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Palermo G, Schouten WM, Alonso LL, Ulens C, Kool J, Slagboom J. Acetylcholine-Binding Protein Affinity Profiling of Neurotoxins in Snake Venoms with Parallel Toxin Identification. Int J Mol Sci 2023; 24:16769. [PMID: 38069093 PMCID: PMC10706727 DOI: 10.3390/ijms242316769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 11/23/2023] [Accepted: 11/24/2023] [Indexed: 12/18/2023] Open
Abstract
Snakebite is considered a concerning issue and a neglected tropical disease. Three-finger toxins (3FTxs) in snake venoms primarily cause neurotoxic effects since they have high affinity for nicotinic acetylcholine receptors (nAChRs). Their small molecular size makes 3FTxs weakly immunogenic and therefore not appropriately targeted by current antivenoms. This study aims at presenting and applying an analytical method for investigating the therapeutic potential of the acetylcholine-binding protein (AChBP), an efficient nAChR mimic that can capture 3FTxs, for alternative treatment of elapid snakebites. In this analytical methodology, snake venom toxins were separated and characterised using high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS) and high-throughput venomics. By subsequent nanofractionation analytics, binding profiling of toxins to the AChBP was achieved with a post-column plate reader-based fluorescence-enhancement ligand displacement bioassay. The integrated method was established and applied to profiling venoms of six elapid snakes (Naja mossambica, Ophiophagus hannah, Dendroaspis polylepis, Naja kaouthia, Naja haje and Bungarus multicinctus). The methodology demonstrated that the AChBP is able to effectively bind long-chain 3FTxs with relatively high affinity, but has low or no binding affinity towards short-chain 3FTxs, and as such provides an efficient analytical platform to investigate binding affinity of 3FTxs to the AChBP and mutants thereof and to rapidly identify bound toxins.
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Affiliation(s)
- Giulia Palermo
- Centre for Analytical Sciences Amsterdam (CASA), 1012 WX Amsterdam, The Netherlands; (G.P.); (W.M.S.); (L.L.A.)
- Amsterdam Institute of Molecular and Life Sciences, Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Faculty of Science, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands
| | - Wietse M. Schouten
- Centre for Analytical Sciences Amsterdam (CASA), 1012 WX Amsterdam, The Netherlands; (G.P.); (W.M.S.); (L.L.A.)
- Amsterdam Institute of Molecular and Life Sciences, Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Faculty of Science, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands
| | - Luis Lago Alonso
- Centre for Analytical Sciences Amsterdam (CASA), 1012 WX Amsterdam, The Netherlands; (G.P.); (W.M.S.); (L.L.A.)
- Amsterdam Institute of Molecular and Life Sciences, Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Faculty of Science, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands
| | - Chris Ulens
- Laboratory of Structural Neurobiology, Department of Cellular and Molecular Medicine, Faculty of Medicine, KU Leuven, 3000 Leuven, Belgium;
| | - Jeroen Kool
- Centre for Analytical Sciences Amsterdam (CASA), 1012 WX Amsterdam, The Netherlands; (G.P.); (W.M.S.); (L.L.A.)
- Amsterdam Institute of Molecular and Life Sciences, Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Faculty of Science, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands
| | - Julien Slagboom
- Centre for Analytical Sciences Amsterdam (CASA), 1012 WX Amsterdam, The Netherlands; (G.P.); (W.M.S.); (L.L.A.)
- Amsterdam Institute of Molecular and Life Sciences, Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Faculty of Science, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands
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Ferraz CR, Arrahman A, Xie C, Casewell NR, Lewis RJ, Kool J, Cardoso FC. Multifunctional Toxins in Snake Venoms and Therapeutic Implications: From Pain to Hemorrhage and Necrosis. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00218] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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Chan YS, Cheung RCF, Xia L, Wong JH, Ng TB, Chan WY. Snake venom toxins: toxicity and medicinal applications. Appl Microbiol Biotechnol 2016; 100:6165-6181. [PMID: 27245678 DOI: 10.1007/s00253-016-7610-9] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 05/01/2016] [Accepted: 05/03/2016] [Indexed: 11/25/2022]
Abstract
Snake venoms are complex mixtures of small molecules and peptides/proteins, and most of them display certain kinds of bioactivities. They include neurotoxic, cytotoxic, cardiotoxic, myotoxic, and many different enzymatic activities. Snake envenomation is a significant health issue as millions of snakebites are reported annually. A large number of people are injured and die due to snake venom poisoning. However, several fatal snake venom toxins have found potential uses as diagnostic tools, therapeutic agent, or drug leads. In this review, different non-enzymatically active snake venom toxins which have potential therapeutic properties such as antitumor, antimicrobial, anticoagulating, and analgesic activities will be discussed.
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Affiliation(s)
- Yau Sang Chan
- State Key Laboratory of Respiratory Disease for Allergy, School of Medicine, Shenzhen University, Nanhai Ave 3688, 518060, Shenzhen, Guangdong, China
| | - Randy Chi Fai Cheung
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
| | - Lixin Xia
- State Key Laboratory of Respiratory Disease for Allergy, School of Medicine, Shenzhen University, Nanhai Ave 3688, 518060, Shenzhen, Guangdong, China.
| | - Jack Ho Wong
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China.
| | - Tzi Bun Ng
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China.
| | - Wai Yee Chan
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China.
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Melani RD, Skinner OS, Fornelli L, Domont GB, Compton PD, Kelleher NL. Mapping Proteoforms and Protein Complexes From King Cobra Venom Using Both Denaturing and Native Top-down Proteomics. Mol Cell Proteomics 2016; 15:2423-34. [PMID: 27178327 DOI: 10.1074/mcp.m115.056523] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2015] [Indexed: 11/06/2022] Open
Abstract
Characterizing whole proteins by top-down proteomics avoids a step of inference encountered in the dominant bottom-up methodology when peptides are assembled computationally into proteins for identification. The direct interrogation of whole proteins and protein complexes from the venom of Ophiophagus hannah (king cobra) provides a sharply clarified view of toxin sequence variation, transit peptide cleavage sites and post-translational modifications (PTMs) likely critical for venom lethality. A tube-gel format for electrophoresis (called GELFrEE) and solution isoelectric focusing were used for protein fractionation prior to LC-MS/MS analysis resulting in 131 protein identifications (18 more than bottom-up) and a total of 184 proteoforms characterized from 14 protein toxin families. Operating both GELFrEE and mass spectrometry to preserve non-covalent interactions generated detailed information about two of the largest venom glycoprotein complexes: the homodimeric l-amino acid oxidase (∼130 kDa) and the multichain toxin cobra venom factor (∼147 kDa). The l-amino acid oxidase complex exhibited two clusters of multiproteoform complexes corresponding to the presence of 5 or 6 N-glycans moieties, each consistent with a distribution of N-acetyl hexosamines. Employing top-down proteomics in both native and denaturing modes provides unprecedented characterization of venom proteoforms and their complexes. A precise molecular inventory of venom proteins will propel the study of snake toxin variation and the targeted development of new antivenoms or other biotherapeutics.
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Affiliation(s)
- Rafael D Melani
- From the ‡Proteomics Unit, Rio de Janeiro Proteomics Network, Departamento de Bioquímica. Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-909, Brazil; §Departments of Chemistry and Molecular Biosciences, the Chemistry of Life Processes Institute, and the Proteomics Center of Excellence, Northwestern University, Evanston, Illinois, 60208
| | - Owen S Skinner
- §Departments of Chemistry and Molecular Biosciences, the Chemistry of Life Processes Institute, and the Proteomics Center of Excellence, Northwestern University, Evanston, Illinois, 60208
| | - Luca Fornelli
- §Departments of Chemistry and Molecular Biosciences, the Chemistry of Life Processes Institute, and the Proteomics Center of Excellence, Northwestern University, Evanston, Illinois, 60208
| | - Gilberto B Domont
- From the ‡Proteomics Unit, Rio de Janeiro Proteomics Network, Departamento de Bioquímica. Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-909, Brazil;
| | - Philip D Compton
- §Departments of Chemistry and Molecular Biosciences, the Chemistry of Life Processes Institute, and the Proteomics Center of Excellence, Northwestern University, Evanston, Illinois, 60208
| | - Neil L Kelleher
- §Departments of Chemistry and Molecular Biosciences, the Chemistry of Life Processes Institute, and the Proteomics Center of Excellence, Northwestern University, Evanston, Illinois, 60208
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From naturally-occurring neurotoxic agents to CNS shuttles for drug delivery. Eur J Pharm Sci 2015; 74:63-76. [DOI: 10.1016/j.ejps.2015.04.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 03/19/2015] [Accepted: 04/08/2015] [Indexed: 12/20/2022]
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Danpaiboon W, Reamtong O, Sookrung N, Seesuay W, Sakolvaree Y, Thanongsaksrikul J, Dong-din-on F, Srimanote P, Thueng-in K, Chaicumpa W. Ophiophagus hannah venom: proteome, components bound by Naja kaouthia antivenin and neutralization by N. kaouthia neurotoxin-specific human ScFv. Toxins (Basel) 2014; 6:1526-58. [PMID: 24828754 PMCID: PMC4052251 DOI: 10.3390/toxins6051526] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Revised: 04/20/2014] [Accepted: 05/05/2014] [Indexed: 12/27/2022] Open
Abstract
Venomous snakebites are an important health problem in tropical and subtropical countries. King cobra (Ophiophagushannah) is the largest venomous snake found in South and Southeast Asia. In this study, the O. hannah venom proteome and the venom components cross-reactive to N. kaouthia monospecific antivenin were studied. O. hannah venom consisted of 14 different protein families, including three finger toxins, phospholipases, cysteine-rich secretory proteins, cobra venom factor, muscarinic toxin, L-amino acid oxidase, hypothetical proteins, low cysteine protein, phosphodiesterase, proteases, vespryn toxin, Kunitz, growth factor activators and others (coagulation factor, endonuclease, 5’-nucleotidase). N. kaouthia antivenin recognized several functionally different O. hannah venom proteins and mediated paratherapeutic efficacy by rescuing the O. hannah envenomed mice from lethality. An engineered human ScFv specific to N. kaouthia long neurotoxin (NkLN-HuScFv) cross-neutralized the O. hannah venom and extricated the O. hannah envenomed mice from death in a dose escalation manner. Homology modeling and molecular docking revealed that NkLN-HuScFv interacted with residues in loops 2 and 3 of the neurotoxins of both snake species, which are important for neuronal acetylcholine receptor binding. The data of this study are useful for snakebite treatment when and where the polyspecific antivenin is not available. Because the supply of horse-derived antivenin is limited and the preparation may cause some adverse effects in recipients, a cocktail of recombinant human ScFvs for various toxic venom components shared by different venomous snakes, exemplified by the in vitro produced NkLN-HuScFv in this study, should contribute to a possible future route for an improved alternative to the antivenins.
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Affiliation(s)
- Witchuda Danpaiboon
- Graduate Program in Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand.
| | - Onrapak Reamtong
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand.
| | - Nitat Sookrung
- Department of Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand.
| | - Watee Seesuay
- Laboratory for Research and Technology Development, Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand.
| | - Yuwaporn Sakolvaree
- Laboratory for Research and Technology Development, Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand.
| | - Jeeraphong Thanongsaksrikul
- Laboratory for Research and Technology Development, Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand.
| | - Fonthip Dong-din-on
- Center for Agriculture Biotechnology and Department of Veterinary Pathology, Faculty of Veterinary Medicine, Kasetsart University, Kam-paeng-saen Campus, Nakhon-pathom 73140, Thailand.
| | - Potjanee Srimanote
- Graduate Program in Biomedical Science, Faculty of Allied Health Sciences, Thammasat University, Pathumthani 12120, Thailand.
| | - Kanyarat Thueng-in
- Laboratory for Research and Technology Development, Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand.
| | - Wanpen Chaicumpa
- Laboratory for Research and Technology Development, Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand.
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7
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Ye Y, Fang F, Li Y. Dimerization of resveratrol induced by red light and its synergistic analgesic effects with cobra neurotoxin. Photochem Photobiol 2014; 90:860-6. [PMID: 24571437 DOI: 10.1111/php.12262] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2013] [Accepted: 02/20/2014] [Indexed: 11/30/2022]
Abstract
Resveratrol polymer has better effects than monomer in some aspects as reported, but most of synthetic methods acquire severe conditions and no analgesic effects are investigated. A novel method is found to synthesize resveratrol polymer by excitation of photosensitizer pheophorbide at red light of 630 nm. The polymer was analyzed by fluorescence spectra and HPLC, further isolated by preparative liquid chromatography and identified as a resveratrol dimer by MS and NMR. Analgesic effects were measured by acetic acid writhing and hot-plate test in mice. The resveratrol dimer has the stronger analgesic effects than monomer, and drug combination of the dimer and cobra neurotoxin enhances and prolongs analgesic effects, suggesting the synergistic action. Simulation of molecular interaction reveals that the dimer spontaneously binds to cobra neurotoxin and makes a complex substance. The dimer can interact with cyclooxygenase-2, μ receptor and nicotine receptor, the synergistic analgesic effects of the complex are attributed to its multiple targets role. The combination of resveratrol dimer and cobra neurotoxin may make up for their deficiencies in analgesic effects, and has prospects in clinical use.
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Affiliation(s)
- Yong Ye
- Department of Pharmaceutical Engineering, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, China
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Chanda C, Sarkar A, Sistla S, Chakrabarty D. Anti-platelet activity of a three-finger toxin (3FTx) from Indian monocled cobra (Naja kaouthia) venom. Biochem Biophys Res Commun 2013; 441:550-4. [PMID: 24183721 DOI: 10.1016/j.bbrc.2013.10.125] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2013] [Accepted: 10/23/2013] [Indexed: 12/16/2022]
Abstract
A low molecular weight anti-platelet peptide (6.9 kDa) has been purified from Naja kaouthia venom and was named KT-6.9. MALDI-TOF/TOF mass spectrometry analysis revealed the homology of KT-6.9 peptide sequence with many three finger toxin family members. KT-6.9 inhibited human platelet aggregation process in a dose dependent manner. It has inhibited ADP, thrombin and arachidonic acid induced platelet aggregation process in dose dependent manner, but did not inhibit collagen and ristocetin induced platelet aggregation. Strong inhibition (70%) of the ADP induced platelet aggregation by KT-6.9 suggests competition with ADP for its receptors on platelet surface. Anti-platelet activity of KT-6.9 was found to be 25 times stronger than that of anti-platelet drug clopidogrel. Binding of KT-6.9 to platelet surface was confirmed by surface plasma resonance analysis using BIAcore X100. Binding was also observed by a modified sandwich ELISA method using anti-KT-6.9 antibodies. KT-6.9 is probably the first 3 FTx from Indian monocled cobra venom reported as a platelet aggregation inhibitor.
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Affiliation(s)
- Chandrasekhar Chanda
- Department of Biological Sciences, Birla Institute of Technology and Science, Pilani, K.K. Birla Goa Campus, Zuarinagar, Goa 403726, India
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Unfolding stabilities of two paralogous proteins from Naja naja naja (Indian cobra) as probed by molecular dynamics simulations. Toxicon 2013; 72:11-22. [DOI: 10.1016/j.toxicon.2013.05.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2013] [Revised: 05/20/2013] [Accepted: 05/30/2013] [Indexed: 11/21/2022]
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He YY, Lee WH, Zhang Y. Cloning and purification of α-neurotoxins from king cobra (Ophiophagus hannah). Toxicon 2004; 44:295-303. [PMID: 15302536 DOI: 10.1016/j.toxicon.2004.06.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2004] [Revised: 06/02/2004] [Accepted: 06/04/2004] [Indexed: 10/26/2022]
Abstract
Thirteen complete and three partial cDNA sequences were cloned from the constructed king cobra (Ophiophagus hannah) venom gland cDNA library. Phylogenetic analysis of nucleotide sequences of king cobra with those from other snake venoms revealed that obtained cDNAs are highly homologous to snake venom alpha-neurotoxins. Alignment of deduced mature peptide sequences of the obtained clones with those of other reported alpha-neurotoxins from the king cobra venom indicates that our obtained 16 clones belong to long-chain neurotoxins (seven), short-chain neurotoxins (seven), weak toxin (one) and variant (one), respectively. Up to now, two out of 16 newly cloned king cobra alpha-neurotoxins have identical amino acid sequences with CM-11 and Oh-6A/6B, which have been characterized from the same venom. Furthermore, five long-chain alpha-neurotoxins and two short-chain alpha-neurotoxins were purified from crude venom and their N-terminal amino acid sequences were determined. The cDNAs encoding the putative precursors of the purified native peptide were also determined based on the N-terminal amino acid sequencing. The purified alpha-neurotoxins showed different lethal activities on mice.
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Affiliation(s)
- Ying-Ying He
- Department of Animal Toxinology, Kunming Institute of Zoology, The Chinese Academy of Sciences, 32 East Jiao Chang Road, Kunming 650223, Yunnan, China
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Zeng H, Hawrot E. NMR-based binding screen and structural analysis of the complex formed between alpha-cobratoxin and an 18-mer cognate peptide derived from the alpha 1 subunit of the nicotinic acetylcholine receptor from Torpedo californica. J Biol Chem 2002; 277:37439-45. [PMID: 12133834 DOI: 10.1074/jbc.m205483200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The alpha18-mer peptide, spanning residues 181-198 of the Torpedo nicotinic acetylcholine receptor alpha1 subunit, contains key binding determinants for agonists and competitive antagonists. To investigate whether the alpha18-mer can bind other alpha-neurotoxins besides alpha-bungarotoxin, we designed a two-dimensional (1)H-(15)N heteronuclear single quantum correlation experiment to screen four related neurotoxins for their binding ability to the peptide. Of the four toxins tested (erabutoxin a, erabutoxin b, LSIII, and alpha-cobratoxin), only alpha-cobratoxin binds the alpha18-mer to form a 1:1 complex. The NMR solution structure of the alpha-cobratoxin.alpha18-mer complex was determined with a backbone root mean square deviation of 1.46 A. In the structure, alpha-cobratoxin contacts the alpha18-mer at the tips of loop I and II and through C-terminal cationic residues. The contact zone derived from the intermolecular nuclear Overhauser effects is in agreement with recent biochemical data. Furthermore, the structural models support the involvement of cation-pi interactions in stabilizing the complex. In addition, the binding screen results suggest that C-terminal cationic residues of alpha-bungarotoxin and alpha-cobratoxin contribute significantly to binding of the alpha18-mer. Finally, we present a structural model for nicotinic acetylcholine receptor-alpha-cobratoxin interaction by superimposing the alpha-cobratoxin.alpha18-mer complex onto the crystal structure of the acetylcholine-binding protein (Protein Data Bank code ).
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Affiliation(s)
- Haoyu Zeng
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Brown Medical School, Providence, Rhode Island 02912, USA
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12
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Meng QX, Wang WY, Lu QM, Jin Y, Wei JF, Zhu SW, Xiong YL. A novel short neurotoxin, cobrotoxin c, from monocellate cobra (Naja kaouthia) venom: isolation and purification, primary and secondary structure determination, and tertiary structure modeling. Comp Biochem Physiol C Toxicol Pharmacol 2002; 132:113-21. [PMID: 12039691 DOI: 10.1016/s1532-0456(02)00049-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A novel short neurotoxin, cobrotoxin c (CBT C) was isolated from the venom of monocellate cobra (Naja kaouthia) using a combination of ion-exchange chromatography and FPLC. Its primary structure was determined by Edman degradation. CBT C is composed of 61 amino acid residues. It differs from cobrotoxin b (CBT B) by only two amino acid substitutions, Thr/Ala11 and Arg/Thr56, which are not located on the functionally important regions by sequence similarity. However, the LD50 is 0.08 mg/g to mice, i.e. approximately five-fold higher than for CBT B. Strikingly, a structure-function relationship analysis suggests the existence of a functionally important domain on the outside of Loop III of CBT C. The functionally important basic residues on the outside of Loop III might have a pairwise interaction with alpha subunit, instead of gamma or delta subunits of the nicotinic acetylcholine receptor (nAChR).
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Affiliation(s)
- Qing-Xiong Meng
- Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, PR China
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Torres AM, Kini RM, Selvanayagam N, Kuchel PW. NMR structure of bucandin, a neurotoxin from the venom of the Malayan krait (Bungarus candidus). Biochem J 2001; 360:539-48. [PMID: 11736642 PMCID: PMC1222255 DOI: 10.1042/0264-6021:3600539] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A high-resolution solution structure of bucandin, a neurotoxin from Malayan krait (Bungarus candidus), was determined by (1)H-NMR spectroscopy and molecular dynamics. The average backbone root-mean-square deviation for the 20 calculated structures and the mean structure is 0.47 A (1 A=0.1 nm) for all residues and 0.24 A for the well-defined region that spans residues 23-58. Secondary-structural elements include two antiparallel beta-sheets characterized by two and four strands. According to recent X-ray analysis, bucandin adopts a typical three-finger loop motif and yet it has some peculiar characteristics that set it apart from other common alpha-neurotoxins. The presence of a fourth strand in the second antiparallel beta-sheet had not been observed before in three-finger toxins, and this feature was well represented in the NMR structure. Although the overall fold of the NMR structure is similar to that of the X-ray crystal structure, there are significant differences between the two structures that have implications for the pharmacological action of the toxin. These include the extent of the beta-sheets, the conformation of the region spanning residues 42-49 and the orientation of some side chains. In comparison with the X-ray structure, the NMR structure shows that the hydrophobic side chains of Trp(27) and Trp(36) are stacked together and are orientated towards the tip of the middle loop. The NMR study also showed that the two-stranded beta-sheet incorporated in the first loop, as defined by residues 1-22, and the C-terminus from Asn(59), is probably flexible relative to the rest of the molecule. On the basis of the dispositions of the hydrophobic and hydrophilic side chains, the structure of bucandin is clearly different from those of cytotoxins.
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Affiliation(s)
- A M Torres
- Department of Biochemistry, University of Sydney, N.S.W. Australia 2006
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Bracci L, Pini A, Lozzi L, Lelli B, Battestin P, Spreafico A, Bernini A, Niccolai N, Neri P. Mimicking the nicotinic receptor binding site by a single chain Fv selected by competitive panning from a synthetic phage library. J Neurochem 2001; 78:24-31. [PMID: 11432970 DOI: 10.1046/j.1471-4159.2001.00398.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We have developed a novel competitive method to select from a phage display library a single chain Fv which is able to mimic the alpha-bungarotoxin binding site of the muscle nicotinic receptor. The single chain Fv was selected from a large synthetic library using alpha-bungarotoxin-coated magnetic beads. Toxin-bound phages were then eluted by competition with affinity purified nicotinic receptor. Recognition of the toxin by the anti-alpha-bungarotoxin single chain Fv was very similar to that of the receptor, such as indicated by the epitope mapping of alpha-bungarotoxin through overlapping synthetic peptides. Moreover, several positively charged residues located in the toxin second loop and in the C-terminal region were found to be critical, to a similar extent, for toxin recognition by the single chain Fv and the receptor. However, although the anti-alpha-bungarotoxin single chain Fv seems to mimic the toxin binding site of the nicotinic receptor, it does not bind other nicotinic agonists or antagonists. Our results suggest that competitive selection of anti-ligand antibody phages can allow the production of receptor-mimicking molecules directly and exclusively targeted at one specific ligand. Since physiologically and pharmacologically different ligands can produce opposite effects on receptor functions, such selective ligand decoys can have important therapeutic applications.
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Affiliation(s)
- L Bracci
- Dipartimento di Biologia Molecolare, Sez. Chimica Biologica, Università di Siena, Via Fiorentina 1, 53100 Siena, Italy.
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15
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Zeng H, Moise L, Grant MA, Hawrot E. The solution structure of the complex formed between alpha-bungarotoxin and an 18-mer cognate peptide derived from the alpha 1 subunit of the nicotinic acetylcholine receptor from Torpedo californica. J Biol Chem 2001; 276:22930-40. [PMID: 11312275 DOI: 10.1074/jbc.m102300200] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The region encompassing residues 181-98 on the alpha1 subunit of the muscle-type nicotinic acetylcholine receptor forms a major determinant for the binding of alpha-neurotoxins. We have prepared an (15)N-enriched 18-amino acid peptide corresponding to the sequence in this region to facilitate structural elucidation by multidimensional NMR. Our aim was to determine the structural basis for the high affinity, stoichiometric complex formed between this cognate peptide and alpha-bungarotoxin, a long alpha-neurotoxin. Resonances in the complex were assigned through heteronuclear and homonuclear NMR experiments, and the resulting interproton distance constraints were used to generate ensemble structures of the complex. Thr(8), Pro(10), Lys(38), Val(39), Val(40), and Pro(69) in alpha-bungarotoxin and Tyr(189), Tyr(190), Thr(191), Cys(192), Asp(195), and Thr(196) in the peptide participate in major intermolecular contacts. A comparison of the free and bound alpha-bungarotoxin structures reveals significant conformational rearrangements in flexible regions of alpha-bungarotoxin, mainly loops I, II, and the C-terminal tail. Furthermore, several of the calculated structures suggest that cation-pi interactions may be involved in binding. The root mean square deviation of the polypeptide backbone in the complex is 2.07 A. This structure provides, to date, the highest resolution description of the contacts between a prototypic alpha-neurotoxin and its cognate recognition sequence.
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Affiliation(s)
- H Zeng
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Brown Medical School, Providence, Rhode Island 02912, USA
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16
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Chang LS, Lin SR, Wang JJ, Chang CC. Probing the structural diversities of long alpha-neurotoxins by fluorescence quenching studies. JOURNAL OF PROTEIN CHEMISTRY 2001; 20:115-21. [PMID: 11563691 DOI: 10.1023/a:1011025323192] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Trp fluorescence of Ophiophagus hannah neurotoxins (Oh-4, Oh-6A, Oh-7, and Oh-8) and Bungarus multicinctus (alpha-bungarotoxin was quenched by acrylamide and iodide. Acrylamide quenching studies indicated that the degree of exposure of Trp residues in the neurotoxins followed the order Oh-8 > Oh-7 > Oh-6A > Oh-4 > alpha-bungarotoxin, as did the accessibility for iodide. These results reveal that the exposed degree of Trp residues and the microenvironment surrounding Trp residues in the neurotoxins differ, even though their Trp residues and positively charged residues are located at the same or homologous positions. In contrast to unfolded Oh-4, Oh-6A, Oh-7, and alpha-bungarotoxin, unfolding of Oh-8 by reduction and S-carboxymethylation caused a notable decrease in the susceptibility of their Trp residues for iodide. These observations support the view that the side chains of Trp residues and positively charged residues in their native structure do not point toward the same spatial positions. Computer models of the neurotoxins are in good agreement with this proposition. These results elucidate why the conserved Trp residues and cationic groups do not always play the same roles in the biological activities of the neurotoxins.
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Affiliation(s)
- L S Chang
- Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan.
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17
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Souza DH, Selistre-de-Araujo HS, Garratt RC. Determination of the three-dimensional structure of toxins by protein crystallography. Toxicon 2000; 38:1307-53. [PMID: 10758270 DOI: 10.1016/s0041-0101(99)00200-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Protein crystallography has significantly contributed to the development of many areas of biochemical research, particularly in the understanding of phenomena related to molecular recognition. Examples include the formation of enzyme-substrate complexes (and their subsequent catalysis), host cell invasion by viruses, antigen neutralization and peptide display by proteins of the immune system and many others. More recently, protein crystallography has also proved to be of great value in unraveling the molecular basis of many diseases as well as in the development of new drugs for their treatment. The X-ray diffraction technique in the elucidation of macromolecular structures is situated at the interface between the traditional research fields of biology, biochemistry, chemistry and physics where researchers are united by a common interest in the detailed understanding of macromolecule function and its relationship to three-dimensional structure. The purpose of this review is to describe, without resort to mathematical detail, all of the necessary steps for the complete determination of a three-dimensional structure by X-ray diffraction techniques. The basic procedures used for protein isolation and crystallization, crystallographic data collection and analysis and, finally, structure determination and refinement are all briefly reviewed. As such our efforts are not directed towards the specialist. Rather, it is our hope that the information presented will aid interested readers from other fields in the understanding of more specialized literature and who may wish to employ the information contained therein in the planning of their biological research. We hope that in so doing we will make clear both the power and limitations of the technique.
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Affiliation(s)
- D H Souza
- Departamento de Ciências Fisiológicas, Universidade Federal de São Carlos, Brazil.
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Ackermann EJ, Ang ET, Kanter JR, Tsigelny I, Taylor P. Identification of pairwise interactions in the alpha-neurotoxin-nicotinic acetylcholine receptor complex through double mutant cycles. J Biol Chem 1998; 273:10958-64. [PMID: 9556574 DOI: 10.1074/jbc.273.18.10958] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
alpha-Neurotoxins are potent inhibitors of the nicotinic acetylcholine receptor (nAChR), binding with high affinity to the two agonist sites located on the extracellular domain. Previous site-directed mutagenesis had identified three residues on the alpha-neurotoxin from Naja mossambica mossambica (Lys27, Arg33, and Lys47) and four residues on the mouse muscle nAChR alpha-subunit (Val188, Tyr190, Pro197, and Asp200) as contributing to binding. In this study, thermodynamic mutant cycle analysis was applied to these sets of residues to identify specific pairwise interactions. Amino acid variants of alpha-neurotoxin from N. mossambica mossambica at position 33 and of the nAChR at position 188 showed strong energetic couplings of 2-3 kcal/mol at both binding sites. Consistently smaller yet significant linkages of 1.6-2.1 kcal/mol were also observed between variants at position 27 on the toxin and position 188 on the receptor. Additionally, toxin residue 27 coupled to the receptor residues 190, 197, and 200 at the alphadelta binding site with observed coupling energies of 1.5-1.9 kcal/mol. No linkages were found between toxin residue Lys47 and the receptor residues studied here. These results provide direct evidence that the two conserved cationic residues Arg33 and Lys27, located on loop II of the toxin structure, are binding in close proximity to the alpha-subunit region between residues 188-200. The toxin residue Arg33 is closer to Val188, where it is likely stabilized by adjacent negative or aromatic residues on the receptor structure. Lys27 is positioned closer to Tyr190, Pro197, and Asp200, where it is likely stabilized through electrostatic interaction with Asp200 and/or cation/pi interactions with Tyr190.
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Affiliation(s)
- E J Ackermann
- Department of Pharmacology 0636, University of California, San Diego, La Jolla, California 92093, USA
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