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de Oliveira IS, Alano-da-Silva NM, Ferreira IG, Cerni FA, Sachett JDAG, Monteiro WM, Pucca MB, Arantes EC. Understanding the complexity of Tityus serrulatus venom: A focus on high molecular weight components. J Venom Anim Toxins Incl Trop Dis 2024; 30:e20230046. [PMID: 38317796 PMCID: PMC10843179 DOI: 10.1590/1678-9199-jvatitd-2023-0046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 12/04/2023] [Indexed: 02/07/2024] Open
Abstract
Tityus serrulatus scorpion is responsible for a significant number of envenomings in Brazil, ranging from mild to severe, and in some cases, leading to fatalities. While supportive care is the primary treatment modality, moderate and severe cases require antivenom administration despite potential limitations and adverse effects. The remarkable proliferation of T. serrulatus scorpions, attributed to their biology and asexual reproduction, contributes to a high incidence of envenomation. T. serrulatus scorpion venom predominantly consists of short proteins acting as neurotoxins (α and β), that primarily target ion channels. Nevertheless, high molecular weight compounds, including metalloproteases, serine proteases, phospholipases, and hyaluronidases, are also present in the venom. These compounds play a crucial role in envenomation, influencing the severity of symptoms and the spread of venom. This review endeavors to comprehensively understand the T. serrulatus scorpion venom by elucidating the primary high molecular weight compounds and exploring their potential contributions to envenomation. Understanding these compounds' mechanisms of action can aid in developing more effective treatments and prevention strategies, ultimately mitigating the impact of scorpion envenomation on public health in Brazil.
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Affiliation(s)
- Isadora Sousa de Oliveira
- Department of BioMolecular Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Nicoly Malachize Alano-da-Silva
- Department of BioMolecular Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Isabela Gobbo Ferreira
- Department of BioMolecular Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Felipe Augusto Cerni
- Health and Sciences Postgraduate Program, Federal University of Roraima, Boa Vista, RR, Brazil
| | - Jacqueline de Almeida Gonçalves Sachett
- School of Health Sciences, Amazonas State University, Manaus, AM, Brazil
- Department of Teaching and Research, Dr. Heitor Vieira Dourado Tropical Medicine Foundation, Manaus, AM, Brazil
| | - Wuelton Marcelo Monteiro
- School of Health Sciences, Amazonas State University, Manaus, AM, Brazil
- Department of Teaching and Research, Dr. Heitor Vieira Dourado Tropical Medicine Foundation, Manaus, AM, Brazil
| | - Manuela Berto Pucca
- Department of Clinical Analysis, School of Pharmaceutical Sciences, São Paulo State University, Araraquara, SP, Brazil
| | - Eliane Candiani Arantes
- Department of BioMolecular Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
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Kalapothakis Y, Miranda K, Pereira AH, Witt ASA, Marani C, Martins AP, Leal HG, Campos-Júnior E, Pimenta AMC, Borges A, Chávez-Olórtegui C, Kalapothakis E. Novel components of Tityus serrulatus venom: A transcriptomic approach. Toxicon 2020; 189:91-104. [PMID: 33181162 DOI: 10.1016/j.toxicon.2020.11.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 10/01/2020] [Accepted: 11/08/2020] [Indexed: 12/13/2022]
Abstract
Several research groups have studied the components produced by the venom gland of the scorpion Tityus serrulatus, which has one of the most lethal venoms in the world. Various methodologies have been employed to clarify the complex mechanisms of action of these components, especially neurotoxins and enzymes. Transcriptomes and proteomes have provided important information for pharmacological, biochemical, and immunological research. Next-generation sequencing (NGS) has allowed the description of new transcripts and completion of partial sequence descriptions for peptides, especially those with low expression levels. In the present work, after NGS sequencing, we searched for new putative venom components. We present a total of nine new transcripts with neurotoxic potential (Ts33-41) and describe the sequences of one hyaluronidase (TsHyal_4); three enzymes involved in amidation (peptidyl-glycine alpha-amidating monooxygenase A, peptidyl-alpha-hydroxyglycine alpha-amidating lyase, and peptidylglycine alpha-hydroxylating monooxygenase), which increases the lethal potential of neurotoxins; and also the enzyme Ts_Chitinase1, which may be involved in the venom's digestive action. In addition, we determined the level of transcription of five groups: toxins, metalloproteases, hyaluronidases, chitinases and amidation enzymes, including new components found in this study. Toxins are the predominant group with an expression level of 91.945%, followed by metalloproteases with only 7.790% and other groups representing 0.265%.
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Affiliation(s)
- Yan Kalapothakis
- Departamento de Genética, Ecologia e Evolução, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, 31270-901, Brazil
| | - Kelton Miranda
- Departamento de Genética, Ecologia e Evolução, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, 31270-901, Brazil
| | - Adriana Heloísa Pereira
- Departamento de Genética, Ecologia e Evolução, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, 31270-901, Brazil
| | - Amanda S A Witt
- Departamento de Genética, Ecologia e Evolução, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, 31270-901, Brazil
| | - Camila Marani
- Departamento de Genética, Ecologia e Evolução, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, 31270-901, Brazil
| | - Ana Paula Martins
- Departamento de Genética, Ecologia e Evolução, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, 31270-901, Brazil
| | - Hortênsia Gomes Leal
- Departamento de Genética, Ecologia e Evolução, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, 31270-901, Brazil
| | - Edimar Campos-Júnior
- Departamento de Genética, Ecologia e Evolução, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, 31270-901, Brazil
| | - Adriano M C Pimenta
- Departamento de Bioquímica-Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, 31270-901, Brazil
| | - Adolfo Borges
- Centro para el Desarrollo de la Investigación Científica (CEDIC), Manduvirá 635 c/15 de Agosto, Asunción, Paraguay
| | - Carlos Chávez-Olórtegui
- Departamento de Bioquímica-Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, 31270-901, Brazil
| | - Evanguedes Kalapothakis
- Departamento de Genética, Ecologia e Evolução, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, 31270-901, Brazil.
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Batista C, Martins J, Restano-Cassulini R, Coronas F, Zamudio F, Procópio R, Possani L. Venom characterization of the Amazonian scorpion Tityus metuendus. Toxicon 2018; 143:51-58. [DOI: 10.1016/j.toxicon.2018.01.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 01/09/2018] [Accepted: 01/10/2018] [Indexed: 01/09/2023]
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Nencioni ALA, Neto EB, de Freitas LA, Dorce VAC. Effects of Brazilian scorpion venoms on the central nervous system. J Venom Anim Toxins Incl Trop Dis 2018; 24:3. [PMID: 29410679 PMCID: PMC5781280 DOI: 10.1186/s40409-018-0139-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 01/02/2018] [Indexed: 12/26/2022] Open
Abstract
In Brazil, the scorpion species responsible for most severe incidents belong to the Tityus genus and, among this group, T. serrulatus, T. bahiensis, T. stigmurus and T. obscurus are the most dangerous ones. Other species such as T. metuendus, T. silvestres, T. brazilae, T. confluens, T. costatus, T. fasciolatus and T. neglectus are also found in the country, but the incidence and severity of accidents caused by them are lower. The main effects caused by scorpion venoms - such as myocardial damage, cardiac arrhythmias, pulmonary edema and shock - are mainly due to the release of mediators from the autonomic nervous system. On the other hand, some evidence show the participation of the central nervous system and inflammatory response in the process. The participation of the central nervous system in envenoming has always been questioned. Some authors claim that the central effects would be a consequence of peripheral stimulation and would be the result, not the cause, of the envenoming process. Because, they say, at least in adult individuals, the venom would be unable to cross the blood-brain barrier. In contrast, there is some evidence showing the direct participation of the central nervous system in the envenoming process. This review summarizes the major findings on the effects of Brazilian scorpion venoms on the central nervous system, both clinically and experimentally. Most of the studies have been performed with T. serrulatus and T. bahiensis. Little information is available regarding the other Brazilian Tityus species.
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Affiliation(s)
| | - Emidio Beraldo Neto
- Laboratory of Pharmacology, Butantan Institute, Av. Dr. Vital Brasil, 1500, São Paulo, SP 05503-900 Brazil
- Graduation Program in Sciences – Toxinology, Butantan Institute, São Paulo, SP Brazil
| | - Lucas Alves de Freitas
- Laboratory of Pharmacology, Butantan Institute, Av. Dr. Vital Brasil, 1500, São Paulo, SP 05503-900 Brazil
- Graduation Program in Sciences – Toxinology, Butantan Institute, São Paulo, SP Brazil
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Cerni FA, Pucca MB, Amorim FG, de Castro Figueiredo Bordon K, Echterbille J, Quinton L, De Pauw E, Peigneur S, Tytgat J, Arantes EC. Isolation and characterization of Ts19 Fragment II, a new long-chain potassium channel toxin from Tityus serrulatus venom. Peptides 2016; 80:9-17. [PMID: 26116782 DOI: 10.1016/j.peptides.2015.06.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 06/05/2015] [Accepted: 06/08/2015] [Indexed: 01/13/2023]
Abstract
Ts19 Fragment II (Ts19 Frag-II) was first isolated from the venom of the scorpion Tityus serrulatus (Ts). It is a protein presenting 49 amino acid residues, three disulfide bridges, Mr 5534Da and was classified as a new member of class (subfamily) 2 of the β-KTxs, the second one described for Ts scorpion. The β-KTx family is composed by two-domain peptides: N-terminal helical domain (NHD), with cytolytic activity, and a C-terminal CSαβ domain (CCD), with Kv blocking activity. The extensive electrophysiological screening (16 Kv channels and 5 Nav channels) showed that Ts19 Frag-II presents a specific and significant blocking effect on Kv1.2 (IC50 value of 544±32nM). However, no cytolytic activity was observed with this toxin. We conclude that the absence of 9 amino acid residues from the N-terminal sequence (compared to Ts19 Frag-I) is responsible for the absence of cytolytic activity. In order to prove this hypothesis, we synthesized the peptide with these 9 amino acid residues, called Ts19 Frag-III. As expected, Ts19 Frag-III showed to be cytolytic and did not block the Kv1.2 channel. The post-translational modifications of Ts19 and its fragments (I-III) are also discussed here. A mechanism of post-translational processing (post-splitting) is suggested to explain Ts19 fragments production. In addition to the discovery of this new toxin, this report provides further evidence for the existence of several compounds in the scorpion venom contributing to the diversity of the venom arsenal.
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Affiliation(s)
- Felipe Augusto Cerni
- Department of Physics and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Av. do Café, s/n, 14040-903 Ribeirão Preto, SP, Brazil
| | - Manuela Berto Pucca
- Department of Physics and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Av. do Café, s/n, 14040-903 Ribeirão Preto, SP, Brazil
| | - Fernanda Gobbi Amorim
- Department of Physics and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Av. do Café, s/n, 14040-903 Ribeirão Preto, SP, Brazil
| | - Karla de Castro Figueiredo Bordon
- Department of Physics and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Av. do Café, s/n, 14040-903 Ribeirão Preto, SP, Brazil
| | - Julien Echterbille
- Laboratory of Mass Spectrometry, Department of Chemistry, University of Liège, Allée de la chimie 6, B6c, B-4000 Liège, Belgium
| | - Loïc Quinton
- Laboratory of Mass Spectrometry, Department of Chemistry, University of Liège, Allée de la chimie 6, B6c, B-4000 Liège, Belgium
| | - Edwin De Pauw
- Laboratory of Mass Spectrometry, Department of Chemistry, University of Liège, Allée de la chimie 6, B6c, B-4000 Liège, Belgium
| | - Steve Peigneur
- Toxicology and Pharmacology, University of Leuven, O&N 2, Herestraat 49, P.O. Box 922, 3000 Leuven, Belgium
| | - Jan Tytgat
- Toxicology and Pharmacology, University of Leuven, O&N 2, Herestraat 49, P.O. Box 922, 3000 Leuven, Belgium
| | - Eliane Candiani Arantes
- Department of Physics and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Av. do Café, s/n, 14040-903 Ribeirão Preto, SP, Brazil.
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Borges A, García CC, Lugo E, Alfonzo MJ, Jowers MJ, Op den Camp HJM. Diversity of long-chain toxins in Tityus zulianus and Tityus discrepans venoms (Scorpiones, Buthidae): molecular, immunological, and mass spectral analyses. Comp Biochem Physiol C Toxicol Pharmacol 2006; 142:240-252. [PMID: 16356783 DOI: 10.1016/j.cbpc.2005.10.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2005] [Revised: 10/11/2005] [Accepted: 10/12/2005] [Indexed: 11/27/2022]
Abstract
In Venezuela, stings by Tityus zulianus scorpions produce cardiorespiratory arrest, whereas envenoming by Tityus discrepans involves gastrointestinal/pancreatic complications, suggesting structural and/or functional differences. We sought to compare their toxin repertoires through immunological, molecular, and mass spectral analyses. First, in vivo tests showed that neutralization of T. zulianus venom toxicity by the anti-T. discrepans antivenom was not complete. To compare T. discrepans and T. zulianus long-chain (sodium channel-active) toxins, their most toxic Sephadex G-50 fractions, TdII and TzII, were subjected to acid-urea PAGE, which showed differences in composition. Amplification of toxin-encoding mRNAs using a leader peptide-based oligonucleotide rendered cDNAs representing twelve T. discrepans and two T. zulianus distinct toxin transcripts, including only one shared component, indicating divergence between T. zulianus and T. discrepans 5' region-encoded, toxin signal peptides. A 3'-UTR polymorphism was also noticed among the transcripts encoding shared components Tz1 and Td4. MALDI-TOF MS profiling of TdII and TzII produced species-specific spectra, with seven of the individual masses matching those predicted by cDNA sequencing. Phylogenetic analysis showed that the unique T. zulianus transcript-encoded sequence, Tz2, is structurally related to Tityus serrulatus and Centruroides toxins. Together with previous reports, this work indicates that T. zulianus and T. discrepans toxin repertoires differ structurally and functionally.
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Affiliation(s)
- Adolfo Borges
- Sección de Biomembranas, Instituto de Medicina Experimental, Universidad Central de Venezuela, Caracas 1051, Venezuela.
| | - Carmen C García
- Sección de Biomembranas, Instituto de Medicina Experimental, Universidad Central de Venezuela, Caracas 1051, Venezuela
| | - Elizabeth Lugo
- Sección de Biomembranas, Instituto de Medicina Experimental, Universidad Central de Venezuela, Caracas 1051, Venezuela
| | - Marcelo J Alfonzo
- Sección de Biomembranas, Instituto de Medicina Experimental, Universidad Central de Venezuela, Caracas 1051, Venezuela
| | - Michael J Jowers
- Institute of Biomedical and Life Sciences, Division of Molecular Genetics, University of Glasgow, Glasgow G11 6NU, United Kingdom
| | - Huub J M Op den Camp
- Department of Microbiology, Faculty of Science, Radboud University Nijmegen, Tooernooiveld 1, Nijmegen, The Netherlands
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Toyama OD, Boschero CA, Martins AM, Fonteles CM, Monteiro SH, Toyama HM. Structure?Function Relationship of New Crotamine Isoform from the Crotalus durissus cascavella. Protein J 2005; 24:9-19. [PMID: 15756813 DOI: 10.1007/s10930-004-0601-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
In this work we isolated a novel crotamine like protein from the Crotalus durissus cascavella venom by combination of molecular exclusion and analytical reverse phase HPLC. Its primary structure was:YKRCHKKGGHCFPKEKICLPPSSDLGKMDCRWKRK-CCKKGS GK. This protein showed a molecular mass of 4892.89 Da that was determined by Matrix Assisted Laser Desorption Ionization Time-of-flight (MALDI-TOF) mass spectrometry. The approximately pI value of this protein was determined in 9.9 by two-dimensional electrophoresis. This crotamine-like protein isolated here and that named as Cro 2 produced skeletal muscle spasm and spastic paralysis in mice similarly to other crotamines like proteins. Cro 2 did not modify the insulin secretion at low glucose concentration (2.8 and 5.6 mM), but at high glucose concentration (16.7 mM) we observed an insulin secretion increasing of 2.7-3.0-fold than to control. The Na+ channel antagonist tetrodoxin (6 mM) decreased glucose and Cro 2-induced insulin secretion. These results suggested that Na+ channel are involved in the insulin secretion. In this article, we also purified some peptide fragment from the treatment of reduced and carboxymethylated Cro 2 (RC-Cro 2) with cyanogen bromide and protease V8 from Staphylococcus aureus. The isolated pancreatic beta-cells were then treated with peptides only at high glucose concentration (16.7 mM), in this condition only two peptides induced insulin secretion. The amino acid sequence homology analysis of the whole crotamine as well as the biologically-active peptide allowed determining the consensus region of the biologically-active crotamine responsible for insulin secretion was KGGHCFPKE and DCRWKWKCCKKGSG.
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Affiliation(s)
- O D Toyama
- Departamento de Bioquìmica, UNICAMP, Campinas, São Paulo, Brazil
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Froy O, Gurevitz M. New insight on scorpion divergence inferred from comparative analysis of toxin structure, pharmacology and distribution. Toxicon 2003; 42:549-55. [PMID: 14529737 DOI: 10.1016/s0041-0101(03)00236-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The divergence of Buthidae, the most abundant family of scorpions, has relied thus far on anatomical and morphological features, but still remains controversial. However, much information has accumulated on Buthidae long-chain scorpion toxins affecting neuronal sodium channel conductance (alpha- and beta-toxins) and their pharmacology. Therefore, we constructed a toxin evolutionary tree, which together with recent data on toxin gene organization, toxin structures, and worldwide dispersion, sheds light on toxin and hence, scorpion divergence. Based on these data, we suggest that in the ancient world, the ancestral long-chain toxins affecting sodium channels developed into beta-like toxins, which most likely developed into alpha- and beta-toxins before the separation of South America from Africa. Subsequently, in the Old World, mostly excitatory and depressant toxins developed from the ancestral beta-like toxin and in the New World a new type of toxin group with beta-toxin structure but alpha-toxin activity developed from the beta-toxins. Assisted by the worldwide distribution of toxins and the zoogeographical dispersion of the studied genera in Asia and Africa (Old World) and in South and North America (New World), we suggest a route of divergence for some of the Buthidae scorpions, a task that has reached a standstill when morphological and anatomical features were used.
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Affiliation(s)
- Oren Froy
- Institute of Biochemistry, Food Science and Nutrition, Faculty of Agricultural, Food and Environmental Quality, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100, Israel.
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Wagner S, Castro MS, Barbosa JARG, Fontes W, Schwartz ENF, Sebben A, Rodrigues Pires O, Sousa MV, Schwartz CA. Purification and primary structure determination of Tf4, the first bioactive peptide isolated from the venom of the Brazilian scorpion Tityus fasciolatus. Toxicon 2003; 41:737-45. [PMID: 12782073 DOI: 10.1016/s0041-0101(03)00008-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In the present study Tityus fasciolatus crude venom toxicity was evaluated and we also report the purification and characterization of a 6.6 kDa neurotoxin isolated from T. fasciolatus venom. This new toxin, named Tf4, has a molecular mass of 6614Da and its primary structure is homologous to TbIT-I from T. bahiensis and TsTX-VI and TsNTxP from T. serrulatus. Tf4 delays frog sodium channel inactivation reversibly, but it is non-toxic to mammals or crustaceans. An attempt to identify the residues responsible for the partial loss of toxicity in Tf4 was carried out based on homology modeling and sequence comparison.
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Affiliation(s)
- Simone Wagner
- Laboratório de Toxinologia, Módulo 05, ICC Ala Sul, Subsolo, Departamento de Ciências Fisiológicas/IB, Universidade de Brasília, Brasília/DF, Brazil CEP 70.910-900
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Gonçalves AA, Toyama MH, Carneiro EM, Marangoni S, Arantes EC, Giglio JR, Boschero AC. Participation of Na(+) channels in the potentiation by Tityus serrulatus alpha-toxin TsTx-V of glucose-induced electrical activity and insulin secretion in rodent islet beta-cells. Toxicon 2003; 41:1039-45. [PMID: 12875879 DOI: 10.1016/s0041-0101(03)00086-2] [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: 10/27/2022]
Abstract
The effects of TsTx-V, an alpha-toxin isolated from Tityus serrulatus venom, on electrical activity and insulin secretion by rodent pancreatic islet cells were studied. TsTx-V (5.6 microg/ml) depolarized mouse pancreatic beta-cells, diminished the membrane input resistance and increased the duration of the active phase of glucose-induced electrical activity. Similar results were observed with the Na(+) channel agonist veratridine (110 microM). Both agents potentiated glucose (8.3 mM)-induced insulin secretion in rat islet. In the presence of TsTx-V or veratridine, insulin secretion increased 2- and 1.4-fold over basal values, respectively (P<0.001). The Na(+) channel antagonist tetrodotoxin (6 microM) significantly decreased glucose- and TsTx-V-induced insulin secretion (P<0.001). TsTx-V also stimulated insulin secretion at low glucose concentrations (2.8 mM) whereas the beta-toxin, Ts-gamma (gamma toxin), also obtained from Tityus serrulatus venom, significantly reduced TsTx-V-induced secretion at sub- and suprathreshold concentrations of glucose. These results are consistent with a model whereby Na(+) channels participate in glucose-induced electrical activity. Alteration in the activity of these channels changes the length of time during which the beta-cell depolarizes, thereby altering the secretory behavior of the cell. The construction of a three-dimensional model for TsTx-V revealed a conserved core containing an alpha-helix and three beta-strands, with minor differences when compared with toxins from other scorpion venoms.
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Affiliation(s)
- Antonio A Gonçalves
- Departamento de Fisiologia e Biofísica, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), CP 6109, CEP 13083-970 Campinas SP, Brazil
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Luca G, Calvitti M, Basta G, Baroni T, Neri LM, Becchetti E, Capitani S, Novaes G, Correa-Giannella ML, Kalapothakis E, Engler SSM, Eliaschewitz FG, Sogayar MC, Fanelli C, Brunetti P, Calafiore R. Mitogenic Effects of Brazilian Arthropod Venom on Isolated Islet Beta Cells: In Vitro Morphologic Ultrastructural and Functional Studies. J Investig Med 2003. [DOI: 10.1177/108155890305100209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Background One of the major pitfalls associated with use of isolated adult islets of Langerhans’ cells is their minimal mitotic capacity. Consequently, maintenance of a steady viable islet cell mass is very difficult. To explore how to enhance beta-cell mitogenesis, we have examined the effects of venom fractions extracted from a Brazilian scorpion on morphologic and functional beta-cell patterns. The venom was previously known to induce nesidioblastosis-like effects with chronic hypoglycemia and pancreatitis in animal models. Methods Venom fractions purified from Tityus bahiensis were incubated with batches of isolated rat islets, while a morphologic examination, glucose-stimulated insulin release, insulin content, and insulin messenger ribonucleic acid (mRNA) were carried out early during incubation. On fixation and double fluorescence immunolabeling (rhodamine for anti-insulin monoclonal antibodies; fluorescein for anti-5-bromodeoxyuridine), the preparations were imaged by confocal laser microscopy (CLM) for morphometric quantification of the mitoses. Insulin recovery and mRNA were also assessed at 21 days of culture. Results Under CLM examination, the beta-cell mitotic rate significantly rose from 1 to 12.8% for the venom-exposed islets. At day 7, insulin release and content were significantly lower for the venom-exposed than the control islets. However, at day 21 of culture, insulin release in response to static incubation with glucose and insulin mRNA from the venom-exposed islets was higher than controls ( p < .05). Conclusions Incubation with the scorpion venom induced a rapid and significant increase in the beta-cell proliferation not associated with a short-term increase in insulin secretion. The latter fully resumed and overcame controls later in culture, possibly after completion of the beta-cell expansion process.
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Affiliation(s)
- Giovanni Luca
- From the Departments of Internal Medicine, Section of Internal Medicine and Endocrine and Metabolic Sciences, University of Perugia, Perugia, Italy
| | - Mario Calvitti
- Experimental Medicine and Biochemical Sciences, University of Perugia, Perugia, Italy
| | - Giuseppe Basta
- From the Departments of Internal Medicine, Section of Internal Medicine and Endocrine and Metabolic Sciences, University of Perugia, Perugia, Italy
| | - Tiziano Baroni
- Experimental Medicine and Biochemical Sciences, University of Perugia, Perugia, Italy
| | - Luca M. Neri
- Department of Morphology and Embryology, Section of Human Anatomy, University of Ferrara, Ferrara, Italy, and Consorzio Interuniversitario peri Trapianti d'Organo, Rome, Italy
| | - Ennio Becchetti
- Experimental Medicine and Biochemical Sciences, University of Perugia, Perugia, Italy
| | - Silvano Capitani
- Department of Morphology and Embryology, Section of Human Anatomy, University of Ferrara, Ferrara, Italy, and Consorzio Interuniversitario peri Trapianti d'Organo, Rome, Italy
| | | | | | | | | | | | | | - Carmine Fanelli
- From the Departments of Internal Medicine, Section of Internal Medicine and Endocrine and Metabolic Sciences, University of Perugia, Perugia, Italy
| | - Paolo Brunetti
- From the Departments of Internal Medicine, Section of Internal Medicine and Endocrine and Metabolic Sciences, University of Perugia, Perugia, Italy
| | - Riccardo Calafiore
- From the Departments of Internal Medicine, Section of Internal Medicine and Endocrine and Metabolic Sciences, University of Perugia, Perugia, Italy
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12
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Luca G, Calvitti M, Basta G, Baroni T, Neri LM, Becchetti E, Capitani S, Novaes G, Correa-Giannella ML, Kalapothakis E, Engler SSM, Eliaschewitz FG, Sogayar MC, Fanelli C, Brunetti P, Calafiore R. Mitogenic Effects of Brazilian Arthropod Venom on Isolated Islet Beta Cells: In Vitro Morphologic Ultrastructural and Functional Studies. J Investig Med 2003. [DOI: 10.2310/6650.2003.34200] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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13
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Barbosa PSF, Havt A, Facó PEG, Sousa TM, Bezerra ISAM, Fonteles MC, Toyama MH, Marangoni S, Novello JC, Monteiro HSA. Renal toxicity of Bothrops moojeni snake venom and its main myotoxins. Toxicon 2002; 40:1427-35. [PMID: 12368112 DOI: 10.1016/s0041-0101(02)00156-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Acute renal failure is one the most common systemic complications after snakebite, however, its pathogenesis remains obscure. In this study we evaluated the renal effects of Bothrops moojeni venom and its myotoxins (Bmtx-I and BmtxII) in rat isolated perfused kidneys. The myotoxins were purified by ion-exchange chromatography and reverse phase HPLC. The whole venom (10 microg/ml) and myotoxins (5 microg/ml) were added to the perfusion system 30 min after the beginning of each perfusion. The renal effects were compared to a control group perfused with modified Krebs-Henseleit solution alone. B. moojeni venom decreased the perfusion pressure (PP), renal vascular resistance (RVR), and the percent sodium, potassium and chloride tubular transport (%TNa(+), %TK(+), %TCl(-)). In contrast, the venom increased the urinary flow (UF), glomerular filtration rate (GFR), and the sodium, potassium and chloride excretion (ENa(+), EK(+), ECl(-)). The renal effects of myotoxin I was very similar to those of the whole venom, but there was an increase rather than a decrease in the PP and RVR. Myotoxin II had no effect on renal physiology, except for a transient decrease in %TK(+). In conclusion, B. moojeni venom caused intense alterations in renal physiology, including a drop in vascular resistance associated with diuresis, natriuresis and kaliuresis. Bmtx-I had an opposite effect when compared to whole venom, showed in the parameters of PP and RVR. Bmtx-II had a mild effect in %TK(+). The apparent inability of Bmtx-II to induce the renal effect similarly to Bmtx-I should be explained by the absence in the Bmtx-II of the C-terminal lysine rich region.
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Affiliation(s)
- P S F Barbosa
- Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceara, Rua Cel Nunes de Melo 1127, 60430-270 Fortaleza, CE, Brazil
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14
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Batista CVF, Zamudio FZ, Lucas S, Fox JW, Frau A, Prestipino G, Possani LD. Scorpion toxins from Tityus cambridgei that affect Na(+)-channels. Toxicon 2002; 40:557-62. [PMID: 11821128 DOI: 10.1016/s0041-0101(01)00252-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
By means of high performance liquid chromatography (HPLC) the soluble venom of the Amazonian scorpion Tityus cambridgei was fractionated into over 50 different components. Four toxic and/or lethal peptides to mice were obtained in pure form and sequenced. Mass spectrometry analysis showed molecular weights of 7310, 7151, 7259 and 7405, respectively, for toxins Tc48a, Tc49a, Tc54 and Tc49b. The N-terminal amino acid sequence was obtained for the three first toxins mentioned, whereas the full primary structure was determined for Tc49b. It contains 64 amino acid residues, closely packed by four disulfide bridges. Sequence comparison analysis showed similarities around 50% with other toxins from scorpions of the genus Tityus of Brazil. It is lethal to mice at doses of 20 microg per 20 g mouse. The toxin was shown to affect the Na(+)-currents permeability of rat cerebellum granular cells in culture. Almost a complete elimination of current was observed with 100 nM toxin concentration. This effect was partially reversible. Furthermore, this toxin does not modify the function of the Shaker B K(+)-channels expressed on Sf9 cells, nor does it modify the Na(+)-channel function in a similar manner as those reported for the alpha-scorpion toxins purified from other scorpions.
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Affiliation(s)
- Cesar V F Batista
- Department of Molecular Recognition and Structural Biology, Institute of Biotechnology-UNAM, Avenida Universidad, 2001, Apartado Postal 510-3, 62210, Cuernavaca, Mexico
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15
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Toyama MH, Carneiro EM, Marangoni S, Amaral MEC, Velloso LA, Boschero AC. Isolation and characterization of a convulxin-like protein from Crotalus durissus collilineatus venom. JOURNAL OF PROTEIN CHEMISTRY 2001; 20:585-91. [PMID: 11838547 DOI: 10.1023/a:1013377331569] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A convulxin (Cvx)-like protein was isolated from Crotalus durissus collilineatus venom by a combination of molecular exclusion and reversed-phase HPLC chromatographies. The molecular mass of the Cvx-like protein in the absence and presence of DTT was 78 kDa and 12-13 kDa, respectively. The Cvx-like protein consisted of two nonidentical polypeptide chains (alpha and beta). The N-terminal amino-acid sequences of the alpha and beta subunits were GLHCPSDWYAYDGHCYKIFNEEMNWED and GFCCPSHWSSYSRYCYKFFSQEMNWEDAEK, respectively, with both subunits having a high content of Glu, Ser, Cys, and Asp. The Cvx-like protein showed high homology with other venom C-type lectins, but had low hemagglutinating activity on intact and trypsinized erythrocytes. The Cvx-like protein stimulated insulin receptor phosphorylation and potentiated insulin secretion from isolated islets in the presence of sub- (2.8 mM) or supra-physiological (16.7 mM) glucose concentrations. These results suggest that the increase in insulin secretion induced by Cvx-like protein may be mediated by a protein tyrosine kinase-dependent pathway and may involve other membrane receptors, such as GP VI or Scr family proteins.
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Affiliation(s)
- M H Toyama
- Departamento de Fisiologia e Biofísica, Instituto de Biologia, Brasil
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16
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Pimenta AM, Martin-Eauclaire M, Rochat H, Figueiredo SG, Kalapothakis E, Afonso LC, De Lima ME. Purification, amino-acid sequence and partial characterization of two toxins with anti-insect activity from the venom of the South American scorpion Tityus bahiensis (Buthidae). Toxicon 2001; 39:1009-19. [PMID: 11223090 DOI: 10.1016/s0041-0101(00)00240-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We report here the isolation by a two-step chromatographic procedure of two new toxins from the South American scorpion Tityus bahiensis. Their amino-acid sequences and some of their biological features were established. The two toxins have different biological properties. Toxin TbIT-I had almost no activity or pharmacological effects in vertebrate tissues whereas it was lethal to house flies (LD50 80.0 ng/house fly). In contrast, Tb2-II was active against both mammals (intracerebroventricular injection of 100 ng/mouse was lethal) and insects (LD50 40.0 ng/house fly). The amino-acid sequences of these toxins were established and found to be similar (60-95%) to previously described beta-toxins from the Tityus genus. Based on the available comparative information, this study attempts identify possible structure-function relationships that may be responsible for the differences in bioactivity displayed by these toxins.
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Affiliation(s)
- A M Pimenta
- Departamento de Fisiologia e Biofísica, ICB, Universidade Federal de Minas Gerais, 31270-901, MG, Belo Horizonte, Brazil.
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17
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Silva JA, Macedo ML, Novello JC, Marangoni S. Biochemical characterization and N-terminal sequences of two new trypsin inhibitors from Copaifera langsdorffii seeds. JOURNAL OF PROTEIN CHEMISTRY 2001; 20:1-7. [PMID: 11330343 DOI: 10.1023/a:1011053002001] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Two new trypsin inhibitors, TDI-I and TDI-II, were purified from the seeds of the native Brazilian tree Copaifera langsdorffii (Caesalpinoideae, Leguminosae). The purification procedure involved ammonium sulfate fractionation, ion-exchange chromatography on DEAE-Sepharose, affinity chromatography on trypsin-Sepharose, and reversed-phase (RP) HPLC. RP-HPLC yielded two forms (TDI-I and TDI-II), as confirmed by isoelectric focusing, with pI values between 7.0 and 8.1. The molecular mass of the TDI forms was 24 kDa based on FPLC gel filtration on Superdex 75. Under reducing conditions in tricine SDS-PAGE the molecular masses of TDI-I and TDI-II were 12 and 10 kDa, respectively. The Ki values were 1.1 and 1.2 nM for TDI-I and TDI-II, respectively, and there was no inhibitory effect on chymotrypsin. Amino acid analysis revealed high levels of aspartic acid, glutamic acid, serine, glycine, proline, and lysine but low levels of methionine and aromatic amino acids in both inhibitors; the calculated molecular masses were 11,456 and 10,008 for TDI-I and II, respectively. Based on the N-terminal sequences of TDI-I and TDI-II, TDI-I belongs to the Kunitz family of trypsin inhibitors, whereas TDI-II showed no homology to any other protein. This observation suggests that TDI-II belongs to a new inhibitor subclass of low-molecular mass proteins in the subfamily Caesalpinoideae.
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Affiliation(s)
- J A Silva
- Departamento de Bioquimica, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), SP, Brazil
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18
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Pimenta AM, Stöcklin R, Favreau P, Bougis PE, Martin-Eauclaire MF. Moving pieces in a proteomic puzzle: mass fingerprinting of toxic fractions from the venom of Tityus serrulatus (Scorpiones, Buthidae). RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2001; 15:1562-1572. [PMID: 11713783 DOI: 10.1002/rcm.415] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Scorpion venoms are very complex mixtures of molecules, most of which are peptides that display different kinds of biological activity. These venoms have been studied in the light of their pharmacological targets and their constituents are able to bind specifically to a variety of ionic channels located in prey tissues, resulting in neurotoxic effects. Toxins that modulate Na(+), K(+), Ca(++) and Cl(-) currents have been described in scorpion venoms. Mass spectrometry was employed to analyze toxic fractions from the venom of the Brazilian scorpion Tityus serrulatus in order to shed light on the molecular composition of this venom and to facilitate the search for novel pharmacologically active compounds. T. serrulatus venom was first subjected to gel filtration to separate its constituents according to their molecular size. The resultant fractions II and III, which account for 90 and 10% respectively of the whole venom toxic effect, were further analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS), on-line liquid chromatography/electrospray mass spectrometry (LC/ESMS) and off-line LC/MALDI-TOFMS in order to establish their mass fingerprints. The molecular masses in fraction II were predominantly between 6500 and 7500 Da. This corresponds to long-chain toxins that mainly act on voltage-gated Na(+) channels. Fraction III is more complex and predominantly contained molecules with masses between 2500 and 5000 Da. This corresponds to the short-chain toxin family, most of which act on K(+) channels, and other unknown peptides. Finally, we were able to measure the molecular masses of 380 different compounds present in the two fractions investigated. To our knowledge, this is the largest number of components ever detected in the venom of a single animal species. Some of the toxins described previously from T. serrulatus venom could be detected by virtue of their molecular masses. The interpretation of this large set of data has provided us with useful proteomic information on the venom, and the implications of these findings are discussed.
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Affiliation(s)
- A M Pimenta
- UMR CNRS 6560, Université de la Méditerranée, Institut Jean Roche, Marseille, France
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19
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Toyama MH, Carneiro EM, Marangoni S, Barbosa RL, Corso G, Boschero AC. Biochemical characterization of two crotamine isoforms isolated by a single step RP-HPLC from Crotalus durissus terrificus (South American rattlesnake) venom and their action on insulin secretion by pancreatic islets. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1474:56-60. [PMID: 10699490 DOI: 10.1016/s0304-4165(99)00211-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Crotamine, a neurotoxin present in the venom of the South American rattlesnake Crotalus durrisus terrificus exists as several polymorphic variants, as demonstrated by recombinant DNA technology (Smith and Schmidt, Toxicon 28 (1990) 575-585). We have isolated native crotamine by chromatography on Sephadex G75, and have purified two crotamine isoforms (F2 and F3) by a single step of RP-HPLC. Native crotamine and RP-HPLC fractions F2 and F3 produced skeletal muscle spasms and spastic paralysis in mice. At low glucose concentrations (2.8-5.6 mmol/l), none of the crotamines altered the insulin secretion by rat isolated islets. In the presence of 16.7 mmol glucose/l, F2 (5 microg/ml), but not F3, increased insulin secretion two-fold, whereas native crotamine (1.5, 5 and 16.5 microg/ml) potentiated the secretion dose-dependently. The increase in insulin secretion induced by F2 fraction (5 microg/ml) was similar to that obtained with 16.5 microg of native crotamine/ml. These results indicate that the mode of action of the F2 and F3 isoforms in beta-cells is different from that in muscle cells. This difference may be related to the binding affinity of each isoform for the Na(+) channels located in the beta-cell membrane. Crotamine isoforms may be valuable tools for studying the involvement of Na(+) channels in the mechanism of insulin secretion.
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Affiliation(s)
- M H Toyama
- Departamento de Bioquímica, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), C.P. 6109, Campinas, Brazil
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Possani LD, Becerril B, Delepierre M, Tytgat J. Scorpion toxins specific for Na+-channels. EUROPEAN JOURNAL OF BIOCHEMISTRY 1999; 264:287-300. [PMID: 10491073 DOI: 10.1046/j.1432-1327.1999.00625.x] [Citation(s) in RCA: 477] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Na+-channel specific scorpion toxins are peptides of 60-76 amino acid residues in length, tightly bound by four disulfide bridges. The complete amino acid sequence of 85 distinct peptides are presently known. For some toxins, the three-dimensional structure has been solved by X-ray diffraction and NMR spectroscopy. A constant structural motif has been found in all of them, consisting of one or two short segments of alpha-helix plus a triple-stranded beta-sheet, connected by variable regions forming loops (turns). Physiological experiments have shown that these toxins are modifiers of the gating mechanism of the Na+-channel function, affecting either the inactivation (alpha-toxins) or the activation (beta-toxins) kinetics of the channels. Many functional variations of these peptides have been demonstrated, which include not only the classical alpha- and beta-types, but also the species specificity of their action. There are peptides that bind or affect the function of Na+-channels from different species (mammals, insects or crustaceans) or are toxic to more than one group of animals. Based on functional and structural features of the known toxins, a classification containing 10 different groups of toxins is proposed in this review. Attempts have been made to correlate the presence of certain amino acid residues or 'active sites' of these peptides with Na+-channel functions. Segments containing positively charged residues in special locations, such as the five-residue turn, the turn between the second and the third beta-strands, the C-terminal residues and a segment of the N-terminal region from residues 2-11, seems to be implicated in the activity of these toxins. However, the uncertainty, and the limited success obtained in the search for the site through which these peptides bind to the channels, are mainly due to the lack of an easy method for expression of cloned genes to produce a well-folded, active peptide. Many scorpion toxin coding genes have been obtained from cDNA libraries and from polymerase chain reactions using fragments of scorpion DNAs, as templates. The presence of an intron at the DNA level, situated in the middle of the signal peptide, has been demonstrated.
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Affiliation(s)
- L D Possani
- Department of Molecular Recognition and Structural Biology, Institute of Biotechnology, National Autonomous University of Mexico, Avenida Universidad 2001, Cuernavaca, Mexico.
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21
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Polikarpov I, Junior MS, Marangoni S, Toyama MH, Teplyakov A. Crystal structure of neurotoxin Ts1 from Tityus serrulatus provides insights into the specificity and toxicity of scorpion toxins. J Mol Biol 1999; 290:175-84. [PMID: 10388565 DOI: 10.1006/jmbi.1999.2868] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The crystal structure of neurotoxin Ts1, a major component of the venom of the Brazilian scorpion Tityus serrulatus, has been determined at 1.7 A resolution. It is the first X-ray structure of a highly toxic anti-mammalian beta-toxin. The folding of the polypeptide chain of Ts1 is similar to that of other scorpion toxins. A cysteine-stabilised alpha-helix/beta-sheet motif forms the core of the flattened molecule. All residues identified as functionally important by chemical modification and site-directed mutagenesis are located on one side of the molecule, which is therefore considered as the Na+channel recognition site. The distribution of charged and non-polar residues over this surface determines the specificity of the toxin-channel interaction. Comparison to other scorpion toxins shows that positively charged groups at positions 1 and 12 as well as a negative charge at position 2 are likely determinants of the specificity of beta-toxins. In contrast, the contribution of the conserved aromatic cluster to the interaction might be relatively small. Comparison of Ts1 to weak beta-toxins from Centruroides sculpturatus Ewing reveals that a number of basic amino acid residues located on the face of the molecule opposite to the binding surface may account for the high toxicity of Ts1.
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Affiliation(s)
- I Polikarpov
- Laboratório Nacional de Luz Síncrotron (LNLS), Campinas SP, CEP 13083-970, Brazil.
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22
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Di Ciero L, Oliva ML, Torquato R, Köhler P, Weder JK, Camillo Novello J, Sampaio CA, Oliveira B, Marangoni S. The complete amino acid sequence of a trypsin inhibitor from Bauhinia variegata var. candida seeds. JOURNAL OF PROTEIN CHEMISTRY 1998; 17:827-34. [PMID: 9988529 DOI: 10.1023/a:1020734519908] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Trypsin inhibitors of two varieties of Bauhinia variegata seeds have been isolated and characterized. Bauhinia variegata candida trypsin inhibitor (BvcTI) and B. variegata lilac trypsin inhibitor (BvlTI) are proteins with Mr of about 20,000 without free sulfhydryl groups. Amino acid analysis shows a high content of aspartic acid, glutamic acid, serine, and glycine, and a low content of histidine, tyrosine, methionine, and lysine in both inhibitors. Isoelectric focusing for both varieties detected three isoforms (pI 4.85, 5.00, and 5.15), which were resolved by HPLC procedure. The trypsin inhibitors show Ki values of 6.9 and 1.2 nM for BvcTI and BvlTI, respectively. The N-terminal sequences of the three trypsin inhibitor isoforms from both varieties of Bauhinia variegata and the complete amino acid sequence of B. variegata var. candida L. trypsin inhibitor isoform 3 (BvcTI-3) are presented. The sequences have been determined by automated Edman degradation of the reduced and carboxymethylated proteins of the peptides resulting from Staphylococcus aureus protease and trypsin digestion. BvcTI-3 is composed of 167 residues and has a calculated molecular mass of 18,529. Homology studies with other trypsin inhibitors show that BvcTI-3 belongs to the Kunitz family. The putative active site encompasses Arg (63)-Ile (64).
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Affiliation(s)
- L Di Ciero
- Department of Biochemistry, Biology Institute, Universidade Estadual de Campinas, SP, Brazil
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23
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Abstract
Scorpion venoms contain a variety of low mol. wt peptides toxic to different organisms. These peptides have been intensively studied because they represent excellent models for investigating structure-function relationships and they are also fine probes for studying ionic channel functions. This review deals with the biological and chemical aspects of toxic peptides that affect Na+ or K+ channels and the cloning of the cDNAs and genes encoding the main alpha and beta neurotoxins present in the venom of the three most dangerous species of Brazilian scorpion, Tityus bahiensis, Tityus stigmurus and Tityus serrulatus, and the Venezuelan scorpion Tityus discrepans. At least 16 different peptides specific for Na+ channels and five affecting K+ channels were isolated and characterized from the venom of these scorpions. The isolation of cDNAs and genes encoding four distinct toxins has permitted the elucidation of their nucleotide sequences as well as their genomic organization. Venoms and isolated toxins from scorpions of the genus Tityus were shown to enhance the secretory activity of the pancreas. Antisera obtained against venom of T. serrulatus show cross-reactivity with other species of the Brazilian scorpions.
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Affiliation(s)
- B Becerril
- Department of Molecular Recognition and Structural Biology, National Autonomous University of Mexico, Morelos, Mexico
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