1
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Luo A, He J, Yu J, Wu Y, Harvey PJ, Kasheverov IE, Kudryavtsev DS, McIntosh JM, Tsetlin VI, Craik DJ, Zhangsun D, Luo S. Aspartic acid mutagenesis of αO-Conotoxin GeXIVA isomers reveals arginine residues crucial for inhibition of the α9α10 nicotinic acetylcholine receptor. Int J Biol Macromol 2024; 271:132472. [PMID: 38772455 DOI: 10.1016/j.ijbiomac.2024.132472] [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: 03/11/2024] [Revised: 05/06/2024] [Accepted: 05/15/2024] [Indexed: 05/23/2024]
Abstract
The two most active disulfide bond isomers of the analgesic αO-conotoxin GeXIVA, namely GeXIVA[1, 2] and GeXIVA[1, 4], were subjected to Asp-scanning mutagenesis to determine the key amino acid residues for activity at the rat α9α10 nicotinic acetylcholine receptor (nAChR). These studies revealed the key role of arginine residues for the activity of GeXIVA isomers towards the α9α10 nAChR. Based on these results, additional analogues with 2-4 mutations were designed and tested. The analogues [T1A,D14A,V28K]GeXIVA[1, 2] and [D14A,I23A,V28K]GeXIVA[1, 4] were developed and showed sub-nanomolar activity for the α9α10 nAChR with IC50 values of 0.79 and 0.38 nM. The latter analogue had exceptional selectivity for the α9α10 receptor subtype over other nAChR subtypes and can be considered as a drug candidate for further development. Molecular dynamics of receptor-ligand complexes allowed us to make deductions about the possible causes of increases in the affinity of key GeXIVA[1, 4] mutants for the α9α10 nAChR.
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Affiliation(s)
- An Luo
- Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou 570228, China; Guangxi Key Laboratory of Special Biomedicine, School of Medicine, Guangxi University, Nanning 530004, China
| | - Jie He
- Guangxi Key Laboratory of Special Biomedicine, School of Medicine, Guangxi University, Nanning 530004, China
| | - Jinpeng Yu
- Guangxi Key Laboratory of Special Biomedicine, School of Medicine, Guangxi University, Nanning 530004, China
| | - Yong Wu
- Guangxi Key Laboratory of Special Biomedicine, School of Medicine, Guangxi University, Nanning 530004, China
| | - Peta J Harvey
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane 4072, Australia
| | - Igor E Kasheverov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya str. 16/10, Moscow 117997, Russian Federation
| | - Denis S Kudryavtsev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya str. 16/10, Moscow 117997, Russian Federation
| | - J Michael McIntosh
- Departments of Biology and Psychiatry, University of Utah, Salt Lake City 84112, USA. George E. Wahlen Veterans Affairs Medical Center, Salt Lake City, USA 84108
| | - Victor I Tsetlin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya str. 16/10, Moscow 117997, Russian Federation
| | - David J Craik
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane 4072, Australia
| | - Dongting Zhangsun
- Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou 570228, China; Guangxi Key Laboratory of Special Biomedicine, School of Medicine, Guangxi University, Nanning 530004, China.
| | - Sulan Luo
- Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou 570228, China; Guangxi Key Laboratory of Special Biomedicine, School of Medicine, Guangxi University, Nanning 530004, China.
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2
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Xu P, Zhang P, Zhu X, Wu Y, Harvey PJ, Kaas Q, Zhangsun D, Craik DJ, Luo S. Structure-Activity Relationships of Alanine Scan Mutants αO-Conotoxins GeXIVA[1,2] and GeXIVA[1,4]. J Med Chem 2023. [PMID: 37464764 DOI: 10.1021/acs.jmedchem.3c01023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2023]
Abstract
αO-Conotoxin GeXIVA is a selective α9α10 nicotinic acetylcholine receptor (nAChR) inhibitor displaying two disulfide bonds that can form three isomers. The bead (GeXIVA[1,2]) and ribbon (GeXIVA[1,4]) isomers possess the highest activity on rat and human α9α10 nAChRs. However, the molecular mechanism by which they inhibit the α9α10 nAChR is unknown. Here, an alanine scan of GeXIVA was used to elucidate key interactions between the peptides and the α9α10 nAChR. The majority of GeXIVA[1,2] analogues preserved affinity at α9α10 nAChR, but [R17A]GeXIVA[1,2] enhanced selectivity on the α9α10 nAChR. The I23A replacement of GeXIVA[1,4] increased activity at both rat and human α9α10 nAChRs by 10-fold. Surprisingly, these results do not support the molecular model of an interaction in the orthosteric binding site proposed previously, but rather may involve allosteric coupling with the voltage-sensitive domain of the α9α10 nAChR. These results could help to guide further development of GeXIVA analogues as analgesics.
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Affiliation(s)
- Pan Xu
- School of Medicine, Guangxi University, Nanning 530004, China
- Guangdong Key Laboratory for Biomedical Measurements and Ultrasound Imaging, School of Biomedical Engineering, Shenzhen University Health Science Center, Shenzhen 518060, China
| | - Panpan Zhang
- School of Medicine, Guangxi University, Nanning 530004, China
| | - Xiaopeng Zhu
- School of Medicine, Guangxi University, Nanning 530004, China
| | - Yong Wu
- School of Medicine, Guangxi University, Nanning 530004, China
| | - Peta J Harvey
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Quentin Kaas
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Dongting Zhangsun
- School of Medicine, Guangxi University, Nanning 530004, China
- Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou 570228, China
| | - David J Craik
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Sulan Luo
- School of Medicine, Guangxi University, Nanning 530004, China
- Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou 570228, China
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3
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Ho TNT, Abraham N, Lewis RJ. Unravelling the allosteric binding mode of αD-VxXXB at nicotinic acetylcholine receptors. Front Pharmacol 2023; 14:1170514. [PMID: 37124228 PMCID: PMC10133702 DOI: 10.3389/fphar.2023.1170514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 03/30/2023] [Indexed: 05/02/2023] Open
Abstract
αD-conotoxins are 11 kDa homodimers that potently inhibit nicotinic acetylcholine receptors (nAChRs) through a non-competitive (allosteric) mechanism. In this study, we describe the allosteric binding mode of the granulin-like C-terminal (CTD) of VxXXB bound to Lymnea stagnalis acetylcholine binding protein (Ls-AChBP), a soluble homologue of the extracellular ligand-binding domain of nAChRs. This co-crystal complex revealed a novel allosteric binding site for nAChR antagonists outside the C-loop that caps the orthosteric site defined by the nAChR agonist nicotine and the antagonist epibatidine. Mutational and docking studies on Ls-AChBP supported a two-site binding mode for full-length VxXXB, with the first CTD binding site located outside the C-loop as seen in the co-crystal complex, with a second CTD binding site located near the N-terminal end of the adjacent subunit of AChBP. These results provide new structural insight into a novel allosteric mechanism of nAChR inhibition and define the cooperative binding mode of the N-terminal domain linked granulin core domains of αD-conotoxins.
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4
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Huang Q, Chu X, Zhang H, Yu S, Zhang L, Zhang X, Yu R, Guo C, Dai Q. Discovery and Structural and Functional Characterization of a Novel A-Superfamily Conotoxin Targeting α9α10 Nicotinic Acetylcholine Receptor. ACS Chem Biol 2022; 17:2483-2494. [PMID: 36048451 DOI: 10.1021/acschembio.2c00315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Nicotinic acetylcholine receptors (nAChRs) are pentameric ligand-gated ion channels widely distributed in the central peripheral nervous system and muscles which participate in rapid synaptic transmission. The α9α10 nAChR is an acetylcholine receptor subtype and is involved in chronic pain. In the present study, a new A-superfamily conotoxin Bt14.12 cloned from Conus betulinus was found to selectively inhibit α9α10 nAChRs with an IC50 of 62.3 nM. Unlike α-conotoxins and other A-superfamily conotoxins, Bt14.12 contains a four Cys (C-C-C-C) framework with a unique disulfide bond connection "C1-C4, C2-C3". The structure-activity studies of Bt14.12 demonstrate that all amino acid residues contribute to its potency. Interestingly, mutation experiments show that the deletion of Asp2 or the addition of three Arg residues at the N-terminus of Bt14.12 significantly enhances its inhibitory activity (IC50 is 21.9 nM or 12.7 nM, respectively) by 2- or 4-fold compared to the wild-type Bt14.12. The NMR structure of Bt14.12 shows that it contains α-helix- and β-turn-like elements, and further computational modelings of the interaction between Bt14.12 and the α9α10 nAChR demonstrate that Bt14.12 possesses a distinctive mode of action and displays a different structure-activity relationship from known α9α10 nAChR targeting α-conotoxins. Our findings provide a novel conotoxin that potently targets α9α10 nAChRs and a new motif for designing potent inhibitors against α9α10 nAChRs.
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Affiliation(s)
- Qiuyuan Huang
- Beijing Institute of Biotechnology, Beijing 100071, China.,Life Sciences Institute of Guangxi Medical University, Nanning, Guangxi 530021, China
| | - Xin Chu
- Beijing Institute of Biotechnology, Beijing 100071, China.,Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao 266003, China
| | - Haoran Zhang
- Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Shuo Yu
- Beijing Institute of Biotechnology, Beijing 100071, China
| | - Longxiao Zhang
- Beijing Institute of Biotechnology, Beijing 100071, China
| | - Xuerong Zhang
- Life Sciences Institute of Guangxi Medical University, Nanning, Guangxi 530021, China
| | - Rilei Yu
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao 266003, China
| | - Chenyun Guo
- Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Qiuyun Dai
- Beijing Institute of Biotechnology, Beijing 100071, China
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5
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A Novel Dimeric Conotoxin, FrXXA, from the Vermivorous Cone Snail Conus fergusoni, of the Eastern Pacific, Inhibits Nicotinic Acetylcholine Receptors. Toxins (Basel) 2022; 14:toxins14080510. [PMID: 35893752 PMCID: PMC9330476 DOI: 10.3390/toxins14080510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 07/05/2022] [Accepted: 07/10/2022] [Indexed: 02/04/2023] Open
Abstract
We isolated a new dimeric conotoxin with inhibitory activity against neuronal nicotinic acetylcholine receptors. Edman degradation and transcriptomic studies indicate a homodimeric conotoxin composed by two chains of 47 amino acid in length. It has the cysteine framework XX and 10 disulfide bonds. According to conotoxin nomenclature, it has been named as αD-FrXXA. The αD-FrXXA conotoxin inhibited the ACh-induced response on nAChR with a IC50 of 125 nM on hα7, 282 nM on hα3β2, 607 nM on α4β2, 351 nM on mouse adult muscle, and 447 nM on mouse fetal muscle. This is first toxin characterized from C. fergusoni and, at the same time, the second αD-conotoxin characterized from a species of the Eastern Pacific.
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6
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Van Baelen AC, Robin P, Kessler P, Maïga A, Gilles N, Servent D. Structural and Functional Diversity of Animal Toxins Interacting With GPCRs. Front Mol Biosci 2022; 9:811365. [PMID: 35198603 PMCID: PMC8859281 DOI: 10.3389/fmolb.2022.811365] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 01/05/2022] [Indexed: 12/12/2022] Open
Abstract
Peptide toxins from venoms have undergone a long evolutionary process allowing host defense or prey capture and making them highly selective and potent for their target. This has resulted in the emergence of a large panel of toxins from a wide diversity of species, with varied structures and multiple associated biological functions. In this way, animal toxins constitute an inexhaustible reservoir of druggable molecules due to their interesting pharmacological properties. One of the most interesting classes of therapeutic targets is the G-protein coupled receptors (GPCRs). GPCRs represent the largest family of membrane receptors in mammals with approximately 800 different members. They are involved in almost all biological functions and are the target of almost 30% of drugs currently on the market. Given the interest of GPCRs in the therapeutic field, the study of toxins that can interact with and modulate their activity with the purpose of drug development is of particular importance. The present review focuses on toxins targeting GPCRs, including peptide-interacting receptors or aminergic receptors, with a particular focus on structural aspects and, when relevant, on potential medical applications. The toxins described here exhibit a great diversity in size, from 10 to 80 amino acids long, in disulfide bridges, from none to five, and belong to a large panel of structural scaffolds. Particular toxin structures developed here include inhibitory cystine knot (ICK), three-finger fold, and Kunitz-type toxins. We summarize current knowledge on the structural and functional diversity of toxins interacting with GPCRs, concerning first the agonist-mimicking toxins that act as endogenous agonists targeting the corresponding receptor, and second the toxins that differ structurally from natural agonists and which display agonist, antagonist, or allosteric properties.
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Affiliation(s)
- Anne-Cécile Van Baelen
- CEA, Département Médicaments et Technologies pour La Santé (DMTS), SIMoS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Philippe Robin
- CEA, Département Médicaments et Technologies pour La Santé (DMTS), SIMoS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Pascal Kessler
- CEA, Département Médicaments et Technologies pour La Santé (DMTS), SIMoS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Arhamatoulaye Maïga
- CEA, Département Médicaments et Technologies pour La Santé (DMTS), SIMoS, Université Paris-Saclay, Gif-sur-Yvette, France
- CHU Sainte Justine, Université de Montréal, Montreal, QC, Canada
| | - Nicolas Gilles
- CEA, Département Médicaments et Technologies pour La Santé (DMTS), SIMoS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Denis Servent
- CEA, Département Médicaments et Technologies pour La Santé (DMTS), SIMoS, Université Paris-Saclay, Gif-sur-Yvette, France
- *Correspondence: Denis Servent,
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7
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Marine Origin Ligands of Nicotinic Receptors: Low Molecular Compounds, Peptides and Proteins for Fundamental Research and Practical Applications. Biomolecules 2022; 12:biom12020189. [PMID: 35204690 PMCID: PMC8961598 DOI: 10.3390/biom12020189] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 02/05/2023] Open
Abstract
The purpose of our review is to briefly show what different compounds of marine origin, from low molecular weight ones to peptides and proteins, offer for understanding the structure and mechanism of action of nicotinic acetylcholine receptors (nAChRs) and for finding novel drugs to combat the diseases where nAChRs may be involved. The importance of the mentioned classes of ligands has changed with time; a protein from the marine snake venom was the first excellent tool to characterize the muscle-type nAChRs from the electric ray, while at present, muscle and α7 receptors are labeled with the radioactive or fluorescent derivatives prepared from α-bungarotoxin isolated from the many-banded krait. The most sophisticated instruments to distinguish muscle from neuronal nAChRs, and especially distinct subtypes within the latter, are α-conotoxins. Such information is crucial for fundamental studies on the nAChR revealing the properties of their orthosteric and allosteric binding sites and mechanisms of the channel opening and closure. Similar data are provided by low-molecular weight compounds of marine origin, but here the main purpose is drug design. In our review we tried to show what has been obtained in the last decade when the listed classes of compounds were used in the nAChR research, applying computer modeling, synthetic analogues and receptor mutants, X-ray and electron-microscopy analyses of complexes with the nAChRs, and their models which are acetylcholine-binding proteins and heterologously-expressed ligand-binding domains.
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8
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Wang J, Dong L, Liu Y, Chen X, Ma Y, Yin H, Du S, Qi Y, Wang K. Efficient Synthesis and Oxidative Folding Studies of Centipede Toxin RhTx. CHINESE J ORG CHEM 2021. [DOI: 10.6023/cjoc202102045] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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9
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Discovery of a Novel Cysteine Framework XXIV Conotoxin from Conus striatus, S24a, with Potential Analgesic Activity. Int J Pept Res Ther 2020. [DOI: 10.1007/s10989-020-10109-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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10
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Jin AH, Muttenthaler M, Dutertre S, Himaya SWA, Kaas Q, Craik DJ, Lewis RJ, Alewood PF. Conotoxins: Chemistry and Biology. Chem Rev 2019; 119:11510-11549. [PMID: 31633928 DOI: 10.1021/acs.chemrev.9b00207] [Citation(s) in RCA: 161] [Impact Index Per Article: 32.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The venom of the marine predatory cone snails (genus Conus) has evolved for prey capture and defense, providing the basis for survival and rapid diversification of the now estimated 750+ species. A typical Conus venom contains hundreds to thousands of bioactive peptides known as conotoxins. These mostly disulfide-rich and well-structured peptides act on a wide range of targets such as ion channels, G protein-coupled receptors, transporters, and enzymes. Conotoxins are of interest to neuroscientists as well as drug developers due to their exquisite potency and selectivity, not just against prey but also mammalian targets, thereby providing a rich source of molecular probes and therapeutic leads. The rise of integrated venomics has accelerated conotoxin discovery with now well over 10,000 conotoxin sequences published. However, their structural and pharmacological characterization lags considerably behind. In this review, we highlight the diversity of new conotoxins uncovered since 2014, their three-dimensional structures and folds, novel chemical approaches to their syntheses, and their value as pharmacological tools to unravel complex biology. Additionally, we discuss challenges and future directions for the field.
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Affiliation(s)
- Ai-Hua Jin
- Institute for Molecular Bioscience , The University of Queensland , Brisbane Queensland 4072 , Australia
| | - Markus Muttenthaler
- Institute for Molecular Bioscience , The University of Queensland , Brisbane Queensland 4072 , Australia.,Institute of Biological Chemistry, Faculty of Chemistry , University of Vienna , 1090 Vienna , Austria
| | - Sebastien Dutertre
- Département des Acides Amines, Peptides et Protéines, Unité Mixte de Recherche 5247, Université Montpellier 2-Centre Nationale de la Recherche Scientifique , Institut des Biomolécules Max Mousseron , Place Eugène Bataillon , 34095 Montpellier Cedex 5 , France
| | - S W A Himaya
- Institute for Molecular Bioscience , The University of Queensland , Brisbane Queensland 4072 , Australia
| | - Quentin Kaas
- Institute for Molecular Bioscience , The University of Queensland , Brisbane Queensland 4072 , Australia
| | - David J Craik
- Institute for Molecular Bioscience , The University of Queensland , Brisbane Queensland 4072 , Australia
| | - Richard J Lewis
- Institute for Molecular Bioscience , The University of Queensland , Brisbane Queensland 4072 , Australia
| | - Paul F Alewood
- Institute for Molecular Bioscience , The University of Queensland , Brisbane Queensland 4072 , Australia
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11
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Abstract
In order to improve stability of a peptide marine drug lead, α-conotoxin TxID, we synthesized and modified TxID at the N-terminal with DSPE-PEG-NHS by a nucleophilic substitution reaction to prepare the DSPE-PEG-TxID for the first time. The reaction conditions, including solvent, ratio, pH, and reaction time, were optimized systematically and the optimal one was reacted in dimethyl formamide at pH 8.2 with triethylamine at room temperature for 120 h. The in vitro stabilities in serum, simulated gastric juice, and intestinal fluid were tested, and improved dramatically compared with TxID. The PEG-modified peptide was functionally tested on α3β4 nicotinic acetylcholine receptor (nAChR) heterologously expressed in Xenopus laevis oocytes. The DSPE-PEG-TxID showed an obvious inhibition effect on α3β4 nAChR. All in all, the PEG modification of TxID was improved in stability, resistance to enzymatic degradation, and may prolong the half-life in vivo, which may pave the way for the future application in smoking cessation and drug rehabilitation, as well as small cell lung cancer.
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12
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Ning J, Li R, Ren J, Zhangsun D, Zhu X, Wu Y, Luo S. Alanine-Scanning Mutagenesis of α-Conotoxin GI Reveals the Residues Crucial for Activity at the Muscle Acetylcholine Receptor. Mar Drugs 2018; 16:md16120507. [PMID: 30551685 PMCID: PMC6315591 DOI: 10.3390/md16120507] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 11/25/2018] [Accepted: 12/10/2018] [Indexed: 01/30/2023] Open
Abstract
Recently, the muscle-type nicotinic acetylcholine receptors (nAChRs) have been pursued as a potential target of several diseases, including myogenic disorders, muscle dystrophies and myasthenia gravis, etc. α-conotoxin GI isolated from Conus geographus selectively and potently inhibited the muscle-type nAChRs which can be developed as a tool to study them. Herein, alanine scanning mutagenesis was used to reveal the structure–activity relationship (SAR) between GI and mouse α1β1δε nAChRs. The Pro5, Gly8, Arg9, and Tyr11 were proved to be the critical residues for receptor inhibiting as the alanine (Ala) replacement led to a significant potency loss on mouse α1β1δε nAChR. On the contrary, substituting Asn4, His10 and Ser12 with Ala respectively did not affect its activity. Interestingly, the [E1A] GI analogue exhibited a three-fold potency for mouse α1β1δε nAChR, whereas it obviously decreased potency at rat α9α10 nAChR compared to wildtype GI. Molecular dynamic simulations also suggest that loop2 of GI significantly affects the interaction with α1β1δε nAChR, and Tyr11 of GI is a critical residue binding with three hydrophobic amino acids of the δ subunit, including Leu93, Tyr95 and Leu103. Our research elucidates the interaction of GI and mouse α1β1δε nAChR in detail that will help to develop the novel analogues of GI.
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Affiliation(s)
- Jiong Ning
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Lab for Marine Drugs of Haikou, Hainan University, Haikou 570228, Hainan, China.
| | - Rui Li
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Lab for Marine Drugs of Haikou, Hainan University, Haikou 570228, Hainan, China.
| | - Jie Ren
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Lab for Marine Drugs of Haikou, Hainan University, Haikou 570228, Hainan, China.
| | - Dongting Zhangsun
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Lab for Marine Drugs of Haikou, Hainan University, Haikou 570228, Hainan, China.
| | - Xiaopeng Zhu
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Lab for Marine Drugs of Haikou, Hainan University, Haikou 570228, Hainan, China.
| | - Yong Wu
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Lab for Marine Drugs of Haikou, Hainan University, Haikou 570228, Hainan, China.
| | - Sulan Luo
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Lab for Marine Drugs of Haikou, Hainan University, Haikou 570228, Hainan, China.
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13
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Abraham N, Lewis RJ. Neuronal Nicotinic Acetylcholine Receptor Modulators from Cone Snails. Mar Drugs 2018; 16:E208. [PMID: 29899286 PMCID: PMC6024932 DOI: 10.3390/md16060208] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 05/25/2018] [Accepted: 06/06/2018] [Indexed: 12/15/2022] Open
Abstract
Marine cone snails are a large family of gastropods that have evolved highly potent venoms for predation and defense. The cone snail venom has exceptional molecular diversity in neuropharmacologically active compounds, targeting a range of receptors, ion channels, and transporters. These conotoxins have helped to dissect the structure and function of many of these therapeutically significant targets in the central and peripheral nervous systems, as well as unravelling the complex cellular mechanisms modulated by these receptors and ion channels. This review provides an overview of α-conotoxins targeting neuronal nicotinic acetylcholine receptors. The structure and activity of both classical and non-classical α-conotoxins are discussed, along with their contributions towards understanding nicotinic acetylcholine receptor (nAChR) structure and function.
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Affiliation(s)
- Nikita Abraham
- IMB Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia.
| | - Richard J Lewis
- IMB Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia.
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14
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Zhangsun D, Zhu X, Kaas Q, Wu Y, Craik DJ, McIntosh JM, Luo S. αO-Conotoxin GeXIVA disulfide bond isomers exhibit differential sensitivity for various nicotinic acetylcholine receptors but retain potency and selectivity for the human α9α10 subtype. Neuropharmacology 2017; 127:243-252. [PMID: 28416445 PMCID: PMC6029978 DOI: 10.1016/j.neuropharm.2017.04.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2017] [Revised: 03/14/2017] [Accepted: 04/11/2017] [Indexed: 11/30/2022]
Abstract
Nicotinic acetylcholine receptor (nAChR) subtypes exhibit distinct neuropharmacological properties that are involved in a range of neuropathological conditions, including pain, addiction, epilepsy, autism, schizophrenia, Tourette's syndrome, Alzheimer's and Parkinson's diseases, as well as many types of cancer. The α9α10 nAChR is a potential target in chronic pain, wound healing, the pathophysiology of the auditory system, and breast and lung cancers. αO-conotoxin GeXIVA is a potent antagonist of rat α9α10 nAChRs, with the 'bead' disulfide bond isomer displaying the lowest IC50 of the three possible isomers. In the rat chronic constriction injury model of neuropathic pain, this isomer reduced mechanical hyperalgesia without affecting motor performance. Here, we report the effects of the three disulfide bond isomers of GeXIVA on human α9α10 nAChRs, other human nAChR subtypes, various rat nAChR subtypes, and 10 rat α9α10 nAChR mutants. The three isomers displayed only ∼5-fold difference in potency on the human vs rat α9α10 receptors and had similar affinities at wild-type rat α9α10 nAChRs and all 10 α9α10 receptor mutants. From these findings, the binding site and mechanism of action of GeXIVA on rat and human α9α10 nAChR was deduced to be different from that of other conotoxins targeting this nAChR subtype. GeXIVA is therefore a unique ligand that might prove useful for further probing of binding sites on the α9α10 nAChR. This article is part of the Special Issue entitled 'Venom-derived Peptides as Pharmacological Tools.'
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Affiliation(s)
- Dongting Zhangsun
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Laboratory for Marine Drug of Haikou, Hainan University, Haikou, Hainan, 570228 China
| | - Xiaopeng Zhu
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Laboratory for Marine Drug of Haikou, Hainan University, Haikou, Hainan, 570228 China
| | - Quentin Kaas
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072 Australia
| | - Yong Wu
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Laboratory for Marine Drug of Haikou, Hainan University, Haikou, Hainan, 570228 China
| | - David J Craik
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072 Australia
| | - J Michael McIntosh
- Department of Biology and Psychiatry, University of Utah, Salt Lake City, UT 84112, USA; George E. Wahlen Department of Veterans Affairs Medical Center, Salt Lake City, UT, 84108, USA
| | - Sulan Luo
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Laboratory for Marine Drug of Haikou, Hainan University, Haikou, Hainan, 570228 China.
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15
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Wu X, Huang YH, Kaas Q, Harvey PJ, Wang CK, Tae HS, Adams DJ, Craik DJ. Backbone cyclization of analgesic conotoxin GeXIVA facilitates direct folding of the ribbon isomer. J Biol Chem 2017; 292:17101-17112. [PMID: 28851841 DOI: 10.1074/jbc.m117.808386] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Indexed: 12/20/2022] Open
Abstract
Conotoxin GeXIVA inhibits the α9α10 nicotinic acetylcholine receptor (nAChR) and is analgesic in animal models of pain. α-Conotoxins have four cysteines that can have three possible disulfide connectivities: globular (CysI-CysIII and CysII-CysIV), ribbon (CysI-CysIV and CysII-CysIII), or bead (CysI-CysII and CysIII-CysIV). Native α-conotoxins preferably adopt the globular connectivity, and previous studies of α-conotoxins have focused on the globular isomers as the ribbon and bead isomers typically have lower potency at nAChRs than the globular form. A recent report showed that the bead and ribbon isomers of GeXIVA are more potent than the globular isomer, with low nanomolar half-maximal inhibitory concentrations (IC50). Despite this high potency, the therapeutic potential of GeXIVA is limited, because like most peptides, it is susceptible to proteolytic degradation and is challenging to synthesize in high yield. Here we used backbone cyclization as a strategy to improve the folding yield as well as increase the serum stability of ribbon GeXIVA while preserving activity at the α9α10 nAChR. Specifically, cyclization of ribbon GeXIVA with a two-residue linker maintained the biological activity at the human α9α10 nAChR and improved stability in human serum. Short linkers led to selective formation of the ribbon disulfide isomer without requiring orthogonal protection. Overall, this study highlights the value of backbone cyclization in directing folding, improving yields, and stabilizing conotoxins with therapeutic potential.
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Affiliation(s)
- Xiaosa Wu
- From the Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia and
| | - Yen-Hua Huang
- From the Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia and
| | - Quentin Kaas
- From the Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia and
| | - Peta J Harvey
- From the Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia and
| | - Conan K Wang
- From the Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia and
| | - Han-Shen Tae
- the Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - David J Adams
- the Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - David J Craik
- From the Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia and
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16
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Dutertre S, Nicke A, Tsetlin VI. Nicotinic acetylcholine receptor inhibitors derived from snake and snail venoms. Neuropharmacology 2017. [PMID: 28623170 DOI: 10.1016/j.neuropharm.2017.06.011] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The nicotinic acetylcholine receptor (nAChR) represents the prototype of ligand-gated ion channels. It is vital for neuromuscular transmission and an important regulator of neurotransmission. A variety of toxic compounds derived from diverse species target this receptor and have been of elemental importance in basic and applied research. They enabled milestone discoveries in pharmacology and biochemistry ranging from the original formulation of the receptor concept, the first isolation and structural analysis of a receptor protein (the nAChR) to the identification, localization, and differentiation of its diverse subtypes and their validation as a target for therapeutic intervention. Among the venom-derived compounds, α-neurotoxins and α-conotoxins provide the largest families and still represent indispensable pharmacological tools. Application of modified α-neurotoxins provided substantial structural and functional details of the nAChR long before high resolution structures were available. α-bungarotoxin represents not only a standard pharmacological tool and label in nAChR research but also for unrelated proteins tagged with a minimal α-bungarotoxin binding motif. A major advantage of α-conotoxins is their smaller size, as well as superior selectivity for diverse nAChR subtypes that allows their development into ligands with optimized pharmacological and chemical properties and potentially novel drugs. In the following, these two groups of nAChR antagonists will be described focusing on their respective roles in the structural and functional characterization of nAChRs and their development into research tools. In addition, we provide a comparative overview of the diverse α-conotoxin selectivities that can serve as a practical guide for both structure activity studies and subtype classification. This article is part of the Special Issue entitled 'Venom-derived Peptides as Pharmacological Tools.'
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Affiliation(s)
- Sébastien Dutertre
- Institut des Biomolécules Max Mousseron, UMR 5247, Université Montpellier - CNRS, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France
| | - Annette Nicke
- Walther Straub Institute for Pharmacology and Toxicology, Ludwig-Maximilians-Universität, Nußbaumstr. 26, 80336 Munich, Germany.
| | - Victor I Tsetlin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya str.16/10, Moscow 117999, Russian Federation
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17
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A Novel Lid-Covering Peptide Inhibitor of Nicotinic Acetylcholine Receptors Derived from αD-Conotoxin GeXXA. Mar Drugs 2017; 15:md15060164. [PMID: 28587231 PMCID: PMC5484114 DOI: 10.3390/md15060164] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 05/28/2017] [Accepted: 05/31/2017] [Indexed: 12/12/2022] Open
Abstract
Nicotinic acetylcholine receptors (nAChRs) play a fundamental role in nervous signal transmission, therefore various antagonists and agonists are highly desired to explore the structure and function of nAChRs. Recently, a novel dimeric αD-conotoxin GeXXA was identified to inhibit nAChRs by binding at the top surface of the receptors, and the monomeric C-terminal domain (CTD) of αD-GeXXA retains some inhibitory activity. In this study, the internal dimeric N-terminal domain (NTD) of this conopeptide was further investigated. We first developed a regio-selective protection strategy to chemically prepare the anti-parallel dimeric NTD, and found that the isolated NTD part of GeXXA possesses the nAChR-inhibitory activity, the subtype-dependence of which implies a preferred binding of NTD to the β subunits of nAChR. Deletion of the NTD N-terminal residues did not affect the activity of NTD, indicating that the N-terminus is not involved in the interaction with nAChRs. By optimizing the sequence of NTD, we obtained a fully active single-chain cyclic NTD, based on which 4 Arg residues were found to interact with nAChRs. These results demonstrate that the NTD part of αD-GeXXA is a “lid-covering” nAChR inhibitor, displaying a novel inhibitory mechanism distinct from other allosteric ligands of nAChRs.
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18
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Structural space of intramolecular peptide disulfides: Analysis of peptide toxins retrieved from venomous peptide databases. Comput Biol Chem 2017; 68:194-203. [DOI: 10.1016/j.compbiolchem.2017.03.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Revised: 02/21/2017] [Accepted: 03/06/2017] [Indexed: 01/22/2023]
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19
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Inhibition of α9α10 nicotinic acetylcholine receptors prevents chemotherapy-induced neuropathic pain. Proc Natl Acad Sci U S A 2017; 114:E1825-E1832. [PMID: 28223528 DOI: 10.1073/pnas.1621433114] [Citation(s) in RCA: 124] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Opioids are first-line drugs for moderate to severe acute pain and cancer pain. However, these medications are associated with severe side effects, and whether they are efficacious in treatment of chronic nonmalignant pain remains controversial. Medications that act through alternative molecular mechanisms are critically needed. Antagonists of α9α10 nicotinic acetylcholine receptors (nAChRs) have been proposed as an important nonopioid mechanism based on studies demonstrating prevention of neuropathology after trauma-induced nerve injury. However, the key α9α10 ligands characterized to date are at least two orders of magnitude less potent on human vs. rodent nAChRs, limiting their translational application. Furthermore, an alternative proposal that these ligands achieve their beneficial effects by acting as agonists of GABAB receptors has caused confusion over whether blockade of α9α10 nAChRs is the fundamental underlying mechanism. To address these issues definitively, we developed RgIA4, a peptide that exhibits high potency for both human and rodent α9α10 nAChRs, and was at least 1,000-fold more selective for α9α10 nAChRs vs. all other molecular targets tested, including opioid and GABAB receptors. A daily s.c. dose of RgIA4 prevented chemotherapy-induced neuropathic pain in rats. In wild-type mice, oxaliplatin treatment produced cold allodynia that could be prevented by RgIA4. Additionally, in α9 KO mice, chemotherapy-induced development of cold allodynia was attenuated and the milder, temporary cold allodynia was not relieved by RgIA4. These findings establish blockade of α9-containing nAChRs as the basis for the efficacy of RgIA4, and that α9-containing nAChRs are a critical target for prevention of chronic cancer chemotherapy-induced neuropathic pain.
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20
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Román-González SA, Robles-Gómez EE, Reyes J, Bernáldez J, Cortés-Guzmán F, Martínez-Mayorga K, Lazcano-Pérez F, Licea A, Arreguín-Espinosa R. A 3D structural model of RsXXVIA, an ω-conotoxin. Struct Chem 2016. [DOI: 10.1007/s11224-016-0877-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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21
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Yu S, Du T, Liu Z, Wu Q, Feng G, Dong M, Zhou X, Jiang L, Dai Q. Im10A, a short conopeptide isolated from Conus imperialis and possesses two highly concentrated disulfide bridges and analgesic activity. Peptides 2016; 81:15-20. [PMID: 27131596 DOI: 10.1016/j.peptides.2016.04.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 04/02/2016] [Accepted: 04/26/2016] [Indexed: 12/27/2022]
Abstract
In the present study, we isolated, synthesized and NMR structurally characterized a novel conopeptide Im10A consisting of 11 amino acids (NTICCEGCMCY-NH2) from Conus imperialis. Unlike other conopeptides with four cysteine residues, Im10A had only two residues in loop 1 and one residue in loop 2 (CC-loop1-C-loop2-C), which formed a stable disulfide connectivity "I-IV, II- III" (framework X) with a type I β-turn. Interestingly, Im10A exhibited 50.7% analgesic activity on rat partial sciatic nerve ligation (PNL) at 2h after Im10A administration. However, 10μM Im10A exhibited no apparent effect on neuronal nicotinic acetylcholine receptor, and it did not target DRG voltage-dependent sodium, potassium and calcium ion channels and opioid receptor. To our knowledge, Im10A had the most concentrated disulfide bridges among conopeptides with four cysteine residues. This finding provided a new motif for the future development of biomimetic compounds.
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Affiliation(s)
- Shuo Yu
- Beijing Institute of Biotechnology, Beijing 10071, PR China
| | - Tianpeng Du
- Key Laboratory of Magnetic Resonance in Biological Systems, National Center for Magnetic Resonance in Wuhan, State Key laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Science, Wuhan 430071, PR China
| | - Zhuguo Liu
- Beijing Institute of Biotechnology, Beijing 10071, PR China
| | - Qiaoling Wu
- Beijing Institute of Biotechnology, Beijing 10071, PR China
| | - Guixue Feng
- Beijing Institute of Biotechnology, Beijing 10071, PR China
| | - Mingxin Dong
- Beijing Institute of Biotechnology, Beijing 10071, PR China
| | - Xiaowei Zhou
- Beijing Institute of Biotechnology, Beijing 10071, PR China
| | - Ling Jiang
- Key Laboratory of Magnetic Resonance in Biological Systems, National Center for Magnetic Resonance in Wuhan, State Key laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Science, Wuhan 430071, PR China.
| | - Qiuyun Dai
- Beijing Institute of Biotechnology, Beijing 10071, PR China.
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22
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Peng C, Yao G, Gao BM, Fan CX, Bian C, Wang J, Cao Y, Wen B, Zhu Y, Ruan Z, Zhao X, You X, Bai J, Li J, Lin Z, Zou S, Zhang X, Qiu Y, Chen J, Coon SL, Yang J, Chen JS, Shi Q. High-throughput identification of novel conotoxins from the Chinese tubular cone snail (Conus betulinus) by multi-transcriptome sequencing. Gigascience 2016; 5:17. [PMID: 27087938 PMCID: PMC4832519 DOI: 10.1186/s13742-016-0122-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 04/07/2016] [Indexed: 01/06/2023] Open
Abstract
Background The venom of predatory marine cone snails mainly contains a diverse array of unique bioactive peptides commonly referred to as conopeptides or conotoxins. These peptides have proven to be valuable pharmacological probes and potential drugs because of their high specificity and affinity to important ion channels, receptors and transporters of the nervous system. Most previous studies have focused specifically on the conopeptides from piscivorous and molluscivorous cone snails, but little attention has been devoted to the dominant vermivorous species. Results The vermivorous Chinese tubular cone snail, Conus betulinus, is the dominant Conus species inhabiting the South China Sea. The transcriptomes of venom ducts and venom bulbs from a variety of specimens of this species were sequenced using both next-generation sequencing and traditional Sanger sequencing technologies, resulting in the identification of a total of 215 distinct conopeptides. Among these, 183 were novel conopeptides, including nine new superfamilies. It appeared that most of the identified conopeptides were synthesized in the venom duct, while a handful of conopeptides were identified only in the venom bulb and at very low levels. Conclusions We identified 215 unique putative conopeptide transcripts from the combination of five transcriptomes and one EST sequencing dataset. Variation in conopeptides from different specimens of C. betulinus was observed, which suggested the presence of intraspecific variability in toxin production at the genetic level. These novel conopeptides provide a potentially fertile resource for the development of new pharmaceuticals, and a pathway for the discovery of new conotoxins. Electronic supplementary material The online version of this article (doi:10.1186/s13742-016-0122-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Chao Peng
- BGI-Shenzhen, Shenzhen, 518083 China
| | - Ge Yao
- Research Institute of Pharmaceutical Chemistry, Beijing, 102205 China
| | - Bing-Miao Gao
- School of Pharmaceutical Sciences, Hainan Medical University, Haikou, 571199 China
| | - Chong-Xu Fan
- Research Institute of Pharmaceutical Chemistry, Beijing, 102205 China
| | - Chao Bian
- BGI-Shenzhen, Shenzhen, 518083 China ; Shenzhen Key Laboratory of Marine Genomics, Guangdong Provincial Key Laboratory of Molecular Breeding in Marine Economic Animals, State Key Laboratory of Agricultural Genomics, Shenzhen, 518083 China
| | | | - Ying Cao
- Research Institute of Pharmaceutical Chemistry, Beijing, 102205 China
| | - Bo Wen
- BGI-Shenzhen, Shenzhen, 518083 China
| | | | - Zhiqiang Ruan
- BGI-Shenzhen, Shenzhen, 518083 China ; Shenzhen Key Laboratory of Marine Genomics, Guangdong Provincial Key Laboratory of Molecular Breeding in Marine Economic Animals, State Key Laboratory of Agricultural Genomics, Shenzhen, 518083 China
| | | | - Xinxin You
- BGI-Shenzhen, Shenzhen, 518083 China ; Shenzhen Key Laboratory of Marine Genomics, Guangdong Provincial Key Laboratory of Molecular Breeding in Marine Economic Animals, State Key Laboratory of Agricultural Genomics, Shenzhen, 518083 China
| | - Jie Bai
- BGI-Shenzhen, Shenzhen, 518083 China ; Shenzhen Key Laboratory of Marine Genomics, Guangdong Provincial Key Laboratory of Molecular Breeding in Marine Economic Animals, State Key Laboratory of Agricultural Genomics, Shenzhen, 518083 China
| | - Jia Li
- BGI-Shenzhen, Shenzhen, 518083 China ; Shenzhen Key Laboratory of Marine Genomics, Guangdong Provincial Key Laboratory of Molecular Breeding in Marine Economic Animals, State Key Laboratory of Agricultural Genomics, Shenzhen, 518083 China
| | | | | | - Xinhui Zhang
- BGI-Shenzhen, Shenzhen, 518083 China ; Shenzhen Key Laboratory of Marine Genomics, Guangdong Provincial Key Laboratory of Molecular Breeding in Marine Economic Animals, State Key Laboratory of Agricultural Genomics, Shenzhen, 518083 China
| | - Ying Qiu
- BGI-Shenzhen, Shenzhen, 518083 China ; Shenzhen Key Laboratory of Marine Genomics, Guangdong Provincial Key Laboratory of Molecular Breeding in Marine Economic Animals, State Key Laboratory of Agricultural Genomics, Shenzhen, 518083 China
| | - Jieming Chen
- BGI-Shenzhen, Shenzhen, 518083 China ; Shenzhen Key Laboratory of Marine Genomics, Guangdong Provincial Key Laboratory of Molecular Breeding in Marine Economic Animals, State Key Laboratory of Agricultural Genomics, Shenzhen, 518083 China
| | - Steven L Coon
- Molecular Genomics Laboratory, National Institutes of Health, Bethesda, MD 20892 USA
| | - Jiaan Yang
- Micro Pharmatech Ltd, Wuhan, 430075 China
| | - Ji-Sheng Chen
- Research Institute of Pharmaceutical Chemistry, Beijing, 102205 China
| | - Qiong Shi
- BGI-Shenzhen, Shenzhen, 518083 China ; Shenzhen Key Laboratory of Marine Genomics, Guangdong Provincial Key Laboratory of Molecular Breeding in Marine Economic Animals, State Key Laboratory of Agricultural Genomics, Shenzhen, 518083 China ; BGI-Zhenjiang Institute of Hydrobiology, Zhenjiang, 212000 China
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23
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Prashanth JR, Dutertre S, Jin AH, Lavergne V, Hamilton B, Cardoso FC, Griffin J, Venter DJ, Alewood PF, Lewis RJ. The role of defensive ecological interactions in the evolution of conotoxins. Mol Ecol 2016; 25:598-615. [PMID: 26614983 DOI: 10.1111/mec.13504] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 11/23/2015] [Accepted: 11/24/2015] [Indexed: 10/22/2022]
Abstract
Venoms comprise of complex mixtures of peptides evolved for predation and defensive purposes. Remarkably, some carnivorous cone snails can inject two distinct venoms in response to predatory or defensive stimuli, providing a unique opportunity to study separately how different ecological pressures contribute to toxin diversification. Here, we report the extraordinary defensive strategy of the Rhizoconus subgenus of cone snails. The defensive venom from this worm-hunting subgenus is unusually simple, almost exclusively composed of αD-conotoxins instead of the ubiquitous αA-conotoxins found in the more complex defensive venom of mollusc- and fish-hunting cone snails. A similarly compartmentalized venom gland as those observed in the other dietary groups facilitates the deployment of this defensive venom. Transcriptomic analysis of a Conus vexillum venom gland revealed the αD-conotoxins as the major transcripts, with lower amounts of 15 known and four new conotoxin superfamilies also detected with likely roles in prey capture. Our phylogenetic and molecular evolution analysis of the αD-conotoxins from five subgenera of cone snails suggests they evolved episodically as part of a defensive strategy in the Rhizoconus subgenus. Thus, our results demonstrate an important role for defence in the evolution of conotoxins.
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Affiliation(s)
- J R Prashanth
- Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Qld, 4072, Australia
| | - S Dutertre
- Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Qld, 4072, Australia.,Institut des Biomolécules Max Mousseron, UMR 5247, Université Montpellier-CNRS, Place Eugène Bataillon, 34095, Montpellier Cedex 5, France
| | - A H Jin
- Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Qld, 4072, Australia
| | - V Lavergne
- Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Qld, 4072, Australia
| | - B Hamilton
- Pathology, Mater Health Services, Raymond Terrace, South Brisbane, Qld, 4101, Australia.,Mater Research Institute, The University of Queensland, St. Lucia, Qld, 4072, Australia
| | - F C Cardoso
- Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Qld, 4072, Australia
| | - J Griffin
- ACRF Microscopy Facility, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Qld, 4072, Australia
| | - D J Venter
- Pathology, Mater Health Services, Raymond Terrace, South Brisbane, Qld, 4101, Australia.,Mater Research Institute, The University of Queensland, St. Lucia, Qld, 4072, Australia.,School of Medicine, The University of Queensland, Brisbane, Qld, 4072, Australia
| | - P F Alewood
- Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Qld, 4072, Australia
| | - R J Lewis
- Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Qld, 4072, Australia
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24
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Conotoxin αD-GeXXA utilizes a novel strategy to antagonize nicotinic acetylcholine receptors. Sci Rep 2015; 5:14261. [PMID: 26395518 PMCID: PMC4585798 DOI: 10.1038/srep14261] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 08/21/2015] [Indexed: 11/19/2022] Open
Abstract
Nicotinic acetylcholine receptors (nAChRs) play essential roles in transmitting acetylcholine-mediated neural signals across synapses and neuromuscular junctions, and are also closely linked to various diseases and clinical conditions. Therefore, novel nAChR-specific compounds have great potential for both neuroscience research and clinical applications. Conotoxins, the peptide neurotoxins produced by cone snails, are a rich reservoir of novel ligands that target receptors, ion channels and transporters in the nervous system. From the venom of Conus generalis, we identified a novel dimeric nAChR-inhibiting αD-conotoxin GeXXA. By solving the crystal structure and performing structure-guided dissection of this toxin, we demonstrated that the monomeric C-terminal domain of αD-GeXXA, GeXXA-CTD, retains inhibitory activity against the α9α10 nAChR subtype. Furthermore, we identified that His7 of the rat α10 nAChR subunit determines the species preference of αD-GeXXA, and is probably part of the binding site of this toxin. These results together suggest that αD-GeXXA cooperatively binds to two inter-subunit interfaces on the top surface of nAChR, thus allosterically disturbing the opening of the receptor. The novel antagonistic mechanism of αD-GeXXA via a new binding site on nAChRs provides a valuable basis for the rational design of new nAChR-targeting compounds.
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25
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Cloning, synthesis, and characterization of αO-conotoxin GeXIVA, a potent α9α10 nicotinic acetylcholine receptor antagonist. Proc Natl Acad Sci U S A 2015; 112:E4026-35. [PMID: 26170295 DOI: 10.1073/pnas.1503617112] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We identified a previously unidentified conotoxin gene from Conus generalis whose precursor signal sequence has high similarity to the O1-gene conotoxin superfamily. The predicted mature peptide, αO-conotoxin GeXIVA (GeXIVA), has four Cys residues, and its three disulfide isomers were synthesized. Previously pharmacologically characterized O1-superfamily peptides, exemplified by the US Food and Drug Administration-approved pain medication, ziconotide, contain six Cys residues and are calcium, sodium, or potassium channel antagonists. However, GeXIVA did not inhibit calcium channels but antagonized nicotinic AChRs (nAChRs), most potently on the α9α10 nAChR subtype (IC50 = 4.6 nM). Toxin blockade was voltage-dependent, and kinetic analysis of toxin dissociation indicated that the binding site of GeXIVA does not overlap with the binding site of the competitive antagonist α-conotoxin RgIA. Surprisingly, the most active disulfide isomer of GeXIVA is the bead isomer, comprising, according to NMR analysis, two well-resolved but uncoupled disulfide-restrained loops. The ribbon isomer is almost as potent but has a more rigid structure built around a short 310-helix. In contrast to most α-conotoxins, the globular isomer is the least potent and has a flexible, multiconformational nature. GeXIVA reduced mechanical hyperalgesia in the rat chronic constriction injury model of neuropathic pain but had no effect on motor performance, warranting its further investigation as a possible therapeutic agent.
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26
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Optimized deep-targeted proteotranscriptomic profiling reveals unexplored Conus toxin diversity and novel cysteine frameworks. Proc Natl Acad Sci U S A 2015; 112:E3782-91. [PMID: 26150494 DOI: 10.1073/pnas.1501334112] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cone snails are predatory marine gastropods characterized by a sophisticated venom apparatus responsible for the biosynthesis and delivery of complex mixtures of cysteine-rich toxin peptides. These conotoxins fold into small highly structured frameworks, allowing them to potently and selectively interact with heterologous ion channels and receptors. Approximately 2,000 toxins from an estimated number of >70,000 bioactive peptides have been identified in the genus Conus to date. Here, we describe a high-resolution interrogation of the transcriptomes (available at www.ddbj.nig.ac.jp) and proteomes of the diverse compartments of the Conus episcopatus venom apparatus. Using biochemical and bioinformatic tools, we found the highest number of conopeptides yet discovered in a single Conus specimen, with 3,305 novel precursor toxin sequences classified into 9 known superfamilies (A, I1, I2, M, O1, O2, S, T, Z), and identified 16 new superfamilies showing unique signal peptide signatures. We were also able to depict the largest population of venom peptides containing the pharmacologically active C-C-CC-C-C inhibitor cystine knot and CC-C-C motifs (168 and 44 toxins, respectively), as well as 208 new conotoxins displaying odd numbers of cysteine residues derived from known conotoxin motifs. Importantly, six novel cysteine-rich frameworks were revealed which may have novel pharmacology. Finally, analyses of codon usage bias and RNA-editing processes of the conotoxin transcripts demonstrate a specific conservation of the cysteine skeleton at the nucleic acid level and provide new insights about the origin of sequence hypervariablity in mature toxin regions.
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Christensen SB, Bandyopadhyay PK, Olivera BM, McIntosh JM. αS-conotoxin GVIIIB potently and selectively blocks α9α10 nicotinic acetylcholine receptors. Biochem Pharmacol 2015; 96:349-56. [PMID: 26074268 DOI: 10.1016/j.bcp.2015.06.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 06/05/2015] [Indexed: 11/18/2022]
Abstract
Although acetylcholine is widely utilized in vertebrate nervous systems, nicotinic acetylcholine receptors (nAChRs), including the α9α10 subtype, also are expressed in a wide variety of non-neuronal cells. These cell types include cochlear hair cells, adrenal chromaffin cells and immune cells. α9α10 nAChRs present in these cells may respectively play roles in protection from noise-induced hearing loss, response to stress and neuroprotection. Despite these critical functions, there are few available selective ligands to confirm mechanistic hypothesis regarding the role of α9α10 nAChRs. Conus, has been a rich source of ligands for receptors and ion channels. Here, we identified Conus geographus venom as a lead source for a novel α9α10 antagonist. The active component was isolated and the encoding gene cloned. The peptide signal sequence and cysteine arrangement had the signature of the σ-conotoxin superfamily. Previously isolated σ-conotoxin GVIIIA, also from Conus geographus, targets the 5-HT3 receptor. In contrast, αS-GVIIIB blocked the α9α10 nAChR with an IC50 of 9.8 nM, yet was inactive at the 5-HT3 receptor. Pharmacological characterization of αS-GVIIIB shows that it is over 100-fold selective for the α9α10 nAChR compared to other nAChR subtypes. Thus, the S-superfamily represents a novel conotoxin scaffold for flexibly targeting a variety of receptor subtypes. Functional competition studies utilized distinct off-rate kinetics of conotoxins to identify the α10/α9 nAChR interface as the site of αS-GVIIIB binding; this adds to the importance of the (+) face of the α10 rather than the (+) face of the α9 nAChR subunit as critical to binding of α9α10-targeted conotoxins.
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Affiliation(s)
- Sean B Christensen
- Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| | | | | | - J Michael McIntosh
- Department of Biology, University of Utah, Salt Lake City, UT 84112, USA; George E. Wahlen Veterans Affairs Medical Center, Salt Lake City, UT 84108, USA; Department of Psychiatry, University of Utah, Salt Lake City, UT 84112, USA.
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Kumar PS, Kumar DS, Umamaheswari S. A perspective on toxicology of Conus venom peptides. ASIAN PAC J TROP MED 2015; 8:337-51. [PMID: 26003592 DOI: 10.1016/s1995-7645(14)60342-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The evolutionarily unique and ecologically diverse family Conidae presents fundamental opportunities for marine pharmacology research and drug discovery. The focus of this investigation is to summarize the worldwide distribution of Conus and their species diversity with special reference to the Indian coast. In addition, this study will contribute to understanding the structural properties of conotoxin and therapeutic application of Conus venom peptides. Cone snails can inject a mix of various conotoxins and these venoms are their major weapon for prey capture, and may also have other biological purposes, and some of these conotoxins fatal to humans. Conus venoms contain a remarkable diversity of pharmacologically active small peptides; their targets are an iron channel and receptors in the neuromuscular system. Interspecific divergence is pronounced in venom peptide genes, which is generally attributed to their species specific biotic interactions. There is a notable interspecific divergence observed in venom peptide genes, which can be justified as of biotic interactions that stipulate species peculiar habitat and ecology of cone snails. There are several conopeptides used in clinical trials and one peptide (Ziconotide) has received FDA approval for treatment of pain. This perspective provides a comprehensive overview of the distribution of cone shells and focus on the molecular approach in documenting their taxonomy and diversity with special reference to geographic distribution of Indian cone snails, structure and properties of conopeptide and their pharmacological targets and future directions.
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Affiliation(s)
| | - Dhanabalan Senthil Kumar
- Department of Zoology, Kandaswami Kandar College, Paramathi Velur-638 182, Namakkal, Tamil Nadu, India
| | - Sundaresan Umamaheswari
- Department of Environmental Biotechnology, Bharathidasan University, Tiruchurapalli, Tamil Nadu 620024, India
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Wang L, Chan JYW, Rêgo JV, Chong CM, Ai N, Falcão CB, Rádis-Baptista G, Lee SMY. Rhodamine B-conjugated encrypted vipericidin nonapeptide is a potent toxin to zebrafish and associated with in vitro cytotoxicity. Biochim Biophys Acta Gen Subj 2015; 1850:1253-60. [PMID: 25731980 DOI: 10.1016/j.bbagen.2015.02.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 02/15/2015] [Accepted: 02/20/2015] [Indexed: 10/23/2022]
Abstract
BACKGROUND Animal venoms contain a diverse array of proteins and enzymes that are toxic toward various physiological systems. However, there are also some practical medicinal uses for these toxins including use as anti-bacterial and anti-tumor agents. METHODS In this study, we identified a nine-residue cryptic oligopeptide, KRFKKFFKK (EVP50) that is repeatedly encoded in tandem within vipericidin sequences. RESULTS EVP50 displayed in vivo potent lethal toxicity to zebrafish larvae (LD50=6 μM) when the peptide's N-terminus was chemically conjugated to rhodamine B (RhoB). In vitro, RhoB-conjugated EVP50 (RhoB-EVP50) exhibited a concentration-dependent cytotoxic effect toward MCF-7 and MDA-MB-231 breast cancer cells. In MCF-7 cells, the RhoB-EVP50 nonapeptide accumulated inside the cells within minutes. In the cytoplasm, the RhoB-EVP50 induced extracellular calcium influx and intracellular calcium release. Membrane budding was also observed after incubation with micromolar concentrations of the fluorescent EVP50 conjugate. CONCLUSIONS The conjugate's interference with calcium homeostasis, its intracellular accumulation and its induced membrane dysfunction (budding and vacuolization) seem to act in concert to disrupt the cell circuitry. Contrastively, unconjugated EVP50 peptide did not display neither toxic nor cytotoxic activities in our in vivo and in vitro models. GENERAL SIGNIFICANCE The synergic mechanism of toxicity was restricted to the structurally modified encrypted vipericidin nonapeptide.
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Affiliation(s)
- Liang Wang
- State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Macao, China
| | - Judy Y W Chan
- State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Macao, China
| | - Juciane V Rêgo
- Northeast Biotechnology Network (RENORBIO), Post-graduation program in Biotechnology, Federal University of Ceara, Brazil; Laboratory of Biochemistry and Biotechnology, Institute for Marine Sciences, Federal University of Ceara, Brazil
| | - Cheong-Meng Chong
- State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Macao, China
| | - Nana Ai
- State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Macao, China
| | - Cláudio B Falcão
- Laboratory of Biochemistry and Biotechnology, Institute for Marine Sciences, Federal University of Ceara, Brazil
| | - Gandhi Rádis-Baptista
- Laboratory of Biochemistry and Biotechnology, Institute for Marine Sciences, Federal University of Ceara, Brazil.
| | - Simon M Y Lee
- State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Macao, China.
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Biass D, Violette A, Hulo N, Lisacek F, Favreau P, Stöcklin R. Uncovering Intense Protein Diversification in a Cone Snail Venom Gland Using an Integrative Venomics Approach. J Proteome Res 2015; 14:628-38. [DOI: 10.1021/pr500583u] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Daniel Biass
- Atheris Laboratories, case postale
314, CH-1233 Bernex-Geneva, Switzerland
| | - Aude Violette
- Atheris Laboratories, case postale
314, CH-1233 Bernex-Geneva, Switzerland
| | - Nicolas Hulo
- Atheris Laboratories, case postale
314, CH-1233 Bernex-Geneva, Switzerland
| | - Frédérique Lisacek
- Proteome
Informatics Group, Swiss Institute of Bioinformatics, rue Michel Servet 1, CH-1211 Geneva 4, Switzerland
- Section
of Biology, University of Geneva, CH-1211 Geneva
4, Switzerland
| | - Philippe Favreau
- Atheris Laboratories, case postale
314, CH-1233 Bernex-Geneva, Switzerland
| | - Reto Stöcklin
- Atheris Laboratories, case postale
314, CH-1233 Bernex-Geneva, Switzerland
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Conotoxin gene superfamilies. Mar Drugs 2014; 12:6058-101. [PMID: 25522317 PMCID: PMC4278219 DOI: 10.3390/md12126058] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 11/29/2014] [Accepted: 12/04/2014] [Indexed: 12/16/2022] Open
Abstract
Conotoxins are the peptidic components of the venoms of marine cone snails (genus Conus). They are remarkably diverse in terms of structure and function. Unique potency and selectivity profiles for a range of neuronal targets have made several conotoxins valuable as research tools, drug leads and even therapeutics, and has resulted in a concerted and increasing drive to identify and characterise new conotoxins. Conotoxins are translated from mRNA as peptide precursors, and cDNA sequencing is now the primary method for identification of new conotoxin sequences. As a result, gene superfamily, a classification based on precursor signal peptide identity, has become the most convenient method of conotoxin classification. Here we review each of the described conotoxin gene superfamilies, with a focus on the structural and functional diversity present in each. This review is intended to serve as a practical guide to conotoxin superfamilies and to facilitate interpretation of the increasing number of conotoxin precursor sequences being identified by targeted-cDNA sequencing and more recently high-throughput transcriptome sequencing.
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Thapa P, Espiritu MJ, Cabalteja CC, Bingham JP. Conotoxins and their regulatory considerations. Regul Toxicol Pharmacol 2014; 70:197-202. [PMID: 25013992 DOI: 10.1016/j.yrtph.2014.06.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 06/29/2014] [Accepted: 06/30/2014] [Indexed: 01/21/2023]
Abstract
Venom derived peptides from marine cone snails, conotoxins, have demonstrated unique pharmacological targeting properties that have been pivotal in advancing medical research. The awareness of their true toxic origins and potent pharmacological nature is emphasized by their 'select agent' classification by the US Centers for Disease Control and Prevention. We briefly introduce the biochemical and pharmacological aspects of conotoxins, highlighting current advancements into their biological engineering, and provide details to the present regulations that govern their use in research.
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Affiliation(s)
- Parashar Thapa
- Department of Molecular Biosciences and Bioengineering, College of Tropical Agriculture and Human Resources, University of Hawai'i, Honolulu, HI 96822, USA
| | - Michael J Espiritu
- Department of Molecular Biosciences and Bioengineering, College of Tropical Agriculture and Human Resources, University of Hawai'i, Honolulu, HI 96822, USA
| | - Chino C Cabalteja
- Department of Molecular Biosciences and Bioengineering, College of Tropical Agriculture and Human Resources, University of Hawai'i, Honolulu, HI 96822, USA
| | - Jon-Paul Bingham
- Department of Molecular Biosciences and Bioengineering, College of Tropical Agriculture and Human Resources, University of Hawai'i, Honolulu, HI 96822, USA.
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Lavergne V, Dutertre S, Jin AH, Lewis RJ, Taft RJ, Alewood PF. Systematic interrogation of the Conus marmoreus venom duct transcriptome with ConoSorter reveals 158 novel conotoxins and 13 new gene superfamilies. BMC Genomics 2013; 14:708. [PMID: 24131469 PMCID: PMC3853152 DOI: 10.1186/1471-2164-14-708] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Accepted: 10/11/2013] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Conopeptides, often generically referred to as conotoxins, are small neurotoxins found in the venom of predatory marine cone snails. These molecules are highly stable and are able to efficiently and selectively interact with a wide variety of heterologous receptors and channels, making them valuable pharmacological probes and potential drug leads. Recent advances in next-generation RNA sequencing and high-throughput proteomics have led to the generation of large data sets that require purpose-built and dedicated bioinformatics tools for efficient data mining. RESULTS Here we describe ConoSorter, an algorithm that categorizes cDNA or protein sequences into conopeptide superfamilies and classes based on their signal, pro- and mature region sequence composition. ConoSorter also catalogues key sequence characteristics (including relative sequence frequency, length, number of cysteines, N-terminal hydrophobicity, sequence similarity score) and automatically searches the ConoServer database for known precursor sequences, facilitating identification of known and novel conopeptides. When applied to ConoServer and UniProtKB/Swiss-Prot databases, ConoSorter is able to recognize 100% of known conotoxin superfamilies and classes with a minimum species specificity of 99%. As a proof of concept, we performed a reanalysis of Conus marmoreus venom duct transcriptome and (i) correctly classified all sequences previously annotated, (ii) identified 158 novel precursor conopeptide transcripts, 106 of which were confirmed by protein mass spectrometry, and (iii) identified another 13 novel conotoxin gene superfamilies. CONCLUSIONS Taken together, these findings indicate that ConoSorter is not only capable of robust classification of known conopeptides from large RNA data sets, but can also facilitate de novo identification of conopeptides which may have pharmaceutical importance.
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Affiliation(s)
| | | | | | | | - Ryan J Taft
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane, Qld 4072, Australia.
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Optimal cleavage and oxidative folding of α-conotoxin TxIB as a therapeutic candidate peptide. Mar Drugs 2013; 11:3537-53. [PMID: 24048271 PMCID: PMC3806463 DOI: 10.3390/md11093537] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 08/16/2013] [Accepted: 08/19/2013] [Indexed: 12/19/2022] Open
Abstract
Alpha6beta2 nicotinic acetylcholine receptors (nAChRs) are potential therapeutic targets for the treatment of several neuropsychiatric diseases, including addiction and Parkinson’s disease. Alpha-conotoxin (α-CTx) TxIB is a uniquely selective ligand, which blocks α6/α3β2β3 nAChRs only, but does not block the other subtypes. Therefore, α-CTx TxIB is a valuable therapeutic candidate peptide. Synthesizing enough α-CTx TxIB with high yield production is required for conducting wide-range testing of its potential medicinal applications. The current study optimized the cleavage of synthesized α-CTx TxIB resin-bounded peptide and folding of the cleaved linear peptide. Key parameters influencing cleavage and oxidative folding of α-CTx TxIB were examined, such as buffer, redox agents, pH, salt, co-solvent and temperature. Twelve conditions were used for cleavage optimization. Fifty-four kinds of one-step oxidative solution were used to assess their effects on each α-CTx TxIB isomers’ yield. The result indicated that co-solvent choices were particularly important. Completely oxidative folding of globular isomer was achieved when the NH4HCO3 or Tris-HCl folding buffer at 4 °C contained 40% of co-solvent DMSO, and GSH:GSSG (2:1) or GSH only with pH 8~8.7.
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Jin AH, Dutertre S, Kaas Q, Lavergne V, Kubala P, Lewis RJ, Alewood PF. Transcriptomic messiness in the venom duct of Conus miles contributes to conotoxin diversity. Mol Cell Proteomics 2013; 12:3824-33. [PMID: 24043424 DOI: 10.1074/mcp.m113.030353] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Marine cone snails have developed sophisticated chemical strategies to capture prey and defend themselves against predators. Among the vast array of bioactive molecules in their venom, peptide components called conotoxins or conopeptides dominate, with many binding with high affinity and selectivity to a broad range of cellular targets, including receptors and transporters of the nervous system. Whereas the conopeptide gene precursor organization has a conserved topology, the peptides in the venom duct are highly processed. Indeed, deep sequencing transcriptomics has uncovered on average fewer than 100 toxin gene precursors per species, whereas advanced proteomics has revealed >10-fold greater diversity at the peptide level. In the present study, second-generation sequencing technologies coupled to highly sensitive mass spectrometry methods were applied to rapidly uncover the conopeptide diversity in the venom of a worm-hunting species, Conus miles. A total of 662 putative conopeptide encoded sequences were retrieved from transcriptomic data, comprising 48 validated conotoxin sequences that clustered into 10 gene superfamilies, including 3 novel superfamilies and a novel cysteine framework (C-C-C-CCC-C-C) identified at both transcript and peptide levels. A surprisingly large number of conopeptide gene sequences were expressed at low levels, including a series of single amino acid variants, as well as sequences containing deletions and frame and stop codon shifts. Some of the toxin variants generate alternative cleavage sites, interrupted or elongated cysteine frameworks, and highly variable isoforms within families that could be identified at the peptide level. Together with the variable peptide processing identified previously, background genetic and phenotypic levels of biological messiness in venoms contribute to the hypervariability of venom peptides and their ability to evolve rapidly.
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Affiliation(s)
- Ai-hua Jin
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland 4072, Australia
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