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Monastyrnaya MM, Kalina RS, Kozlovskaya EP. The Sea Anemone Neurotoxins Modulating Sodium Channels: An Insight at Structure and Functional Activity after Four Decades of Investigation. Toxins (Basel) 2022; 15:toxins15010008. [PMID: 36668828 PMCID: PMC9863223 DOI: 10.3390/toxins15010008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/13/2022] [Accepted: 12/15/2022] [Indexed: 12/24/2022] Open
Abstract
Many human cardiovascular and neurological disorders (such as ischemia, epileptic seizures, traumatic brain injury, neuropathic pain, etc.) are associated with the abnormal functional activity of voltage-gated sodium channels (VGSCs/NaVs). Many natural toxins, including the sea anemone toxins (called neurotoxins), are an indispensable and promising tool in pharmacological researches. They have widely been carried out over the past three decades, in particular, in establishing different NaV subtypes functional properties and a specific role in various pathologies. Therefore, a large number of publications are currently dedicated to the search and study of the structure-functional relationships of new sea anemone natural neurotoxins-potential pharmacologically active compounds that specifically interact with various subtypes of voltage gated sodium channels as drug discovery targets. This review presents and summarizes some updated data on the structure-functional relationships of known sea anemone neurotoxins belonging to four structural types. The review also emphasizes the study of type 2 neurotoxins, produced by the tropical sea anemone Heteractis crispa, five structurally homologous and one unique double-stranded peptide that, due to the absence of a functionally significant Arg14 residue, loses toxicity but retains the ability to modulate several VGSCs subtypes.
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Menezes C, Thakur NL. Sea anemone venom: Ecological interactions and bioactive potential. Toxicon 2022; 208:31-46. [DOI: 10.1016/j.toxicon.2022.01.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 01/05/2022] [Accepted: 01/06/2022] [Indexed: 10/19/2022]
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Voltage-Gated Sodium Channels: A Prominent Target of Marine Toxins. Mar Drugs 2021; 19:md19100562. [PMID: 34677461 PMCID: PMC8537899 DOI: 10.3390/md19100562] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 09/29/2021] [Accepted: 10/02/2021] [Indexed: 12/19/2022] Open
Abstract
Voltage-gated sodium channels (VGSCs) are considered to be one of the most important ion channels given their remarkable physiological role. VGSCs constitute a family of large transmembrane proteins that allow transmission, generation, and propagation of action potentials. This occurs by conducting Na+ ions through the membrane, supporting cell excitability and communication signals in various systems. As a result, a wide range of coordination and physiological functions, from locomotion to cognition, can be accomplished. Drugs that target and alter the molecular mechanism of VGSCs’ function have highly contributed to the discovery and perception of the function and the structure of this channel. Among those drugs are various marine toxins produced by harmful microorganisms or venomous animals. These toxins have played a key role in understanding the mode of action of VGSCs and in mapping their various allosteric binding sites. Furthermore, marine toxins appear to be an emerging source of therapeutic tools that can relieve pain or treat VGSC-related human channelopathies. Several studies documented the effect of marine toxins on VGSCs as well as their pharmaceutical applications, but none of them underlined the principal marine toxins and their effect on VGSCs. Therefore, this review aims to highlight the neurotoxins produced by marine animals such as pufferfish, shellfish, sea anemone, and cone snail that are active on VGSCs and discuss their pharmaceutical values.
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D’Ambra I, Lauritano C. A Review of Toxins from Cnidaria. Mar Drugs 2020; 18:E507. [PMID: 33036158 PMCID: PMC7600780 DOI: 10.3390/md18100507] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 09/23/2020] [Accepted: 09/30/2020] [Indexed: 12/13/2022] Open
Abstract
Cnidarians have been known since ancient times for the painful stings they induce to humans. The effects of the stings range from skin irritation to cardiotoxicity and can result in death of human beings. The noxious effects of cnidarian venoms have stimulated the definition of their composition and their activity. Despite this interest, only a limited number of compounds extracted from cnidarian venoms have been identified and defined in detail. Venoms extracted from Anthozoa are likely the most studied, while venoms from Cubozoa attract research interests due to their lethal effects on humans. The investigation of cnidarian venoms has benefited in very recent times by the application of omics approaches. In this review, we propose an updated synopsis of the toxins identified in the venoms of the main classes of Cnidaria (Hydrozoa, Scyphozoa, Cubozoa, Staurozoa and Anthozoa). We have attempted to consider most of the available information, including a summary of the most recent results from omics and biotechnological studies, with the aim to define the state of the art in the field and provide a background for future research.
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Affiliation(s)
- Isabella D’Ambra
- Integrative Marine Ecology Department, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Napoli, Italy
| | - Chiara Lauritano
- Marine Biotechnology Department, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Napoli, Italy;
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Mikov AN, Kozlov SA. [Structural Features of Cysteine-Stabilized Polypeptides from Sea Anemones Venoms]. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2016; 41:511-23. [PMID: 26762088 DOI: 10.1134/s1068162015050088] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nowadays, venom-based drug discovery becomes popular again: pharmaceutical companies evaluate animal venom potential as a combinatory library of biologically-active compounds. Collaborations with research groups from academia are intensified, new toxins are being investigated, among which polypeptides are of paramount importance. Sea anemones produce the most diversified, from structural point of view, polypep- tide venom components among other animals. This particular review considers known polypeptide toxins from sea anemones, basically taking into account its classification by primary structural features. The most important functional characteristics are analyzed in each structural class.
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Oliveira JS, Fuentes-Silva D, King GF. Development of a rational nomenclature for naming peptide and protein toxins from sea anemones. Toxicon 2012; 60:539-50. [DOI: 10.1016/j.toxicon.2012.05.020] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 05/21/2012] [Accepted: 05/24/2012] [Indexed: 01/30/2023]
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Frazão B, Vasconcelos V, Antunes A. Sea anemone (Cnidaria, Anthozoa, Actiniaria) toxins: an overview. Mar Drugs 2012; 10:1812-1851. [PMID: 23015776 PMCID: PMC3447340 DOI: 10.3390/md10081812] [Citation(s) in RCA: 138] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Revised: 07/09/2012] [Accepted: 07/25/2012] [Indexed: 01/20/2023] Open
Abstract
The Cnidaria phylum includes organisms that are among the most venomous animals. The Anthozoa class includes sea anemones, hard corals, soft corals and sea pens. The composition of cnidarian venoms is not known in detail, but they appear to contain a variety of compounds. Currently around 250 of those compounds have been identified (peptides, proteins, enzymes and proteinase inhibitors) and non-proteinaceous substances (purines, quaternary ammonium compounds, biogenic amines and betaines), but very few genes encoding toxins were described and only a few related protein three-dimensional structures are available. Toxins are used for prey acquisition, but also to deter potential predators (with neurotoxicity and cardiotoxicity effects) and even to fight territorial disputes. Cnidaria toxins have been identified on the nematocysts located on the tentacles, acrorhagi and acontia, and in the mucous coat that covers the animal body. Sea anemone toxins comprise mainly proteins and peptides that are cytolytic or neurotoxic with its potency varying with the structure and site of action and are efficient in targeting different animals, such as insects, crustaceans and vertebrates. Sea anemones toxins include voltage-gated Na⁺ and K⁺ channels toxins, acid-sensing ion channel toxins, Cytolysins, toxins with Kunitz-type protease inhibitors activity and toxins with Phospholipase A2 activity. In this review we assessed the phylogentic relationships of sea anemone toxins, characterized such toxins, the genes encoding them and the toxins three-dimensional structures, further providing a state-of-the-art description of the procedures involved in the isolation and purification of bioactive toxins.
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Affiliation(s)
- Bárbara Frazão
- CIMAR/CIIMAR, Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Rua dos Bragas 177, 4050-123 Porto, Portugal; (B.F.); (V.V.)
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal
| | - Vitor Vasconcelos
- CIMAR/CIIMAR, Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Rua dos Bragas 177, 4050-123 Porto, Portugal; (B.F.); (V.V.)
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal
| | - Agostinho Antunes
- CIMAR/CIIMAR, Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Rua dos Bragas 177, 4050-123 Porto, Portugal; (B.F.); (V.V.)
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal
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Moran Y, Gordon D, Gurevitz M. Sea anemone toxins affecting voltage-gated sodium channels--molecular and evolutionary features. Toxicon 2009; 54:1089-101. [PMID: 19268682 DOI: 10.1016/j.toxicon.2009.02.028] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The venom of sea anemones is rich in low molecular weight proteinaceous neurotoxins that vary greatly in structure, site of action, and phyletic (insect, crustacean or vertebrate) preference. This toxic versatility likely contributes to the ability of these sessile animals to inhabit marine environments co-habited by a variety of mobile predators. Among these toxins, those that show prominent activity at voltage-gated sodium channels and are critical in predation and defense, have been extensively studied for more than three decades. These studies initially focused on the discovery of new toxins, determination of their covalent and folded structures, understanding of their mechanisms of action on different sodium channels, and identification of the primary sites of interaction of the toxins with their channel receptors. The channel binding site for Type I and the structurally unrelated Type III sea anemone toxins was identified as neurotoxin receptor site 3, a site previously shown to be targeted by scorpion alpha-toxins. The bioactive surfaces of toxin representatives from these two sea anemone types have been characterized by mutagenesis. These analyses pointed to heterogeneity of receptor site 3 at various sodium channels. A turning point in evolutionary studies of sea anemone toxins was the recent release of the genome sequence of Nematostella vectensis, which enabled analysis of the genomic organization of the corresponding genes. This analysis demonstrated that Type I toxins in Nematostella and other species are encoded by gene families and suggested that these genes developed by concerted evolution. The current review provides a brief historical description of the discovery and characterization of sea anemone toxins that affect voltage-gated sodium channels and delineates recent advances in the study of their structure-activity relationship and evolution.
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Affiliation(s)
- Yehu Moran
- Department of Plant Sciences, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel.
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Functional discrimination of sea anemone neurotoxins using 3D-plotting. Open Life Sci 2009. [DOI: 10.2478/s11535-008-0064-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
AbstractOne of the most important goals in structural biology is the identification of functional relationships among the structure of proteins and peptides. The purpose of this study was to (1) generate a model based on theoretical and computational considerations among amino acid sequences within select neurotoxin peptides, and (2) compare the relationship these values have to the various toxins tested. We employed isolated neurotoxins from sea anemones with established specific potential to act on voltage-dependent sodium and potassium channel activity as our model. Values were assigned to each amino acid in the peptide sequence of the neurotoxins tested using the Number of Lareo and Acevedo algorithm (NULA). Once the NULA number was obtained, it was then plotted using three dimensional space coordinates. The results of this study allow us to report, for the first time, that there is a different numerical and functional relationship between the sequences of amino acids from sea anemone neurotoxins, and the resulting numerical relationship for each peptide, or NULA number, has a unique location in three-dimensional space.
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Diochot S, Lazdunski M. Sea anemone toxins affecting potassium channels. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2009; 46:99-122. [PMID: 19184586 DOI: 10.1007/978-3-540-87895-7_4] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The great diversity of K(+) channels and their wide distribution in many tissues are associated with important functions in cardiac and neuronal excitability that are now better understood thanks to the discovery of animal toxins. During the past few decades, sea anemones have provided a variety of toxins acting on voltage-sensitive sodium and, more recently, potassium channels. Currently there are three major structural groups of sea anemone K(+) channel (SAK) toxins that have been characterized. Radioligand binding and electrophysiological experiments revealed that each group contains peptides displaying selective activities for different subfamilies of K(+) channels. Short (35-37 amino acids) peptides in the group I display pore blocking effects on Kv1 channels. Molecular interactions of SAK-I toxins, important for activity and binding on Kv1 channels, implicate a spot of three conserved amino acid residues (Ser, Lys, Tyr) surrounded by other less conserved residues. Long (58-59 amino acids) SAK-II peptides display both enzymatic and K(+) channel inhibitory activities. Medium size (42-43 amino acid) SAK-III peptides are gating modifiers which interact either with cardiac HERG or Kv3 channels by altering their voltage-dependent properties. SAK-III toxins bind to the S3C region in the outer vestibule of Kv channels. Sea anemones have proven to be a rich source of pharmacological tools, and some of the SAK toxins are now useful drugs for the diagnosis and treatment of autoimmune diseases.
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Affiliation(s)
- Sylvie Diochot
- Institut de Pharmacologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifi que, Université de Nice-Sophia-Antipolis, 660 Route des Lucioles, Valbonne, 06560, France
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11
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Salceda E, Pérez-Castells J, López-Méndez B, Garateix A, Salazar H, López O, Aneiros A, Ständker L, Béress L, Forssmann WG, Soto E, Jiménez-Barbero J, Giménez-Gallego G. CgNa, a type I toxin from the giant Caribbean sea anemone Condylactis gigantea shows structural similarities to both type I and II toxins, as well as distinctive structural and functional properties(1). Biochem J 2007; 406:67-76. [PMID: 17506725 PMCID: PMC1948996 DOI: 10.1042/bj20070130] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
CgNa (Condylactis gigantea neurotoxin) is a 47-amino-acid- residue toxin from the giant Caribbean sea anemone Condylactis gigantea. The structure of CgNa, which was solved by 1H-NMR spectroscopy, is somewhat atypical and displays significant homology with both type I and II anemone toxins. CgNa also displays a considerable number of exceptions to the canonical structural elements that are thought to be essential for the activity of this group of toxins. Furthermore, unique residues in CgNa define a characteristic structure with strong negatively charged surface patches. These patches disrupt a surface-exposed cluster of hydrophobic residues present in all anemone-derived toxins described to date. A thorough characterization by patch-clamp analysis using rat DRG (dorsal root ganglion) neurons indicated that CgNa preferentially binds to TTX-S (tetrodotoxin-sensitive) voltage-gated sodium channels in the resting state. This association increased the inactivation time constant and the rate of recovery from inactivation, inducing a significant shift in the steady state of inactivation curve to the left. The specific structural features of CgNa may explain its weaker inhibitory capacity when compared with the other type I and II anemone toxins.
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Affiliation(s)
- Emilio Salceda
- *Instituto de Fisiología, Universidad Autónoma de Puebla, 14 Sur 6301, 72570 Puebla, México
| | - Javier Pérez-Castells
- †Centro de Investigaciones Biológicas (CIB/CSIC), C. Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Blanca López-Méndez
- †Centro de Investigaciones Biológicas (CIB/CSIC), C. Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Anoland Garateix
- ‡Centro de Bioproductos Marinos (CEBIMAR), Calle Loma entre 35 y 37, Alturas del Vedado, 10600 Ciudad de la Habana, Cuba
| | - Hector Salazar
- *Instituto de Fisiología, Universidad Autónoma de Puebla, 14 Sur 6301, 72570 Puebla, México
| | - Omar López
- *Instituto de Fisiología, Universidad Autónoma de Puebla, 14 Sur 6301, 72570 Puebla, México
| | - Abel Aneiros
- ‡Centro de Bioproductos Marinos (CEBIMAR), Calle Loma entre 35 y 37, Alturas del Vedado, 10600 Ciudad de la Habana, Cuba
| | - Ludger Ständker
- †Centro de Investigaciones Biológicas (CIB/CSIC), C. Ramiro de Maeztu 9, 28040 Madrid, Spain
- §Hannover Medical School, Center of Pharmacology, 30625 Hannover, Germany
| | - Lászlo Béress
- §Hannover Medical School, Center of Pharmacology, 30625 Hannover, Germany
| | | | - Enrique Soto
- *Instituto de Fisiología, Universidad Autónoma de Puebla, 14 Sur 6301, 72570 Puebla, México
| | - Jesús Jiménez-Barbero
- †Centro de Investigaciones Biológicas (CIB/CSIC), C. Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Guillermo Giménez-Gallego
- †Centro de Investigaciones Biológicas (CIB/CSIC), C. Ramiro de Maeztu 9, 28040 Madrid, Spain
- To whom correspondence should be addressed ()
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Smith JJ, Blumenthal KM. Site-3 sea anemone toxins: Molecular probes of gating mechanisms in voltage-dependent sodium channels. Toxicon 2007; 49:159-70. [PMID: 17095031 DOI: 10.1016/j.toxicon.2006.09.020] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Sea anemone toxins, whose biological function is the capture of marine prey, are invaluable tools for studying the structure and function of mammalian voltage-gated sodium channels. Their high degree of specificity and selectivity have allowed for detailed analysis of inactivation gating and assignment of molecular entities responsible for this process. Because of their ability to discriminate among channel isoforms, and their high degree of structural conservation, these toxins could serve as important lead compounds for future pharmaceutical design.
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Affiliation(s)
- Jaime J Smith
- Department of Biochemistry, School of Medicine and Biomedical Sciences, State University of New York, 3435 Main St. Buffalo, NY 14214, USA
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Ständker L, Béress L, Garateix A, Christ T, Ravens U, Salceda E, Soto E, John H, Forssmann WG, Aneiros A. A new toxin from the sea anemone Condylactis gigantea with effect on sodium channel inactivation. Toxicon 2006; 48:211-20. [PMID: 16814340 DOI: 10.1016/j.toxicon.2006.05.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2006] [Revised: 05/04/2006] [Accepted: 05/08/2006] [Indexed: 11/18/2022]
Abstract
A new peptide toxin exhibiting a molecular weight of 5043Da (av.) and comprising 47 amino acid residues was isolated from the sea anemone Condylactis gigantea. Purification of the peptide was achieved by a multistep chromatographic procedure monitoring its strong paralytic activity on crustacea (LD(50) approx. 1microg/kg). Complete sequence analysis of the toxic peptide revealed the isolation of a new member of type I sea anemone sodium channel toxins containing the typical pattern of the six cysteine residues. From 11kg of wet starting material, approximately 1g of the peptide toxin was isolated. The physiological action of the new toxin from C. gigantea CgNa was investigated on sodium currents of rat dorsal root ganglion neurons in culture using whole-cell patch clamp technique (n=60). Under current clamp condition (CgNa) increased action potential duration. This effect is due to slowing down of the TTX-S sodium current inactivation, without modifying the activation process. CgNa prolonged the cardiac action potential duration and enhanced contractile force albeit at 100-fold higher concentrations than the Anemonia sulcata toxin ATXII. The action on sodium channel inactivation and on cardiac excitation-contraction coupling resemble previous results with compounds obtained from this and other sea anemones [Shapiro, B.I., 1968. Purification of a toxin from tentacles of the anemone C. gigantea. Toxicon 5, 253-259; Pelhate, M., Zlotkin, E., 1982. Actions of insect toxin and other toxins derived from the venom of scorpion Androtonus australis on isolated giant axons of the cockroach Periplaneta americana. J. Exp. Biol. 97, 67-77; Salgado, V., Kem, W., 1992. Actions of three structurally distinct sea anemone toxins on crustacean and insect sodium channels. Toxicon 30, 1365-1381; Bruhn, T., Schaller, C., Schulze, C., Sanchez-Rodriquez, J., Dannmeier, C., Ravens, U., Heubach, J.F., Eckhardt, K., Schmidtmayer, J., Schmidt, H., Aneiros, A., Wachter, E., Béress, L., 2001. Isolation and characterization of 5 neurotoxic and cardiotoxic polypeptides from the sea anemone Anthopleura elegantissima. Toxicon, 39, 693-702]. Comprehensive analysis of the purified active fractions suggests that CgNa may represent the main peptide toxin of this sea anemone species.
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Affiliation(s)
- Ludger Ständker
- IPF PharmaCeuticals GmbH, Feodor-Lynen Strasse 31, 30625 Hannover, Germany.
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Honma T, Shiomi K. Peptide toxins in sea anemones: structural and functional aspects. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2006; 8:1-10. [PMID: 16372161 PMCID: PMC4271777 DOI: 10.1007/s10126-005-5093-2] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2005] [Accepted: 08/15/2005] [Indexed: 05/05/2023]
Abstract
Sea anemones are a rich source of two classes of peptide toxins, sodium channel toxins and potassium channel toxins, which have been or will be useful tools for studying the structure and function of specific ion channels. Most of the known sodium channel toxins delay channel inactivation by binding to the receptor site 3 and most of the known potassium channel toxins selectively inhibit Kv1 channels. The following peptide toxins are functionally unique among the known sodium or potassium channel toxins: APETx2, which inhibits acid-sensing ion channels in sensory neurons; BDS-I and II, which show selectivity for Kv3.4 channels and APETx1, which inhibits human ether-a-go-go-related gene potassium channels. In addition, structurally novel peptide toxins, such as an epidermal growth factor (EGF)-like toxin (gigantoxin I), have also been isolated from some sea anemones although their functions remain to be clarified.
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Affiliation(s)
- Tomohiro Honma
- Department of Food Science and Technology, Tokyo University of Marine Science and Technology, Konan-4, Minato-ku, Tokyo, 108-8477 Japan
| | - Kazuo Shiomi
- Department of Food Science and Technology, Tokyo University of Marine Science and Technology, Konan-4, Minato-ku, Tokyo, 108-8477 Japan
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Béress L. Biologically Active Polypeptides ofAnemonia sulcata—and of Other Sea Anemones—Tools in the Study of Exitable Membranes. ACTA ACUST UNITED AC 2004. [DOI: 10.1081/txr-200038380] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Wang L, Ou J, Peng L, Zhong X, Du J, Liu Y, Huang Y, Liu W, Zhang Y, Dong M, Xu AL. Functional expression and characterization of four novel neurotoxins from sea anemone Anthopleura sp. Biochem Biophys Res Commun 2004; 313:163-70. [PMID: 14672713 DOI: 10.1016/j.bbrc.2003.11.102] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The genes of four novel neurotoxins, named Hk2a, Hk7a, Hk8a, and Hk16a, were obtained from sea anemone Anthopleura sp. All four neurotoxins were composed of 47 amino acid residues and the variable residues among them were found in positions 14, 22, 25, and 37. To study their activities, the four toxins fused to the Escherichia coli thioredoxin were overexpressed by BL21 (DE3), cleaved off from the fusion partner, purified, and characterized with MALDI-TOF and CD assays. Contractile force studies of isolated SD atria indicated that rHk2a had the strongest and rHk7a the longest heart stimulation effect. Consequently, the Arg14, a highly conserved residue in various sea anemone neurotoxins, can be inferred to contribute to the duration but not the intensity of contraction-stimulating activity. Our work renders useful information to studies of sea anemone neurotoxins, especially to the clarification of the function of the disputative Arg14.
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Affiliation(s)
- Lei Wang
- Department of Biochemistry, College of Life Sciences, Sun Yat-sen (Zhongshan) University, Guangzhou 510275, People's Republic of China
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Rossi S, Snyder MJ. Competition for space among sessile marine invertebrates: changes in HSP70 expression in two Pacific cnidarians. THE BIOLOGICAL BULLETIN 2001; 201:385-393. [PMID: 11751250 DOI: 10.2307/1543616] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The role of stress proteins-either constitutive (HSC) or inducible (HSP)-of the HSP70 family in intra- and interspecific competition for space was examined in two sessile Pacific cnidarians. Anthopleura elegantissima, an intertidal anemone, and Corynactis californica, a subtidal corallimorpharian, express HSP70 in the absence of apparent physical stress. HSP70 protein expression is concentrated in the tentacles of A. elegantissima when the animal is exposed to contact with other benthic organisms. Under the same conditions, however, HSP concentrations are similar in the body and tentacles of C. californica. When two different clones of A. elegantissima interact in the field, the outside polyps (warriors) express more HSP70 than the inside ones (2.4 versus 0.6 ng HSP70/microg Protein). When different C. californica clones interact, HSP70 expression in the outside and inside polyps is similar (1.5 versus 1.8 ng HSP70/microg P) and is fairly constant in the corallimorpharian in the different interspecific encounters. HSP70 expression is related to the different kinds of aggression encountered by both cnidarians. HSP70 expression may be involved in the recovery of tissues damaged by the allelochemical, cytotoxical, or corrosive substances produced by different enemies. C. californica clones appear prepared for war, as evidenced by the high constant expression of HSP70 in the polyps. A. elegantissima exhibits differential HSP70 expression depending on the identity of each neighboring intra- or interspecific sessile competitor. We propose that stress proteins can be used to quantify space competition or aggression among sessile marine invertebrates.
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Affiliation(s)
- S Rossi
- University of California, Davis, and Bodega Marine Laboratory, P.O. Box 247, Bodega Bay, California 94923, USA.
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Bruhn T, Schaller C, Schulze C, Sanchez-Rodriguez J, Dannmeier C, Ravens U, Heubach JF, Eckhardt K, Schmidtmayer J, Schmidt H, Aneiros A, Wachter E, Béress L. Isolation and characterisation of five neurotoxic and cardiotoxic polypeptides from the sea anemone Anthopleura elegantissima. Toxicon 2001; 39:693-702. [PMID: 11072049 DOI: 10.1016/s0041-0101(00)00199-9] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Five toxins (APE 1 to APE 5) of the sea anemone species Anthopleura elegantissima (Brandt) have been isolated from a toxic by-product fraction of its concentrated crude watery-methanolic extract, prepared previously for the isolation of a neuropeptide (the head-activator) by Schaller and Bodenmüller (Proc. Natl. Acad. Sci. USA 78 (1981) 7000) from 200kg sea anemones. Toxin purification was performed by desalting of the starting material by dialysis (MWCO 3500) against distilled water, anion exchange chromatography on QAE-Sephadex A25 at pH 8, twice gel filtration on Sephadex G50 m, repeated chromatography on QAE-Sephadex at pH 10 and chromatography on the cation exchanger Fractogel EMD SO(3)(-)-650 M.Final purification of the toxins was achieved by HPLC on MN SP 250/10 Nucleosil 500-5 C(18) PPN and MN SP 250/21 Nucleosil 300-7 C(18). Each toxin was composed of at least two isotoxins of which APE 1-1, APE 1-2, APE 2-1, APE 2-2 and APE 5-3 were isolated in preparative scale. With exception of APE 5-3 the sequences of the isotoxins have been elucidated. They resemble the 47 residue type-I long polypeptide toxins native to Anemonia sulcata (Pennant). All isotoxins paralyse the shore crab (Carcinus maenas) by tetanic contractions after i.m. application. The toxins modify current passing through the fast Na(+) channel in neuroblastoma cells, leading to delayed and incomplete inactivation. APE 1-1, APE 2-1 and APE 5-3 produce a positive inotropic effect in mammalian heart muscle, although they differ in potency. The order of potency is APE 2-1>APE 1-1>APE 5-3 (i.e. threshold concentrations are 1, 10 and 300nM, respectively). In addition, they enhance the spontaneous beating frequency in isolated right atria (guinea pig). The most potent cardiotoxic isotoxin is APE 2-1, its sequence is identical with that of AP-C, a toxin isolated and characterised previously by Norton et al. (Drugs and Foods from the Sea, 1978, University of Oklahoma Press, p. 37-50).LD50 APE 2-1:1 micro g/kg b.w. C. maenas (i.m.). LD50 APE 1-1:10 microg/kg b.w. C. maenas (i. m.). LD50 APE 5-3:50 microg/kg b.w. C. maenas (i.m.).
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Affiliation(s)
- T Bruhn
- Institute of Toxicology, Medical Faculty Christian-Albrechts-University, Brunswikerstrasse 10, 24105, Kiel, Germany
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