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Oliveira CS, Caldeira CAS, Diniz-Sousa R, Romero DL, Marcussi S, Moura LA, Fuly AL, de Carvalho C, Cavalcante WLG, Gallacci M, Pai MD, Zuliani JP, Calderon LA, Soares AM. Pharmacological characterization of cnidarian extracts from the Caribbean Sea: evaluation of anti-snake venom and antitumor properties. J Venom Anim Toxins Incl Trop Dis 2018; 24:22. [PMID: 30181737 PMCID: PMC6114500 DOI: 10.1186/s40409-018-0161-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 08/07/2018] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Cnidarians produce toxins, which are composed of different polypeptides that induce pharmacological effects of biotechnological interest, such as antitumor, antiophidic and anti-clotting activities. This study aimed to evaluate toxicological activities and potential as antitumor and antiophidic agents contained in total extracts from five cnidarians: Millepora alcicornis, Stichodactyla helianthus, Plexaura homomalla, Bartholomea annulata and Condylactis gigantea (total and body wall). METHODS The cnidarian extracts were evaluated by electrophoresis and for their phospholipase, proteolytic, hemorrhagic, coagulant, fibrinogenolytic, neuromuscular blocking, muscle-damaging, edema-inducing and cytotoxic activities. RESULTS All cnidarian extracts showed indirect hemolytic activity, but only S. helianthus induced direct hemolysis and neurotoxic effect. However, the hydrolysis of NBD-PC, a PLA2 substrate, was presented only by the C. gigantea (body wall) and S. helianthus. The extracts from P. homomalla and S. helianthus induced edema, while only C. gigantea and S. helianthus showed intensified myotoxic activity. The proteolytic activity upon casein and fibrinogen was presented mainly by B. annulata extract and all were unable to induce hemorrhage or fibrinogen coagulation. Cnidarian extracts were able to neutralize clotting induced by Bothrops jararacussu snake venom, except M. alcicornis. All cnidarian extracts were able to inhibit hemorrhagic activity induced by Bothrops moojeni venom. Only the C. gigantea (body wall) inhibited thrombin-induced coagulation. All cnidarian extracts showed antitumor effect against Jurkat cells, of which C. gigantea (body wall) and S. helianthus were the most active; however, only C. gigantea (body wall) and M. alcicornis were active against B16F10 cells. CONCLUSION The cnidarian extracts analyzed showed relevant in vitro inhibitory potential over the activities induced by Bothrops venoms; these results may contribute to elucidate the possible mechanisms of interaction between cnidarian extracts and snake venoms.
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Affiliation(s)
- Cláudia S. Oliveira
- Centro de Estudos de Biomoléculas Aplicadas a Saúde (CEBio), Fundação Oswaldo Cruz de Rondônia (Fiocruz Rondônia), Porto Velho, RO Brazil
- Brazilian Marine Biotechnology Network (BioTecMar Network), Porto Velho, Brazil
- Departamento de Medicina, Universidade Federal de Rondônia (UNIR), Porto Velho, RO Brazil
| | - Cleópatra A. S. Caldeira
- Centro de Estudos de Biomoléculas Aplicadas a Saúde (CEBio), Fundação Oswaldo Cruz de Rondônia (Fiocruz Rondônia), Porto Velho, RO Brazil
- Brazilian Marine Biotechnology Network (BioTecMar Network), Porto Velho, Brazil
- Departamento de Medicina, Universidade Federal de Rondônia (UNIR), Porto Velho, RO Brazil
| | - Rafaela Diniz-Sousa
- Centro de Estudos de Biomoléculas Aplicadas a Saúde (CEBio), Fundação Oswaldo Cruz de Rondônia (Fiocruz Rondônia), Porto Velho, RO Brazil
- Brazilian Marine Biotechnology Network (BioTecMar Network), Porto Velho, Brazil
- Departamento de Medicina, Universidade Federal de Rondônia (UNIR), Porto Velho, RO Brazil
| | - Dolores L. Romero
- Centro de Estudios de Proteínas, Facultad de Biología, Universidad de La Habana, Havana, Cuba
| | - Silvana Marcussi
- Departamento de Química, Universidade Federal de Lavras (UFLA), Lavras, MG Brazil
| | - Laura A. Moura
- Departamento de Biologia Celular e Molecular (GCM), Instituto de Biologia, Universidade Federal Fluminense (UFF), Niterói, RJ Brazil
| | - André L. Fuly
- Departamento de Biologia Celular e Molecular (GCM), Instituto de Biologia, Universidade Federal Fluminense (UFF), Niterói, RJ Brazil
| | - Cicília de Carvalho
- Departamento de Farmacologia, Instituto de Biociências, Universidade Estadual Paulista (UNESP), Botucatu, SP Brazil
| | - Walter L. G. Cavalcante
- Departamento de Farmacologia, Instituto de Biociências, Universidade Estadual Paulista (UNESP), Botucatu, SP Brazil
- Instituto de Ciências Biológicas, Departamento de Farmacologia, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG Brazil
| | - Márcia Gallacci
- Departamento de Farmacologia, Instituto de Biociências, Universidade Estadual Paulista (UNESP), Botucatu, SP Brazil
| | - Maeli Dal Pai
- Departamento de Morfologia, Instituto de Biociências, Universidade Estadual Paulista (UNESP), Botucatu, SP Brazil
| | - Juliana P. Zuliani
- Centro de Estudos de Biomoléculas Aplicadas a Saúde (CEBio), Fundação Oswaldo Cruz de Rondônia (Fiocruz Rondônia), Porto Velho, RO Brazil
- Brazilian Marine Biotechnology Network (BioTecMar Network), Porto Velho, Brazil
- Departamento de Medicina, Universidade Federal de Rondônia (UNIR), Porto Velho, RO Brazil
| | - Leonardo A. Calderon
- Centro de Estudos de Biomoléculas Aplicadas a Saúde (CEBio), Fundação Oswaldo Cruz de Rondônia (Fiocruz Rondônia), Porto Velho, RO Brazil
- Brazilian Marine Biotechnology Network (BioTecMar Network), Porto Velho, Brazil
- Departamento de Medicina, Universidade Federal de Rondônia (UNIR), Porto Velho, RO Brazil
| | - Andreimar M. Soares
- Centro de Estudos de Biomoléculas Aplicadas a Saúde (CEBio), Fundação Oswaldo Cruz de Rondônia (Fiocruz Rondônia), Porto Velho, RO Brazil
- Brazilian Marine Biotechnology Network (BioTecMar Network), Porto Velho, Brazil
- Departamento de Medicina, Universidade Federal de Rondônia (UNIR), Porto Velho, RO Brazil
- Centro Universitário São Lucas (UniSL), Porto Velho, RO Brazil
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Ahumada M, Calderon C, Lissi E, Alvarez C, Lanio M, Pazos F. The pore forming capacity of Sticholysin I in dipalmitoyl phosphatidyl vesicles is tuned by osmotic stress. Chem Phys Lipids 2017; 203:87-93. [DOI: 10.1016/j.chemphyslip.2016.12.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 12/28/2016] [Accepted: 12/28/2016] [Indexed: 11/25/2022]
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3
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Cabezas S, Ho S, Ros U, Lanio ME, Alvarez C, van der Goot FG. Damage of eukaryotic cells by the pore-forming toxin sticholysin II: Consequences of the potassium efflux. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:982-992. [PMID: 28173991 DOI: 10.1016/j.bbamem.2017.02.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 01/06/2017] [Accepted: 02/03/2017] [Indexed: 01/17/2023]
Abstract
Pore-forming toxins (PFTs) form holes in membranes causing one of the most catastrophic damages to a target cell. Target organisms have evolved a regulated response against PFTs damage including cell membrane repair. This ability of cells strongly depends on the toxin concentration and the properties of the pores. It has been hypothesized that there is an inverse correlation between the size of the pores and the time required to repair the membrane, which has been for long a non-intuitive concept and far to be completely understood. Moreover, there is a lack of information about how cells react to the injury triggered by eukaryotic PFTs. Here, we investigated some molecular events related with eukaryotic cells response against the membrane damage caused by sticholysin II (StII), a eukaryotic PFT produced by a sea anemone. We evaluated the change in the cytoplasmic potassium, identified the main MAPK pathways activated after pore-formation by StII, and compared its effect with those from two well-studied bacterial PFTs: aerolysin and listeriolysin O (LLO). Strikingly, we found that membrane recovery upon StII damage takes place in a time scale similar to LLO in spite of the fact that they form pores by far different in size. Furthermore, our data support a common role of the potassium ion, as well as MAPKs in the mechanism that cells use to cope with these toxins injury.
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Affiliation(s)
- Sheila Cabezas
- Center for Protein Studies, Faculty of Biology, Havana University, Street 25 # 455, CP 10400, Havana, Cuba.
| | - Sylvia Ho
- École Polytechnique Fédérale de Lausanne, Global Health Institution, Faculty of Life Sciences, Station 15, CH 1015 Lausanne, Switzerland.
| | - Uris Ros
- Center for Protein Studies, Faculty of Biology, Havana University, Street 25 # 455, CP 10400, Havana, Cuba; Interfakultäres Institut für Biochemie, Universität Tübingen, Hoppe Seyler Strasse, 4, 72076, Tübingen, Germany.
| | - María E Lanio
- Center for Protein Studies, Faculty of Biology, Havana University, Street 25 # 455, CP 10400, Havana, Cuba.
| | - Carlos Alvarez
- Center for Protein Studies, Faculty of Biology, Havana University, Street 25 # 455, CP 10400, Havana, Cuba.
| | - F Gisou van der Goot
- École Polytechnique Fédérale de Lausanne, Global Health Institution, Faculty of Life Sciences, Station 15, CH 1015 Lausanne, Switzerland.
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Fauth EVF, Cilli EM, Ligabue-Braun R, Verli H. Differential effect of solution conditions on the conformation of the actinoporins Sticholysin II and Equinatoxin II. AN ACAD BRAS CIENC 2015; 86:1949-62. [PMID: 25590731 DOI: 10.1590/0001-3765201420140270] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 08/11/2014] [Indexed: 11/22/2022] Open
Abstract
Actinoporins are a family of pore-forming proteins with hemolytic activity. The structural basis for such activity appears to depend on their correct folding. Such folding encompasses a phosphocholine binding site, a tryptophan-rich region and the activity-related N-terminus segment. Additionally, different solution conditions are known to be able to influence the pore formation by actinoporins, as for Sticholysin II (StnII) and Equinatoxin II (EqtxII). In this context, the current work intends to characterize the influence of distinct solution conditions in the conformational behavior of these proteins through molecular dynamics (MD) simulations. The obtained data offer structural insights into actinoporins dynamics in solution, characterizing its conformational behavior at the atomic level, in accordance with previous experimental data on StnII and EqtxII hemolytic activities.
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Affiliation(s)
| | - Eduardo M Cilli
- Departamento de Bioquímica e Tecnologia Química, UNESP, Instituto de Química, Universidade Estadual Paulista, Araraquara, SP, Brasil
| | | | - Hugo Verli
- Centro de Biotecnologia, UFRGS, Porto Alegre, RS, Brasil
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5
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Perforin oligomers form arcs in cellular membranes: a locus for intracellular delivery of granzymes. Cell Death Differ 2014; 22:74-85. [PMID: 25146929 DOI: 10.1038/cdd.2014.110] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 07/01/2014] [Accepted: 07/03/2014] [Indexed: 01/28/2023] Open
Abstract
Perforin-mediated cytotoxicity is an essential host defense, in which defects contribute to tumor development and pathogenic disorders including autoimmunity and autoinflammation. How perforin (PFN) facilitates intracellular delivery of pro-apoptotic and inflammatory granzymes across the bilayer of targets remains unresolved. Here we show that cellular susceptibility to granzyme B (GzmB) correlates with rapid PFN-induced phosphatidylserine externalization, suggesting that pores are formed at a protein-lipid interface by incomplete membrane oligomers (or arcs). Supporting a role for these oligomers in protease delivery, an anti-PFN antibody (pf-80) suppresses necrosis but increases phosphatidylserine flip-flop and GzmB-induced apoptosis. As shown by atomic force microscopy on planar bilayers and deep-etch electron microscopy on mammalian cells, pf-80 increases the proportion of arcs which correlates with the presence of smaller electrical conductances, while large cylindrical pores decline. PFN appears to form arc structures on target membranes that serve as minimally disrupting conduits for GzmB translocation. The role of these arcs in PFN-mediated pathology warrants evaluation where they may serve as novel therapeutic targets.
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Vequi-Suplicy CC, Coutinho K, Teresa Lamy M. Optical characterization of Prodan aggregates in water medium. Phys Chem Chem Phys 2013; 15:11800-7. [DOI: 10.1039/c3cp51776d] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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7
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Pharmacological effects of two cytolysins isolated from the sea anemone Stichodactyla helianthus. J Biosci 2009; 34:891-8. [DOI: 10.1007/s12038-009-0103-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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8
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Álvarez C, Mancheño JM, Martínez D, Tejuca M, Pazos F, Lanio ME. Sticholysins, two pore-forming toxins produced by the Caribbean Sea anemone Stichodactyla helianthus: Their interaction with membranes. Toxicon 2009; 54:1135-47. [DOI: 10.1016/j.toxicon.2009.02.022] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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9
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Abstract
Sea anemones produce a variety of toxic peptides and proteins, including many ion channel blockers and modulators, as well as potent cytolysins. This review describes the structures that have been determined to date for the major classes of peptide and protein toxins. In addition, established and emerging methods for structure determination are summarized and the prospects for modelling newly described toxins are evaluated. In common with most other classes of proteins, toxins display conformational flexibility which may play a role in receptor binding and function. The prospects for obtaining atomic resolution structures of toxins bound to their receptors are also discussed.
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11
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Celedón G, González G, Barrientos D, Pino J, Venegas F, Lissi EA, Soto C, Martinez D, Alvarez C, Lanio ME. Stycholysin II, a cytolysin from the sea anemone Stichodactyla helianthus promotes higher hemolysis in aged red blood cells. Toxicon 2008; 51:1383-90. [PMID: 18423792 DOI: 10.1016/j.toxicon.2008.03.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2007] [Revised: 12/20/2007] [Accepted: 03/04/2008] [Indexed: 01/09/2023]
Abstract
We have investigated the relationship between the status of red blood cells (RBCs) and their susceptibility to toxin sticholysin II (StII) hemolytic activity; we have evaluated this effect in different RBC ensembles, comprising young and old cells, and in cells partially damaged by their pre-exposition to a free radical source. Upon action of StII, young cell populations are less prone to hemolysis than the whole population, while old cell populations and peroxyl-oxidized red cells are lysed faster than the whole population. Cell K(+) content was higher in young cells and lower in both senescent cells and in peroxyl-damaged cells relative to whole cell population. The relevance of cell K(+) content in St II-induced lysis was shown when external Na(+) was partially replaced by K(+); under this condition, RBC lysed faster in the presence of St II but no difference was observed among young cells, whole cells population and peroxyl-damaged cells; only old cells lysed faster that the whole population, response that can be due to an enhanced St II-induced pore formation as supported by evaluation of St II irreversible binding to RBC. It is concluded that this factor and the amount of intracellular K(+) are the dominant parameters that modulate the resistance of RBC to St II-induced lysis.
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Affiliation(s)
- Gloria Celedón
- Departamento de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Chile
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12
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Vakorina TI, Klyshko EV, Monastyrnaya MM, Kozlovskaya EP. Conformational Stability and Hemolytic Activity of Actinoporin RTX-SII from the Sea Anemone Radianthus macrodactylus. BIOCHEMISTRY (MOSCOW) 2005; 70:790-8. [PMID: 16097943 DOI: 10.1007/s10541-005-0185-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The spatial organization of actinoporin RTX-SII from the sea anemone Radianthus macrodactylus on the level of tertiary and secondary structures was studied by UV and CD spectroscopy and intrinsic protein fluorescence. The specific and molar extinction coefficients of RTX-SII were determined. The percentages of canonical secondary structures of actinoporin were calculated. The tertiary structure of the polypeptide is well developed and its secondary structure is highly ordered and contains about 50% antiparallel folded beta-sheets. The irreversible thermal denaturation of RTX-SII was studied by CD spectroscopy; a conformational transition occurs at 53 degrees C. Above this temperature irreversible conformational changes are observed in the secondary and tertiary structures. This is accompanied by redistribution of the content of regular and distorted forms of beta-sheet and also by increase in the content of an unordered form. It is suggested that an intermediate is formed in the process of thermal denaturation. Acid-base titration of RTX-SII results in irreversible conformational changes at pH below 2.0 and above 12.0. As shown by intrinsic protein fluorescence, tyrosine residues of RTX-SII make a fundamental contribution to emission, and the total fluorescence depends more on temperature and ionic strength of the solution than tryptophan fluorescence. The data on conformational stability of actinoporin are correlated with data on its hemolytic activity. Activity of RTX-SII significantly decreases at increased temperature and slightly decreases at low pH. Hemolytic activity drastically increases at high pH. Increase in the actinoporin activity at pH above 10 seems to be caused by ionization of the molecule.
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Affiliation(s)
- T I Vakorina
- Pacific Institute of Bioorganic Chemistry, Far East Branch of the Russian Academy of Sciences, Vladivostok, 690022, Russia.
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13
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Alvarez C, Tejuca M, Pazos I, Lanio M, Garateix A, Aneiros A. Overview of Marine Toxin Research in Cuba. ACTA ACUST UNITED AC 2003. [DOI: 10.1080/08865140302430] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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14
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Lanio ME, Alvarez C, Pazos F, Martinez D, Martínez Y, Casallanovo F, Abuin E, Schreier S, Lissi E. Effects of sodium dodecyl sulfate on the conformation and hemolytic activity of St I and St II, two isotoxins purified from Stichodactyla helianthus. Toxicon 2003; 41:65-70. [PMID: 12467663 DOI: 10.1016/s0041-0101(02)00210-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The effect of sodium dodecyl sulfate (SDS) upon the conformation and hemolytic activity of St I and St II strongly depends on its concentration. At relatively low surfactant concentrations (ca. 0.5-5mM range) the surfactant leads to the formation of aggregates, as suggested by the turbidity observed even at relatively low (micromolar range) protein concentrations. In this surfactant range, the proteins show an increase in intrinsic fluorescence intensity and reduced quenching by acrylamide, with an almost total loss of its hemolytic activity. At higher surfactant concentrations the protein adducts disaggregates. This produces a decrease in fluorescence intensity, increase in quenching efficiency by acrylamide, loss of the native tertiary conformation (as reported by the near UV-CD spectra), and increase in alpha-helix content (as evidenced by the far UV-CD spectra). However, and in spite of these substantial changes, the toxins partially recover their hemolytic activity. The reasons for this recovering of the activity at high surfactant concentrations is discussed.
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Affiliation(s)
- M E Lanio
- Faculty of Biology, University of Habana, La Habana, Cuba
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15
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Lanio ME, Alvarez C, Martinez FD, Casallanovo F, Schreier S, Campos AM, Abuin E, Lissi E. Effect of a zwitterionic surfactant (HPS) on the conformation and hemolytic activity of St I and St II, two isotoxins purified from Stichodactyla helianthus. JOURNAL OF PROTEIN CHEMISTRY 2002; 21:401-5. [PMID: 12492150 DOI: 10.1023/a:1021130516229] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
N-hexadecyl-N-N'-dimethyl-3-ammonio-1-propane-sulfonate (BPS) is a zwitterionic surfactant that readily binds to sticholysins I and II, two sea toxins isolated from Stichodactyla helianthus. The binding constants, evaluated from changes in fluorescence intensities elicited by the surfactant, are approximately 0.5-0.7 microM(-1). The binding of the surfactant changes the conformation of the tertiary protein, without significant changes in its secondary structure, as reported from far-ultraviolet circular dichroism spectra. The changes elicited by HPS lead to loss of the native conformation (as reported from near-ultraviolet circular dichroism spectra) and to a shift of the intrinsic protein fluorescence toward longer wavelengths, an increase in fluorescence intensities and lifetimes, and a faster quenching by acrylamide. All these changes are indicative of a more expanded tertiary conformation. Despite this, the toxins fully retain their hemolytic activities, indicating that spectroscopic changes can be poor predictors of toxin activity.
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Affiliation(s)
- M E Lanio
- Center for Protein Studies, Faculty of Biology, University of Havana, La Habana, Cuba
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16
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Martínez D, Morera V, Alvarez C, Tejuca M, Pazos F, García Y, Raida M, Padrón G, Eliana Lanio M. Identity between cytolysins purified from two morphos of the Caribbean sea anemone Stichodactyla helianthus. Toxicon 2002; 40:1219-221. [PMID: 12165325 DOI: 10.1016/s0041-0101(02)00101-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Stichodactyla helianthus is a sea anemone relatively abundant along Cuban coasts appearing in two morphos with different colors in their tentacles: green or brownish, probably due to their association with algal symbionts. Traditionally, the brownish morpho has been used as a source of sticholysins I and II, the most characterized cytolysins from this anemone, but the green morpho is the most abundant along the western coasts of Havana. The present work is aimed to establish if the cytolysins purified from the green morpho (StIg and StIIg) are similar to those purified from brownish anemones (StI and StII). Following the same chromatographic procedure used to purify the toxins from morphos, the electrophoretic mobilities, amino acid compositions, amino terminal sequences and molecular masses were practically identical between analogal cytolysins. In conclusion, homologous sticholysins purified from the green and brownish variants of Stichodactyla helianthus are the same molecular entities.
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Affiliation(s)
- Diana Martínez
- Department of Biochemistry, Biology Faculty, University of Havana, Calle 25 No 455, Plaza, P.O. Box 10400, Havana City, Cuba
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17
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Martinez D, Campos AM, Pazos F, Alvarez C, Lanio ME, Casallanovo F, Schreier S, Salinas RK, Vergara C, Lissi E. Properties of St I and St II, two isotoxins isolated from Stichodactyla helianthus: a comparison. Toxicon 2001; 39:1547-60. [PMID: 11478962 DOI: 10.1016/s0041-0101(01)00127-1] [Citation(s) in RCA: 53] [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
Sticholysins I and II are two highly hemolytic polypeptides purified from the Caribbean Sea anemone Stichodactyla helianthus. Their high sequence homology (93%) indicates that they correspond to isoforms of the same hemolysin. The spectroscopic measurements show a close similarity in the secondary structure content, conformation and stability of both toxins. Exposure of the toxins to high pHs (>11), a free radical source (AAPH), urea or temperature produce permanent changes in the toxin that lead to a significant loss of HA. It is significant to note that this loss of hemolytic activity occurs when other indicators, probably with the only exception of near-UV CD spectra, barely detect changes in the protein structure. This emphasizes the sensitivity of the protein function to changes in the macromolecule conformation. The most noticeable difference between both toxins is the considerably higher activity of St II, both measured in terms of erythrocyte internal K(+) exit or hemolysis; which is related to enthalpic factors. This difference is not due to an incomplete association of St I to the membrane. We consider then that the different pore forming capacity of both toxins in erythrocytes can be explained in terms of the difference in charge of the N-terminal fragment, than can considerably reduce the St I insertion rate in the membrane probably due to the negatively charged outer leaflet of the red blood cell, without a significant reduction of its capacity to bind to the cell membrane. This electrostatic effect, together with a slightly more relaxed structure in St II, could explain the higher pore forming capacity of St II in the red blood cell membrane.
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Affiliation(s)
- D Martinez
- Faculty of Biology, University of La Habana, Cuba
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