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Mineev KS, Chernykh MA, Motov VV, Prudnikova DA, Pavlenko DM, Kuzmenkov AI, Peigneur S, Tytgat J, Vassilevski AA. A scorpion toxin affecting sodium channels shows double cis-trans isomerism. FEBS Lett 2023; 597:2358-2368. [PMID: 37501371 DOI: 10.1002/1873-3468.14705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 07/14/2023] [Indexed: 07/29/2023]
Abstract
Scorpion α-toxins (α-NaTx) inhibiting the inactivation of voltage-gated sodium channels (Nav ) are a well-studied family of small proteins. We previously showed that the structure of α-NaTx specificity module responsible for selective Nav binding is governed by an interplay between the nest and niche protein motifs. Here, we report the solution structure of the toxin Lqq4 from the venom of the scorpion Leiurus quinquestriatus. Unexpectedly, we find that this toxin presents an ensemble of long-lived structurally distinct states. We unequivocally assign these states to the alternative configurations (cis-trans isomers) of two peptide bonds: V56-P57 and C17-G18; neither of the cis isomers has been described in α-NaTx so far. We argue that the native conformational space of α-NaTx is wider than assumed previously.
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Affiliation(s)
- Konstantin S Mineev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Mikhail A Chernykh
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Vladislav V Motov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
- Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Daria A Prudnikova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Daniil M Pavlenko
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Alexey I Kuzmenkov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | | | - Jan Tytgat
- Toxicology and Pharmacology, KU Leuven, Belgium
| | - Alexander A Vassilevski
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
- Moscow Institute of Physics and Technology, Dolgoprudny, Russia
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2
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Das B, Saviola AJ, Mukherjee AK. Biochemical and Proteomic Characterization, and Pharmacological Insights of Indian Red Scorpion Venom Toxins. Front Pharmacol 2021; 12:710680. [PMID: 34650430 PMCID: PMC8505525 DOI: 10.3389/fphar.2021.710680] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 08/16/2021] [Indexed: 12/16/2022] Open
Abstract
The Indian red scorpion (Mesobuthus tamulus) is one of the world's deadliest scorpions, with stings representing a life-threatening medical emergency. This species is distributed throughout the Indian sub-continent, including eastern Pakistan, eastern Nepal, and Sri Lanka. In India, Indian red scorpions are broadly distributed in western Maharashtra, Saurashtra, Kerala, Andhra Pradesh, Tamil Nadu, and Karnataka; however, fatal envenomations have been recorded primarily in the Konkan region of Maharashtra. The Indian red scorpion venom proteome comprises 110 proteins belonging to 13 venom protein families. The significant pharmacological activity is predominantly caused by the low molecular mass non-enzymatic Na+ and K+ ion channel toxins. Other minor toxins comprise 15.6% of the total venom proteome. Indian red scorpion stings induce the release of catecholamine, which leads to pathophysiological abnormalities in the victim. A strong correlation has been observed between venom proteome composition and local (swelling, redness, heat, and regional lymph node involvement) and systemic (tachycardia, mydriasis, hyperglycemia, hypertension, toxic myocarditis, cardiac failure, and pulmonary edema) manifestations. Immediate administration of antivenom is the preferred treatment for Indian red scorpion stings. However, scorpion-specific antivenoms have exhibited poor immunorecognition and neutralization of the low molecular mass toxins. The proteomic analysis also suggests that Indian red scorpion venom is a rich source of pharmacologically active molecules that may be envisaged as drug prototypes. The following review summarizes the progress made towards understanding the venom proteome of the Indian red scorpion and addresses the current understanding of the pathophysiology associated with its sting.
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Affiliation(s)
- Bhabana Das
- Department of Molecular Biology and Biotechnology, School of Sciences, Tezpur University, Tezpur, India
| | - Anthony J. Saviola
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Ashis K. Mukherjee
- Department of Molecular Biology and Biotechnology, School of Sciences, Tezpur University, Tezpur, India
- Institute of Advanced Study in Science and Technology, Guwahati, India
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3
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Pharmacology of the Na v1.1 domain IV voltage sensor reveals coupling between inactivation gating processes. Proc Natl Acad Sci U S A 2017; 114:6836-6841. [PMID: 28607094 DOI: 10.1073/pnas.1621263114] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Nav1.1 voltage-gated sodium channel is a critical contributor to excitability in the brain, where pathological loss of function leads to such disorders as epilepsy, Alzheimer's disease, and autism. This voltage-gated sodium (Nav) channel subtype also plays an important role in mechanical pain signaling by primary afferent somatosensory neurons. Therefore, pharmacologic modulation of Nav1.1 represents a potential strategy for treating excitability disorders of the brain and periphery. Inactivation is a complex aspect of Nav channel gating and consists of fast and slow components, each of which may involve a contribution from one or more voltage-sensing domains. Here, we exploit the Hm1a spider toxin, a Nav1.1-selective modulator, to better understand the relationship between these temporally distinct modes of inactivation and ask whether they can be distinguished pharmacologically. We show that Hm1a inhibits the gating movement of the domain IV voltage sensor (VSDIV), hindering both fast and slow inactivation and leading to an increase in Nav1.1 availability during high-frequency stimulation. In contrast, ICA-121431, a small-molecule Nav1.1 inhibitor, accelerates a subsequent VSDIV gating transition to accelerate entry into the slow inactivated state, resulting in use-dependent block. Further evidence for functional coupling between fast and slow inactivation is provided by a Nav1.1 mutant in which fast inactivation removal has complex effects on slow inactivation. Taken together, our data substantiate the key role of VSDIV in Nav channel fast and slow inactivation and demonstrate that these gating processes are sequential and coupled through VSDIV. These findings provide insight into a pharmacophore on VSDIV through which modulation of inactivation gating can inhibit or facilitate Nav1.1 function.
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Carmo AO, Chatzaki M, Horta CCR, Magalhães BF, Oliveira-Mendes BBR, Chávez-Olórtegui C, Kalapothakis E. Evolution of alternative methodologies of scorpion antivenoms production. Toxicon 2015; 97:64-74. [PMID: 25701676 DOI: 10.1016/j.toxicon.2015.02.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2014] [Revised: 11/10/2014] [Accepted: 02/17/2015] [Indexed: 12/23/2022]
Abstract
Scorpionism represents a serious public health problem resulting in the death of children and debilitated individuals. Scorpion sting treatment employs various strategies including the use of specific medicines such as antiserum, especially for patients with severe symptoms. In 1909 Charles Todd described the production of an antiserum against the venom of the scorpion Buthus quinquestriatus. Based on Todd's work, researchers worldwide began producing antiserum using the same approach i.e., immunization of horses with crude venom as antigen. Despite achieving satisfactory results using this approach, researchers in this field have developed alternative approaches for the production of scorpion antivenom serum. In this review, we describe the work published by experts in toxinology to the development of scorpion venom antiserum. Methods and results describing the use of specific antigens, detoxified venom or toxins, purified toxins and or venom fractions, native toxoids, recombinant toxins, synthetic peptides, monoclonal and recombinant antibodies, and alternative animal models are presented.
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Affiliation(s)
- A O Carmo
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos, 6627, Pampulha, Belo Horizonte, MG 31270-901, Brazil.
| | - M Chatzaki
- Department of Molecular Biology & Genetics, Democritus University of Thrace, University Campus, 69100 Komotini, Greece.
| | - C C R Horta
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos, 6627, Pampulha, Belo Horizonte, MG 31270-901, Brazil.
| | - B F Magalhães
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos, 6627, Pampulha, Belo Horizonte, MG 31270-901, Brazil.
| | - B B R Oliveira-Mendes
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos, 6627, Pampulha, Belo Horizonte, MG 31270-901, Brazil.
| | - C Chávez-Olórtegui
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos, 6627, Pampulha, Belo Horizonte, MG 31270-901, Brazil.
| | - E Kalapothakis
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos, 6627, Pampulha, Belo Horizonte, MG 31270-901, Brazil.
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Crystallographic insights into sodium-channel modulation by the β4 subunit. Proc Natl Acad Sci U S A 2013; 110:E5016-24. [PMID: 24297919 DOI: 10.1073/pnas.1314557110] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Voltage-gated sodium (Nav) channels are embedded in a multicomponent membrane signaling complex that plays a crucial role in cellular excitability. Although the mechanism remains unclear, β-subunits modify Nav channel function and cause debilitating disorders when mutated. While investigating whether β-subunits also influence ligand interactions, we found that β4 dramatically alters toxin binding to Nav1.2. To explore these observations further, we solved the crystal structure of the extracellular β4 domain and identified (58)Cys as an exposed residue that, when mutated, eliminates the influence of β4 on toxin pharmacology. Moreover, our results suggest the presence of a docking site that is maintained by a cysteine bridge buried within the hydrophobic core of β4. Disrupting this bridge by introducing a β1 mutation implicated in epilepsy repositions the (58)Cys-containing loop and disrupts β4 modulation of Nav1.2. Overall, the principles emerging from this work (i) help explain tissue-dependent variations in Nav channel pharmacology; (ii) enable the mechanistic interpretation of β-subunit-related disorders; and (iii) provide insights in designing molecules capable of correcting aberrant β-subunit behavior.
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6
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Nie Y, Zeng XC, Luo X, Wu S, Zhang L, Cao H, Zhou J, Zhou L. Tremendous intron length differences of the BmKBT and a novel BmKBT-like peptide genes provide a mechanical basis for the rapid or constitutive expression of the peptides. Peptides 2012; 37:150-6. [PMID: 22705625 DOI: 10.1016/j.peptides.2012.06.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Revised: 06/07/2012] [Accepted: 06/07/2012] [Indexed: 11/17/2022]
Abstract
The cDNA sequence encoding a novel BmKBT-like peptide (referred to as BmKBy) was cloned and sequenced from the scorpion Mesobuthus martensii Karsch. Functional analysis indicated that both BmKBT and BmKBy possess strong toxicity in mice, but very weak toxicity in cotton bollworm. Phylogenetic analysis showed that BmKBy and BmKBT represent evolutionary intermediates between the α- and β-toxins from scorpions. The genomic sequences of BmKBT and BmKBy were also obtained. It is interesting to see that two genes, which contain an intron of 225 and 1529bp, respectively, exactly code for the BmKBT peptide. One gene, which contains an intron of 1312bp, codes for BmKBy. Given that genes with long introns favor constitutive expression, whereas those with short introns are rapidly regulated in response to stimulations, the BmKBT_a and BmKBT_b genes provide a mechanical basis for either constitutive expression or rapid generation of the toxic peptides in response to different signals.
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Affiliation(s)
- Yao Nie
- Department of Biological Science and Technology, School of Environmental Studies & State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Wuhan), Wuhan 430074, China
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7
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Caliskan F, Quintero-Hernández V, Restano-Cassulini R, Batista CVF, Zamudio FZ, Coronas FI, Possani LD. Turkish scorpion Buthacus macrocentrus: general characterization of the venom and description of Bu1, a potent mammalian Na⁺-channel α-toxin. Toxicon 2012; 59:408-15. [PMID: 22245624 DOI: 10.1016/j.toxicon.2011.12.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Revised: 12/26/2011] [Accepted: 12/29/2011] [Indexed: 11/25/2022]
Abstract
The venom of the scorpion Buthacus macrocentrus of Turkey was fractionated by high performance liquid chromatography (HPLC) and its mass finger print analysis was obtained by spectrometry. More than 70 different fractions were obtained, allowing the determination of the molecular masses of at least 60 peptides ranging between 648 and 44,336 Da. The venom is enriched with peptides containing molecular masses between 3200-4500 Da, and 6000-7500 Da. They very likely correspond to K⁺-channel and Na⁺-channel specific peptides, respectively, as expected from venoms of scorpions of the family Buthidae, already determined for other species. The major component obtained from HPLC was shown to be lethal to mice and was further purified and characterized. It contains 65 amino acid residues maintained closely packed by 4 disulfide bridges, and shows a molecular weight of 7263 Da. Additionally, a cDNA from the venomous glands of this scorpion was used in conjunction with sequence data from Edman degradation and mass spectrometry for cloning the gene that codes for Bu1 as we named this toxin. This gene codes for a 67 amino acid residues peptide, where the two last are eliminated post-translationally for production of an amidated C-terminal arginine. Its sequence is closely related to toxins from the species Leiurus quinquestriatus, as revealed by a phylogenetic tree analysis. Electrophysiological results conducted with Bu1 using patch-clamp techniques indicate that it modifies the Na⁺ currents, in a similar way as other well known α-scorpion toxins. These results support the conclusion that this species of scorpions is dangerous to humans, having an epidemiological interest for the country.
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Affiliation(s)
- F Caliskan
- Department of Biology, Faculty of Science and Art, Eskisehir Osmangazi University, 26480 Eskisehir, Turkey
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Gordon D, Savarin P, Gurevitz M, Zinn-Justin S. Functional Anatomy of Scorpion Toxins Affecting Sodium Channels. ACTA ACUST UNITED AC 2009. [DOI: 10.3109/15569549809009247] [Citation(s) in RCA: 140] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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9
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Cordeiro MDN, Richardson M, Gilroy J, Figueiredo SGD, Beirão PSL, Diniz CR. Properties of the Venom from the South American ‘‘Armed'’ Spider Phoneutria Nigriventer (Keyserling, 1891). ACTA ACUST UNITED AC 2008. [DOI: 10.3109/15569549509019466] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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10
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11
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Alami M, Céard B, Legros C, Bougis PE, Martin-Eauclaire MF. Genomic characterisation of the toxin Amm VIII from the scorpion Androctonus mauretanicus mauretanicus. Toxicon 2006; 47:531-6. [PMID: 16533515 DOI: 10.1016/j.toxicon.2006.01.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2005] [Revised: 12/28/2005] [Accepted: 01/06/2006] [Indexed: 11/20/2022]
Abstract
The genomic DNA sequence encoding the scorpion toxin Amm VIII was amplified from genomic DNA of the scorpion Androctonus mauretanicus mauretanicus from Morocco, subcloned and sequenced. An intron, with a high A+T content (73.5%), split a Gly codon at the end of the precursor signal peptide and the consensus GT/AG splice junction was identified in the Amm VIII gene. This intron of only 166 bp is the smallest intron described so far for a long-chain scorpion toxin gene. In addition, this study led to the identification of three new toxin-related genes. From the deduced amino acid sequences of the encoded precursor proteins, we found that the mature putative toxins were highly similar to the scorpion toxins Leiurus quinquestriatus quinquestriatus IV and Odonthobuthus doriae 1.
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Affiliation(s)
- Meriem Alami
- Institut Pasteur du Maroc, 1 Rue Abou Kacem Ezzahroui, Casablanca, Morocco
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Ali SA, Wang B, Alam M, Beck A, Stoeva S, Voelter W, Abbasi A, Duszenko M. Structure-activity relationship of an alpha-toxin Bs-Tx28 from scorpion (Buthus sindicus) venom suggests a new alpha-toxin subfamily. Arch Biochem Biophys 2005; 445:81-94. [PMID: 16309623 DOI: 10.1016/j.abb.2005.10.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2005] [Revised: 10/14/2005] [Accepted: 10/14/2005] [Indexed: 11/18/2022]
Abstract
Scorpion venoms are among the most widely known source of peptidyl neurotoxins used for callipering different ion channels, e.g., for Na(+), K(+), Ca(+) or Cl(-). An alpha-toxin (Bs-Tx28) has been purified from the venom of scorpion Buthus sindicus, a common yellow scorpion of Sindh, Pakistan. The primary structure of Bs-Tx28 was established using a combination of MALDI-TOF-MS, LC-ESI-MS, and automated Edman degradation analysis. Bs-Tx28 consists of 65 amino acid residues (7274.3+/-2Da), including eight cysteine residues, and shows very high sequence identity (82-94%) with other long-chain alpha-neurotoxins, active against receptor site-3 of mammalian (e.g., Lqq-IV and Lqh-IV from scorpions Leiurus sp.) and insect (e.g., BJalpha-IT and Od-1 from Buthotus judaicus and Odonthobuthus doriae, respectively) voltage-gated Na(+) channels. Multiple sequence alignment and phylogenetic analysis of Bs-Tx28 with other known alpha- and alpha-like toxins suggests the presence of a new and separate subfamily of scorpion alpha-toxins. Bs-Tx28 which is weakly active in both, mammals and insects (LD(50) 0.088 and 14.3microg/g, respectively), shows strong induction of the rat afferent nerve discharge in a dose-dependent fashion (EC(50)=0.01microg/mL) which was completely abolished in the presence of tetrodotoxin suggesting the binding of Bs-Tx28 to the TTX-sensitive Na(+)-channel. Three-dimensional structural features of Bs-Tx28, established by homology modeling, were compared with other known classical alpha-mammal (AaH-II), alpha-insect (Lqh-alphaIT), and alpha-like (BmK-M4) toxins and revealed subtle variations in the Nt-, Core-, and RT-CT-domains (functional domains) which constitute a "necklace-like" structure differing significantly in all alpha-toxin subfamilies. On the other hand, a high level of conservation has been observed in the conserved hydrophobic surface with the only substitution of W43 (Y43/42) and an additional hydrophobic character at position F40 (L40/A/V/G39), as compared to the other mentioned alpha-toxins. Despite major differences within the primary structure and activities of Bs-Tx28, it shares a common structural and functional motif (e.g., transRT-farCT) within the RT-CT domain which is characteristic of scorpion alpha-mammal toxins.
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Affiliation(s)
- Syed Abid Ali
- International Center for Chemical Sciences, HEJ Research Institute of Chemistry, University of Karachi, Karachi 75270, Pakistan.
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Xu X, Cao Z, Sheng J, Wu W, Luo F, Sha Y, Mao X, Liu H, Jiang D, Li W. Genomic Sequence Analysis and Organization of BmKαTx11 and BmKαTx15 from Buthus martensii Karsch: Molecular Evolution of α-toxin genes. BMB Rep 2005; 38:386-90. [PMID: 16053704 DOI: 10.5483/bmbrep.2005.38.4.386] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Based on the reported cDNA sequences of BmKalphaTxs , the genes encoding toxin BmKalphaTx11 and BmKalphaTx15 were amplified by PCR from the Chinese scorpion Buthus martensii Karsch genomic DNA employing synthetic oligonucleotides. Sequences analysis of nucleotide showed that an intron about 500 bp length interrupts signal peptide coding regions of BmKalphaTx11 and BmKalphaTx15. Using cDNA sequence of BmKalphaTx11 as probe, southern hybridization of BmK genome total DNA was performed. The result indicates that BmKalphaTx11 is multicopy genes or belongs to multiple gene family with high homology genes. The similarity of BmKalpha-toxin gene sequences and southern hybridization revealed the evolution trace of BmKalpha-toxins: BmKalpha-toxin genes evolve from a common progenitor, and the genes diversity is associated with a process of locus duplication and gene divergence.
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Affiliation(s)
- Xiuling Xu
- Department of Biotechnology, College of Life Sciences, Wuhan University,Wuhan 430072, Hubei Province, PR China
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Jalali A, Bosmans F, Amininasab M, Clynen E, Cuypers E, Zaremirakabadi A, Sarbolouki MN, Schoofs L, Vatanpour H, Tytgat J. OD1, the first toxin isolated from the venom of the scorpionOdonthobuthus doriaeactive on voltage-gated Na+channels. FEBS Lett 2005; 579:4181-6. [PMID: 16038905 DOI: 10.1016/j.febslet.2005.06.052] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2005] [Revised: 06/20/2005] [Accepted: 06/20/2005] [Indexed: 11/23/2022]
Abstract
In this study, we isolated and pharmacologically characterized the first alpha-like toxin from the venom of the scarcely studied Iranian scorpion Odonthobuthus doriae. The toxin was termed OD1 and its primary sequence was determined: GVRDAYIADDKNCVYTCASNGYCNTECTKNGAESGYCQWIGRYGNACWCIKLPDEVPIRIPGKCR. Using the two-electrode voltage clamp technique, the pharmacological effects of OD1 were studied on three cloned voltage-gated Na+ channels expressed in Xenopus laevis oocytes (Na(v)1.2/beta1, Na(v)1.5/beta1, para/tipE). The inactivation process of the insect channel, para/tipE, was severely hampered by 200 nM of OD1 (EC50 = 80+/-14 nM) while Na(v)1.2/beta1 still was not affected at concentrations up to 5 microM. Na(v)1.5/beta1 was influenced at micromolar concentrations.
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Affiliation(s)
- Amir Jalali
- Department of Toxicology and Pharmacology, Shaheed Beheshti University of Medical Science, Tehran, Iran
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Arnon T, Potikha T, Sher D, Elazar M, Mao W, Tal T, Bosmans F, Tytgat J, Ben-Arie N, Zlotkin E. BjalphaIT: a novel scorpion alpha-toxin selective for insects--unique pharmacological tool. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2005; 35:187-195. [PMID: 15705498 DOI: 10.1016/j.ibmb.2004.11.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2004] [Revised: 10/21/2004] [Accepted: 11/01/2004] [Indexed: 05/24/2023]
Abstract
Long-chain neurotoxins derived from the venom of the Buthidae scorpions, which affect voltage-gated sodium channels (VGSCs) can be subdivided according to their toxicity to insects into insect-selective excitatory and depressant toxins (beta-toxins) and the alpha-like toxins which affect both mammals and insects. In the present study by the aid of reverse-phase HPLC column chromatography, RT-PCR, cloning and various toxicity assays, a new insect selective toxin designated as BjalphaIT was isolated from the venom of the Judean Black Scorpion (Buthotus judaicus), and its full primary sequence was determined: MNYLVVICFALLLMTVVESGRDAYIADNLNCAYTCGSNSYCNTECTKNGAVSGYCQWLGKYGNACWCINLPDKVPIRIPGACR (leader sequence is underlined). Despite its lack of toxicity to mammals and potent toxicity to insects, BjalphaIT reveals an amino acid sequence and an inferred spatial arrangement that is characteristic of the well-known scorpion alpha-toxins highly toxic to mammals. BjalphaITs sharp distinction between insects and mammals was also revealed by its effect on sodium conductance of two cloned neuronal VGSCs heterloguously expressed in Xenopus laevis oocytes and assayed with the two-electrode voltage-clamp technique. BjalphaIT completely inhibits the inactivation process of the insect para/tipE VGSC at a concentration of 100 nM, in contrast to the rat brain Na(v)1.2/beta1 which is resistant to the toxin. The above categorical distinction between mammal and insect VGSCs exhibited by BjalphaIT enables its employment in the clarification of the molecular basis of the animal group specificity of scorpion venom derived neurotoxic polypeptides and voltage-gated sodium channels.
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Affiliation(s)
- Tal Arnon
- Department of Cell and Animal biology, Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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Affiliation(s)
- J Andy Tincu
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, 8602 La Jolla Shores Dr., MC 0204, San Diego, La Jolla, CA 92093-0204.
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Ali SA, Stoeva S, Grossmann JG, Abbasi A, Voelter W. Purification, characterization, and primary structure of four depressant insect-selective neurotoxin analogs from scorpion (Buthus sindicus) venom. Arch Biochem Biophys 2001; 391:197-206. [PMID: 11437351 DOI: 10.1006/abbi.2001.2363] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Four depressant insect-selective neurotoxin analogs (termed Bs-dprIT1 to 4) from the venom of the scorpion Buthus sindicus were purified to homogeneity in a single step using reverse-phase HPLC. The molecular masses of the purified toxins were 6820.9, 6892.4, 6714.7, and 6657.1 Da, respectively, as determined by mass spectrometry. These long-chain neurotoxins were potent against insects with half lethal dose values of 67, 81, 103, and 78 ng/100 mg larva and 138, 160, 163, and 142 ng/100 mg cockroach, respectively, but were not lethal to mice even at the highest applied dose of 10 microg/20 g mouse. When injected into blowfly larvae (Sarcophaga falculata), Bs-dprIT1 to 4 induced classical manifestations of depressant toxins, i.e., a slow depressant flaccid paralysis. The primary structures of Bs-dprIT 1 to 4 revealed high sequence homology (60-75%) with other depressant insect toxins isolated from scorpion venoms. Despite the high sequence conservation, Bs-dprIT1 to 4 showed some remarkable features such as (i) the presence of methionine (Met(6) in Bs-dprIT1 and Met(24) in Bs-dprIT2 to 4) and histidine (His(53) and His(57) in Bs-dprIT1) residues, i.e., amino acid residues that are uncommon to this type of toxin; (ii) the substitution of two highly conserved tryptophan residues (Trp43 --> Ala and Trp53 --> His) in the sequence of Bs-dprIT1; and (iii) the occurrence of more positively charged amino acid residues at the C-terminal end than in other depressant insect toxins. Multiple sequence alignment, sequence analysis, sequence-based structure prediction, and 3D homology modeling studies revealed a protein fold and secondary structural elements similar to those of other scorpion toxins affecting sodium channel activation. The electrostatic potential calculated on the surface of the predicted 3D model of Bs-dprIT1 revealed a significant positive patch in the region of the toxin that is supposed to bind to the sodium channel.
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Affiliation(s)
- S A Ali
- Abteilung für Physikalische Biochemie, Physiologisch-Chemisches Institut der Universität Tübingen, Hoppe-Seyler-Strasse 4, Tübingen, D-72076, Germany.
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18
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Srinivasan KN, Nirthanan S, Sasaki T, Sato K, Cheng B, Gwee MC, Kini RM, Gopalakrishnakone P. Functional site of bukatoxin, an alpha-type sodium channel neurotoxin from the Chinese scorpion (Buthus martensi Karsch) venom: probable role of the (52)PDKVP(56) loop. FEBS Lett 2001; 494:145-9. [PMID: 11311230 DOI: 10.1016/s0014-5793(01)02342-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Alpha-toxins from scorpion venoms prolong the action potential of excitable cells by blocking sodium channel inactivation. We have purified bukatoxin, an alpha-toxin from scorpion (Buthus martensi Karsch) venom, to homogeneity. Bukatoxin produced marked relaxant responses in the carbachol-precontracted rat anococcygeus muscle (ACM), which were mediated through the L-arginine-nitric oxide synthase-nitric oxide pathway, consequent to a neuronal release of nitric oxide. Based on the presence of proline residues in the flanking segments of protein-protein interaction sites, we predicted the site between (52)PP(56) to be the potential interaction site of bukatoxin. A homology model of bukatoxin indicated the presence of this site on the surface. Buka11, a synthetic peptide designed based on this predicted site, produced a concentration-dependent nitric oxide-mediated relaxant response in ACM. Using alanine-substituted peptides, we have shown the importance (53)DKV(55) flanked by proline residues in the functional site of bukatoxin.
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19
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Chen Z, Reddy G, Hahin R. The isolation and purification of two peptides from the venom of Buthus martensii Karsch. Toxicon 2000; 38:1817-32. [PMID: 10858519 DOI: 10.1016/s0041-0101(00)00110-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Two peptides that extensively prolong action potentials (APs) in rat and frog nerves have been isolated and purified from the venom of the scorpion Buthus martensii Karsch (BMK). The peptides were purified using gel filtration, ion exchange, FPLC, and HPLC chromatography. Action potentials recorded in the presence of nanomolar concentrations of the peptides were extensively prolonged without much attenuation in their heights. The N-terminal sequences of both the peptides, BMK 9(3)-1 and BMK 9(3)-2, were determined. The N-terminal sequences of BMK 9(3)-1 and BMK 9(3)-2 were found to be: GRDAYIADSEN-PYF-GANPN and GRDAYIADSEN-PYT-ALNP. Sequence similarity comparisons to other alpha-scorpion toxins suggest that the two blanks in each of the sequences are cysteines. The first 20 residues of the two BMK peptides differ by only three amino acid substitutions. The molecular weight (MW) of BMK 9(3)-1 and BMK 9(3)-2 were determined by LC/MS/MS to be 7020 and 7037 Da. Since both of the peptides prolong APs when both K(+) and Ca(++) channels are blocked and show sequence similarity to other alpha-neurotoxins, it appears likely that BMK 9(3)-1 and BMK 9(3)-2 act to alter Na channel inactivation to produce their effects. The first 20 residues of BMK 9(3)-2 are identical to those observed for makatoxin I, a toxin isolated from Buthus martensii Karsch venom, that alters nitric oxide transmitter release. Since the two toxins also have very similar molecular weights, BMK 9(3)-2 may be identical to makatoxin I; however, BMK 9(3)-2 acts to alter Na channels to exert its effect, thus the two toxins may differ, or if they are identical, they can exert effects on both neural transmission and AP propagation.
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Affiliation(s)
- Z Chen
- Department of Biological Sciences, Northern Illinois University, DeKalb 60115, USA
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20
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Zeng XC, Li WX, Zhu SY, Peng F, Jiang DH, Yang FH, Wu KL. Cloning and characterization of the cDNA sequences of two venom peptides from Chinese scorpion Buthus martensii Karsch (BmK). Toxicon 2000; 38:893-9. [PMID: 10728828 DOI: 10.1016/s0041-0101(99)00192-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
From a cDNA library made from venom glands of Chinese scorpions of Buthus martensii Karsch, full-length cDNAs encoding precursors of two venom peptides have been isolated using a cDNA probe synthesized by polymerase chain reaction. Sequence analysis of the cDNAs revealed that one encoded precursor was 85 amino acid residues long including a signal peptide of 19 residues and a mature peptide (named BmK T) of 66 residues, and another encoded precursor was 84 residues long containing the same length signal peptide and a mature peptide (BmK M4 isoform, named BmK M4') of 64 residues. The analysis of amino acid sequence similarity indicated that the BmK T was homologous with both mammalian and insect toxins from BmK scorpion or other scorpions, and the BmK M4' was highly homologous with the members of the mammalian neurotoxin family of BmK, having two point mutations in amino acid residue sequence compared to BmK M4, a natural toxin from BmK.
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Affiliation(s)
- X C Zeng
- School of Life Sciences, Wuhan University, People's Republic of China
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21
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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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22
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Gong J, Kini RM, Gwee MC, Gopalakrishnakone P, Chung MC. Makatoxin I, a novel toxin isolated from the venom of the scorpion Buthus martensi Karsch, exhibits nitrergic actions. J Biol Chem 1997; 272:8320-4. [PMID: 9079654 DOI: 10.1074/jbc.272.13.8320] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Buthus martensi Karsch venom exhibits nitrergic action in rat anococcygeus muscle (ACM). We have purified a novel toxin, makatoxin I (MkTx I), which exhibits nitrergic action, to homogeneity from this venom by a combination of gel-filtration, cation-exchange chromatography, and reverse-phase chromatography. Its purity was assessed by capillary electrophoresis and mass spectrometry. Its molecular weight was found to be 7031.71 +/- 2.88 as calculated from electrospray mass spectrographic data. The complete amino acid sequence was elucidated by sequencing of reduced and S-pyridylethylated toxin and a carboxyl-terminal peptide, P55-64, generated by the cleavage of toxin with endoproteinase Lys-C. The complete sequence of MkTx I is GRDAYIADSENCTYTCALNPYCNDLCTKNGAKSGYCQWAGRYGNACWCIDLPDKVPIRISGSCR. This toxin is composed of 64 amino acid residues and contains 8 half-cystine residues. Structurally, MkTx I has high similarity to Bot I and Bot II when compared with toxins from other scorpion species. The effects of MkTx I on nitrergic responses were investigated using the rat isolated ACM mounted in Krebs solution (37 degrees C, 5% CO2 in O2). MkTx I (2 microg/ml) markedly relaxed the carbachol-precontracted ACM; the relaxation was inhibited by the stereoselective inhibitor of nitric oxide synthase, Nomega-nitro-L-arginine methyl ester (50 microM). Thus, MkTx I is the first alpha-toxin that can mediate nitrergic responses in the rat isolated ACM.
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Affiliation(s)
- J Gong
- Venom and Toxin Research Group, National University of Singapore, Lower Kent Ridge Road, Singapore 119260, Singapore
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23
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Tugarinov V, Kustanovich I, Zilberberg N, Gurevitz M, Anglister J. Solution structures of a highly insecticidal recombinant scorpion alpha-toxin and a mutant with increased activity. Biochemistry 1997; 36:2414-24. [PMID: 9054546 DOI: 10.1021/bi961497l] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The solution structure of a recombinant active alpha-neurotoxin from Leiurus quinquestriatus hebraeus, Lqh(alpha)IT, was determined by proton two-dimensional nuclear magnetic resonance spectroscopy (2D NMR). This toxin is the most insecticidal among scorpion alpha-neurotoxins and, therefore, serves as a model for clarifying the structural basis for their biological activity and selective toxicity. A set of 29 structures was generated without constraint violations exceeding 0.4 A. These structures had root mean square deviations of 0.49 and 1.00 A with respect to the average structure for backbone atoms and all heavy atoms, respectively. Similarly to other scorpion toxins, the structure of Lqh(alpha)IT consists of an alpha-helix, a three-strand antiparallel beta-sheet, three type I tight turns, a five-residue turn, and a hydrophobic patch that includes tyrosine and tryptophan rings in a "herringbone" arrangement. Positive phi angles were found for Ala50 and Asn11, suggesting their proximity to functionally important regions of the molecule. The sample exhibited conformational heterogeneity over a wide range of experimental conditions, and two conformations were observed for the majority of protein residues. The ratio between these conformations was temperature-dependent, and the rate of their interconversions was estimated to be on the order of 1-5 s(-1) at 308 K. The conformation of the polypeptide backbone of Lqh(alpha)IT is very similar to that of the most active antimammalian scorpion alpha-toxin, AaHII, from Androctonus australis Hector (60% amino acid sequence homology). Yet, several important differences were observed at the 5-residue turn comprising residues Lys8-Cys12, the C-terminal segment, and the mutual disposition of these two regions. 2D NMR studies of the R64H mutant, which is 3 times more toxic than the unmodified Lqh(alpha)IT, demonstrated the importance of the spatial orientation of the last residue side chain for toxicity of Lqh(alpha)IT.
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Affiliation(s)
- V Tugarinov
- Department of Structural Biology, The Weizmann Institute of Science, Rehovot, Israel
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24
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Devaux C, Fourquet P, Granier C. A conserved sequence region of scorpion toxins rendered immunogenic induces broadly cross-reactive, neutralizing antibodies. EUROPEAN JOURNAL OF BIOCHEMISTRY 1996; 242:727-35. [PMID: 9022703 DOI: 10.1111/j.1432-1033.1996.0727r.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Scorpion toxins constitute a family of proteins with a high degree of sequence diversity but a common mode of action. Neutralization of the toxic effects of scorpion stings by serotherapy is limited due to the various serotypes expressed by these proteins. We explored the possibility of raising antibodies to conserved parts of the toxins which could recognize several members of the family. We established the variability profile of a set of 25 scorpion toxin sequences, then evaluated systematically by peptide-scanning methods the antigenicity of one scorpion toxin. The most conserved regions were generally very poorly antigenic. One exception was the N-terminal region, which is both conserved and antigenic. Antibodies were raised in rabbits against an eight-residue synthetic peptide mimicking the N-terminal region. These peptide antibodies were cross-reactive with several scorpion toxins belonging to different serotypes and neutralized both the pharmacological effects (binding to rat brain synaptosomes) and the biological activity (toxicity in mice) of the parent toxin. The molecular model of the toxin indicates that antibody binding to residues 1-8 probably either masks some residue(s) of the N-terminus critical for the biological activity or overlaps with the epitope previously defined by neutralizing monoclonal antibody. These findings could open the way for new therapeutic strategies for the medical care of envenomations.
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Affiliation(s)
- C Devaux
- CNRS URA 1455, Laboratoire de Biochimie, IFR Jean Roche, Faculté de Médecine Nord, Marseille, France
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25
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Zilberberg N, Gordon D, Pelhate M, Adams ME, Norris TM, Zlotkin E, Gurevitz M. Functional expression and genetic alteration of an alpha scorpion neurotoxin. Biochemistry 1996; 35:10215-22. [PMID: 8756487 DOI: 10.1021/bi9528309] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The alpha neurotoxin Lqh alpha IT is toxic to both insects and mammals but exhibits a bioactivity ratio favoring insects (insect/mammal approximately 2). With the objective of increasing this ratio by genetic manipulation of the amino acid sequence, a cDNA clone encoding Lqh alpha IT was used to produce recombinant variants of the toxin in a high efficiency bacterial expression system. The unmodified recombinant toxin, isolated from inclusion bodies and renatured in vitro, exhibited chemical and biological properties indistinguishable from those of the authentic native toxin. Alteration of the toxin by site-directed mutagenesis led to a substantial reduction in anti-mammalian toxicity (mouse LD50 reduced 6.4-fold) but only a slight reduction (x 1.5) in the insect ED50 value for paralysis. The reduction in anti-mammalian toxicity was correlated with a approximately 2-fold reduction of its potency for slowing of sodium channel inactivation in mammalian neurons, while no change in mutant toxin binding affinity to insect neuronal receptors was registered. These results demonstrate for the first time expression of a recombinant sodium channel neurotoxin in Escherichia coli and the use of site-directed mutagenesis to improve phylogenetic selectivity. This recombinant approach provides a promising strategy for optimizing the selective toxicity of peptide neurotoxins.
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Affiliation(s)
- N Zilberberg
- Department of Botany, Faculty of Life Sciences, Tel-Aviv University, Israel
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26
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Gordon D, Martin-Eauclaire MF, Cestèle S, Kopeyan C, Carlier E, Khalifa RB, Pelhate M, Rochat H. Scorpion toxins affecting sodium current inactivation bind to distinct homologous receptor sites on rat brain and insect sodium channels. J Biol Chem 1996; 271:8034-45. [PMID: 8626486 DOI: 10.1074/jbc.271.14.8034] [Citation(s) in RCA: 153] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Sodium channels posses receptor sites for many neurotoxins, of which several groups were shown to inhibit sodium current inactivation. Receptor sites that bind alpha- and alpha-like scorpion toxins are of particular interest since neurotoxin binding at these extracellular regions can affect the inactivation process at intramembranal segments of the channel. We examined, for the first time, the interaction of different scorpion neurotoxins, all affecting sodium current inactivation and toxic to mammals, with alpha-scorpion toxin receptor sites on both mammalian and insect sodium channels. As specific probes for rat and insect sodium channels, we used the radiolabeled alpha-scorpion toxins AaH II and LqhalphaIT, the most active alpha-toxins on mammals and insect, respectively. We demonstrate that the different scorpion toxins may be classified to several groups, according to their in vivo and in vitro activity on mammalian and insect sodium channels. Analysis of competitive binding interaction reveal that each group may occupy a distinct receptor site on sodium channels. The alpha-mammal scorpion toxins and the anti-insect Lqh alphaIT bind to homologous but not identical receptor sites on both rat brain and insect sodium channels. Sea anemone toxin ATX II, previously considered to share receptor site 3 with alpha-scorpion toxins, is suggested to bind to a partially overlapping receptor site with both AaH II and Lqh alphaIT. Competitive binding interactions with other scorpion toxins suggest the presence of a putative additional receptor site on sodium channels, which may bind a unique group of these scorpion toxins (Bom III and IV), active on both mammals and insects. We suggest the presence of a cluster of receptor sites for scorpion toxins that inhibit sodium current inactivation, which is very similar on insect and rat brain sodium channels, in spite of the structural and pharmacological differences between them. The sea anemone toxin ATX II is also suggested to bind within this cluster.
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Affiliation(s)
- D Gordon
- Laboratory of Biochemistry, CNRS URA 1455, INSERM U 374, Faculty of Medicine Nord, Jean Roche Institute, Bd. Pierre Dramard, 13916 Marseille Cedex 20, France
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27
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Kopeyan C, Mansuelle P, Martin-Eauclaire MF, Rochat H, Miranda F. Characterization of toxin III of the scorpion Leiurus quinquestriatus quinquestriatus: a new type of alpha-toxin highly toxic both to mammals and insects. NATURAL TOXINS 1993; 1:308-12. [PMID: 8167952 DOI: 10.1002/nt.2620010510] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The primary structure of toxin III of Leiurus quinquestriatus quinquestriatus (Lqq III) was elucidated by automatic Edman degradation of the reduced and S-carboxymethylated protein and derived tryptic peptides. Like other scorpion toxins that are active on sodium channels, Lqq III, consisting of 64 amino acids, is a 7 kDa single-chain polypeptide crosslinked by four disulfide bridges. It belongs to the alpha-toxin group, as judged by competition experiments with 125I AaH II for binding to rat brain synaptosomes (K0.5 = 7 x 10(-7) M). Lqq III is the first alpha-toxin to be characterized that is highly toxic to mice [LD50 = 50 micrograms (7.1 nmol)/kg body wt], by subcutaneous injection, insects Blatella germanica [LD50 = 60 ng (8.5 pmol)/g body wt.] and Musca domestica [LD50 = 120 ng (17 pmol)/g body wt]. When tested via the intracerebroventricular route, the toxicity for mice [55 micrograms (8 nmol)/kg] was of the same order as that found by subcutaneous injection, indicating that Lqq III has a higher affinity for peripheral sodium channels that for those of the central nervous system. There are three differences between the sequences of Lqq III and Lqh alpha IT, an alpha-toxin isolated from the venom of Leiurus quinquestriatus hebraeus. These substitutions are found at positions 20, 24, and 64 (Ser-->Ala,Asp-->Glu and His-->Arg, respectively). Surprisingly Lqh alpha IT is only weakly active in mice [LD50 = 5 mg (0.7 mumol)/kg], while in insects its toxicity is similar to that of Lqq III [140 ng (20 pmol)/g body wt blowfly larvae]. These observations are relevant to the definition of scorpion toxin structure-activity relationships.
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Affiliation(s)
- C Kopeyan
- Laboratoire de Biochime, Centre National de la Recherche Scientifique URA 1455, Faculté de Médecine, Secteur Nord, Marseille, France
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28
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Cordeiro MDN, Diniz CR, Valentim ADC, von Eickstedt VR, Gilroy J, Richardson M. The purification and amino acid sequences of four Tx2 neurotoxins from the venom of the Brazilian 'armed' spider Phoneutria nigriventer (Keys). FEBS Lett 1992; 310:153-6. [PMID: 1397265 DOI: 10.1016/0014-5793(92)81318-g] [Citation(s) in RCA: 85] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Four neurotoxic polypeptides (Tx2-1, Txt2-5, Tx2-6 and Tx2-9) were purified from the venom of the South American 'armed' spider Phoneutria nigriventer (Keys) by gel filtration and reverse phase FPLC and HPLC. These cysteine-rich polypeptides exhibited different levels of neurotoxicity in mice after intracerebroventricular injection. Tx2-1, Tx2-5 and Tx2-6 caused spastic paralysis and death, but the less toxic Tx2-9 produced only tail erection and scratching. The molecular weights of the polypeptides as determined by desorption mass spectroscoopy were 5838.8 for Tx2-1, 5116.6 (Tx2-5), 5291.3 (Tx2-6) and 3742.1 (Tx2-9). The complete amino acid sequences of the neurotoxins were determined by automated Edman degradation and by manual DABITC-PITC microsequence analysis of peptides obtained after digestions with various proteases. The amino acid sequences of Tx2-1 (53 residues), Tx2-5 (49 residues) and Tx2-6 (48 residues) were homologous, but had only limited similarities to the less toxic Tx2-9 (32 residues). All four polypeptides had varying sequence identities with other neurotoxins from different spider species and biologically active peptides from scorpions, a sea snail and seeds of Mirabilis jalapa.
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Affiliation(s)
- M do N Cordeiro
- Centro de Pesquisa e Desenvolvimento, Fundação Ezequiel Dias, Belo Horizonte (MG), Brazil
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29
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Sauermann U, Meyermann R, Schluesener HJ. Cloning of a novel TGF-beta related cytokine, the vgr, from rat brain: cloning of and comparison to homologous human cytokines. J Neurosci Res 1992; 33:142-7. [PMID: 1453478 DOI: 10.1002/jnr.490330118] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Here we describe cloning of a TGF-beta related cytokine from a rat brain cDNA library. This novel cytokine, the vgr (vegetal related), is homologous to the vegetal (Vg1) gene of Xenopus (DL Weeks and DA Melton, Cell, 51:861-867, 1987). In rat brain mRNA a single 3.5 kb RNA could be detected by Northern blot analysis. Thus, this new cytokine is constitutively expressed in the central nervous system. A monoclonal antibody reactive with a synthetic peptide of vgr revealed a faint vgr-like immunoreactivity throughout the CNS, with more pronounced staining of hippocampal neurons, ependymal cells, cells of the choroid plexus, and hypophysis. Using the rat cDNA, two homologous human cytokine cDNAs encoding the human vgr and op-1 were cloned.
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Affiliation(s)
- U Sauermann
- Department of Neurology, University of Wuerzburg, Federal Republic of Germany
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30
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Rasmussen K, Printz MP. Depolarization potentiates endothelin-induced effects on cytosolic calcium in bovine adrenal chromaffin cells. Biochem Biophys Res Commun 1989; 165:306-11. [PMID: 2556139 DOI: 10.1016/0006-291x(89)91070-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The effects of endothelin on intracellular calcium concentrations ([Ca2+i]) in primary cultures of bovine adrenal chromaffin cells (BAM) were measured using Fura 2. Endothelin had minimal effects on [Ca2+i] over a broad dose range (1 nM to 1 microM). However, in conjunction with K+ depolarization there was a synergistic increase in [Ca2+i]. This effect was dependent on extracellular calcium as was the response to KCl alone. A partial synergistic effect was evident with endothelin and nicotinic stimulation. The effects of endothelin and angiotensin II on [Ca2+i] are only additive. Blockade of voltage sensitive calcium channels failed to alter the synergistic effects. Our results indicate that endothelin influences BAM calcium mobilization through sites regulated by membrane depolarization but differing from traditional voltage sensitive calcium channels.
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Affiliation(s)
- K Rasmussen
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093
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31
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Martin ER, Marsden PA, Brenner BM, Ballermann BJ. Identification and characterization of endothelin binding sites in rat renal papillary and glomerular membranes. Biochem Biophys Res Commun 1989; 162:130-7. [PMID: 2546542 DOI: 10.1016/0006-291x(89)91972-4] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The present study was designed to identify and characterize specific endothelin binding sites in membranes of rat renal papillae and glomeruli which appear to be target tissues for this new peptide hormone. Saturation binding studies indicate that the sites have a high and uniform affinity. The dissociation constants averaged 662 +/- 151 and 1309 +/- 123 pM and the receptor densities 7666 +/- 920 and 5831 +/- 348 fmol/mg protein for papillary and glomerular membranes, respectively. Endothelin 1, endothelin 3 and sarafotoxin all inhibited [125I]-endothelin binding with IC50's in the 100-300 pM range, whereas unrelated peptides, namely angiotensin II, atrial natriuretic peptide, and platelet-derived growth factor failed to compete for [125I]-endothelin binding. Deletion of the carboxyterminal tryptophan in endothelin 1 reduced its affinity for glomerular binding sites by 2 orders of magnitude. Specific endothelin binding to these membranes was maximal at pH 4 and was markedly inhibited as the pH was raised above 8. When [125I]-endothelin is covalently linked to glomerular membrane binding sites, SDS-PAGE of these solubilized membranes followed by autoradiography reveals a predominant specifically labeled band of 45 kDa. Whether this band represents a subunit of the endothelin receptor(s), the receptor proper, or an intracellular endothelin binding protein remains to be determined.
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Affiliation(s)
- E R Martin
- Renal Division, Brigham and Women's Hospital, Boston, Massachusetts
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Kozuka M, Ito T, Hirose S, Takahashi K, Hagiwara H. Endothelin induces two types of contractions of rat uterus: phasic contractions by way of voltage-dependent calcium channels and developing contractions through a second type of calcium channels. Biochem Biophys Res Commun 1989; 159:317-23. [PMID: 2538125 DOI: 10.1016/0006-291x(89)92440-6] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Effects of endothelin on nonvascular smooth muscle have been examined using rat uterine horns and two modes of endothelin action have been revealed. Endothelin (0.3 nM) caused rhythmic contractions of isolated uterus in the presence of extracellular calcium. The rhythmic contractions were completely inhibited by calcium channel antagonists. These characteristics of endothelin-induced contractions were very similar to those induced by oxytocin. Binding assays using 125I-endothelin showed that endothelin and the calcium channel blockers did not compete for the binding sites. However, endothelin was unique in that it caused, in addition to rhythmic contractions, a slowly developing monophasic contraction that was insensitive to calcium channel blockers. This developing contraction became dominant at higher concentrations of endothelin and was also calcium dependent.
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Affiliation(s)
- M Kozuka
- Department of Biological Sciences, Tokyo Institute of Technology, Japan
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Nakamura T, Furunaka H, Miyata T, Tokunaga F, Muta T, Iwanaga S, Niwa M, Takao T, Shimonishi Y. Tachyplesin, a class of antimicrobial peptide from the hemocytes of the horseshoe crab (Tachypleus tridentatus). Isolation and chemical structure. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)37448-9] [Citation(s) in RCA: 374] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Yanagisawa M, Kurihara H, Kimura S, Tomobe Y, Kobayashi M, Mitsui Y, Yazaki Y, Goto K, Masaki T. A novel potent vasoconstrictor peptide produced by vascular endothelial cells. Nature 1988; 332:411-5. [PMID: 2451132 DOI: 10.1038/332411a0] [Citation(s) in RCA: 7891] [Impact Index Per Article: 219.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
An endothelium-derived 21-residue vasoconstrictor peptide, endothelin, has been isolated, and shown to be one of the most potent vasoconstrictors known. Cloning and sequencing of preproendothelin complementary DNA shows that mature endothelin is generated through an unusual proteolytic processing, and regional homologies to a group of neurotoxins suggest that endothelin is an endogenous modulator of voltage-dependent ion channels. Expression of the endothelin gene is regulated by several vasoactive agents, indicating the existence of a novel cardiovascular control system.
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Affiliation(s)
- M Yanagisawa
- Institute of Basic Medical Sciences, University of Tsukuba, Ibaraki, Japan
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Martin M, Garcia y Perez L, el Ayeb M, Kopeyan C, Bechis G, Jover E, Rochat H. Purification and chemical and biological characterizations of seven toxins from the Mexican scorpion, Centruroides suffusus suffusus. J Biol Chem 1987. [DOI: 10.1016/s0021-9258(18)61214-1] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Vargas O, Martin MF, Rochat H. Characterization of six toxins from the venom of the Moroccan scorpion Buthus occitanus mardochei. EUROPEAN JOURNAL OF BIOCHEMISTRY 1987; 162:589-99. [PMID: 3104036 DOI: 10.1111/j.1432-1033.1987.tb10680.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
When the venom of the Moroccan scorpion Buthus occitanus mardochei was submitted to a combination of several chromatographic steps (including gel-filtration and ion-exchange chromatographies), seven proteins were obtained, six being lethal to mice. These proteins have been characterized by their chemical, immunological and toxic properties. The amino acid sequence (66 residues) of Bom III, the most noteworthy toxin of the venom as for its amino acid composition, is proposed following automatic sequencing of the reduced and S-methylated protein and of chymotryptic peptides. It was obvious that this sequence is somewhat different from those of toxins belonging to the same structural and immunological group (Bom III was found to be immunologically related to Buthus occitanus tunetanus toxins I and II which both share with it 56% of homology. Furthermore, Bom III was found to be unable to compete (as does Bot I) with toxin II of Androctonus australis Hector (an alpha-type toxin) for neurotoxin binding site 3 on the sodium channel of rat brain synaptosomes. Bom III was also unable to compete with toxin II of Centruroides suffusus suffusus (a beta-type toxin) to neurotoxin binding site 4 of the same channel.
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Sampieri F, Habersetzer-Rochat C, Martin MF, Kopeyan C, Rochat H. Amino acid sequence of toxin XI of the scorpion Buthus occitanus tunetanus. Evidence of a mutation having an important effect upon neurotoxic activity. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1987; 29:231-7. [PMID: 3570664 DOI: 10.1111/j.1399-3011.1987.tb02249.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The complete amino acid sequence of toxin XI of the North African scorpion Buthus occitanus tunetanus has been elucidated by automatic sequencing of the reduced and alkylated toxin and of the peptides obtained after tryptic cleavage restricted to arginyl bonds. This toxin is structurally homologous to toxin II of Androctonus australis Hector, the most active among the alpha-toxins, but is far less potent, both in vivo and in vitro. This work points out 12 mutations, many of which are conservative. Nevertheless, the most striking difference is the replacement of the lysine residue at position 58, known to be important in the activity of AaH toxin II, by a valine residue. Thus, it seems that the presence of a positive charge at this location facilitates the interactions between the receptor on the sodium channel and the alpha-type toxins.
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