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Ramanan da Cruz J, Bulet P, Mendonça de Moraes C. Exploring the potential of Brazilian Amazonian scorpion venoms: A comprehensive review of research from 2001 to 2021. Toxicon X 2024; 21:100182. [PMID: 38226138 PMCID: PMC10788795 DOI: 10.1016/j.toxcx.2023.100182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 12/18/2023] [Accepted: 12/20/2023] [Indexed: 01/17/2024] Open
Abstract
The Amazon biome is home to many scorpion species, with around two hundred identified in the region. Of these, forty-eight species have been reported in Brazil so far and six of them are of medical importance: Tityus apiacas, T. metuendus, T. obscurus, T. raquelae, T. silvestris, and T. strandi. Three non-medically important species have also been studied: Opisthanthuscayaporum, Brotheas amazonicus and Rhopalurus laticauda. The venom of the scorpion T. obscurus is the most studied, followed by O. cayaporum. We aim to update the study of these Amazonian scorpion species. We will explore the harmful and beneficial properties of scorpion venom toxins and how they could be applied in drug development. This systematic review will focus on collecting and analyzing venoms from scorpions in Brazil. Only papers on Amazonian scorpion venom studies published between 2001 and 2021 (scientific articles, theses, and dissertations) were selected, based on the lists of scorpions available in the literature. Species found in the Amazon but not confirmed to be Brazilian were omitted from the review. Theses and dissertations were chosen over their derived articles. We found 42 eligible studies (13 theses, 27 articles and 2 patents) out of 17,950 studies and a basic statistical analysis was performed. The literature showed that T. obscurus was the most studied venom with 28 publications, followed by O. cayaporum with seven articles, B. amazonicus with four articles, T. metuendus with two article and R. laticauda with one article. No publication on the characterization of T. silvestris and T. apiacas venoms were found during the reviewed period, only the clinical aspects were covered. There is still much to be explored despite the increasing number of studies conducted in recent years. Amazonian scorpions have promising potential for pharmaceutical and clinical applications.
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Affiliation(s)
- Joel Ramanan da Cruz
- Post-graduation Program in Health and Biodiversity, Federal University of Roraima, Boa Vista, Roraima, Brazil
| | - Philippe Bulet
- Institute pour l’Avancée des Biosciences, CR Université Grenoble Alpes, Inserm U1209, CNRS UMR 5309, 38000, Grenoble, France
- Platform BioPark Archamps, ArchParc, 218 Avenue Marie Curie, 74160, Archamps, France
| | - Cléria Mendonça de Moraes
- Post-graduation Program in Health and Biodiversity, Federal University of Roraima, Boa Vista, Roraima, Brazil
- Health Sciences Center and Post-graduation Program in Health and Biodiversity, Federal University of Roraima, Boa Vista, Roraima, Brazil
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Kalapothakis Y, Miranda K, Molina DAM, Conceição IMCA, Larangote D, Op den Camp HJM, Kalapothakis E, Chávez-Olórtegui C, Borges A. An overview of Tityus cisandinus scorpion venom: Transcriptome and mass fingerprinting reveal conserved toxin homologs across the Amazon region and novel lipolytic components. Int J Biol Macromol 2023; 225:1246-1266. [PMID: 36427608 DOI: 10.1016/j.ijbiomac.2022.11.185] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Revised: 11/09/2022] [Accepted: 11/18/2022] [Indexed: 11/23/2022]
Abstract
Tityus cisandinus, a neglected medically important scorpion in Ecuadorian and Peruvian Amazonia, belongs to a complex of species related to the eastern Amazon endemic Tityus obscurus, spanning a distribution of ca. 4000 km. Despite high morbidity and mortality rates, no effective scorpion antivenom is currently available in the Amazon region. Knowledge of the structural/functional relationships between T. cisandinus venom components and those from related Amazonian species is crucial for designing region-specific therapeutic antivenoms. In this work, we carried out the first venom gland transcriptomic study of an Amazonian scorpion outside Brazil, T. cisandinus. We also fingerprinted its total venom through MALDI-TOF MS, which supported our transcriptomic findings. We identified and calculated the expression level of 94 components: 60 toxins, 25 metalloproteases, five disulfide isomerases, three amidating enzymes, one hyaluronidase, and also uncovered transcripts encoding novel lipolytic beta subunits produced by New World buthid scorpions. This study demonstrates the high similarity between T. cisandinus and T. obscurus venoms, reinforcing the existence of a neglected complex of genetically and toxinologically related Amazonian scorpions of medical importance. Finally, we demonstrated the low recognition of currently available therapeutic sera against T. cisandinus and T. obscurus venoms, and concluded that these should be improved to protect against envenomation by Amazonian Tityus spp.
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Affiliation(s)
- Yan Kalapothakis
- Departamento de Genética, Ecologia e Evolução, ICB, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, CEP: 31270-901 Belo Horizonte, Minas Gerais, Brazil
| | - Kelton Miranda
- Departamento de Genética, Ecologia e Evolução, ICB, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, CEP: 31270-901 Belo Horizonte, Minas Gerais, Brazil
| | - Denis Alexis Molina Molina
- Departamento de Bioquímica e Imunologia, ICB, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, CEP: 31270-901 Belo Horizonte, Minas Gerais, Brazil
| | - Izabela Mamede Costa Andrade Conceição
- Departamento de Bioquímica e Imunologia, ICB, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, CEP: 31270-901 Belo Horizonte, Minas Gerais, Brazil
| | - Débora Larangote
- Departamento de Genética, Ecologia e Evolução, ICB, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, CEP: 31270-901 Belo Horizonte, Minas Gerais, Brazil
| | - Huub J M Op den Camp
- Department of Microbiology, Faculty of Science, Radboud University Nijmegen, Heyendaalseweg 135, NL-6525 AJ Nijmegen, the Netherlands
| | - Evanguedes Kalapothakis
- Departamento de Genética, Ecologia e Evolução, ICB, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, CEP: 31270-901 Belo Horizonte, Minas Gerais, Brazil
| | - Carlos Chávez-Olórtegui
- Departamento de Bioquímica e Imunologia, ICB, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, CEP: 31270-901 Belo Horizonte, Minas Gerais, Brazil
| | - Adolfo Borges
- Instituto de Medicina Experimental, Universidad Central de Venezuela, Caracas, Venezuela; Centro para el Desarrollo de la Investigación Científica, CEDIC, Asunción 1255, Paraguay.
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Borges A, Graham MR, Cândido DM, Pardal PPO. Amazonian scorpions and scorpionism: integrating toxinological, clinical, and phylogenetic data to combat a human health crisis in the world's most diverse rainfores. J Venom Anim Toxins Incl Trop Dis 2021; 27:e20210028. [PMID: 34887908 PMCID: PMC8629433 DOI: 10.1590/1678-9199-jvatitd-2021-0028] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 05/21/2021] [Indexed: 11/21/2022] Open
Abstract
Venom from Amazonian scorpions of the genus Tityus contains components capable of eliciting a distinct clinical, mostly neurological, syndrome. This contrasts with the mainly autonomic manifestations produced after envenomation by congeneric southern and northern South American species. Herein, we summarize Pan-Amazonian scorpionism by synthesizing available toxinological, clinical, and molecular data gathered from all affected areas in Amazonia, including Brazil, Ecuador, Colombia, Peru, Venezuela, and French Guiana. We searched multiple databases, as well as our own records, for reports of scorpion envenomations in Amazonia by confirmed Tityus spp., and compared the clinical manifestations. To help uncover clinical and venom relationships among problematic species, we explored phylogenetic relationships with a rate-calibrated analysis of mitochondrial COI data from available species. The possible existence of diversity gradients for venom toxic and immunogenic components despite the predicted strong phylogenetic association among species is underscored by discussed clinical and toxinological findings. A multicentric effort, involving all nations affected by this neglected disease, is urgently needed to offer alternatives for treating and understanding this pathology, including the preparation of neutralizing antibodies with a broad range of efficacy.
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Affiliation(s)
- Adolfo Borges
- Center for the Development of Scientific Research (CEDIC), Asunción,
Paraguay
- Laboratory of Molecular Biology of Toxins and Receptors, Institute
of Experimental Medicine, School of Medicine, Central University of Venezuela,
Caracas, Venezuela
| | - Matthew R. Graham
- Department of Biology, Eastern Connecticut State University,
Willimantic, CT, United States
| | | | - Pedro P. O. Pardal
- Laboratory of Medical Entomology and Venomous Animals, Center of
Tropical Medicine, Federal University of Pará (UFPA), Belém, PA, Brazil
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Park JH, Carlin KP, Wu G, Ilyin VI, Kyle DJ. Cysteine racemization during the Fmoc solid phase peptide synthesis of the Nav1.7-selective peptide - protoxin II. J Pept Sci 2012; 18:442-8. [DOI: 10.1002/psc.2407] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2012] [Revised: 02/01/2012] [Accepted: 02/17/2012] [Indexed: 12/16/2022]
Affiliation(s)
- Jae H. Park
- Discovery Research; Purdue Pharma LP. 6 Cedar Brook Drive Cranbury NJ 08512 USA
| | - Kevin P. Carlin
- Discovery Research; Purdue Pharma LP. 6 Cedar Brook Drive Cranbury NJ 08512 USA
| | - Gang Wu
- Discovery Research; Purdue Pharma LP. 6 Cedar Brook Drive Cranbury NJ 08512 USA
| | - Victor I. Ilyin
- Discovery Research; Purdue Pharma LP. 6 Cedar Brook Drive Cranbury NJ 08512 USA
| | - Donald J. Kyle
- Discovery Research; Purdue Pharma LP. 6 Cedar Brook Drive Cranbury NJ 08512 USA
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Vandendriessche T, Kopljar I, Wulff H, Diego-Garcia E, Abdel-Mottaleb Y, Vermassen E, Clynen E, Schoofs L, Snyders D, Tytgat J. Purification, molecular cloning and functional characterization of HelaTx1 (Heterometrus laoticus): the first member of a new κ-KTX subfamily. Biochem Pharmacol 2012; 83:1307-17. [PMID: 22305749 PMCID: PMC3644210 DOI: 10.1016/j.bcp.2012.01.021] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Revised: 01/14/2012] [Accepted: 01/17/2012] [Indexed: 10/14/2022]
Abstract
Given their medical importance, most attention has been paid toward the venom composition of scorpions of the Buthidae family. Nevertheless, research has shown that the venom of scorpions of other families is also a remarkable source of unique peptidyl toxins. The κ-KTx family of voltage-gated potassium channel (VGPC) scorpion toxins is hereof an example. From the telson of the scorpion Heterometrus laoticus (Scorpionidae), a peptide, HelaTx1, with unique primary sequence was purified through HPLC and sequenced by Edman degradation. Based on the amino acid sequence, the peptide could be cloned and the cDNA sequence revealed. HelaTx1 was chemically synthesized and functionally characterized on VGPCs of the Shaker-related, Shab-related, Shaw-related and Shal-related subfamilies. Furthermore, the toxin was also tested on small- and intermediate conductance Ca(2+)-activated K(+) channels. From the channels studied, K(v)1.1 and K(v)1.6 were found to be the most sensitive (K(v)1.1 EC(50)=9.9±1.6 μM). The toxin did not alter the activation of the channels. Competition experiments with TEA showed that the toxin is a pore blocker. Mutational studies showed that the residues E353 and Y379 in the pore of K(v)1.1 act as major interaction points for binding of the toxin. Given the amino acid sequence, the predicted secondary structure and the biological activity on VGPCs, HelaTx1 should be included in the κ-KTX family. Based on a phylogenetic study, we rearranged this family of VGPC toxins into five subfamilies and suggest that HelaTx1 is the first member of the new κ-KTx5 subfamily.
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Affiliation(s)
- Thomas Vandendriessche
- Laboratory of Toxicology, Katholieke Universiteit Leuven, Onderwijs & Navorsing II, P.O Box 922, Herestraat 49, 3000 Leuven, Belgium
| | - Ivan Kopljar
- Laboratory for Molecular Biophysics, Physiology and Pharmacology, Universiteit Antwerpen, 2610 Antwerpen, Belgium
| | - Heike Wulff
- Department of Pharmacology, University of California, 451 Health Sciences Drive, GBSF 3502, Davis, CA 95616, USA
| | - Elia Diego-Garcia
- Laboratory of Toxicology, Katholieke Universiteit Leuven, Onderwijs & Navorsing II, P.O Box 922, Herestraat 49, 3000 Leuven, Belgium
| | - Yousra Abdel-Mottaleb
- Laboratory of Toxicology, Katholieke Universiteit Leuven, Onderwijs & Navorsing II, P.O Box 922, Herestraat 49, 3000 Leuven, Belgium
| | - Elke Vermassen
- Laboratory of Toxicology, Katholieke Universiteit Leuven, Onderwijs & Navorsing II, P.O Box 922, Herestraat 49, 3000 Leuven, Belgium
| | - Elke Clynen
- Research Group Functional Genomics and Proteomics, Katholieke Universiteit Leuven, Naamsestraat 59, 3000 Leuven, Belgium
| | - Liliane Schoofs
- Research Group Functional Genomics and Proteomics, Katholieke Universiteit Leuven, Naamsestraat 59, 3000 Leuven, Belgium
| | - Dirk Snyders
- Laboratory for Molecular Biophysics, Physiology and Pharmacology, Universiteit Antwerpen, 2610 Antwerpen, Belgium
| | - Jan Tytgat
- Laboratory of Toxicology, Katholieke Universiteit Leuven, Onderwijs & Navorsing II, P.O Box 922, Herestraat 49, 3000 Leuven, Belgium
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Abdel-Mottaleb Y, Corzo G, Martin-Eauclaire MF, Satake H, Céard B, Peigneur S, Nambaru P, Bougis PE, Possani LD, Tytgat J. A common "hot spot" confers hERG blockade activity to alpha-scorpion toxins affecting K+ channels. Biochem Pharmacol 2008; 76:805-15. [PMID: 18687312 DOI: 10.1016/j.bcp.2008.07.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2008] [Revised: 07/02/2008] [Accepted: 07/02/2008] [Indexed: 02/01/2023]
Abstract
While alpha-KTx peptides are generally known for their modulation of the Shaker-type and the Ca(2+)-activated potassium channels, gamma-KTxs are associated with hERG channels modulation. An exception to the rule is BmTx3 which belongs to subfamily alpha-KTx15 and can block hERG channels. To explain the peculiar behavior of BmTx3, a tentative "hot spot" formed of 2 basic residues (R18 and K19) was suggested but never further studied [Huys I, et al. BmTx3, a scorpion toxin with two putative functional faces separately active on A-type K(+) and HERG currents. Biochem J 2004;378:745-52]. In this work, we investigated if the "hot spot" is a commonality in subfamily alpha-KTx15 by testing the effect of (AmmTx3, Aa1, discrepin). Furthermore, single mutations altering the "hot spot" in discrepin, have introduced for the very first time a hERG blocking activity to a previously non-active alpha-KTx. Additionally, we could extend our results to other alpha-KTx subfamily members belonging to alpha-KTx1, 4 and 6, therefore, the "hot spot" represents a common pharmacophore serving as a predictive tool for yet to be discovered alpha-KTxs.
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Affiliation(s)
- Yousra Abdel-Mottaleb
- Laboratory of Toxicology, University of Leuven, O&N 2, Herestraat 49, P.O. Box 922, 3000 Leuven, Belgium
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Batista CVF, Román-González SA, Salas-Castillo SP, Zamudio FZ, Gómez-Lagunas F, Possani LD. Proteomic analysis of the venom from the scorpion Tityus stigmurus: biochemical and physiological comparison with other Tityus species. Comp Biochem Physiol C Toxicol Pharmacol 2007; 146:147-157. [PMID: 17270501 DOI: 10.1016/j.cbpc.2006.12.004] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2006] [Revised: 11/21/2006] [Accepted: 12/07/2006] [Indexed: 11/21/2022]
Abstract
The venom from the Brazilian scorpion Tityus stigmurus was fractionated by high performance liquid chromatography (HPLC) and the corresponding components were used for molecular mass determination using electrospray ion trap mass spectrometry. One hundred distinct components were clearly assigned showing molecular masses from 216.5 to 44,800.0 Da. Fifteen new components were isolated and sequenced, four of them to completion: Tst-3 (similar to Na(+) channel specific scorpion toxins), Tst-17 (a K(+) channel blocking peptide similar to Tc1), Tst beta KTx (a peptide with identical sequence as that of TsTX-K beta toxin earlier described to exist in T. serrulatus venom) and finally a novel proline-rich peptide of unknown function. Among the eleven components partially sequenced were two enzymes: hyaluronidase and lysozyme. The first enzyme has a molecular mass of 44,800.0 Da. This enzyme showed high activity against the substrate hyaluronan in vitro. Amino acid sequence of the second enzyme showed that it is similar to other known lysozymes, with similar molecular mass and sequence to that of bona fide lysozymes reported in public protein data banks. Finally, this communication reports a correlation among HPLC retention times and molecular masses of folded scorpion toxins as well as a comparative structural and physiological analysis of components from the venom of several species of the genus Tityus.
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Affiliation(s)
- C V F Batista
- Department of Molecular Medicine and Bioprocesses, Institute of Biotechnology, National Autonomous University of Mexico, Avenida Universidad, 2001, Apartado Postal 510-3, Cuernavaca 62210, Mexico
| | - S A Román-González
- Department of Molecular Medicine and Bioprocesses, Institute of Biotechnology, National Autonomous University of Mexico, Avenida Universidad, 2001, Apartado Postal 510-3, Cuernavaca 62210, Mexico
| | - S P Salas-Castillo
- Department of Molecular Medicine and Bioprocesses, Institute of Biotechnology, National Autonomous University of Mexico, Avenida Universidad, 2001, Apartado Postal 510-3, Cuernavaca 62210, Mexico
| | - F Z Zamudio
- Department of Molecular Medicine and Bioprocesses, Institute of Biotechnology, National Autonomous University of Mexico, Avenida Universidad, 2001, Apartado Postal 510-3, Cuernavaca 62210, Mexico
| | - F Gómez-Lagunas
- Department of Physiology, Medical School, National Autonomous University of Mexico, Ciudad Universitaria, Mexico D.F. 04510, Mexico
| | - L D Possani
- Department of Molecular Medicine and Bioprocesses, Institute of Biotechnology, National Autonomous University of Mexico, Avenida Universidad, 2001, Apartado Postal 510-3, Cuernavaca 62210, Mexico.
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Oyama S, Pristovsek P, Franzoni L, Pertinhez TA, Schininá E, Lücke C, Rüterjans H, Arantes EC, Spisni A. Probing the pH-dependent structural features of alpha-KTx12.1, a potassium channel blocker from the scorpion Tityus serrulatus. Protein Sci 2005; 14:1025-38. [PMID: 15772309 PMCID: PMC2253457 DOI: 10.1110/ps.041131205] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Potassium channels are widespread in living cells and are involved in many diseases. The scorpion toxin alpha-KTx(12.1) interacts with various K(+) channels, suggesting its capacity to match diverse channel pores. It is recognized that tissue injuries may affect the pH at toxins site of action, thereby modulating both protein conformation and activity. To better understand its molecular mechanism of action, we studied alpha-KTx(12.1) using pH as a tool to explore its plasticity and NMR in combination with MD calculations to detect it. The toxin solution structure consists of an alpha-helix and a triple-stranded beta-sheet stabilized by four disulfide bridges. The NMR results show, in addition, that His28 possesses an unusually low pK(a) of 5.2. The best set of protein conformers is obtained at pH 4.5, while at pH 7.0, the reduced number of NOEs resulting from a faster hydrogen exchange does not allow to reach a good structural convergence. Nonetheless, MD calculations show that the toxin structure does not vary significantly in that pH range, while conformational changes and modifications of the surface charge distribution occur when His28 is fully protonated. Moreover, essential dynamics analysis reveals variations in the toxin's coherent motions. In conclusion, His28, with its low pK(a) value, provides alpha-KTx(12.1) with the ability to preserve its active conformation over a wide pH interval, thus expanding the range of cellular conditions where the toxin can fully exhibit its activity. Overall, the results further underline the role of histidine as a natural controller of proteins' functionality.
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Affiliation(s)
- Sérgio Oyama
- Department of Experimental Medicine, Section of Chemistry and Structural Biochemistry, University of Parma, Via Volturno 39, 43100 Parma, Italy
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Abstract
The major challenges in structural proteomics include identifying all the proteins on the genome-wide scale, determining their structure-function relationships, and outlining the precise three-dimensional structures of the proteins. Protein structures are typically determined by experimental approaches such as X-ray crystallography or nuclear magnetic resonance (NMR) spectroscopy. However, the knowledge of three-dimensional space by these techniques is still limited. Thus, computational methods such as comparative and de novo approaches and molecular dynamic simulations are intensively used as alternative tools to predict the three-dimensional structures and dynamic behavior of proteins. This review summarizes recent developments in structural proteomics for protein structure determination; including instrumental methods such as X-ray crystallography and NMR spectroscopy, and computational methods such as comparative and de novo structure prediction and molecular dynamics simulations.
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Affiliation(s)
- Hsuan-Liang Liu
- Department of Chemical Engineering, National Taipei University of Technology, Taiwan.
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Liu HL, Lin JC. Molecular docking of the scorpion toxin Tc1 to the structural model of the voltage-gated potassium channel Kv1.1 from human Homo sapiens. J Biomol Struct Dyn 2004; 21:639-50. [PMID: 14769056 DOI: 10.1080/07391102.2004.10506954] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
In this study, structural model of the pore loop region of the voltage-gated potassium channel Kv1.1 from human Homo sapiens was constructed based on the crystallographic structure of KcsA by structural homology. The pore loop region of Kv1.1 exhibits similar folds as that of KcsA. The structural feature of the selectivity filter of Kv1.1 is nearly identical to that of KcsA, whereas most of the structural variations occur in the turret as well as in the inner and outer helices. Molecular docking experiments of the scorpion toxin Tc1 from Tityus cambridgei to the outer vestibule of KcsA as well as Kv1.1 were subsequently performed with various initial Tc1 orientations. Tc1 was found to form the most stable complexes with these two K+ channels when the side chain of Lys14 occupies the pore of the selectivity filter through electrostatic interaction. Tc1 binds preferentially towards Kv1.1 than KcsA due to stronger hydrophobic and electrostatic interactions formed between the toxin and the selectivity filter and outer vestibule of Kv1.1. Furthermore, surface complementarity of the outer vestibules of the channels to the Tc1 spatial conformations also plays an important role in stabilizing both the Tc1/KcsA and Tc1/Kv1.1 complexes.
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Affiliation(s)
- Hsuan-Liang Liu
- Department of Chemical Engineering, Graduate Institute of Biotechnology, National Taipei University of Technology, No 1 Sec 3 Chung-Hsiao E Rd, Taipei, Taiwan 10608.
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Zhang N, Li M, Chen X, Wang Y, Wu G, Hu G, Wu H. Solution structure of BmKK2, a new potassium channel blocker from the venom of chinese scorpion Buthus martensi Karsch. Proteins 2004; 55:835-45. [PMID: 15146482 DOI: 10.1002/prot.20117] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A natural K+ channel blocker, BmKK2 (a member of scorpion toxin subfamily alpha-KTx 14), which is composed of 31 amino acid residues and purified from the venom of the Chinese scorpion Buthus martensi Karsch, was characterized using whole-cell patch-clamp recording in rat hippocampal neurons. The three dimensional structure of BmKK2 was determined with two-dimensional NMR spectroscopy and molecular modelling techniques. In solution this toxin adopted a common alpha/beta-motif, but showed distinct local conformation in the loop between alpha-helix and beta-sheet in comparison with typical short-chain scorpion toxins (e.g., CTX and NTX). Also, the alpha helix is shorter and the beta-sheet element is smaller (each strand consisted only two residues). The unusual structural feature of BmKK2 was attributed to the shorter loop between the alpha-helix and beta-sheet and the presence of two consecutive Pro residues at position 21 and 22 in the loop. Moreover, two models of BmKK2/hKv1.3 channel and BmKK2/rSK2 channel complexes were simulated with docking calculations. The results demonstrated the existence of a alpha-mode binding between the toxin and the channels. The model of BmKK2/rSK2 channel complex exhibited favorable contacts both in electrostatic and hydrophobic, including a network of five hydrogen bonds and bigger interface containing seven pairs of inter-residue interactions. In contrast, the model of BmKK2/hKv1.3 channel complex, containing only three pairs of inter-residue interactions, exhibited poor contacts and smaller interface. The results well explained its lower activity towards Kv channel, and predicted that it may prefer a type of SK channel with a narrower entryway as its specific receptor.
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Affiliation(s)
- Naixia Zhang
- State Key Laboratory of Bio-organic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, People's Republic of China
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12
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Liu HL, Lin JC. Structural model of the voltage-gated potassium channel Kv1.1 and molecular docking of Tc1 toxin from Tityus cambridgei to KcsA and Kv1.1. Chem Phys Lett 2003. [DOI: 10.1016/j.cplett.2003.10.040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Abstract
Toxins that block voltage-gated potassium (Kv) channels provide a possible template for improved homology models of the Kv pore. In assessing the interactions of Kv channels and their toxins it is important to determine the dynamic flexibility of the toxins. Multiple 10 ns duration molecular dynamics simulations combined with essential dynamics analysis have been used to explore the flexibility of four different Kv channel-blocking toxins. Three toxins (Tc1, AgTx and ChTx) share a common fold. They also share a common pattern of conformational dynamics, as revealed by essential dynamics analysis of the simulation results. This suggests that some aspects of dynamic behaviour are conserved across a single protein fold class. In each of these three toxins, the residue exhibiting minimum flexibility corresponds to a conserved lysine residue that is suggested to interact with the filter domain of the channel. Thus, comparative simulations reveal functionally important conservation of molecular dynamics as well as protein fold across a family of related toxins.
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Affiliation(s)
- Alessandro Grottesi
- Laboratory of Molecular Biophysics, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
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