1
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Lin J, Chen S, Butt UD, Yan M, Wu B. A comprehensive review on ziconotide. Heliyon 2024; 10:e31105. [PMID: 38779019 PMCID: PMC11110537 DOI: 10.1016/j.heliyon.2024.e31105] [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: 11/21/2023] [Revised: 05/09/2024] [Accepted: 05/09/2024] [Indexed: 05/25/2024] Open
Abstract
Managing severe chronic pain is a challenging task, given the limited effectiveness of available pharmacological and non-pharmacological treatments. This issue continues to be a significant public health concern, requiring a substantial therapeutic response. Ziconotide, a synthetic peptide initially isolated from Conus magus in 1982 and approved by the US Food and Drug Administration and the European Medicines Agency in 2004, is the first-line intrathecal method for individuals experiencing severe chronic pain refractory to other therapeutic measures. Ziconotide produces powerful analgesia by blocking N-type calcium channels in the spinal cord, which inhibits the release of pain-relevant neurotransmitters from the central terminals of primary afferent neurons. However, despite possessing many favorable qualities, including the absence of tolerance development, respiratory depression, and withdrawal symptoms (largely due to the absence of a G-protein mediation mechanism), ziconotide's application is limited due to factors such as intrathecal administration and a narrow therapeutic window resulting from significant dose-related undesired effects of the central nervous system. This review aims to provide a comprehensive and clinically relevant summary of the literatures concerning the pharmacokinetics and metabolism of intrathecal ziconotide. It will also describe strategies intended to enhance clinical efficacy while reducing the incidence of side effects. Additionally, the review will explore the current efforts to refine the structure of ziconotide for better clinical outcomes. Lastly, it will prospect potential developments in the new class of selective N-type voltage-sensitive calcium-channel blockers.
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Affiliation(s)
- Jinping Lin
- Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310000, China
| | - Shuwei Chen
- Fuyang People's Hospital, Hangzhou 311400, China
| | | | - Min Yan
- Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310000, China
| | - Bin Wu
- Ocean College, Zhejiang University, Zhoushan 321000, China
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2
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Zhang H, Chen S. Cyclic peptide drugs approved in the last two decades (2001-2021). RSC Chem Biol 2022; 3:18-31. [PMID: 35128405 PMCID: PMC8729179 DOI: 10.1039/d1cb00154j] [Citation(s) in RCA: 109] [Impact Index Per Article: 54.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 11/05/2021] [Indexed: 01/01/2023] Open
Abstract
In contrast to the major families of small molecules and antibodies, cyclic peptides, as a family of synthesizable macromolecules, have distinct biochemical and therapeutic properties for pharmaceutical applications. Cyclic peptide-based drugs have increasingly been developed in the past two decades, confirming the common perception that cyclic peptides have high binding affinities and low metabolic toxicity as antibodies, good stability and ease of manufacture as small molecules. Natural peptides were the major source of cyclic peptide drugs in the last century, and cyclic peptides derived from novel screening and cyclization strategies are the new source. In this review, we will discuss and summarize 18 cyclic peptides approved for clinical use in the past two decades to provide a better understanding of cyclic peptide development and to inspire new perspectives. The purpose of the present review is to promote efforts to resolve the challenges in the development of cyclic peptide drugs that are more effective.
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Affiliation(s)
- Huiya Zhang
- Biotech Drug Research Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences Shanghai 201203 China
| | - Shiyu Chen
- Biotech Drug Research Center, Shanghai Institute of Materia Medica, Chinese Academy of Sciences Shanghai 201203 China
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3
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Aridoss G, Kim D, Kim JI, Kang JE. Ziconotide (
ω‐conotoxin MVIIA
)—Efficient solid‐phase synthesis of a linear precursor peptide and its strategic native folding. Pept Sci (Hoboken) 2021. [DOI: 10.1002/pep2.24223] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Gopalakrishnan Aridoss
- Peptide Smart Process Department Anygen Co., Ltd Cheongju‐si Chungcheongbuk‐do South Korea
| | - Dong‐Min Kim
- Peptide Smart Process Department Anygen Co., Ltd Cheongju‐si Chungcheongbuk‐do South Korea
| | - Jae Il Kim
- Peptide Smart Process Department Anygen Co., Ltd Cheongju‐si Chungcheongbuk‐do South Korea
| | - Jae Eun Kang
- Peptide Smart Process Department Anygen Co., Ltd Cheongju‐si Chungcheongbuk‐do South Korea
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4
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Yu S, Li Y, Chen J, Zhang Y, Tao X, Dai Q, Wang Y, Li S, Dong M. TAT-Modified ω-Conotoxin MVIIA for Crossing the Blood-Brain Barrier. Mar Drugs 2019; 17:md17050286. [PMID: 31083641 PMCID: PMC6562543 DOI: 10.3390/md17050286] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 05/08/2019] [Accepted: 05/08/2019] [Indexed: 01/25/2023] Open
Abstract
As the first in a new class of non-opioid drugs, ω-Conotoxin MVIIA was approved for the management of severe chronic pains in patients who are unresponsive to opioid therapy. Unfortunately, clinical application of MVIIA is severely limited due to its poor ability to penetrate the blood-brain barrier (BBB), reaching the central nervous system (CNS). In the present study, we have attempted to increase MVIIA’s ability to cross the BBB via a fusion protein strategy. Our results showed that when the TAT-transducing domain was fused to the MVIIA C-terminal with a linker of varied numbers of glycine, the MVIIA-TAT fusion peptide exhibited remarkable ability to cross the bio-membranes. Most importantly, both intravenous and intranasal administrations of MVIIA-TAT in vivo showed therapeutic efficacy of analgesia. Compared to the analgesic effects of intracerebral administration of the nascent MVIIA, these systemic administrations of MVIIA-TAT require higher doses, but have much prolonged effects. Taken together, our results showed that TAT conjugation of MVIIA not only enables its peripheral administration, but also maintains its analgesic efficiency with a prolonged effective time window. Intranasal administration also rendered the MVIIA-TAT advantages of easy applications with potentially reduced side effects. Our results may present an alternative strategy to improve the CNS accessibility for neural active peptides.
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Affiliation(s)
- Shuo Yu
- Department of Protein Engineering, Beijing Institute of Biotechnology, Beijing 100071, China.
| | - Yumeng Li
- State Key Laboratory of Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China.
| | - Jinqin Chen
- Department of Protein Engineering, Beijing Institute of Biotechnology, Beijing 100071, China.
| | - Yue Zhang
- Department of Protein Engineering, Beijing Institute of Biotechnology, Beijing 100071, China.
| | - Xinling Tao
- State Key Laboratory of Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China.
| | - Qiuyun Dai
- Department of Protein Engineering, Beijing Institute of Biotechnology, Beijing 100071, China.
| | - Yutian Wang
- Djavad Mowafaghian Centre for Brain Health and Department of Medicine, University of British Columbia, Vancouver, BC V5Z 1M9, Canada.
| | - Shupeng Li
- State Key Laboratory of Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China.
- Campbell Research Institute, Centre for Addiction and Mental Health, Toronto, ON M5T 1R8, Canada.
- Department of Psychiatry, University of Toronto, Toronto, ON M5T 1R8, Canada.
| | - Mingxin Dong
- Institute of Neuroregeneration & Neurorehabilitation, Qingdao University, 308 Ningxia Street, Qingdao 266021, China.
- Department of Protein Engineering, Beijing Institute of Biotechnology, Beijing 100071, China.
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5
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Engineering of an Anti-Inflammatory Peptide Based on the Disulfide-Rich Linaclotide Scaffold. Biomedicines 2018; 6:biomedicines6040097. [PMID: 30301200 PMCID: PMC6316043 DOI: 10.3390/biomedicines6040097] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Revised: 09/11/2018] [Accepted: 09/21/2018] [Indexed: 12/19/2022] Open
Abstract
Inflammatory bowel diseases are a set of complex and debilitating diseases, for which there is no satisfactory treatment. Peptides as small as three amino acids have been shown to have anti-inflammatory activity in mouse models of colitis, but they are likely to be unstable, limiting their development as drug leads. Here, we have grafted a tripeptide from the annexin A1 protein into linaclotide, a 14-amino-acid peptide with three disulfide bonds, which is currently in clinical use for patients with chronic constipation or irritable bowel syndrome. This engineered disulfide-rich peptide maintained the overall fold of the original synthetic guanylate cyclase C agonist peptide, and reduced inflammation in a mouse model of acute colitis. This is the first study to show that this disulfide-rich peptide can be used as a scaffold to confer a new bioactivity.
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6
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Hemu X, Tam JP. Macrocyclic Antimicrobial Peptides Engineered from ω-Conotoxin. Curr Pharm Des 2018; 23:2131-2138. [PMID: 28245769 PMCID: PMC5470054 DOI: 10.2174/1381612822666161027120518] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 10/13/2016] [Indexed: 11/22/2022]
Abstract
The potent calcium channel blocker ω-conotoxin MVIIA is a linear cystine-knot peptide with multiple basic amino acids at both termini. This work shows that macrocyclization of MVIIA linking two positive-charge terminal clusters as a contiguous segment converts a conotoxin into an antimicrobial peptide. In addition, conversion of disulfide bonds to amino butyric acids improved the antimicrobial activity of the cyclic analogs. Ten macrocyclic analogs, with or without disulfide bonds, were prepared by both Boc and Fmoc chemistry using native chemical ligation. All cyclic analogs were active against selected Gram-positive and Gram-negative bacteria with minimal inhibitory concentrations in a low μM range. In contrast, MVIIA and its linear analog were inactive at concentrations up to 0.5 mM. The cyclic analogs also showed 2 to 3-fold improved chemotactic activity against human monocytes THP-1 compared with MVIIA. Reduction of molecular stability against thermal and acid treatment due to the reduced number of disulfide crosslinks can be partly restored by backbone cyclization. Together, these results show that macrocyclization and side chain modification of a linear conopeptide lead to a gain-of-function, which brings a new perspective in designing and engineering of peptidyl therapeutics.
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Affiliation(s)
- Xinya Hemu
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 03s-71, Singapore 637551, Singapore
| | - James P Tam
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 03s-71, Singapore 637551, Singapore
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7
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Lebbe EKM, Peigneur S, Brullot W, Verbiest T, Tytgat J. Ala-7, His-10 and Arg-12 are crucial amino acids for activity of a synthetically engineered μ-conotoxin. Peptides 2014; 53:300-6. [PMID: 23871692 DOI: 10.1016/j.peptides.2013.07.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 07/01/2013] [Accepted: 07/01/2013] [Indexed: 12/19/2022]
Abstract
Cone snail toxins or conotoxins are often small cysteine-rich peptides which have shown to be highly selective ligands for a wide range of ion channels such as voltage-gated sodium channels (Na(V)s). Na(V)s participate in a wide range of electrophysiological processes. Consequently, their malfunction has been associated with numerous diseases. The development of subtype-selective modulators of Na(V)s remains highly important in the treatment of such disorders. In order to expand our knowledge in the search for novel therapeutics to treat Na(V)-related diseases, we explored the field of peptide engineering. In the current study, the impact of well considered point mutations into a bioactive peptide that was found to be a very potent and selective inhibitor of Na(V)s (i.e. Midi R2) was examined. We designed two peptides, named Midi R2[A7G] and Midi R2[H10A, R12A] which have mutations at position 7, and both 10 and 12, respectively. Electrophysiological recordings indicated that an Ala to Gly mutation at position 7 increased IC50-values from the nanomolar range to the micromolar range. For Midi R2[H10A, R12A] at a concentration of 10 μM, activity is even reduced to 0-10% for all of the tested Na(V)-channels. Circular dichroism measurements proved that overall structural conformations did not change. These findings suggest that the minimal space between the second and the third intercysteine loop of Midi R2 is the sequence RRWARDHSR and that His at position 10 and Arg at position 12 are crucial amino acids for the potency and specificity of Midi R2. In this way, new insights into the structure-activity relationships of μ-conotoxins were found.
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Affiliation(s)
- Eline K M Lebbe
- Toxicology and Pharmacology, University of Leuven (KU Leuven), Campus Gasthuisberg O&N2, Herestraat 49, P.O. Box 922, 3000 Leuven, Belgium.
| | - Steve Peigneur
- Toxicology and Pharmacology, University of Leuven (KU Leuven), Campus Gasthuisberg O&N2, Herestraat 49, P.O. Box 922, 3000 Leuven, Belgium.
| | - Ward Brullot
- Laboratory for Molecular Electronics and Photonics, Division Molecular Imaging and Photonics, Department of Chemistry, University of Leuven, Celestijnenlaan 200D, P.O. Box 2425, 3001 Heverlee, Belgium.
| | - Thierry Verbiest
- Laboratory for Molecular Electronics and Photonics, Division Molecular Imaging and Photonics, Department of Chemistry, University of Leuven, Celestijnenlaan 200D, P.O. Box 2425, 3001 Heverlee, Belgium.
| | - Jan Tytgat
- Toxicology and Pharmacology, University of Leuven (KU Leuven), Campus Gasthuisberg O&N2, Herestraat 49, P.O. Box 922, 3000 Leuven, Belgium.
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8
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Lee CW, Sato K, Kim JI. Determination of Disulfide Bond Connectivity of Cysteine-rich Peptide IpTxa. B KOREAN CHEM SOC 2013. [DOI: 10.5012/bkcs.2013.34.6.1903] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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9
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Schroeder CI, Nielsen KJ, Adams DA, Loughnan M, Thomas L, Alewood PF, Lewis RJ, Craik DJ. Effects of Lys2 to Ala2 substitutions on the structure and potency of ω-conotoxins MVIIA and CVID. Biopolymers 2012. [DOI: 10.1002/bip.22031] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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10
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Norton RS. Structure and Function of Peptide and Protein Toxins from Marine Organisms. ACTA ACUST UNITED AC 2009. [DOI: 10.3109/15569549809009246] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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11
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Craik DJ, Adams DJ. Chemical modification of conotoxins to improve stability and activity. ACS Chem Biol 2007; 2:457-68. [PMID: 17649970 DOI: 10.1021/cb700091j] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Conotoxins are small disulfide-rich peptides from the venom of cone snails. Along with other conopeptides, they target a wide range of membrane receptors, ion channels, and transporters, and because of their high potency and selectivity for defined subtypes of these receptors, they have attracted a great deal of attention recently as leads in drug development. However, like most peptides, conopeptides potentially suffer from the disadvantages of poor absorption, poor stability, or short biological half-lives. Recently, various chemical approaches, including residue substitutions, backbone cyclization, and disulfide-bridge modification, have been reported to increase the stability of conopeptides. These manufactured interventions add to the array of post-translational modifications that occur naturally in conopeptides. They enhance the versatility of these peptides as tools in neuroscience and as drug leads.
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Affiliation(s)
- David J Craik
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
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12
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Abstract
Ziconotide is a powerful analgesic drug that has a unique mechanism of action involving potent and selective block of N-type calcium channels, which control neurotransmission at many synapses. The analgesic efficacy of ziconotide likely results from its ability to interrupt pain signaling at the level of the spinal cord. Ziconotide is a peptidic drug and has been approved for the treatment of severe chronic pain in patients only when administered by the intrathecal route. Importantly, prolonged administration of ziconotide does not lead to the development of addiction or tolerance. The current review discusses the various studies that have addressed the in vitro biochemical and electrophysiological actions of ziconotide as well as the numerous pre-clinical studies that were conducted to elucidate its antinociceptive mechanism of action in animals. In addition, this review considers the pivotal Phase 3 (and other) clinical trials that were conducted in support of ziconotide's approval for the treatment of severe chronic pain and tries to offer some insights regarding the future discovery and development of newer analgesic drugs that would act by a similar mechanism to ziconotide but which might offer improved safety, tolerability and ease of use.
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13
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Wang YX, Bowersox SS. Analgesic Properties of Ziconotide, a Selective Blocker of N-Type Neuronal Calcium Channels. CNS DRUG REVIEWS 2006. [DOI: 10.1111/j.1527-3458.2000.tb00134.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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14
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15
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Ver Donck A, Dissanayake S, Bostyn A, Vercruysse P. A Prospective, Open-label Study of Long-term Intrathecal Ziconotide for Chronic Nonmalignant Back Pain: A Case Report. Neuromodulation 2006; 9:68-71. [DOI: 10.1111/j.1525-1403.2006.00044.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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16
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17
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Ferrat G, Bosmans F, Tytgat J, Pimentel C, Chagot B, Gilles N, Nakajima T, Darbon H, Corzo G. Solution structure of two insect-specific spider toxins and their pharmacological interaction with the insect voltage-gated Na+ channel. Proteins 2005; 59:368-79. [PMID: 15726637 DOI: 10.1002/prot.20424] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Delta-paluIT1 and delta-paluIT2 are toxins purified from the venom of the spider Paracoelotes luctuosus. Similar in sequence to mu-agatoxins from Agelenopsis aperta, their pharmacological target is the voltage-gated insect sodium channel, of which they alter the inactivation properties in a way similar to alpha-scorpion toxins, but they bind on site 4 in a way similar to beta-scorpion toxins. We determined the solution structure of the two toxins by use of two-dimensional nuclear magnetic resonance (NMR) techniques followed by distance geometry and molecular dynamics. The structures of delta-paluIT1 and delta-paluIT2 belong to the inhibitory cystine knot structural family, i.e. a compact disulfide-bonded core from which four loops emerge. Delta-paluIT1 and delta-paluIT2 contain respectively two- and three-stranded anti-parallel beta-sheets as unique secondary structure. We compare the structure and the electrostatic anisotropy of those peptides to other sodium and calcium channel toxins, analyze the topological juxtaposition of key functional residues, and conclude that the recognition of insect voltage-gated sodium channels by these toxins involves the beta-sheet, in addition to loops I and IV. Besides the position of culprit residues on the molecular surface, difference in dipolar moment orientation is another determinant of receptor binding and biological activity differences. We also demonstrate by electrophysiological experiments on the cloned insect voltage-gated sodium channel, para, heterologuously co-expressed with the tipE subunit in Xenopus laevis oocytes, that delta-paluIT1 and delta-paluIT2 procure an increase of Na+ current. delta-PaluIT1-OH seems to have less effect when the same concentrations are used.
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Affiliation(s)
- G Ferrat
- Suntory Institute for Bioorganic Research, Mishima-Gun, Shimamoto-Cho, Osaka, Japan
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18
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Bernard C, Corzo G, Adachi-Akahane S, Foures G, Kanemaru K, Furukawa Y, Nakajima T, Darbon H. Solution structure of ADO1, a toxin extracted from the saliva of the assassin bug, Agriosphodrus dohrni. Proteins 2004; 54:195-205. [PMID: 14696181 DOI: 10.1002/prot.10513] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
ADO1 is a toxin purified from the saliva of the assassin bug, Agriosphodrus dohrni. Because of its similarity in sequence to Ptu1 from another assassin bug, we did not assess its pharmacologic target. Here, we demonstrate by electrophysiologic means that ADO1 targets the P/Q-type voltage-sensitive calcium channel. We also determine the solution structure of ADO1 using two-dimensional NMR techniques, followed by distance geometry and molecular dynamics. The structure of ADO1 belongs to the inhibitory cystine knot (ICK) structural family (i.e., a compact disulfide-bonded core from which four loops emerge). ADO1 contains a two-stranded, antiparallel beta-sheet structure. We compare the structure of ADO1 with other voltage-sensitive calcium-channel blockers, analyze the topologic juxtaposition of key functional residues, and conclude that the recognition of voltage-sensitive calcium channels by toxins belonging to the ICK structural family requires residues located on two distinct areas of the molecular surface of the toxins.
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Affiliation(s)
- Cédric Bernard
- Architecture et Fonction des Macromolécules Biologiques, UMR 6098, CNRS and Universités d'Aix-Marseille I and II, Marseille, France
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19
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Dai Q, Liu F, Zhou Y, Lu B, Yu F, Huang P. The synthesis of SO-3, a conopeptide with high analgesic activity derived from Conus striatus. JOURNAL OF NATURAL PRODUCTS 2003; 66:1276-1279. [PMID: 14510617 DOI: 10.1021/np030099y] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The synthesis and characterization of the conopeptide, SO-3, originally derived from Conus striatus is reported. It contains 25 amino acid residues and three disulfide bridges and manifests 72% sequence identity with MVIIA, an N-type Ca2+ channel inhibitor of high analgesic activity. We evaluated SO-3 in several mouse models of pain. The results indicate that SO-3 is a potent, nonaddictive, analgesic agent.
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Affiliation(s)
- Qiuyun Dai
- Institute of Biotechnology, Beijing 100071, People's Republic of China.
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20
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Yan Y, Tu G, Luo X, Dai Q, Huang P, Zhang R. Three-dimensional solution structure of ω-conotoxin SO3 determined by1H NMR. ACTA ACUST UNITED AC 2003. [DOI: 10.1007/bf03185760] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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21
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Wu JH, Morris-Natschke SL, Lee KH. Progress in the Recent Discovery and Development of Promising Anticancer and Anti-HIV Agents from Natural Products in the United States. J CHIN CHEM SOC-TAIP 2003. [DOI: 10.1002/jccs.200300002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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22
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Kohno T, Sasaki T, Kobayashi K, Fainzilber M, Sato K. Three-dimensional solution structure of the sodium channel agonist/antagonist delta-conotoxin TxVIA. J Biol Chem 2002; 277:36387-91. [PMID: 12145313 DOI: 10.1074/jbc.m206833200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The three-dimensional solution structure of delta-conotoxin TxVIA, a 27-mer peptide agonist/antagonist of sodium channels, was determined by two-dimensional (1)H NMR spectroscopy with simulated annealing calculations. A total of 20 converged structures of delta-conotoxin TxVIA were obtained on the basis of 360 distance constraints obtained from nuclear Overhauser effect connectivities, 28 torsion angle constraints, and 27 constraints associated with hydrogen bonds and disulfide bonds. The atomic root mean square difference about the averaged coordinate positions is 0.35 +/- 0.07 A for the backbone atoms (N, C(alpha), C) and 0.98 +/- 0.14 A for all heavy atoms of the entire peptide. The molecular structure of delta-conotoxin TxVIA is composed of a short triple-stranded antiparallel beta-sheet. The overall beta-sheet topology is +2x, -1, which is the same as those for other conotoxins. However, the three-dimensional structure of delta-conotoxin TxVIA has an unusual hydrophobic patch on one side of the molecule, which may play an important role in the sodium channel binding. These results provide a molecular basis for understanding the mechanism of sodium channel modulation through the toxin-channel interaction and insight into the discrimination of different ion channels.
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Affiliation(s)
- Toshiyuki Kohno
- Mitsubishi Kagaku Institute of Life Sciences (MITILS), 11 Minamiooya, Machida, Tokyo 194-8511, Japan.
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23
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Takeuchi K, Park E, Lee C, Kim J, Takahashi H, Swartz K, Shimada I. Solution structure of omega-grammotoxin SIA, a gating modifier of P/Q and N-type Ca(2+) channel. J Mol Biol 2002; 321:517-26. [PMID: 12162963 DOI: 10.1016/s0022-2836(02)00595-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
omega-Grammotoxin SIA (GrTx) is a 36 amino acid residue protein toxin from spider venom that inhibits P/Q and N-type voltage-gated Ca(2+) channels by modifying voltage-dependent gating. We determined the three-dimensional structure of GrTx using NMR spectroscopy. The toxin adopts an "inhibitor cystine knot" motif composed of two beta-strands (Leu19-Cys21 and Cys30-Trp32) and a beta-bulge (Trp6, Gly7-Cys30) with a +2x, -1 topology, which are connected by four chain reversals. Although GrTx was originally identified as an inhibitor of voltage-gated Ca(2+) channel, it also binds to K(+) channels with lower affinity. A similar cross-reaction was observed for Hanatoxin1 (HaTx), which binds to the voltage-sensing domains of K(+) and Ca(2+) channels with different affinities. A detailed comparison of the GrTx and HaTx structures identifies a conserved face containing a large hydrophobic patch surrounded by positively charged residues. The slight differences in the surface shape, which result from the orientation of the surface aromatic residues and/or the distribution of the charged residues, may explain the differences in the binding affinity of these gating modifiers with different voltage-gated ion channels.
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Affiliation(s)
- Koh Takeuchi
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 113-0033, Tokyo, Japan
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24
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Smith MT, Cabot PJ, Ross FB, Robertson AD, Lewis RJ. The novel N-type calcium channel blocker, AM336, produces potent dose-dependent antinociception after intrathecal dosing in rats and inhibits substance P release in rat spinal cord slices. Pain 2002; 96:119-27. [PMID: 11932068 DOI: 10.1016/s0304-3959(01)00436-5] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
N-type calcium channels modulate the release of key pro-nociceptive neurotransmitters such as glutamate and substance P (SP) in the central nervous system. Considerable research interest has focused on the therapeutic potential of the peptidic omega-conopeptides, GVIA and MVIIA as novel analgesic agents, due to their potent inhibition of N-type calcium channels. Recently, the novel peptidic N-type calcium channel blocker, AM336, was isolated from the venom of the cone snail, Conus catus. Thus, the aims of this study were to (i) document the antinociceptive effects of AM336 (also known as CVID) relative to MVIIA following intrathecal (i.t.) bolus dosing in rats with adjuvant-induced chronic inflammatory pain of the right hindpaw and to (ii) quantify the inhibitory effects of AM336 relative to MVIIA on K+-evoked SP release from slices of rat spinal cord. Both AM336 and MVIIA inhibited the K+-evoked release of the pro-nociceptive neurotransmitter, SP, from rat spinal cord slices in a concentration-dependent manner (EC50 values=21.1 and 62.9 nM, respectively), consistent with the antinociceptive actions of omega-conopeptides. Following acute i.t. dosing, AM336 evoked dose-dependent antinociception (ED50 approximately 0.110 nmol) but the doses required to produce side-effects were an order of magnitude larger than the doses required to produce antinociception. For i.t. doses of MVIIA<or=0.07 nmol, dose-dependent antinociception was also produced (ED50 approximately 0.016 nmol). Unexpectedly, however, i.t. doses of MVIIA>0.07 nmol, produced a dose-dependent decrease in antinociception but the incidence and severity of the side-effects continued to increase for all doses of MVIIA investigated, suggesting that dose-titration with MVIIA in the clinical setting, may be difficult.
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Affiliation(s)
- Maree T Smith
- School of Pharmacy, The University of Queensland, St Lucia, Queensland, Brisbane, Australia.
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25
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Bernard C, Corzo G, Mosbah A, Nakajima T, Darbon H. Solution structure of Ptu1, a toxin from the assassin bug Peirates turpis that blocks the voltage-sensitive calcium channel N-type. Biochemistry 2001; 40:12795-800. [PMID: 11669615 DOI: 10.1021/bi015537j] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ptu1 is a toxin from the assassin bug Peirates turpis which has been demonstrated to bind reversibly the N-type calcium channels and to have lower affinity than the omega-conotoxin MVIIA. We have determined the solution structure of Ptu1 by use of conventional two-dimensional NMR techniques followed by distance-geometry and molecular dynamics. The calculated structure of Ptu1 belongs to the inhibitory cystin knot structural family (ICK) that consists of a compact disulfide-bonded core from which four loops emerge. Analysis of the 25 converged solutions indicates that the molecular structure of Ptu1 contains a 2-stranded antiparallel beta-sheet (residues 24-27 and 31-34) as the only secondary structure. The loop 2 that has been described to be critical for the binding of the toxin on the channel is similar in Ptu1 and MVIIA. In this loop, the critical residue, Tyr13, in MVIIA is retrieved in Ptu1 as Phe13, but the presence of an acidic residue (Asp16) in Ptu1 could disturb the binding of Ptu1 on the channel and could explain the lower affinity of Ptu1 toward the N-type calcium channel compared to the one of MVIIA. Analysis of the electrostatic charge's repartition gives some insights about the importance of the basic residues, which could interact with acidic residues of the channel and then provide a stabilization of the toxin on the channel.
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Affiliation(s)
- C Bernard
- Architecture et Fonction des Macromolécules Biologiques, UMR 6098, CNRS and Universités d'Aix-Marseille I and II, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
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26
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Peng K, Chen XD, Liang SP. The effect of Huwentoxin-I on Ca(2+) channels in differentiated NG108-15 cells, a patch-clamp study. Toxicon 2001; 39:491-8. [PMID: 11024489 DOI: 10.1016/s0041-0101(00)00150-1] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Huwentoxin-I (HWTX-I), a 3.75 kDa peptide toxin isolated from the venom of the spider Selenocosmia huwena, was found to be a reversible presynaptic inhibitor by our previous work. Using whole-cell patch clamp methods, we found that HWTX-I had no significant effect on the TTX-sensitive Na(+) current or the delayed rectifier K(+) current (K(r)) in low-serum medium cultured NG108-15 cells, but High-Voltage-Activated Ca(2+) channel expressed in prostaglandin E(1) differentiated NG108-15 cells could be potently inhibited by HWTX-I (EC(50) approximately 100 nM), while it hardly affected low-voltage-activated Ca(2+) channel. Among types of high-voltage-activated Ca(2+) channel, HWTX-I selectively inhibited N-type Ca(2+) channel and had only very weak effect on L-type Ca(2+) channel in prostaglandin E(1) differentiated NG108-15 cells.
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Affiliation(s)
- K Peng
- College of life science, Hunan Normal University, 410081, Hunan 410006, Changsha, People's Republic of China
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27
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Goldenberg DP, Koehn RE, Gilbert DE, Wagner G. Solution structure and backbone dynamics of an omega-conotoxin precursor. Protein Sci 2001; 10:538-50. [PMID: 11344322 PMCID: PMC2374133 DOI: 10.1110/ps.30701] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Nuclear magnetic resonance spectroscopy was used to characterize the solution structure and backbone dynamics of a putative precursor form of omega-conotoxin MVIIA, a 25-amino-acid residue peptide antagonist of voltage-gated Ca(2+) channels. The mature peptide is found in the venom of a fish-hunting marine snail Conus magus and contains an amidated carboxyl terminus that is generated by oxidative cleavage of a Gly residue. The form examined in this study is identical to the mature peptide except for the presence of the unmodified carboxy-terminal Gly. This form, referred to as omega-MVIIA-Gly, has previously been shown to refold and form its disulfides more efficiently than the mature form, suggesting that the presence of the terminal Gly may favor folding in vivo. The nuclear magnetic resonance (NMR) structure determination indicated that the fold of omega-MVIIA-Gly is very similar to that previously determined for the mature form, but revealed that the terminal Gly residue participates in a network of hydrogen bonds involving both backbone and side chain atoms, very likely accounting for the enhanced stability and folding efficiency. (15)N relaxation experiments indicated that the backbone is well ordered on the nanosecond time scale but that residues 9-15 undergo a conformational exchange processes with a time constant of approximately 35 microseconds. Other studies have implicated this segment in the binding of the peptide to its physiological target, and the observed motions may play a role in allowing the peptide to enter the binding site
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Affiliation(s)
- D P Goldenberg
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
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28
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Kobayashi K, Sasaki T, Sato K, Kohno T. Three-dimensional solution structure of omega-conotoxin TxVII, an L-type calcium channel blocker. Biochemistry 2000; 39:14761-7. [PMID: 11101291 DOI: 10.1021/bi001506x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We determined the three-dimensional structure of omega-conotoxin TxVII, a 26-residue peptide that is an L-type calcium channel blocker, by (1)H NMR in aqueous solution. Twenty converged structures of this peptide were obtained on the basis of 411 distance constraints obtained from nuclear Overhauser effect connectivities, 20 torsion angle constraints, and 21 constraints associated with hydrogen bonds and disulfide bonds. The root-mean-square deviations about the averaged coordinates of the backbone atoms (N, C(alpha), C, and O) and all heavy atoms were 0.50 +/- 0.09 A and 0.99 +/- 0.13 A, respectively. The structure of omega-conotoxin TxVII is composed of a triple-stranded antiparallel beta-sheet and four turns. The three disulfide bonds in omega-conotoxin TxVII form the classical cystine knot motif of toxic or inhibitory polypeptides. The overall folding of omega-conotoxin TxVII is similar to those of the N-type calcium channel blockers, omega-conotoxin GVIA and MVIIA, despite the low amino acid sequence homology among them. omega-Conotoxin TxVII exposes many hydrophobic residues to a certain surface area. In contrast, omega-conotoxin GVIA and MVIIA expose basic residues in the same way as omega-conotoxin TxVII. The channel binding site of omega-conotoxin TxVII is different from those of omega-conotoxin GVIA and MVIIA, although the overall folding of these three peptides is similar. The gathered hydrophobic residues of omega-conotoxin TxVII probably interact with the hydrophobic cluster of the alpha(1) subunit of the L-type calcium channel, which consists of 13 residues located in segments 5 and 6 in domain III and in segment 6 in domain IV.
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Affiliation(s)
- K Kobayashi
- Mitsubishi Kasei Institute of Life Sciences, Minamiooya, Machida, Tokyo 194-8511, Japan
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29
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Atkinson RA, Kieffer B, Dejaegere A, Sirockin F, Lefèvre JF. Structural and dynamic characterization of omega-conotoxin MVIIA: the binding loop exhibits slow conformational exchange. Biochemistry 2000; 39:3908-19. [PMID: 10747778 DOI: 10.1021/bi992651h] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
omega-Conotoxin MVIIA is a 25-residue, disulfide-bridged polypeptide from the venom of the sea snail Conus magus that binds to neuronal N-type calcium channels. It forms a compact folded structure, presenting a loop between Cys8 and Cys15 that contains a set of residues critical for its binding. The loop does not have a unique defined structure, nor is it intrinsically flexible. Broadening of a subset of resonances in the NMR spectrum at low temperature, anomalous temperature dependence of the chemical shifts of some resonances, and exchange contributions to J(0) from (13)C relaxation measurements reveal that conformational exchange affects the residues in this loop. The effects of this exchange on the calculated structure of omega-conotoxin MVIIA are discussed. The exchange appears to be associated with a change in the conformation of the disulfide bridge Cys8-Cys20. The implications for the use of the omega-conotoxins as a scaffold for carrying other functions is discussed.
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Affiliation(s)
- R A Atkinson
- UPR 9003 du CNRS, Ecole Supérieure de Biotechnologie de Strasbourg, Bld. Sébastien Brant, 67400 Illkirch, France.
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30
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Sato K, Raymond C, Martin-Moutot N, Sasaki T, Ohtake A, Minami K, Van Renterghem C, Kim JI, Takahashi M, Seagar MJ. Binding of Ala-scanning analogs of omega-conotoxin MVIIC to N- and P/Q-type calcium channels. FEBS Lett 2000; 469:147-50. [PMID: 10713260 DOI: 10.1016/s0014-5793(00)01263-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
omega-Conotoxin MVIIC binds to P/Q-type calcium channels with high affinity and N-type channels with low affinity. To reveal the residues essential for subtype selectivity, we synthesized Ala-scanning analogs of MVIIC. Binding assays using rat cerebellar P(2) membranes suggested that Thr(11), Tyr(13) and Lys(2) are essential for binding to both N- and P/Q-type channels, whereas Lys(4) and Arg(22) are important for binding to P/Q-type channels. These results suggest that MVIIC interacts with P/Q-type channels via a large surface, in good agreement with previous observations using chimeric analogs.
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Affiliation(s)
- K Sato
- Mitsubishi Kasei Institute of Life Sciences, 11 Minamiooya, Machida, Tokyo, Japan.
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31
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Sato K, Raymond C, Martin-Moutot N, Sasaki T, Ohtake A, Minami K, Van Renterghem C, Takahashi M, Seagar MJ. Binding of six chimeric analogs of omega-conotoxin MVIIA and MVIIC to N- and P/Q-type calcium channels. Biochem Biophys Res Commun 2000; 269:254-6. [PMID: 10694509 DOI: 10.1006/bbrc.2000.2284] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Replacement of the N-terminal half of omega-conotoxin MVIIC, a peptide blocker of P/Q-type calcium channels, with that of omega-conotoxin MVIIA significantly increased the affinity for N-type calcium channels. To identify the residues essential for subtype selectivity, we examined single reverse mutations from MVIIA-type to MVIIC-type in this chimeric analog. A reverse mutation from Lys(7) to Pro(7) decreased the affinity for both P/Q- and N-type channels, whereas that from Leu(11) to Thr(11) increased the affinity for P/Q-type channels and decreased the affinity for N-type channels. The roles of these two residues were confirmed by synthesizing two MVIIC analogs in which Pro(7) and Thr(11) were replaced with Lys(7) and Leu(11), respectively.
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Affiliation(s)
- K Sato
- Mitsubishi Kasei Institute of Life Sciences, 11 Minamiooya, Machida, Tokyo, 194-8511, Japan.
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32
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Abstract
Due to their selectivity towards voltage-sensitive calcium channels (VSCCs) omega-conotoxins are being exploited as a new class of therapeutics in pain management and may also have potential application in ischaemic brain injury. Here, the structure-activity relationships (SARs) of several omega-conotoxins including GVIA, MVIIA, CVID and MVIIC are explored. In addition, the three-dimensional structures of these omega-conotoxins and some structurally related peptides that form the cysteine knot are compared, and the effects of the solution environment on structure discussed. The diversity of binding and functional assays used to measure omega-conotoxin potencies at the N-type VSCC warranted a re-evaluation of the relationship between these assays. With one exception, [A22]-GVIA, this analysis revealed a linear correlation between functional (peripheral N-type VSCCs) and radioligand binding assays (central N-type VSCCs) for the omega-conotoxins and analogues that were tested over three studies. The binding and functional results of several studies are compared in an attempt to identify and distinguish those residues that are important in omega-conotoxin function as opposed to those that form part of the structural scaffold. Further to determining what omega-conotoxin residues are important for VSCC binding, the range of possible interactions between the ligand and channel are considered and the factors that influence the selectivity of MVIIA, GVIA and CVID towards N-type VSCCs examined.
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Affiliation(s)
- K J Nielsen
- Centre for Drug Design and Development (3D), Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
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33
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Sasaki T, Kobayashi K, Kohno T, Sato K. Combinatorial synthesis of omega-conotoxin MVIIC analogues and their binding with N- and P/Q-type calcium channels. FEBS Lett 2000; 466:125-9. [PMID: 10648826 DOI: 10.1016/s0014-5793(99)01772-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Omega-conotoxin MVIIC (MVIIC) blocks P/Q-type calcium channels with high affinity and N-type calcium channels with low affinity, while the highly homologous omega-conotoxin MVIIA blocks only N-type calcium channels. We wished to obtain MVIIC analogues more selective for P/Q-type calcium channels than MVIIC to elucidate structural differences among the channels, which discriminate the omega-conotoxins. To prepare a number of MVIIC analogues efficiently, we developed a combinatorial method which includes a random air oxidation step. Forty-seven analogues were prepared in six runs and some of them exhibited higher selectivity for P/Q-type calcium channels than MVIIC in binding assays.
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Affiliation(s)
- T Sasaki
- Mitsubishi Kasei Institute of Life Sciences, 11 Minamiooya, Machida-shi, Tokyo, Japan.
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34
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Belva H, Lange C. Conformational studies of omega-conotoxins using electrospray mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2000; 14:1433-1439. [PMID: 10920366 DOI: 10.1002/1097-0231(20000815)14:15<1433::aid-rcm39>3.0.co;2-u] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
MVIIA and MVIIB omega-conotoxins were chosen to investigate the effect of experimental conditions on their conformations, because of the presence of three disulfide bridges in these toxins. There were no significant effects of ion-source temperature, cone voltage, pH and percentage of cosolvent. We show that charge state distributions (CSDs) observed in their electrospray mass spectra are not a true reflection of the behaviour in the bulk solution because of electrostatic effects during the ion-evaporation process in the ion source. As a result it is not possible to deduce from the observed CSDs that some basic amino acids are hidden in the core of the peptide structure. This is important in view of the complementary finding that nearly all labile hydrogens are rapidly exchanged in deuterated solvents. The mass spectrometry results can be reconciled with results of NMR experiments and molecular calculations from the literature.
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Affiliation(s)
- H Belva
- Spectrométrie de Masse Bio-Organique, CNRS-UMR 6014, FR11, INSERM-IFR23, UFR des sciences, Université de Rouen, 76821 Mont Saint Aignan-Cedex, France
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35
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Three-dimensional structure of α-conotoxin EI determined by1H NMR spectroscopy. Int J Pept Res Ther 1999. [DOI: 10.1007/bf02443507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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36
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Nielsen KJ, Adams DA, Alewood PF, Lewis RJ, Thomas L, Schroeder T, Craik DJ. Effects of chirality at Tyr13 on the structure-activity relationships of omega-conotoxins from Conus magus. Biochemistry 1999; 38:6741-51. [PMID: 10346894 DOI: 10.1021/bi982980u] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The effects of chirality inversions of Tyr13 on the structure-activity relationships of omega-conotoxins MVIIA and MVIIC were examined using a combination of 2D 1H NMR spectroscopy and radioligand binding studies specific for N-type ([125I]GVIA) and P/Q-type ([125I]MVIIC) voltage-sensitive calcium channels (VSCCs). A comparison of the Halpha secondary shifts suggests that the structural scaffolds of MVIIA and MVIIC are little altered by the L- to D- inversion of Tyr13; however, the conformations of several residues in loop 2 (residues 9-14) are significantly altered. The experimentally determined 3D structure of [D-Y13]MVIIA indicates that the positions of key residues in this loop which are involved in the binding of MVIIA to the N-type VSCC (Tyr13, Arg10, and Leu11) are so changed as to render the peptide unrecognizable by its cognate ion channel. The large reduction in potency observed for MVIIA and MVIIC at both N-type and P/Q-type VSCCs is likely to stem from the change in conformation and orientation of loop 2.
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Affiliation(s)
- K J Nielsen
- Centre for Drug Design and Development, The University of Queensland, Brisbane
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37
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Gilquin B, Lecoq A, Desn� F, Guenneugues M, Zinn-Justin S, M�nez A. Conformational and functional variability supported by the BPTI fold: Solution structure of the Ca2+ channel blocker calcicludine. Proteins 1999. [DOI: 10.1002/(sici)1097-0134(19990301)34:4<520::aid-prot11>3.0.co;2-n] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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38
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Pallaghy PK, Norton RS. Refined solution structure of omega-conotoxin GVIA: implications for calcium channel binding. THE JOURNAL OF PEPTIDE RESEARCH : OFFICIAL JOURNAL OF THE AMERICAN PEPTIDE SOCIETY 1999; 53:343-51. [PMID: 10231724 DOI: 10.1034/j.1399-3011.1999.00040.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The polypeptide omega-conotoxin GVIA (GVIA) is an N-type calcium channel blocker from the venom of Conus geographus, a fish-hunting cone shell. Here we describe a high-resolution solution structure of this member of the 'inhibitor cystine knot' protein family. The structure, based on NMR data acquired at 600 MHz, has mean pairwise RMS differences of 0.25 +/- 0.06 and 1.07 +/- 0.14 A over the backbone heavy atoms and all heavy atoms, respectively. The solvent-accessible side chains are better defined than in previously published structures and provide an improved basis for docking GVIA with models of the calcium channel. Moreover, some side chain interactions important in GVIA folding in vitro and in stabilizing the native structure are defined clearly in the refined structure. Two qualitatively different backbone conformations in the segment from Thr11 to Asn14 persisted in the restrained simulated annealing calculations until a small number of lower bound constraints was included to prevent close contacts from occurring that did not correspond with peaks in the NOESY spectrum. It is possible that GVIA is genuinely flexible at this segment, spending a finite time in the alternative conformation, and this may influence its interaction with the calcium channel.
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Affiliation(s)
- P K Pallaghy
- Biomolecular Research Institute, Parkville, Vic., Australia
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39
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Norton RS, Pallaghy PK, Baell JB, Wright CE, Lew MJ, Angus JA. Polypeptide ?-conotoxin GVIA as a basis for new analgesic and neuroprotective agents. Drug Dev Res 1999. [DOI: 10.1002/(sici)1098-2299(199903/04)46:3/4<206::aid-ddr6>3.0.co;2-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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40
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Reily MD, Bokman AM, Offord J, McConnell P. Nuclear magnetic resonance spectroscopy of peptide ion channel ligands: cloning and expression as aid to evaluation of structural and dynamic properties. Methods Enzymol 1999; 294:92-117. [PMID: 9916224 DOI: 10.1016/s0076-6879(99)94008-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Affiliation(s)
- M D Reily
- Department of Chemistry, Parke-Davis Pharmaceutical Research, Division of Warner Lambert Company, Ann Arbor, Michigan 48105, USA
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41
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Bowersox SS, Luther R. Pharmacotherapeutic potential of omega-conotoxin MVIIA (SNX-111), an N-type neuronal calcium channel blocker found in the venom of Conus magus. Toxicon 1998; 36:1651-8. [PMID: 9792182 DOI: 10.1016/s0041-0101(98)00158-5] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Affiliation(s)
- S S Bowersox
- Department of Pharmacology, Neurex Corporation, Menlo Park, CA 94025, USA
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42
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Price-Carter M, Hull MS, Goldenberg DP. Roles of individual disulfide bonds in the stability and folding of an omega-conotoxin. Biochemistry 1998; 37:9851-61. [PMID: 9657699 DOI: 10.1021/bi9803978] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Although it contains only 25 amino acid residues, omega-conotoxin MVIIA folds into a well-defined three-dimensional structure that is stabilized by 3 disulfide bonds. To assess the contributions of the disulfides to folding and stability, three analogues, each with one pair of disulfide-bonded Cys residues replaced with Ala, were prepared and characterized. The analogues also contained a C-terminal Gly residue that is believed to be present when the peptide folds in vivo and has been shown previously to stabilize the native structure. Circular dichroism spectra and biological assays of the analogues indicated that removing any one of the disulfides greatly destabilized the native conformation. The two disulfides in each analogue were also reduced much more rapidly than in the native form with three disulfides. When the analogues were fully reduced and allowed to form disulfides in the presence of oxidized and reduced glutathione, the native disulfides were not formed in preference to non-native disulfides, further indicating that the forms with two-native disulfides are not significantly stabilized by noncovalent interactions. However, the measured equilibrium constants for disulfide formation indicate that forming any two of the three native disulfides leads to an effective concentration of approximately 25-50 M for the two remaining thiols. The two-disulfide analogues thus appear to represent a stage of folding in which the polypeptide is constrained to a distribution of relatively compact conformations that greatly favor formation of the third disulfide and the final folded structure.
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Affiliation(s)
- M Price-Carter
- Department of Biology, University of Utah, Salt Lake City 84112-0840, USA
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43
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Sato K, Raymond C, Martin-Moutot N, Sasaki T, Omori A, Ohtake A, Kim JI, Kohno T, Takahashi M, Seagar M. Binding of chimeric analogs of omega-conotoxin MVIIA and MVIIC to the N- and P/Q-type calcium channels. FEBS Lett 1997; 414:480-4. [PMID: 9315745 DOI: 10.1016/s0014-5793(97)01056-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Despite their high sequence homology, the peptide neurotoxins omega-conotoxin MVIIA and MVIIC selectively block N- and P/Q-type calcium channels, respectively. To study the recognition mechanism of calcium channel subtypes, two chimeric analogs of omega-conotoxin MVIIA and MVIIC were synthesized by exchanging their N- and C-terminal halves. Binding assay for both N- and P/Q-type calcium channels showed that amino acid residues restricted to the N-terminal half are important for the recognition of N-type channels, whereas essential residues for P/Q-type channel recognition are widely spread over the whole omega-conotoxin molecule.
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Affiliation(s)
- K Sato
- Mitsubishi Kasei Institute of Life Sciences, Tokyo, Japan.
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44
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Qu Y, Liang S, Ding J, Liu X, Zhang R, Gu X. Proton nuclear magnetic resonance studies on huwentoxin-I from the venom of the spider Selenocosmia huwena: 2. Three-dimensional structure in solution. JOURNAL OF PROTEIN CHEMISTRY 1997; 16:565-74. [PMID: 9263120 DOI: 10.1023/a:1026314722607] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The three-dimensional structure in aqueous solution of native huwentoxin-I, a neurotoxin from the venom of the spider Selenocosmia huwena, has been determined from two-dimensional H NMR data recorded at 500 and 600 MHz. Structural constraints consisting of interproton distances inferred from NOEs and dihedral angles from spin-spin coupling constants were used as input for distance geometry calculation with the program XPLOR 3.1. The best 10 structures have NOE violations < 0.3 A, dihedral violations < 2 degrees, and pairwise root-mean-square differences of 1.08 (+/- 0.20) A over backbone atoms (N, C alpha, C). The molecule adopts a compact structure consisting of a small triple-stranded antiparallel beta-sheet and five beta-turns. A small hydrophobic patch consisting of Phe 6, Trp 28, and Trp 31 is located on one side of the molecule. All six lysine residues are distributed on the molecular surface. The three disulfide bridges are buried within the molecule. The structure contains an "inhibitor cystine knot motif" which is adopted by several other small proteins, such as omega-conotoxin, agatoxin IVA, and gurmarin.
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Affiliation(s)
- Y Qu
- Department of Biology, Peking University, Beijing, China
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Abstract
The selective block of N-type Ca2+ channels by omega-conotoxins has been a hallmark of these channels, critical in delineating their biological roles and molecular characteristics. Here we report that the omega-conotoxin-channel interaction depends strongly on channel gating. N-type channels (alpha1B, alpha2, and beta1) expressed in Xenopus oocytes were blocked with a variety of omega-conotoxins, including omega-CTx-GVIA, omega-CTx-MVIIA, and SNX-331, a derivative of omega-CTx-MVIIC. Changes in holding potential (HP) markedly altered the severity of toxin block and the kinetics of its onset and removal. Notably, strong hyperpolarization renders omega-conotoxin block completely reversible. These effects could be accounted for by a modulated receptor model, in which toxin dissociation from the inactivated state is approximately 60-fold slower than from the resting state. Because omega-conotoxins act exclusively outside cells, our results suggest that voltage-dependent inactivation of Ca2+ channels must be associated with an externally detectable conformational change.
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Lew MJ, Flinn JP, Pallaghy PK, Murphy R, Whorlow SL, Wright CE, Norton RS, Angus JA. Structure-function relationships of omega-conotoxin GVIA. Synthesis, structure, calcium channel binding, and functional assay of alanine-substituted analogues. J Biol Chem 1997; 272:12014-23. [PMID: 9115267 DOI: 10.1074/jbc.272.18.12014] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The structure-function relationships of the N-type calcium channel blocker, omega-conotoxin GVIA (GVIA), have been elucidated by structural, binding and in vitro and in vivo functional studies of alanine-substituted analogues of the native molecule. Alanine was substituted at all non-bridging positions in the sequence. In most cases the structure of the analogues in aqueous solution was shown to be native-like by 1H NMR spectroscopy. Minor conformational changes observed in some cases were characterized by two-dimensional NMR. Replacement of Lys2 and Tyr13 with Ala caused reductions in potency of more than 2 orders of magnitude in three functional assays (sympathetic nerve stimulation of rat isolated vas deferens, right atrium and mesenteric artery) and a rat brain membrane binding assay. Replacement of several other residues with Ala (particularly Arg17, Tyr22 and Lys24) resulted in significant reductions in potency (<100-fold) in the functional assays, but not the binding assay. The potencies of the analogues were strongly correlated between the different functional assays but not between the functional assays and the binding assay. Thus, the physiologically relevant assays employed in this study have shown that the high affinity of GVIA for the N-type calcium channel is the result of interactions between the channel binding site and the toxin at more sites than the previously identified Lys2 and Tyr13.
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Affiliation(s)
- M J Lew
- Department of Pharmacology, University of Melbourne, Parkville 3052, Victoria, Australia.
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Kim JI, Ohtake A, Sato K. Circular dichroism spectra of calcium channel antagonist omega-conotoxins. Biochem Biophys Res Commun 1997; 230:133-5. [PMID: 9020029 DOI: 10.1006/bbrc.1996.5900] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The circular dichroism (CD) spectrum of omega-conotoxin GVIA is quite different from those of omega-conotoxin MVIIA and MVIIC, despite their distinct similarity in three dimensional structures. In order to characterize the unique CD spectrum of omega-conotoxin GVIA, we focused our attention on the aromatic chromophore and analyzed the CD spectra of three synthetic analogs, in which Tyr13, Tyr22, and Tyr27 were individually replaced by alanine. Replacement of Tyr27 caused a significant change in both the near- and far-ultraviolet CD spectrum of omega-conotoxin GVIA and resulted in the omega-conotoxin MVIIA/MVIIC-like pattern, suggesting that Tyr27 has a dominant contribution to the unique CD profile of omega-conotoxin GVIA.
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Affiliation(s)
- J I Kim
- Mitsubishi Kasei Institute of Life Sciences, Machida-shi, Tokyo, Japan
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Price-Carter M, Gray WR, Goldenberg DP. Folding of omega-conotoxins. 1. Efficient disulfide-coupled folding of mature sequences in vitro. Biochemistry 1996; 35:15537-46. [PMID: 8952508 DOI: 10.1021/bi961574c] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Disulfide-coupled refolding reactions of five omega-conotoxins, Ca2+ channel antagonists derived from marine snails of the genus Conus, were examined. These peptides are 23-26 amino acid residues long, and the native conformation of each is stabilized by three disulfide bonds. Although the primary structures of the peptides show only limited sequence similarity, the patterns of disulfides and three-dimensional conformations are very similar. Refolding of the reduced proteins was promoted by the disulfide form of glutathione (GSSG) in the presence of reduced glutathione (GSH). All five of the peptides examined were able to refold to the native conformation, as judged by reversed-phase HPLC behavior, with efficiencies of 16% for omega-MVIIC, 28% for omega-MVIID, and 50% for omega-MVIIA, omega-GVIA, and omega-SVIA. The refolded form of omega-MVIIA was further shown to have biological activity indistinguishable from that of the native form, as well as the same rate of reductive unfolding in the presence of dithiothreitol. The overall folding rate and efficiency of omega-MVIIA was found to be quite sensitive to the thiol-disulfide redox potential, with optimum rates and yields obtained in the presence of GSSG and GSH at concentrations similar to those believed to be present in the endoplasmic reticulum. The folding efficiency of this peptide was greatly reduced by the addition of 8 M urea, indicating that formation of the correct disulfides is determined largely by noncovalent interactions, as opposed to steric constraints arising from the spacing between Cys residues. These results demonstrate that the mature forms of at least some omega-conotoxins contain sufficient information to direct correct folding and disulfide formation, in spite of their small size and limited sequence conservation.
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Affiliation(s)
- M Price-Carter
- Department of Biology, University of Utah, Salt Lake City 84112, USA
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Price-Carter M, Gray WR, Goldenberg DP. Folding of omega-conotoxins. 2. Influence of precursor sequences and protein disulfide isomerase. Biochemistry 1996; 35:15547-57. [PMID: 8952509 DOI: 10.1021/bi9615755] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The peptide Ca2+ channel antagonists found in the venoms of Conus snails, omega-conotoxins, are synthesized as precursors that include a leader peptide, presumed to direct the polypeptide to the endoplasmic reticulum, and a propeptide of unknown function. In addition, the precursors are synthesized with a C-terminal Gly residue that is posttranslationally converted to a terminal amide group. In order to determine whether the precursor sequences contain information that helps direct folding of the mature sequences, the disulfide-coupled folding of mature omega-conotoxin MVIIA was compared with that of two putative precursor forms: pro-omega-MVIIA-Gly, which contains the propeptide and the C-terminal Gly residue, and omega-MVIIA-Gly, which differs from the mature form only at the C-terminus. The three forms folded with similar kinetics, but the folding efficiency of omega-MVIIA-Gly was greater than 80%, versus approximately 50% for both mature omega-MVIIA and the form containing the propeptide. The enzyme protein disulfide isomerase was found to catalyze disulfide formation and folding of all three forms similarly. The affinity of omega-MVIIA-Gly for receptors in chick brain synaptosomes was approximately 10-fold lower than that of the mature peptide, and the N-terminal propeptide of pro-omega-MVIIA-Gly was found to decrease binding further, by approximately 100-fold. These results suggest that the omega-conotoxins do not rely on the propeptide region of their precursors to facilitate folding. Rather, the mature sequence contains most of the information required to specify the native disulfide pairings and three-dimensional conformation. The C-terminal Gly may enhance the folding efficiency by forming interactions that stabilize the native conformation with respect to other disulfide-bonded forms.
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Affiliation(s)
- M Price-Carter
- Department of Biology, University of Utah, Salt Lake City 84112, USA
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Omecinsky DO, Holub KE, Adams ME, Reily MD. Three-dimensional structure analysis of mu-agatoxins: further evidence for common motifs among neurotoxins with diverse ion channel specificities. Biochemistry 1996; 35:2836-44. [PMID: 8608119 DOI: 10.1021/bi952605r] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We report the solution structure of mu-agatoxin-I (mu-Aga-I) and model structures of the closely related mu-agatoxin-IV (mu-Aga-IV) which were isolated from venom of the American funnel web spider, Agelenopsis aperta. These toxins, which modify the kinetics of neuronal voltage-activated sodium channels in insects, are C-terminally amidated peptides composed to 36 amino acids, including four internal disulfide bonds. The structure of mu-Aga-I was determined by NMR and distance geometry/molecular dynamics calculations. Structural calculations were carried out using 256 interresidue NOE-derived distance restraints and 25 angle restraints obtained from vicinal coupling constants. The peptide contains eight cysteines involved in disulfide bonds, the pairings of which were uncertain and had to be determined from preliminary structure calculations. The toxin has an average rmsd of 0.89 A for the backbone atoms among 38 converged conformers. The structure consists of a well-defined triple-stranded beta-sheet involving residues 7-9, 20-24, and 30-34 and four tight turns. A homologous peptide, mu-Aga-IV, exhibited two distinct and equally populated conformations in solution, which complicated spectral analysis. Analysis of sequential NOE's confirmed that the conformers arose from cis and trans peptide bonds involving a proline at position 15. Models were developed for both conformers based on the mu-Aga-I structure. Our structural data show that the mu-agatoxins, although specific modifiers of sodium channels, share common secondary and tertiary structural motifs with phylogenetically diverse peptide toxins targeting a variety of channel types. The mu-agatoxins add voltage-sensitive sodium channel activity to a growing list of neurotoxic effects elicited by peptide toxins which share the same global fold yet differ in their animal origin and ion channel selectivity.
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Affiliation(s)
- D O Omecinsky
- Department of Chemistry, Parke-Davis Pharmaceutical Research Division of Warner Lambert Company, Ann Arbor, Michigan 48105, USA
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