the vermivorous Conus spurius. We found that peptide sr11a inhibits the delayed rectifiers Kv1.2 and Kv1.6 but had not effect on the slowly inactivating Kv1.3 channel. The functional dyad composed of a basic Lys and a hydrophobic amino acid residue is a crucial structural element, regarding the binding properties and blocking activities of more than a hundred K(+) channel toxins. Peptide sr11a does not contain Lys residues and then, it lacks the functional dyad. Molecular modeling of peptide sr11a reveals the presence of exposed basic residues of Arg and suggests that Arg17 and Arg29 are important on its biological activity.
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Affiliation(s)
- Manuel B Aguilar
- Laboratorio de Neurofarmacología Marina, Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Campus Juriquilla, Querétaro 76230, Mexico
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Chagot B, Pimentel C, Dai L, Pil J, Tytgat J, Nakajima T, Corzo G, Darbon H, Ferrat G. An unusual fold for potassium channel blockers: NMR structure of three toxins from the scorpion Opisthacanthus madagascariensis. Biochem J 2009; 388:263-71. [PMID: 15631621 PMCID: PMC1186715 DOI: 10.1042/bj20041705] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The Om-toxins are short peptides (23-27 amino acids) purified from the venom of the scorpion Opisthacanthus madagascariensis. Their pharmacological targets are thought to be potassium channels. Like Csalpha/beta (cystine-stabilized alpha/beta) toxins, the Om-toxins alter the electrophysiological properties of these channels; however, they do not share any sequence similarity with other scorpion toxins. We herein demonstrate by electrophysiological experiments that Om-toxins decrease the amplitude of the K+ current of the rat channels Kv1.1 and Kv1.2, as well as human Kv1.3. We also determine the solution structure of three of the toxins by use of two-dimensional proton NMR techniques followed by distance geometry and molecular dynamics. The structures of these three peptides display an uncommon fold for ion-channel blockers, Csalpha/alpha (cystine-stabilized alpha-helix-loop-helix), i.e. two alpha-helices connected by a loop and stabilized by two disulphide bridges. We compare the structures obtained and the dipole moments resulting from the electrostatic anisotropy of these peptides with those of the only other toxin known to share the same fold, namely kappa-hefutoxin1.
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Affiliation(s)
- Benjamin Chagot
- *Architecture et Fonction des Macromolécules Biologiques, UMR 6098, CNRS et Universités d'Aix-Marseille I et II, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
| | - Cyril Pimentel
- *Architecture et Fonction des Macromolécules Biologiques, UMR 6098, CNRS et Universités d'Aix-Marseille I et II, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
| | - Li Dai
- †Department of Entomology, University of California, Riverside, Riverside, CA 92521, U.S.A
| | - Joost Pil
- ‡Laboratory of Toxicology, University of Leuven, E, Van Evenstraat 4, B-3000 Leuven, Belgium
| | - Jan Tytgat
- ‡Laboratory of Toxicology, University of Leuven, E, Van Evenstraat 4, B-3000 Leuven, Belgium
| | - Terumi Nakajima
- §Suntory Institute for Bioorganic Research, Mishima-Gun, Shimamoto-Cho, Wakayamadai 1-1-1, Osaka 618-8503, Japan
| | - Gerardo Corzo
- §Suntory Institute for Bioorganic Research, Mishima-Gun, Shimamoto-Cho, Wakayamadai 1-1-1, Osaka 618-8503, Japan
- ∥Department of Molecular Recognition and Structural Biology, Institute of Biotechnology, Av. Universidad, Cuernavaca, Morelos, Mexico
| | - Hervé Darbon
- *Architecture et Fonction des Macromolécules Biologiques, UMR 6098, CNRS et Universités d'Aix-Marseille I et II, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
- To whom correspondence should be addressed (email )
| | - Gilles Ferrat
- *Architecture et Fonction des Macromolécules Biologiques, UMR 6098, CNRS et Universités d'Aix-Marseille I et II, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
- §Suntory Institute for Bioorganic Research, Mishima-Gun, Shimamoto-Cho, Wakayamadai 1-1-1, Osaka 618-8503, Japan
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Corzo G, Papp F, Varga Z, Barraza O, Espino-Solis PG, Rodríguez de la Vega RC, Gaspar R, Panyi G, Possani LD. A selective blocker of Kv1.2 and Kv1.3 potassium channels from the venom of the scorpion Centruroides suffusus suffusus. Biochem Pharmacol 2008; 76:1142-54. [DOI: 10.1016/j.bcp.2008.08.018] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2008] [Revised: 07/29/2008] [Accepted: 08/04/2008] [Indexed: 11/30/2022]
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Wang F, Li H, Liu MN, Song H, Han HM, Wang QL, Yin CC, Zhou YC, Qi Z, Shu YY, Lin ZJ, Jiang T. Structural and functional analysis of natrin, a venom protein that targets various ion channels. Biochem Biophys Res Commun 2006; 351:443-8. [PMID: 17070778 DOI: 10.1016/j.bbrc.2006.10.067] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2006] [Accepted: 10/09/2006] [Indexed: 11/25/2022]
Abstract
Cysteine-rich secretory proteins (CRISPs) are secreted single-chain proteins found in different sources. Natrin is a member of the CRISP family purified from the snake venom of Naja naja atra, which has been reported as a BKca channel blocker. In our study, crystals of natrin were obtained in two different crystal forms and the structure of one of them was solved at a resolution of 1.68A. Our electrophysiological experiments indicated that natrin can block the ion channel currents of the voltage-gated potassium channel Kv1.3. Docking analyses of the interaction between natrin and Kv1.3 revealed a novel interaction pattern different from the two previously reported K(+) channel inhibition models termed "functional dyad" and "basic ring". These findings offered new insights into the function of natrin and how the specific interactions between CRISPs and different ion channels can be achieved.
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Affiliation(s)
- Feng Wang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101, China
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Judge SIV, Bever CT. Potassium channel blockers in multiple sclerosis: Neuronal Kv channels and effects of symptomatic treatment. Pharmacol Ther 2006; 111:224-59. [PMID: 16472864 DOI: 10.1016/j.pharmthera.2005.10.006] [Citation(s) in RCA: 200] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2005] [Accepted: 10/12/2005] [Indexed: 02/07/2023]
Abstract
Multiple sclerosis (MS) is an inflammatory disease of the central nervous system (CNS) characterized by demyelination, with a relative sparing of axons. In MS patients, many neurologic signs and symptoms have been attributed to the underlying conduction deficits. The idea that neurologic function might be improved if conduction could be restored in CNS demyelinated axons led to the testing of potassium (K(+)) channel blockers as a symptomatic treatment. To date, only 2 broad-spectrum K(+) channel blockers, 4-aminopyridine (4-AP) and 3,4-diaminopyridine (3,4-DAP), have been tested in MS patients. Although both 4-AP and 3,4-DAP produce clear neurologic benefits, their use has been limited by toxicity. Here we review the current status of basic science and clinical research related to the therapeutic targeting of voltage-gated K(+) channels (K(v)) in MS. By bringing together 3 distinct but interrelated disciplines, we aim to provide perspective on a vast body of work highlighting the lengthy and ongoing process entailed in translating fundamental K(v) channel knowledge into new clinical treatments for patients with MS and other demyelinating diseases. Covered are (1) K(v) channel nomenclature, structure, function, and pharmacology; (2) classic and current experimental morphology and neurophysiology studies of demyelination and conduction deficits; and (3) a comprehensive overview of clinical trials utilizing 4-AP and 3,4-DAP in MS patients.
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Affiliation(s)
- Susan I V Judge
- MS Center of Excellence-East, Research and Neurology Services, VA Maryland Health Care System, USA.
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Imperial JS, Bansal PS, Alewood PF, Daly NL, Craik DJ, Sporning A, Terlau H, López-Vera E, Bandyopadhyay PK, Olivera BM. A Novel Conotoxin Inhibitor of Kv1.6 Channel and nAChR Subtypes Defines a New Superfamily of Conotoxins,. Biochemistry 2006; 45:8331-40. [PMID: 16819832 DOI: 10.1021/bi060263r] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Using assay-directed fractionation of the venom from the vermivorous cone snail Conus planorbis, we isolated a new conotoxin, designated pl14a, with potent activity at both nicotinic acetylcholine receptors and a voltage-gated potassium channel subtype. pl14a contains 25 amino acid residues with an amidated C-terminus, an elongated N-terminal tail (six residues), and two disulfide bonds (1-3, 2-4 connectivity) in a novel framework distinct from other conotoxins. The peptide was chemically synthesized, and its three-dimensional structure was demonstrated to be well-defined, with an alpha-helix and two 3(10)-helices present. Analysis of a cDNA clone encoding the prepropeptide precursor of pl14a revealed a novel signal sequence, indicating that pl14a belongs to a new gene superfamily, the J-conotoxin superfamily. Five additional peptides in the J-superfamily were identified. Intracranial injection of pl14a in mice elicited excitatory symptoms that included shaking, rapid circling, barrel rolling, and seizures. Using the oocyte heterologous expression system, pl14a was shown to inhibit both a K+ channel subtype (Kv1.6, IC50 = 1.59 microM) and neuronal (IC50 = 8.7 microM for alpha3beta4) and neuromuscular (IC50 = 0.54 microM for alpha1beta1 epsilondelta) subtypes of the nicotinic acetylcholine receptor (nAChR). Similarities in sequence and structure are apparent between the middle loop of pl14a and the second loop of a number of alpha-conotoxins. This is the first conotoxin shown to affect the activity of both voltage-gated and ligand-gated ion channels.
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Affiliation(s)
- Julita S Imperial
- Department of Biology, University of Utah, Salt Lake City, Utah 84112, USA.
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Wang Y, Chen X, Zhang N, Wu G, Wu H. The solution structure of BmTx3B, a member of the scorpion toxin subfamily alpha-KTx 16. Proteins 2006; 58:489-97. [PMID: 15558557 DOI: 10.1002/prot.20322] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
This article reports the solution structure of BmTx3B (alpha-KTx16.2), a potassium channel blocker belonging to the subfamily alpha-KTx16, purified from the venom of the Chinese scorpion Buthus martensi Karsch. In solution, BmTx3B assumes a typical CSalphabeta motif, with an alpha-helix connected to a triple-stranded beta-sheet by 3 disulfide bridges, which belongs to the first structural group of short-chain scorpion toxins. On the other hand, BmTx3B is quite different from other toxins (such as ChTx and AgTx2) of this group in terms of the electrostatic and hydrophobic surface distribution. The functional surface (beta-face) of the molecule is characterized by less basic residues (only 2: Lys28 and Arg35) and extra aromatic residues (Phe1, Phe9, Trp15, and Tyr37). The peptide shows a great preference for the Kca1.1 channel over the Kv channel (about a 10(3)-fold difference). The model of BmTx3B/Kca1.1 channel complex generated by docking and dynamic simulation reveals that the stable binding between the BmTx3B and Kca1.1 channel is favored by a number of aromatic pi-pi stacking interactions. The influences of these structural features on the kinetic behavior of the toxin binding to Kca1.1 channel are also discussed.
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Affiliation(s)
- Yuefeng Wang
- State Key Laboratory of Bio-Organic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, PR China
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Carrega L, Mosbah A, Ferrat G, Beeton C, Andreotti N, Mansuelle P, Darbon H, De Waard M, Sabatier JM. The impact of the fourth disulfide bridge in scorpion toxins of the alpha-KTx6 subfamily. Proteins 2006; 61:1010-23. [PMID: 16247791 DOI: 10.1002/prot.20681] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Animal toxins are highly reticulated and structured polypeptides that adopt a limited number of folds. In scorpion species, the most represented fold is the alpha/beta scaffold in which an helical structure is connected to an antiparallel beta-sheet by two disulfide bridges. The intimate relationship existing between peptide reticulation and folding remains poorly understood. Here, we investigated the role of disulfide bridging on the 3D structure of HsTx1, a scorpion toxin potently active on Kv1.1 and Kv1.3 channels. This toxin folds along the classical alpha/beta scaffold but belongs to a unique family of short-chain, four disulfide-bridged toxins. Removal of the fourth disulfide bridge of HsTx1 does not affect its helical structure, whereas its two-stranded beta-sheet is altered from a twisted to a nontwisted configuration. This structural change in HsTx1 is accompanied by a marked decrease in Kv1.1 and Kv1.3 current blockage, and by alterations in the toxin to channel molecular contacts. In contrast, a similar removal of the fourth disulfide bridge of Pi1, another scorpion toxin from the same structural family, has no impact on its 3D structure, pharmacology, or channel interaction. These data highlight the importance of disulfide bridging in reaching the correct bioactive conformation of some toxins.
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Affiliation(s)
- Louis Carrega
- Laboratoire d'Ingénierie des Protéines, CNRS FRE 2738, IFR Jean Roche, Faculté de Médecine Nord, Marseille Cedex, France
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Möller C, Rahmankhah S, Lauer-Fields J, Bubis J, Fields GB, Marí F. A novel conotoxin framework with a helix-loop-helix (Cs alpha/alpha) fold. Biochemistry 2006; 44:15986-96. [PMID: 16331958 DOI: 10.1021/bi0511181] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Venomous predatory animals, such as snakes, spiders, scorpions, sea anemones, and cone snails, produce a variety of highly stable cystine-constrained peptide scaffolds as part of their neurochemical strategy for capturing prey. Here we report a new family of four-cystine, three-loop conotoxins (designated framework 14). Three peptides of this family (flf14a-c) were isolated from the venom of Conus floridanus floridensis, and one (vil14a) was isolated from the venom of Conus villepinii, two worm-hunting Western Atlantic cone snail species. The primary structure for these peptides was determined using Edman degradation sequencing, and their cystine pairing was assessed by limited hydrolysis with a combination of CNBr and chymotrypsin under nonreducing, nonalkylating conditions in combination with MALDI-TOF MS analysis of the resulting peptidic fragments. CD spectra and nanoNMR spectroscopy of these conotoxins directly isolated from the cone snails revealed a highly helical secondary structure for the four conotoxins. Sequence-specific nanoNMR analysis at room temperature revealed a well-defined helix-loop-helix tertiary structure that resembles that of the Cs alpha/alpha scorpion toxins kappa-hefutoxin, kappa-KTx1.3, and Om-toxins, which adopt a stable three-dimensional fold where the two alpha-helices are linked by the two disulfide bridges. One of these conotoxins (vil14a) has a Lys/Tyr dyad, separated by approximately 6A, which is a conserved structural feature in K(+) channel blockers. The presence of this framework in scorpions and in cone snails indicates a common molecular imprint in the venom of apparently unrelated predatory animals and suggests a common ancestral genetic origin.
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Affiliation(s)
- Carolina Möller
- Department of Chemistry and Biochemistry and Center of Excellence in Biomedical and Marine Biotechnology, Florida Atlantic University, Boca Raton, Florida 33431, USA
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48
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Abdel-Mottaleb Y, Coronas FV, de Roodt AR, Possani LD, Tytgat J. A novel toxin from the venom of the scorpionTityus trivittatus, is the first member of a new α-KTX subfamily. FEBS Lett 2006; 580:592-6. [PMID: 16405970 DOI: 10.1016/j.febslet.2005.12.073] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2005] [Accepted: 12/17/2005] [Indexed: 11/27/2022]
Abstract
The first example of a new sub-family of toxins (alpha-KTx20.1) from the scorpion Tityus trivittatus was purified, sequenced and characterized physiologically. It has 29 amino acid residues, three disulfide bridges assumed to adopt the cysteine-stabilized alpha/beta scaffold with a pI value of 8.98. The sequence identities with all the other known alpha-KTx are less than 40%. Its effects were verified using seven different cloned K(+) channels (vertebrate Kv1.1-1.5, Shaker IR and hERG) expressed in Xenopus leavis oocytes. The toxin-induced effects show large differences among the different K(+) channels and a preference towards Kv1.3 (EC50=7.9+/-1.4 nM).
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Affiliation(s)
- Yousra Abdel-Mottaleb
- Laboratory of Toxicology, University of Leuven, Onderwijs and Navorsing II, Herestraat 49, Postbus 922, 3000 Leuven, Belgium
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Tan PTJ, Ranganathan S, Brusic V. Deduction of functional peptide motifs in scorpion toxins. J Pept Sci 2006; 12:420-7. [PMID: 16432807 DOI: 10.1002/psc.744] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Scorpion toxins are important physiological probes for characterizing ion channels. Molecular databases have limited functional annotation of scorpion toxins. Their function can be inferred by searching for conserved motifs in sequence signature databases that are derived statistically but are not necessarily biologically relevant. Mutation studies provide biological information on residues and positions important for structure-function relationship but are not normally used for extraction of binding motifs. 3D structure analyses also aid in the extraction of peptide motifs in which non-contiguous residues are clustered spatially. Here we present new, functionally relevant peptide motifs for ion channels, derived from the analyses of scorpion toxin native and mutant peptides.
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Affiliation(s)
- Paul T J Tan
- Institute for Infocomm Research, 21 Heng Mui Keng Terrace, Singapore 119613
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Mouhat S, Visan V, Ananthakrishnan S, Wulff H, Andreotti N, Grissmer S, Darbon H, De Waard M, Sabatier JM. K+ channel types targeted by synthetic OSK1, a toxin from Orthochirus scrobiculosus scorpion venom. Biochem J 2005; 385:95-104. [PMID: 15588251 PMCID: PMC1134677 DOI: 10.1042/bj20041379] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
OSK1 (alpha-KTx3.7) is a 38-residue toxin cross-linked by three disulphide bridges that was initially isolated from the venom of the Asian scorpion Orthochirus scrobiculosus. OSK1 and several structural analogues were produced by solid-phase chemical synthesis, and were tested for lethality in mice and for their efficacy in blocking a series of 14 voltage-gated and Ca2+-activated K+ channels in vitro. In the present paper, we report that OSK1 is lethal in mice by intracerebroventricular injection, with a LD50 (50% lethal dose) value of 2 microg/kg. OSK1 blocks K(v)1.1, K(v)1.2, K(v)1.3 channels potently and K(Ca)3.1 channel moderately, with IC50 values of 0.6, 5.4, 0.014 and 225 nM respectively. Structural analogues of OSK1, in which we mutated positions 16 (Glu16-->Lys) and/or 20 (Lys20-->Asp) to amino acid residues that are conserved in all other members of the alpha-KTx3 toxin family except OSK1, were also produced and tested. Among the OSK1 analogues, [K16,D20]-OSK1 (OSK1 with Glu16-->Lys and Lys20-->Asp mutations) shows an increased potency on K(v)1.3 channel, with an IC50 value of 0.003 nM, without loss of activity on K(Ca)3.1 channel. These data suggest that OSK1 or [K16,D20]-OSK1 could serve as leads for the design and production of new immunosuppressive drugs.
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Affiliation(s)
- Stéphanie Mouhat
- *Laboratoire Cellpep S.A., 13-15 Rue Ledru-Rollin, 13015 Marseille, France
| | - Violeta Visan
- †Universität Ulm, Albert Einstein Allee 11, 89081 Ulm, Germany
| | - S. Ananthakrishnan
- ‡Department of Medical Pharmacology and Toxicology, University of California, Davis, CA 95616, U.S.A
| | - Heike Wulff
- ‡Department of Medical Pharmacology and Toxicology, University of California, Davis, CA 95616, U.S.A
| | - Nicolas Andreotti
- *Laboratoire Cellpep S.A., 13-15 Rue Ledru-Rollin, 13015 Marseille, France
| | | | - Hervé Darbon
- §AFMB, CNRS UPR 9039, 31 Chemin Joseph Aiguier, 13402 Marseille, France
| | - Michel De Waard
- ∥INSERM U607, CEA, 17 Rue des Martyrs, 38054 Grenoble Cedex 09, France
| | - Jean-Marc Sabatier
- *Laboratoire Cellpep S.A., 13-15 Rue Ledru-Rollin, 13015 Marseille, France
- ¶CNRS FRE 2738, Boulevard Pierre Dramard, 13916 Marseille Cedex 20, France
- To whom correspondence should be addressed (email )
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