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Romero-Imbachi MR, Cupitra N, Ángel K, González B, Estrada O, Calderón JC, Guerrero-Vargas J, Beltrán J, Narvaez-Sanchez R. Centruroides margaritatus scorpion complete venom exerts cardiovascular effects through alpha-1 adrenergic receptors. Comp Biochem Physiol C Toxicol Pharmacol 2021; 240:108939. [PMID: 33166680 DOI: 10.1016/j.cbpc.2020.108939] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 10/23/2020] [Accepted: 11/03/2020] [Indexed: 02/07/2023]
Abstract
Centruroides margaritatus scorpion stings are common in Colombia. However, the cardiovascular toxicity of the venom has not been clarified. AIM To study the effect and mechanisms of action of the complete venom of C. margaritatus (CmV) on the murine cardiovascular system. METHODS We evaluated the in vivo effect of CmV LD50 on the mean arterial pressure (MABP), heart rate, and surface electrocardiogram in male adult normotensive Wistar rats. Ex vivo, we evaluated the vascular reactivity of rat aortic rings to increasing concentrations (1 to 60 μg/mL) of CmV using the blockers L-NAME, indomethacin, seratrodast, and prazosin. RESULTS In the first hour of poisoning, CmV increased the MABP. In the second hour after poisoning, the heart rate decreased as the normalized PR interval and QT corrected increased. After that, cardiovascular shock was demonstrated by a drastic fall in the MABP and signs of cardiac conduction system block. In aortic rings, CmV caused a direct vasoconstrictor effect mediated by alpha-1 adrenergic receptors and counteracted by nitric oxide. CONCLUSION The direct vascular and probably the cardiac alpha-1 effects likely explain the transient hypertension and the maintenance of cardiac function, while interval lengthening may be due to K+ channel blockage. Afterwards, the effects of both the alpha-1 pathway and the K+ channel pathway converged, resulting in fatal cardiovascular shock. This knowledge could aid in understanding the dynamics of the effects of the venom and in designing treatments to address its cardiovascular effects.
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Affiliation(s)
- Margarita Rosa Romero-Imbachi
- Physiology and Biochemistry Research Group-PHYSIS, Faculty of Medicine, University of Antioquia, Medellin, Colombia; Herpetological and Toxinological Research Group, Faculty of Natural, Exact and Educational Sciences, University of Cauca, Popayán, Colombia
| | - Nelson Cupitra
- Physiology and Biochemistry Research Group-PHYSIS, Faculty of Medicine, University of Antioquia, Medellin, Colombia
| | - Karen Ángel
- Herpetological and Toxinological Research Group, Faculty of Natural, Exact and Educational Sciences, University of Cauca, Popayán, Colombia
| | - Beatriz González
- Laboratory of Cellular Physiology, Center for Biophysics and Biochemistry, Venezuelan Institute for Scientific Research, Venezuela
| | - Omar Estrada
- Laboratory of Cellular Physiology, Center for Biophysics and Biochemistry, Venezuelan Institute for Scientific Research, Venezuela
| | - Juan C Calderón
- Physiology and Biochemistry Research Group-PHYSIS, Faculty of Medicine, University of Antioquia, Medellin, Colombia
| | - Jimmy Guerrero-Vargas
- Herpetological and Toxinological Research Group, Faculty of Natural, Exact and Educational Sciences, University of Cauca, Popayán, Colombia
| | - José Beltrán
- Herpetological and Toxinological Research Group, Faculty of Natural, Exact and Educational Sciences, University of Cauca, Popayán, Colombia
| | - Raul Narvaez-Sanchez
- Physiology and Biochemistry Research Group-PHYSIS, Faculty of Medicine, University of Antioquia, Medellin, Colombia.
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2
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Bachmann M, Li W, Edwards MJ, Ahmad SA, Patel S, Szabo I, Gulbins E. Voltage-Gated Potassium Channels as Regulators of Cell Death. Front Cell Dev Biol 2020; 8:611853. [PMID: 33381507 PMCID: PMC7767978 DOI: 10.3389/fcell.2020.611853] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 11/23/2020] [Indexed: 12/11/2022] Open
Abstract
Ion channels allow the flux of specific ions across biological membranes, thereby determining ion homeostasis within the cells. Voltage-gated potassium-selective ion channels crucially contribute to the setting of the plasma membrane potential, to volume regulation and to the physiologically relevant modulation of intracellular potassium concentration. In turn, these factors affect cell cycle progression, proliferation and apoptosis. The present review summarizes our current knowledge about the involvement of various voltage-gated channels of the Kv family in the above processes and discusses the possibility of their pharmacological targeting in the context of cancer with special emphasis on Kv1.1, Kv1.3, Kv1.5, Kv2.1, Kv10.1, and Kv11.1.
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Affiliation(s)
- Magdalena Bachmann
- Department of Biology, University of Padova, Padua, Italy.,Department of Surgery, Medical School, University of Cincinnati, Cincinnati, OH, United States
| | - Weiwei Li
- Department of Surgery, Medical School, University of Cincinnati, Cincinnati, OH, United States
| | - Michael J Edwards
- Department of Surgery, Medical School, University of Cincinnati, Cincinnati, OH, United States
| | - Syed A Ahmad
- Department of Surgery, Medical School, University of Cincinnati, Cincinnati, OH, United States
| | - Sameer Patel
- Department of Surgery, Medical School, University of Cincinnati, Cincinnati, OH, United States
| | - Ildiko Szabo
- Department of Biology, University of Padova, Padua, Italy.,Consiglio Nazionale delle Ricerche Institute of Neuroscience, Padua, Italy
| | - Erich Gulbins
- Department of Surgery, Medical School, University of Cincinnati, Cincinnati, OH, United States.,Department of Molecular Biology, University of Duisburg-Essen, Essen, Germany
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3
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Díaz-García A, Varela D. Voltage-Gated K +/Na + Channels and Scorpion Venom Toxins in Cancer. Front Pharmacol 2020; 11:913. [PMID: 32655396 PMCID: PMC7325878 DOI: 10.3389/fphar.2020.00913] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 06/04/2020] [Indexed: 12/25/2022] Open
Abstract
Ion channels have recently been recognized as novel therapeutic targets in cancer research since they are overexpressed in different histological tissues, and their activity is linked to proliferation, tumor progression, angiogenesis, metastasis, and apoptosis. Voltage gated-potassium channels (VGKC) are involved in cell proliferation, cancer progression, cell cycle transition, and apoptosis. Moreover, voltage-dependent sodium channels (VGSC) contribute to decreases in extracellular pH, which, in turn, promotes cancer cell migration and invasion. Furthermore, VGSC and VGKC modulate voltage-sensitive Ca2+ channel activity by controlling the membrane potential and regulating Ca2+ influx, which functions as a second messenger in processes related to proliferation, invasion, migration, and metastasis. The subgroup of these types of channels that have shown a high oncogenic potential have become known as “oncochannels”, and the evidence has highlighted them as key potential therapeutic targets. Scorpion venoms contain a high proportion of peptide toxins that act by modulating voltage-gated Na+/K+ channel activity. Increasing scientific data have pointed out that scorpion venoms and their toxins can affect the activity of oncochannels, thus showing their potential for anticancer therapy. In this review, we provide an update of the most relevant voltage-gated Na+\K+ ion channels as cellular targets and discuss the possibility of using scorpion venom and toxins for anticancer therapy.
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Affiliation(s)
- Alexis Díaz-García
- LifEscozul Chile SpA, Santiago, Chile.,Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Universidad de Chile, Santiago, Chile
| | - Diego Varela
- Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Universidad de Chile, Santiago, Chile.,Program of Physiology and Biophysics, Faculty of Medicine, Institute of Biomedical Sciences (ICBM), Universidad de Chile, Santiago, Chile
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4
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Ward MJ, Ellsworth SA, Rokyta DR. Venom-gland transcriptomics and venom proteomics of the Hentz striped scorpion (Centruroides hentzi; Buthidae) reveal high toxin diversity in a harmless member of a lethal family. Toxicon 2018; 142:14-29. [DOI: 10.1016/j.toxicon.2017.12.042] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 12/07/2017] [Accepted: 12/11/2017] [Indexed: 01/02/2023]
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5
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Jiménez-Vargas JM, Possani LD, Luna-Ramírez K. Arthropod toxins acting on neuronal potassium channels. Neuropharmacology 2017; 127:139-160. [PMID: 28941737 DOI: 10.1016/j.neuropharm.2017.09.025] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 09/13/2017] [Accepted: 09/15/2017] [Indexed: 01/01/2023]
Abstract
Arthropod venoms are a rich mixture of biologically active compounds exerting different physiological actions across diverse phyla and affecting multiple organ systems including the central nervous system. Venom compounds can inhibit or activate ion channels, receptors and transporters with high specificity and affinity providing essential insights into ion channel function. In this review, we focus on arthropod toxins (scorpions, spiders, bees and centipedes) acting on neuronal potassium channels. A brief description of the K+ channels classification and structure is included and a compendium of neuronal K+ channels and the arthropod toxins that modify them have been listed. This article is part of the Special Issue entitled 'Venom-derived Peptides as Pharmacological Tools.'
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Affiliation(s)
- Juana María Jiménez-Vargas
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad, 2001, Colonia Chamilpa, Apartado Postal 510-3, Cuernavaca 62210, Mexico
| | - Lourival D Possani
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad, 2001, Colonia Chamilpa, Apartado Postal 510-3, Cuernavaca 62210, Mexico
| | - Karen Luna-Ramírez
- Illawarra Health and Medical Research Institute, University of Wollongong, Northfields Avenue, Wollongong, NSW 2522, Australia.
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6
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Zylberberg J, Strowbridge BW. Mechanisms of Persistent Activity in Cortical Circuits: Possible Neural Substrates for Working Memory. Annu Rev Neurosci 2017; 40:603-627. [PMID: 28772102 PMCID: PMC5995341 DOI: 10.1146/annurev-neuro-070815-014006] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A commonly observed neural correlate of working memory is firing that persists after the triggering stimulus disappears. Substantial effort has been devoted to understanding the many potential mechanisms that may underlie memory-associated persistent activity. These rely either on the intrinsic properties of individual neurons or on the connectivity within neural circuits to maintain the persistent activity. Nevertheless, it remains unclear which mechanisms are at play in the many brain areas involved in working memory. Herein, we first summarize the palette of different mechanisms that can generate persistent activity. We then discuss recent work that asks which mechanisms underlie persistent activity in different brain areas. Finally, we discuss future studies that might tackle this question further. Our goal is to bridge between the communities of researchers who study either single-neuron biophysical, or neural circuit, mechanisms that can generate the persistent activity that underlies working memory.
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Affiliation(s)
- Joel Zylberberg
- Department of Physiology and Biophysics, Center for Neuroscience, and Computational Bioscience Program, University of Colorado School of Medicine, Aurora, Colorado 80045
- Department of Applied Mathematics, University of Colorado, Boulder, Colorado 80309
- Learning in Machines and Brains Program, Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8, Canada
| | - Ben W Strowbridge
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106;
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106
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7
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Valdez-Velazquéz LL, Romero-Gutierrez MT, Delgado-Enciso I, Dobrovinskaya O, Melnikov V, Quintero-Hernández V, Ceballos-Magaña SG, Gaitan-Hinojosa MA, Coronas FI, Puebla-Perez AM, Zamudio F, De la Cruz-García I, Vázquez-Vuelvas OF, Soriano-Hernandez AD, Possani LD. Comprehensive analysis of venom from the scorpion Centruroides tecomanus reveals compounds with antimicrobial, cytotoxic, and insecticidal activities. Toxicon 2016; 118:95-103. [PMID: 27130039 DOI: 10.1016/j.toxicon.2016.04.046] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 04/06/2016] [Accepted: 04/26/2016] [Indexed: 10/21/2022]
Abstract
Centruroides tecomanus is a medically important scorpion of the state of Colima (Mexico). This communication reports the identification of venom components of this scorpion with biological activity over insects/crickets (Acheta domestica), crustaceans/fresh water shrimps (Cambarellus montezumae), and mammalians/mice (Mus musculus, strain CD1). It also describes the pharmacological effects on cell lines in culture (L5178Y cells, HeLa cells, HuTu cells and Jurkat E6-1 cells), as well as on several types of bacteria (see below). The soluble venom of this scorpion was fractionated by high-performance liquid chromatography (HPLC) and collected separately in twelve independent fractions collected over 60 min run (5 min time apart each other). The HPLC components of fraction VII were lethal to all three species used for assay. The IVth fraction had a toxic effect on freshwater shrimps. In this species, fractions VI, VII and VIII were all lethal. For crickets, fractions V and VI were toxic and fraction VII was lethal. In mouse, the lethal components were found in fraction VII, whereas fraction VIII was toxic, but not lethal, at the doses assayed. The molecular weight of peptides from the various group of fractions were identified by mass spectrometry determination. Components lethal to mice showed molecular weights from 7013 to 7487 Da. Two peptides were obtained in homogeneous form and shown to be lethal to the three species of animal used for assay. The soluble venom tested on L5178Y cell line survival was shown to be cytotoxic, at 10-100 μg/mL concentration, when compared to control murine splenocytes (p = 0.007). The soluble venom applied to Hela, Hutu and Jurkat cell lines did not show cytotoxic effects at these concentrations. On the contrary, it seems to have a proliferative effect. However the HPLC fractions I, III, VI and XII do have a cytotoxic effect on Jurkat E06-1 cells in culture at 200 μg/mL concentration. The antimicrobial activity of the venom fractions on Staphylococcus aureus (gram-positive), Escherichia coli, Pseudomonas aeruginosa y Salmonella spp (gram-negative) was measured, using the liquid inhibition growth system. The four strains of bacteria used were susceptible to fractions III and IV, affecting all four bacterial strains at concentrations below 5 μg/mL.
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Affiliation(s)
- L L Valdez-Velazquéz
- Facultad de Ciencias Químicas, Universidad de Colima, Kilometro 9 Carretera Colima-Coquimatlan, Código Postal 28400, Coquimatlan, Colima, Mexico; Facultad de Medicina, Universidad de Colima, Av. Universidad 333, Colonia las Viboras, Código Postal 28040, Colima, Mexico.
| | - M T Romero-Gutierrez
- Facultad de Medicina, Universidad de Colima, Av. Universidad 333, Colonia las Viboras, Código Postal 28040, Colima, Mexico
| | - I Delgado-Enciso
- Facultad de Ciencias Químicas, Universidad de Colima, Kilometro 9 Carretera Colima-Coquimatlan, Código Postal 28400, Coquimatlan, Colima, Mexico; Facultad de Medicina, Universidad de Colima, Av. Universidad 333, Colonia las Viboras, Código Postal 28040, Colima, Mexico
| | - O Dobrovinskaya
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Av. 25 de Julio 965, Código Postal 28045, Colima, Mexico
| | - V Melnikov
- Facultad de Medicina, Universidad de Colima, Av. Universidad 333, Colonia las Viboras, Código Postal 28040, Colima, Mexico
| | - V Quintero-Hernández
- CONACYT Research Fellow - Laboratorio de Ecología Molecular Microbiana, Centro de Investigaciones en Ciencias Microbiológicas-Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Ciudad Universitaria, Código Postal 72570, Puebla, Mexico
| | - S G Ceballos-Magaña
- Facultad de Ciencias, Universidad de Colima, c/Bernal Díaz del Castillo 340, Código Postal 28045, Colima, Mexico
| | - M A Gaitan-Hinojosa
- Facultad de Ciencias Químicas, Universidad de Colima, Kilometro 9 Carretera Colima-Coquimatlan, Código Postal 28400, Coquimatlan, Colima, Mexico
| | - F I Coronas
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Colonia Chamilpa, Apartado Postal 510-3, Cuernavaca, Morelos, Mexico
| | - A M Puebla-Perez
- Universidad de Guadalajara, Centro Universitario de Ciencias Exactas, Blvd. Gral. Marcelino García Barragán 1421, Olímpica, Apartado Postal 44430, Guadalajara, Jalisco, Mexico
| | - F Zamudio
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Colonia Chamilpa, Apartado Postal 510-3, Cuernavaca, Morelos, Mexico
| | - I De la Cruz-García
- Facultad de Ciencias Químicas, Universidad de Colima, Kilometro 9 Carretera Colima-Coquimatlan, Código Postal 28400, Coquimatlan, Colima, Mexico
| | - O F Vázquez-Vuelvas
- Facultad de Ciencias Químicas, Universidad de Colima, Kilometro 9 Carretera Colima-Coquimatlan, Código Postal 28400, Coquimatlan, Colima, Mexico
| | - A D Soriano-Hernandez
- Facultad de Medicina, Universidad de Colima, Av. Universidad 333, Colonia las Viboras, Código Postal 28040, Colima, Mexico
| | - L D Possani
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Colonia Chamilpa, Apartado Postal 510-3, Cuernavaca, Morelos, Mexico
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8
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Estrada-Gómez S, Cupitra NI, Arango WM, Muñoz LJV. Intraspecific variation of centruroides edwardsii venom from two regions of Colombia. Toxins (Basel) 2014; 6:2082-96. [PMID: 25025710 PMCID: PMC4113743 DOI: 10.3390/toxins6072082] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 05/20/2014] [Accepted: 06/06/2014] [Indexed: 01/01/2023] Open
Abstract
We report the first description studies, partial characterization, and intraspecific difference of Centruroides edwardsii, Gervais 1843, venom. C. edwardsii from two Colombian regions (Antioquia and Tolima) were evaluated. Both venoms showed hemolytic activity, possibly dependent of enzymatic active phospholipases, and neither coagulant nor proteolytic activities were observed. Venom electrophoretic profile showed significant differences between C. edwardsii venom from both regions. A high concentration of proteins with molecular masses between 31 kDa and 97.4 kDa, and an important concentration close or below 14.4 kDa were detected. RP-HPLC retention times between 38.2 min and 42.1 min, showed bands close to 14.4 kDa, which may correspond to phospholipases. RP-HPLC venom profile showed a well conserved region in both venoms between 7 and 17 min, after this, significant differences were detected. From Tolima region venom, 50 well-defined peaks were detected, while in the Antioquia region venom, 55 well-defined peaks were detected. Larvicidal activity was only detected in the C. edwardsii venom from Antioquia. No antimicrobial activity was observed using complete venom or RP-HPLC collected fractions of both venoms. Lethally activity (carried out on female albino swiss mice) was detected at doses over 19.2 mg/kg of crude venom. Toxic effects included distress, excitability, eye irritation and secretions, hyperventilation, ataxia, paralysis, and salivation.
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Affiliation(s)
- Sebastián Estrada-Gómez
- Facultad de Quimica Farmaceutica, Universidad de Antioquia UdeA, Carrera 53 No. 61-30, Medellín 050010, Colombia.
| | - Nelson Ivan Cupitra
- Grupo de Investigación de Productos Naturales, Facultad de Ciencias, Universidad del Tolima, Barrio Santa Helena Parte Alta, Ibagué 731020, Colombia.
| | - Walter Murillo Arango
- Grupo de Investigación de Productos Naturales, Facultad de Ciencias, Universidad del Tolima, Barrio Santa Helena Parte Alta, Ibagué 731020, Colombia.
| | - Leidy Johana Vargas Muñoz
- Facultad de Medicina, Universidad Cooperativa de Colombia, Calle 50 A No. 41-20, Medellín 050010, Colombia.
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Quintero-Hernández V, Jiménez-Vargas J, Gurrola G, Valdivia H, Possani L. Scorpion venom components that affect ion-channels function. Toxicon 2013; 76:328-42. [PMID: 23891887 PMCID: PMC4089097 DOI: 10.1016/j.toxicon.2013.07.012] [Citation(s) in RCA: 193] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 07/16/2013] [Indexed: 12/31/2022]
Abstract
The number and types of venom components that affect ion-channel function are reviewed. These are the most important venom components responsible for human intoxication, deserving medical attention, often requiring the use of specific anti-venoms. Special emphasis is given to peptides that recognize Na(+)-, K(+)- and Ca(++)-channels of excitable cells. Knowledge generated by direct isolation of peptides from venom and components deduced from cloned genes, whose amino acid sequences are deposited into databanks are nowadays in the order of 1.5 thousands, out of an estimate biodiversity closed to 300,000. Here the diversity of components is briefly reviewed with mention to specific references. Structural characteristic are discussed with examples taken from published work. The principal mechanisms of action of the three different types of peptides are also reviewed. Na(+)-channel specific venom components usually are modifier of the open and closing kinetic mechanisms of the ion-channels, whereas peptides affecting K(+)-channels are normally pore blocking agents. The Ryanodine Ca(++)-channel specific peptides are known for causing sub-conducting stages of the channels conductance and some were shown to be able to internalize penetrating inside the muscle cells.
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Affiliation(s)
- V. Quintero-Hernández
- Department of Molecular Medicine and Bioprocesses, Instituto de Biotecnologia, Universidad Nacional Autonoma de Mexico, Avenida Universidad, 2001, Apartado Postal 510-3, Cuernavaca 62210, Morelos, Mexico
| | - J.M. Jiménez-Vargas
- Department of Molecular Medicine and Bioprocesses, Instituto de Biotecnologia, Universidad Nacional Autonoma de Mexico, Avenida Universidad, 2001, Apartado Postal 510-3, Cuernavaca 62210, Morelos, Mexico
| | - G.B. Gurrola
- Department of Molecular Medicine and Bioprocesses, Instituto de Biotecnologia, Universidad Nacional Autonoma de Mexico, Avenida Universidad, 2001, Apartado Postal 510-3, Cuernavaca 62210, Morelos, Mexico
- Cardiovascular Center 2139, Michigan University, Ann Arbor, MI 48109-5644, U.S.A
| | - H.H.F. Valdivia
- Cardiovascular Center 2139, Michigan University, Ann Arbor, MI 48109-5644, U.S.A
| | - L.D. Possani
- Department of Molecular Medicine and Bioprocesses, Instituto de Biotecnologia, Universidad Nacional Autonoma de Mexico, Avenida Universidad, 2001, Apartado Postal 510-3, Cuernavaca 62210, Morelos, Mexico
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10
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Arrhythmogenic effect of a crude extract from sea anemone Condylactis gigantea: possible involvement of rErg1 channels. Toxicon 2013; 67:47-54. [PMID: 23499927 DOI: 10.1016/j.toxicon.2013.02.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Revised: 02/11/2013] [Accepted: 02/22/2013] [Indexed: 11/21/2022]
Abstract
Sea anemones possess a number of peptide toxins that target ion channels which provide powerful tools to study the molecular basis of diverse signaling pathways. It is also acknowledged that currents through Erg1 K(+) channels in cardiac myocytes are important for electrical stability of the heart and alterations in its activity has been linked to the onset of a potentially life-threatening heart condition named long QT syndrome type 2. Here, we report that a crude extract from sea anemone Condylactis gigantea significantly increases the QT interval and has arrhythmogenic effects in the rat heart. Furthermore, a bioassay-guided purification procedure allowed the isolation of a chromatographic fraction containing a major component with a molecular mass of 4478 Da from the crude extract, which causes a significant inhibition of whole-cell patch-clamp currents through recombinant Erg1 channels, responsible of the rapid delayed rectifying current crucial for electrical activity in the heart. Further studies could provide relevant information on the molecular mechanism of C. gigantea peptide toxins which represent promising tools in studying the physiology of diverse ion channels.
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11
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Wang X, Jimenez-Vargas JM, Xu C, Possani LD, Zhu S. Positive selection-guided mutational analysis revealing two key functional sites of scorpion ERG K(+) channel toxins. Biochem Biophys Res Commun 2012; 429:111-6. [PMID: 23103547 DOI: 10.1016/j.bbrc.2012.10.065] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2012] [Accepted: 10/16/2012] [Indexed: 10/27/2022]
Abstract
Scorpion γ-KTx toxins are important molecular tools for studying physiological and pharmacological functions of human ether-á-go-go related gene (hERG) K(+) channels. To pinpoint functional residues of this class of toxins involved in channel binding, we employed a combined approach that integrates evolutionary information and site-directed mutagenesis. Among three positively selected sites (PSSs) identified here, two (Gln18 and Met35) were found to be associated with the toxin's function because their changes significantly decreased the potency of ErgTx1 (also called CnErg1) on hERG1 channel. On the contrary, no potency alteration was observed at the third PSS (Ala42) when the mutation was introduced, which could be due to its location far from the functional surface of the toxin. Our strategy will accelerate the research of structure-function relationship of scorpion K(+) channel toxins.
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Affiliation(s)
- Xueli Wang
- Group of Animal Innate Immunity, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, PR China
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12
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Jiménez-Vargas JM, Restano-Cassulini R, Possani LD. Toxin modulators and blockers of hERG K(+) channels. Toxicon 2012; 60:492-501. [PMID: 22497787 DOI: 10.1016/j.toxicon.2012.03.024] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Accepted: 03/27/2012] [Indexed: 12/24/2022]
Abstract
The K(+) channel encoded by the Ether-á-go-go-Related Gene (ERG) is expressed in different tissues of different animal species. There are at least three subtypes of this channel, being the sub-type 1 (ERG1) crucial in the repolarization phase of the cardiac action potential. Mutations in this gene can affect the properties of the channel producing the type II long QT syndrome (LQTS2) and many drugs are also known to affect this channel with a similar side effect. Various scorpion, spider and sea anemone toxins affect the ERG currents by blocking the ion-conducting pore from the external side or by modulating channel gating through binding to the voltage-sensor domain. By doing so, these toxins become very useful tools for better understanding the structural and functional characteristics of these ion channels. This review discusses the interaction between the ERG channels and the peptides isolated from venoms of these animals. Special emphasis is placed on scorpion toxins, although the effects of several spider venom toxins and anemone toxins will be also revised.
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Affiliation(s)
- J M Jiménez-Vargas
- Department of Molecular Medicine and Bioprocesses, Institute of Biotechnology, National Autonomous University of Mexico, Av. Universidad 2001, P.O. Box 501-3, Cuernavaca 62210, Mexico.
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Qu Y, Fang M, Gao B, Chui RW, Vargas HM. BeKm-1, a Peptide Inhibitor of Human ether-a-go-go-Related Gene Potassium Currents, Prolongs QTc Intervals in Isolated Rabbit Heart. J Pharmacol Exp Ther 2010; 337:2-8. [DOI: 10.1124/jpet.110.176883] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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14
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Rowe AH, Rowe MP. Physiological resistance of grasshopper mice (Onychomys spp.) to Arizona bark scorpion (Centruroides exilicauda) venom. Toxicon 2008; 52:597-605. [DOI: 10.1016/j.toxicon.2008.07.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2008] [Revised: 06/12/2008] [Accepted: 07/03/2008] [Indexed: 10/21/2022]
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15
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Abdel-Mottaleb Y, Corzo G, Martin-Eauclaire MF, Satake H, Céard B, Peigneur S, Nambaru P, Bougis PE, Possani LD, Tytgat J. A common "hot spot" confers hERG blockade activity to alpha-scorpion toxins affecting K+ channels. Biochem Pharmacol 2008; 76:805-15. [PMID: 18687312 DOI: 10.1016/j.bcp.2008.07.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2008] [Revised: 07/02/2008] [Accepted: 07/02/2008] [Indexed: 02/01/2023]
Abstract
While alpha-KTx peptides are generally known for their modulation of the Shaker-type and the Ca(2+)-activated potassium channels, gamma-KTxs are associated with hERG channels modulation. An exception to the rule is BmTx3 which belongs to subfamily alpha-KTx15 and can block hERG channels. To explain the peculiar behavior of BmTx3, a tentative "hot spot" formed of 2 basic residues (R18 and K19) was suggested but never further studied [Huys I, et al. BmTx3, a scorpion toxin with two putative functional faces separately active on A-type K(+) and HERG currents. Biochem J 2004;378:745-52]. In this work, we investigated if the "hot spot" is a commonality in subfamily alpha-KTx15 by testing the effect of (AmmTx3, Aa1, discrepin). Furthermore, single mutations altering the "hot spot" in discrepin, have introduced for the very first time a hERG blocking activity to a previously non-active alpha-KTx. Additionally, we could extend our results to other alpha-KTx subfamily members belonging to alpha-KTx1, 4 and 6, therefore, the "hot spot" represents a common pharmacophore serving as a predictive tool for yet to be discovered alpha-KTxs.
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Affiliation(s)
- Yousra Abdel-Mottaleb
- Laboratory of Toxicology, University of Leuven, O&N 2, Herestraat 49, P.O. Box 922, 3000 Leuven, Belgium
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16
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Two novel ergtoxins, blockers of K+-channels, purified from the Mexican scorpion Centruroides elegans elegans. Neurochem Res 2008; 33:1525-33. [PMID: 18338253 DOI: 10.1007/s11064-008-9634-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2007] [Accepted: 02/19/2008] [Indexed: 10/22/2022]
Abstract
Voltage-gated potassium channels of the ether-a-go-go related gene (ERG) family are implicated in many important cellular processes. Three such genes have been cloned (erg1, erg2 and erg3) and shown to be expressed in the central nervous system (CNS) of mammalians. This communication describes the isolation and characterization of two isoforms of scorpion toxin (CeErg4 and CeErg5, systematic nomenclature gamma-KTx1.7 and gamma-KTx1.8, respectively) that can discriminate the various subtypes of ERG channels of human and rat. These peptides were purified from the venom of the Mexican scorpion Centruroides elegans elegans. They contain 42 amino acid residues, tightly folded by four disulfide bridges. Both peptides block in a reversible manner human and rat ERG1 channels, but have no effect on human ERG2. They also block completely and irreversibly the rat ERG2 and the human ERG3 channels hence are excellent tools for the discrimination of the various sub-types of ion-channels studied.
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17
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Chtcheglova LA, Atalar F, Ozbek U, Wildling L, Ebner A, Hinterdorfer P. Localization of the ergtoxin-1 receptors on the voltage sensing domain of hERG K+ channel by AFM recognition imaging. Pflugers Arch 2008; 456:247-54. [DOI: 10.1007/s00424-007-0418-9] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Accepted: 12/05/2007] [Indexed: 11/29/2022]
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18
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Zhang M, Liu XS, Diochot S, Lazdunski M, Tseng GN. APETx1 from Sea Anemone Anthopleura elegantissima Is a Gating Modifier Peptide Toxin of the Human Ether-a-go-go- Related Potassium Channel. Mol Pharmacol 2007; 72:259-68. [PMID: 17473056 DOI: 10.1124/mol.107.035840] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We studied the mechanism of action and the binding site of APETx1, a peptide toxin purified from sea anemone, on the human ether-a-go-go-related gene (hERG) channel. Similar to the effects of gating modifier toxins (hanatoxin and SGTx) on the voltage-gated potassium (Kv) 2.1 channel, APETx1 shifts the voltage-dependence of hERG activation in the positive direction and suppresses its current amplitudes elicited by strong depolarizing pulses that maximally activate the channels. The APETx1 binding site is distinctly different from that of a pore-blocking peptide toxin, BeKm-1. Mutations in the S3b region of hERG have dramatic impact on the responsiveness to APETx1: G514C potentiates whereas E518C abolishes the APETx1 effect. Restoring the negative charge at position 518 (methanethiosulfonate ethylsulfonate modification of 518C) partially restores APETx1 responsiveness, supporting an electrostatic interaction between E518 and APETx1. Among the three hERG isoforms, hERG1 and hERG3 are equally responsive to APETx1, whereas hERG2 is insensitive. The key feature seems to be an arginine residue uniquely present at the 514-equivalent position in hERG2, where the other two isoforms possess a glycine. Our data show that APETx1 is a gating modifier toxin of the hERG channel, and its binding site shares characteristics with those of gating modifier toxin binding sites on other Kv channels.
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Affiliation(s)
- M Zhang
- Department of Physiology, Medical College of Virginia, Virginia Commonwealth University, 1101 E. Marshall Street, Richmond, VA 23298, USA
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19
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Wanke E, Restano-Cassulini R. Toxins interacting with ether-à-go-go-related gene voltage-dependent potassium channels. Toxicon 2007; 49:239-48. [PMID: 17097705 DOI: 10.1016/j.toxicon.2006.09.025] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The critical role that ether-à-go-go-related gene (erg) K(+) channels play in mating in Caenorhabditis elegans, neuronal seizures in Drosophila and cardiac action potential repolarization in humans has been well documented. Three erg genes (erg1, erg2 and erg3) have been identified and characterized. A structurally diverse number of compounds block these channels, but do not display specificity among the different channel isoforms. In this review we describe the blocking properties of several peptides, purified from scorpion, sea anemone and spider venoms, which are selective for certain members of the ERG family of channels. These peptides do not behave as classical pore blockers and appear to modify the gating properties of the channel. Genomic studies predict the existence of many other novel peptides with the potential of being more selective for ERG channels than those discussed here.
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Affiliation(s)
- Enzo Wanke
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, Piazza della Scienza 2, 20126 Milano, Italy.
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20
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Yi H, Cao Z, Yin S, Dai C, Wu Y, Li W. Interaction Simulation of hERG K+ Channel with Its Specific BeKm-1 Peptide: Insights into the Selectivity of Molecular Recognition. J Proteome Res 2006; 6:611-20. [PMID: 17269718 DOI: 10.1021/pr060368g] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Potassium channels show a huge variability in the affinity when recognizing enormous bioactive peptides, and the elucidation of their recognition mechanism remains a great challenge due to an undetermined peptide-channel complex structure. Here, we employed combined computation methods to study the specific binding of BeKm-1 peptide to the hERG potassium channel, which is an essential determinant of the long-QT syndrome. By the use of a segment-assembly homology modeling method, the closed-state hERG structure containing unusual longer S5P linker was successfully constructed. It has a "petunia" shape, while four "petals" of symmetrically distributed S5P segments always decentralize. Starting from the hERG and BeKm-1 structures, a considerably reasonable BeKm-1-hERG complex structure was then screened out and identified by protein-protein docking, molecular dynamics (MD) simulations, and calculation of relative binding free energies. The validity of this predicted complex was further assessed by computational alanine-scanning, with the results correlating reasonably well with experimental data. In the novel complex structure, four considerably flexible S5P linkers are far from the BeKm-1 peptide. The BeKm-1 mainly uses its helical region to associate the channel outer vestibule, except for the S5P linker region; however, structural analysis further implies this neutral pore region with wiggling S5P linker is highly beneficial to the binding of BeKm-1 with lower positive charges. The most critical Lys18 of BeKm-1 plugs its side chain into the channel selectivity filter, while the secondarily important Arg20 forms three hydrogen bonds with spatially neighboring residues in the hERG channel. Different from the classical peptide-K+ channel interaction mainly induced by electrostatic interaction, a synergetic effect of the electrostatic and van der Waals interactions was found to mediate the molecular recognition between BeKm-1 and the hERG channel. And this specific binding process is revealed to be a dynamic change of reduction of binding free energy and conformational rearrangement mainly in the interface of both BeKm-1 and the hERG channel. All these structural and energy features yield deep insights on the high selective binding mechanism of hERG-specific peptides, present a diversity of peptide-K+ channel interactions, and also provide important clues to further study structure-function relationships of the hERG channel.
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Affiliation(s)
- Hong Yi
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, People's Republic of China
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21
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Restano-Cassulini R, Korolkova YV, Diochot S, Gurrola G, Guasti L, Possani LD, Lazdunski M, Grishin EV, Arcangeli A, Wanke E. Species diversity and peptide toxins blocking selectivity of ether-a-go-go-related gene subfamily K+ channels in the central nervous system. Mol Pharmacol 2006; 69:1673-83. [PMID: 16497878 DOI: 10.1124/mol.105.019729] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The ether-à-go-go-related gene (erg) K+ channels are known to be crucial for life in Caenorhabditis elegans (mating), Drosophila melanogaster (seizure), and humans (LQT syndrome). The erg genes known to date (erg1, erg2, and erg3) are highly expressed in various areas of the rat and mouse central nervous system (CNS), and ERG channel blockers alter firing accommodation. To assign physiological roles to each isoform, it is necessary to design pharmacological strategies to distinguish individual currents. To this purpose, we have investigated the blocking properties of specific peptide inhibitors of hERG1 channels on the human and rat isoforms. In particular, we have tested ErgTx1 (from the scorpion Centruroides noxious), BeKm-1 (from the scorpion Buthus eupeus), and APETx1 (from the sea anemone Anthopleura elegantissima). Because these peptides had different species-specific effects on the six different channels, we have also carried out a biophysical characterization of hERG2 and hERG3 channels that turned out to be different from the rat homologs. It emerged that APETx1 is exquisitely selective for ERG1 and does not compete with the other two toxins. BeKm-1 discriminates well among the three rat members. ErgTx1 is unable to block hERG2, but blocks rERG2 and has the lowest KD for hERG3. BeKm-1 and ErgTx1 compete for hERG3 but not for rERG2 blockade. Our findings should be helpful for structure-function studies and for novel CNS ERG-specific drug design.
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Affiliation(s)
- Rita Restano-Cassulini
- Dipartimento di Biotecnologie e Bioscienze Università di Milano-Bicocca, Piazza della Scienza 2, 20126 Milano, Italy
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22
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Abstract
Much of our knowledge on K+-channels was elucidated using specific peptide ligands isolated from a number of venomous organisms. Recently, this field received a strong support and increased interest due to the solution of the three-dimensional structure of a couple of K+-channels. At the same time, several new subfamilies of specific toxins for K+-channels were isolated from scorpion venoms, enhancing the availability and diversity of such useful molecular tools. It opened new lines of research for the better understanding of K+-channel biophysics and pharmacology. In this review, we listed 120 amino acid sequences of peptides isolated from scorpion venoms. They were demonstrated or assumed to be specific for K+-channels. These sequences were aligned and used to generate a rooted phylogenetic tree. The evolutionary tree indicates that several clusters of divergent peptides show preference for specific subtypes of channels. The three-dimensional structures of representative examples of these peptides were drawn and analysed concerning the molecular fitness of their interactions with the channel targets. Four different interacting modes were identified to exist between scorpion toxins and the various subtypes of K+-channels.
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Affiliation(s)
- Ricardo C Rodríguez de la Vega
- Department of Molecular Medicine and Bioprocesses, Institute of Biotechnology, National Autonomous University of Mexico, Avenida Universidad, 2001, Apartado Postal 510-3, Cuernavaca 62210, Mexico
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23
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Rodríguez de la Vega RC, Merino E, Becerril B, Possani LD. Novel interactions between K+ channels and scorpion toxins. Trends Pharmacol Sci 2003; 24:222-7. [PMID: 12767720 DOI: 10.1016/s0165-6147(03)00080-4] [Citation(s) in RCA: 138] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
K(+) channels are macromolecules embedded in biological membranes, where they play a key role in cellular excitability and signal transduction pathways. Knowledge of their structure should help improve our understanding of their function and lead to the design of therapeutic compounds. Most pharmacological and structural characteristics of these channels have been elucidated by using high-affinity channel blockers isolated from scorpion venoms. Recent data on the three-dimensional structures of K(+) channels and novel scorpion toxins suggest a variety of novel interacting modes of these channels and toxins, which should help increase our understanding of the K(+) channel structure-function relationship.
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Affiliation(s)
- Ricardo C Rodríguez de la Vega
- Institute of Biotechnology, National Autonomous University of Mexico, Avenida Universidad, 2001, Apartado Postal 510-3, Cuernavaca 62210, Mexico
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24
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Zhang M, Korolkova YV, Liu J, Jiang M, Grishin EV, Tseng GN. BeKm-1 is a HERG-specific toxin that shares the structure with ChTx but the mechanism of action with ErgTx1. Biophys J 2003; 84:3022-36. [PMID: 12719233 PMCID: PMC1302864 DOI: 10.1016/s0006-3495(03)70028-9] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Peptide toxins with disulfide-stabilized structures have been used as molecular calipers to probe the outer vestibule structure of K channels. We want to apply this approach to the human ether-a-go-go-related gene (HERG) channel, whose outer vestibule is unique in structure and function among voltage-gated K channels. Our focus here is BeKm-1, a HERG-specific peptide toxin that can suppress HERG in the low nM concentration range. Although BeKm-1 shares the three-dimensional scaffold with the well-studied charybdotoxin, the two use different mechanisms in suppressing currents through their target K channels. BeKm-1 binds near, but not inside, the HERG pore, and it is possible that BeKm-1-bound HERG channels can conduct currents although with markedly altered voltage-dependence and kinetics of gating. BeKm-1 and ErgTx1 differ in three-dimensional scaffold, but the two share mechanism of action and have overlapping binding sites on the HERG channel. For both, residues in the middle of the S5-P linker (the putative 583-597 helix) and residues at the pore entrance are critical for binding, although specific contact points vary between the two. Toxin foot printing using BeKm-1 and ErgTx1 will likely provide complementary information about the unique outer vestibule structure of the HERG channel.
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Affiliation(s)
- Mei Zhang
- Department of Physiology, Virginia Commonwealth University, Richmond 23298, USA
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25
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Torres AM, Bansal P, Alewood PF, Bursill JA, Kuchel PW, Vandenberg JI. Solution structure of CnErg1 (Ergtoxin), a HERG specific scorpion toxin. FEBS Lett 2003; 539:138-42. [PMID: 12650941 DOI: 10.1016/s0014-5793(03)00216-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The three-dimensional structure of chemically synthesized CnErg1 (Ergtoxin), which specifically blocks HERG (human ether-a-go-go-related gene) K+ channels, was determined by nuclear magnetic resonance spectroscopy. CnErg1 consists of a triple-stranded beta-sheet and an alpha-helix, as is typical of K+ channel scorpion toxins. The peptide structure differs from the canonical structures in that the first beta-strand is shorter and is nearer to the second beta-strand rather than to the third beta-strand on the C-terminus. There is also a large hydrophobic patch on the surface of the toxin, surrounding a central lysine residue, Lys13. We postulate that this hydrophobic patch is likely to form part of the binding surface of the toxin.
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Affiliation(s)
- Allan M Torres
- School of Molecular and Microbial Biosciences, University of Sydney, NSW 2006, Australia.
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26
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Corona M, Gurrola GB, Merino E, Cassulini RR, Valdez-Cruz NA, García B, Ramírez-Domínguez ME, Coronas FIV, Zamudio FZ, Wanke E, Possani LD. A large number of novel Ergtoxin-like genes and ERG K+-channels blocking peptides from scorpions of the genus Centruroides. FEBS Lett 2002; 532:121-6. [PMID: 12459475 DOI: 10.1016/s0014-5793(02)03652-9] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Twenty-three novel sequences similar to Ergtoxin (ErgTx) were obtained by direct sequencing of peptides or deduced from gene cloned using cDNAs of venomous glands of Centruroides (C.) elegans, C. exilicauda, C. gracilis, C. limpidus limpidus, C. noxius and C. sculpturatus. These peptides have from 42 to 47 amino acid residues cross-linked by four disulfide bridges. They share sequence similarities (60-98% compared with ErgTx1) and were shown to block ERG K(+)-channels of F-11 clone (N18TG-2xrat DRG) cultured cells. An unrooted phylogenetic tree analysis of these peptides showed that they conform at least five different subfamilies, of which three are novel subfamilies.
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Affiliation(s)
- Miguel Corona
- Institute of Biotechnology, National Autonomous University of Mexico, Avenida Universidad, 2001, P.O. Box 510-3, Cuernavaca 62210, Mexico
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