1
|
Pei S, Wang N, Mei Z, Zhangsun D, Craik DJ, McIntosh JM, Zhu X, Luo S. Conotoxins Targeting Voltage-Gated Sodium Ion Channels. Pharmacol Rev 2024; 76:828-845. [PMID: 38914468 PMCID: PMC11331937 DOI: 10.1124/pharmrev.123.000923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 06/17/2024] [Accepted: 06/18/2024] [Indexed: 06/26/2024] Open
Abstract
Voltage-gated sodium (NaV) channels are intimately involved in the generation and transmission of action potentials, and dysfunction of these channels may contribute to nervous system diseases, such as epilepsy, neuropathic pain, psychosis, autism, and cardiac arrhythmia. Many venom peptides selectively act on NaV channels. These include conotoxins, which are neurotoxins secreted by cone snails for prey capture or self-defense but which are also valuable pharmacological tools for the identification and/or treatment of human diseases. Typically, conotoxins contain two or three disulfide bonds, and these internal crossbraces contribute to conotoxins having compact, well defined structures and high stability. Of the conotoxins containing three disulfide bonds, some selectively target mammalian NaV channels and can block, stimulate, or modulate these channels. Such conotoxins have great potential to serve as pharmacological tools for studying the functions and characteristics of NaV channels or as drug leads for neurologic diseases related to NaV channels. Accordingly, discovering or designing conotoxins targeting NaV channels with high potency and selectivity is important. The amino acid sequences, disulfide bond connectivity, and three-dimensional structures are key factors that affect the biological activity of conotoxins, and targeted synthetic modifications of conotoxins can greatly improve their activity and selectivity. This review examines NaV channel-targeted conotoxins, focusing on their structures, activities, and designed modifications, with a view toward expanding their applications. SIGNIFICANCE STATEMENT: NaV channels are crucial in various neurologic diseases. Some conotoxins selectively target NaV channels, causing either blockade or activation, thus enabling their use as pharmacological tools for studying the channels' characteristics and functions. Conotoxins also have promising potential to be developed as drug leads. The disulfide bonds in these peptides are important for stabilizing their structures, thus leading to enhanced specificity and potency. Together, conotoxins targeting NaV channels have both immediate research value and promising future application prospects.
Collapse
Affiliation(s)
- Shengrong Pei
- Guangxi Key Laboratory of Special Biomedicine, School of Medicine, Guangxi University, Nanning, China (S.P., N.W., Z.M., D.Z., X.Z., S.L.); Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou, China (D.Z., S.L.); Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, Australia (D.J.C.); Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah (J.M.M.); and George E. Wahlen Veterans Affairs Medical Center, Salt Lake City, Utah (J.M.M.)
| | - Nan Wang
- Guangxi Key Laboratory of Special Biomedicine, School of Medicine, Guangxi University, Nanning, China (S.P., N.W., Z.M., D.Z., X.Z., S.L.); Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou, China (D.Z., S.L.); Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, Australia (D.J.C.); Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah (J.M.M.); and George E. Wahlen Veterans Affairs Medical Center, Salt Lake City, Utah (J.M.M.)
| | - Zaoli Mei
- Guangxi Key Laboratory of Special Biomedicine, School of Medicine, Guangxi University, Nanning, China (S.P., N.W., Z.M., D.Z., X.Z., S.L.); Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou, China (D.Z., S.L.); Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, Australia (D.J.C.); Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah (J.M.M.); and George E. Wahlen Veterans Affairs Medical Center, Salt Lake City, Utah (J.M.M.)
| | - Dongting Zhangsun
- Guangxi Key Laboratory of Special Biomedicine, School of Medicine, Guangxi University, Nanning, China (S.P., N.W., Z.M., D.Z., X.Z., S.L.); Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou, China (D.Z., S.L.); Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, Australia (D.J.C.); Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah (J.M.M.); and George E. Wahlen Veterans Affairs Medical Center, Salt Lake City, Utah (J.M.M.)
| | - David J Craik
- Guangxi Key Laboratory of Special Biomedicine, School of Medicine, Guangxi University, Nanning, China (S.P., N.W., Z.M., D.Z., X.Z., S.L.); Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou, China (D.Z., S.L.); Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, Australia (D.J.C.); Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah (J.M.M.); and George E. Wahlen Veterans Affairs Medical Center, Salt Lake City, Utah (J.M.M.)
| | - J Michael McIntosh
- Guangxi Key Laboratory of Special Biomedicine, School of Medicine, Guangxi University, Nanning, China (S.P., N.W., Z.M., D.Z., X.Z., S.L.); Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou, China (D.Z., S.L.); Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, Australia (D.J.C.); Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah (J.M.M.); and George E. Wahlen Veterans Affairs Medical Center, Salt Lake City, Utah (J.M.M.)
| | - Xiaopeng Zhu
- Guangxi Key Laboratory of Special Biomedicine, School of Medicine, Guangxi University, Nanning, China (S.P., N.W., Z.M., D.Z., X.Z., S.L.); Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou, China (D.Z., S.L.); Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, Australia (D.J.C.); Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah (J.M.M.); and George E. Wahlen Veterans Affairs Medical Center, Salt Lake City, Utah (J.M.M.)
| | - Sulan Luo
- Guangxi Key Laboratory of Special Biomedicine, School of Medicine, Guangxi University, Nanning, China (S.P., N.W., Z.M., D.Z., X.Z., S.L.); Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou, China (D.Z., S.L.); Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, Australia (D.J.C.); Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah (J.M.M.); and George E. Wahlen Veterans Affairs Medical Center, Salt Lake City, Utah (J.M.M.)
| |
Collapse
|
2
|
Li WJ, Chen JY, Zhu HX, Li YM, Xu Y. Synthesis of Asp-based lactam cyclic peptides using an amide-bonded diaminodiacid to prevent aspartimide formation. Org Biomol Chem 2024; 22:3584-3588. [PMID: 38623862 DOI: 10.1039/d4ob00472h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/17/2024]
Abstract
Asp-based lactam cyclic peptides are considered promising drug candidates. However, using Fmoc solid-phase peptide synthesis (Fmoc-SPPS) for these peptides also causes aspartimide formation, resulting in low yields or even failure to obtain the target peptides. Here, we developed a diaminodiacid containing an amide bond as a β-carboxyl-protecting group for Asp to avoid aspartimide formation. The practicality of this diaminodiacid has been illustrated by the synthesis of lactam cyclic peptide cyclo[Lys9,Asp13] KIIIA7-14 and 1Y.
Collapse
Affiliation(s)
- Wen-Jie Li
- School of Food and Biological Engineering, Engineering Research Center of Bio-process, Ministry of Education, Hefei University of Technology, Hefei 230009, China.
| | - Jun-You Chen
- School of Food and Biological Engineering, Engineering Research Center of Bio-process, Ministry of Education, Hefei University of Technology, Hefei 230009, China.
| | - Hui-Xia Zhu
- School of Food and Biological Engineering, Engineering Research Center of Bio-process, Ministry of Education, Hefei University of Technology, Hefei 230009, China.
| | - Yi-Ming Li
- School of Food and Biological Engineering, Engineering Research Center of Bio-process, Ministry of Education, Hefei University of Technology, Hefei 230009, China.
| | - Yang Xu
- School of Food and Biological Engineering, Engineering Research Center of Bio-process, Ministry of Education, Hefei University of Technology, Hefei 230009, China.
| |
Collapse
|
3
|
McMahon KL, Vetter I, Schroeder CI. Voltage-Gated Sodium Channel Inhibition by µ-Conotoxins. Toxins (Basel) 2024; 16:55. [PMID: 38251271 PMCID: PMC10819908 DOI: 10.3390/toxins16010055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 01/10/2024] [Accepted: 01/11/2024] [Indexed: 01/23/2024] Open
Abstract
µ-Conotoxins are small, potent pore-blocker inhibitors of voltage-gated sodium (NaV) channels, which have been identified as pharmacological probes and putative leads for analgesic development. A limiting factor in their therapeutic development has been their promiscuity for different NaV channel subtypes, which can lead to undesirable side-effects. This review will focus on four areas of µ-conotoxin research: (1) mapping the interactions of µ-conotoxins with different NaV channel subtypes, (2) µ-conotoxin structure-activity relationship studies, (3) observed species selectivity of µ-conotoxins and (4) the effects of µ-conotoxin disulfide connectivity on activity. Our aim is to provide a clear overview of the current status of µ-conotoxin research.
Collapse
Affiliation(s)
- Kirsten L. McMahon
- Institute for Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Irina Vetter
- Institute for Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
- The School of Pharmacy, The University of Queensland, Woolloongabba, QLD 4102, Australia
| | - Christina I. Schroeder
- Institute for Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
- Genentech, 1 DNA Way, South San Francisco, CA 94080, USA
| |
Collapse
|
4
|
McMahon KL, O'Brien H, Schroeder CI, Deuis JR, Venkatachalam D, Huang D, Green BR, Bandyopadhyay PK, Li Q, Yandell M, Safavi-Hemami H, Olivera BM, Vetter I, Robinson SD. Identification of sodium channel toxins from marine cone snails of the subgenera Textilia and Afonsoconus. Cell Mol Life Sci 2023; 80:287. [PMID: 37689602 PMCID: PMC10492761 DOI: 10.1007/s00018-023-04935-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Revised: 08/20/2023] [Accepted: 08/22/2023] [Indexed: 09/11/2023]
Abstract
Voltage-gated sodium (NaV) channels are transmembrane proteins that play a critical role in electrical signaling in the nervous system and other excitable tissues. µ-Conotoxins are peptide toxins from the venoms of marine cone snails (genus Conus) that block NaV channels with nanomolar potency. Most species of the subgenera Textilia and Afonsoconus are difficult to acquire; therefore, their venoms have yet to be comprehensively interrogated for µ-conotoxins. The goal of this study was to find new µ-conotoxins from species of the subgenera Textilia and Afonsoconus and investigate their selectivity at human NaV channels. Using RNA-seq of the venom gland of Conus (Textilia) bullatus, we identified 12 µ-conotoxin (or µ-conotoxin-like) sequences. Based on these sequences we designed primers which we used to identify additional µ-conotoxin sequences from DNA extracted from historical specimens of species from Textilia and Afonsoconus. We synthesized six of these µ-conotoxins and tested their activity on human NaV1.1-NaV1.8. Five of the six synthetic peptides were potent blockers of human NaV channels. Of these, two peptides (BuIIIB and BuIIIE) were potent blockers of hNaV1.3. Three of the peptides (BuIIIB, BuIIIE and AdIIIA) had submicromolar activity at hNaV1.7. This study serves as an example of the identification of new peptide toxins from historical DNA and provides new insights into structure-activity relationships of µ-conotoxins with activity at hNaV1.3 and hNaV1.7.
Collapse
Affiliation(s)
- Kirsten L McMahon
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Henrik O'Brien
- Biology Department, University of Utah, Salt Lake City, UT, 84112, USA
| | - Christina I Schroeder
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
- Peptide Therapeutics, Genentech, 1 DNA Way, South San Francisco, CA, 94080, USA
| | - Jennifer R Deuis
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | | | - Di Huang
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Brad R Green
- Biology Department, University of Utah, Salt Lake City, UT, 84112, USA
| | | | - Qing Li
- Department of Human Genetics, Utah Center for Genetic Discovery, University of Utah, Salt Lake City, UT, 84112, USA
- Cancer Bioinformatics, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, 84112, USA
| | - Mark Yandell
- Department of Human Genetics, Utah Center for Genetic Discovery, University of Utah, Salt Lake City, UT, 84112, USA
| | | | | | - Irina Vetter
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Samuel D Robinson
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, 4072, Australia.
- Biology Department, University of Utah, Salt Lake City, UT, 84112, USA.
| |
Collapse
|
5
|
Sanches K, Wai DCC, Norton RS. Conformational dynamics in peptide toxins: Implications for receptor interactions and molecular design. Toxicon 2021; 201:127-140. [PMID: 34454969 DOI: 10.1016/j.toxicon.2021.08.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 08/19/2021] [Accepted: 08/23/2021] [Indexed: 10/20/2022]
Abstract
Peptide toxins are potent and often exquisitely selective probes of the structure and function of ion channels and receptors, and are therefore of significant interest to the pharmaceutical and biotech industries as both pharmacological tools and therapeutic leads. The three-dimensional structures of peptide toxins are essential as a basis for understanding their structure-activity relationships and their binding to target receptors, as well as in guiding the design of analogues with modified potency and/or selectivity for key targets. NMR spectroscopy has played a key role in elucidating the structures of peptide toxins and probing their structure-function relationships. In this article, we highlight the additional important contribution of NMR to characterising the dynamics of peptide toxins. We also compare the information available from NMR measurements with that afforded by molecular dynamics simulations. We describe several examples of the importance of dynamics measurements over a range of timescales for understanding the structure-function relationships of peptide toxins and their receptor engagement. Peptide toxins that inhibit the voltage-gated potassium channel KV1.3 with pM affinities display different degrees of conformational flexibility, even though they contain multiple disulfide bonds, and this flexibility can affect the relative orientation of residues that have been shown to be critical for channel binding. Information on the dynamic properties of peptide toxins is important in the design of analogues or mimetics where receptor-bound structures are not available.
Collapse
Affiliation(s)
- Karoline Sanches
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia; ARC Centre for Fragment-Based Design, Monash University, Parkville, Victoria, 3052, Australia
| | - Dorothy C C Wai
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia
| | - Raymond S Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia; ARC Centre for Fragment-Based Design, Monash University, Parkville, Victoria, 3052, Australia.
| |
Collapse
|
6
|
McMahon KL, Tran HN, Deuis JR, Lewis RJ, Vetter I, Schroeder CI. Discovery, Pharmacological Characterisation and NMR Structure of the Novel µ-Conotoxin SxIIIC, a Potent and Irreversible Na V Channel Inhibitor. Biomedicines 2020; 8:biomedicines8100391. [PMID: 33023152 PMCID: PMC7599555 DOI: 10.3390/biomedicines8100391] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 09/25/2020] [Accepted: 09/29/2020] [Indexed: 12/19/2022] Open
Abstract
Voltage-gated sodium (NaV) channel subtypes, including NaV1.7, are promising targets for the treatment of neurological diseases, such as chronic pain. Cone snail-derived µ-conotoxins are small, potent NaV channel inhibitors which represent potential drug leads. Of the 22 µ-conotoxins characterised so far, only a small number, including KIIIA and CnIIIC, have shown inhibition against human NaV1.7. We have recently identified a novel µ-conotoxin, SxIIIC, from Conus striolatus. Here we present the isolation of native peptide, chemical synthesis, characterisation of human NaV channel activity by whole-cell patch-clamp electrophysiology and analysis of the NMR solution structure. SxIIIC displays a unique NaV channel selectivity profile (1.4 > 1.3 > 1.1 ≈ 1.6 ≈ 1.7 > 1.2 >> 1.5 ≈ 1.8) when compared to other µ-conotoxins and represents one of the most potent human NaV1.7 putative pore blockers (IC50 152.2 ± 21.8 nM) to date. NMR analysis reveals the structure of SxIIIC includes the characteristic α-helix seen in other µ-conotoxins. Future investigations into structure-activity relationships of SxIIIC are expected to provide insights into residues important for NaV channel pore blocker selectivity and subsequently important for chronic pain drug development.
Collapse
Affiliation(s)
- Kirsten L. McMahon
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia; (K.L.M.); (H.N.T.T.); (J.R.D.); (R.J.L.)
| | - Hue N.T. Tran
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia; (K.L.M.); (H.N.T.T.); (J.R.D.); (R.J.L.)
| | - Jennifer R. Deuis
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia; (K.L.M.); (H.N.T.T.); (J.R.D.); (R.J.L.)
| | - Richard J. Lewis
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia; (K.L.M.); (H.N.T.T.); (J.R.D.); (R.J.L.)
| | - Irina Vetter
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia; (K.L.M.); (H.N.T.T.); (J.R.D.); (R.J.L.)
- The School of Pharmacy, The University of Queensland, Woolloongabba, QLD 4102, Australia
- Correspondence: (I.V.); (C.I.S.)
| | - Christina I. Schroeder
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia; (K.L.M.); (H.N.T.T.); (J.R.D.); (R.J.L.)
- National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
- Correspondence: (I.V.); (C.I.S.)
| |
Collapse
|
7
|
Gallo A, Boni R, Tosti E. Neurobiological activity of conotoxins via sodium channel modulation. Toxicon 2020; 187:47-56. [PMID: 32877656 DOI: 10.1016/j.toxicon.2020.08.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 07/20/2020] [Accepted: 08/22/2020] [Indexed: 01/02/2023]
Abstract
Conotoxins (CnTX) are bioactive peptides produced by marine molluscs belonging to Conus genus. The biochemical structure of these venomous peptides is characterized by a low number of amino acids linked with disulfide bonds formed by a high degree of post-translational modifications and glycosylation steps which increase the diversity and rate of evolution of these molecules. CnTX different isoforms are known to target ion channels and, in particular, voltage-gated sodium (Na+) channels (Nav channels). These are transmembrane proteins fundamental in excitable cells for generating the depolarization of plasma membrane potential known as action potential which propagates electrical signals in muscles and nerves for physiological functions. Disorders in Nav channel activity have been shown to induce neurological pathologies and pain states. Here, we describe the current knowledge of CnTX isoform modulation of the Nav channel activity, the mechanism of action and the potential therapeutic use of these toxins in counteracting neurological dysfunctions.
Collapse
Affiliation(s)
- Alessandra Gallo
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy.
| | - Raffele Boni
- Department of Sciences, University of Basilicata, 85100, Potenza, Italy.
| | - Elisabetta Tosti
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy.
| |
Collapse
|
8
|
Kumar S, Venkatesha MA, Lall S, Prakash S, Balaram P. Mechanistic Insights into an Unusual Side-Chain-Mediated N-C α Bond Cleavage under Collision-Induced Dissociation Conditions in the Disulfide-Containing Peptide Conopressin. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2020; 31:1083-1092. [PMID: 32175740 DOI: 10.1021/jasms.0c00023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Conopressin, a nonapeptide disulfide CFIRNCPKG amide present in cone snail venom, undergoes a facile cleavage at the Cys6-Pro7 peptide bond to yield a disulfide bridged b6 ion. Analysis of the mass spectral fragmentation pattern reveals the presence of a major fragment ion, which is unambiguously assigned as the tripeptide sequence IRN amide. The sequence dependence of this unusual fragmentation process has been investigated by comparing it with the fragmentation patterns of related peptides, oxytocin (CYIQNCPLG amide), Lys-vasopressin (CYFQNCPKG amide), and a series of synthetic analogues. The results establish the role of the Arg4 residue in facilitating the unusual N-Cα bond cleavage at Cys6. Structures are proposed for a modified disulfide bridged fragment containing the Cys1 and Cys6 residues. Gas-phase molecular dynamics simulations provide evidence for the occurrence of conformational states that permit close approach of the Arg4 side chain to the Cys6 Cβ methylene protons.
Collapse
Affiliation(s)
- Sanjeev Kumar
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore 560065, India
| | - M Achanna Venkatesha
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore 560065, India
| | - Sahil Lall
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore 560065, India
| | - Sunita Prakash
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
| | - Padmanabhan Balaram
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore 560065, India
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
| |
Collapse
|
9
|
NMR Structure of μ-Conotoxin GIIIC: Leucine 18 Induces Local Repacking of the N-Terminus Resulting in Reduced Na V Channel Potency. Molecules 2018; 23:molecules23102715. [PMID: 30360356 PMCID: PMC6222493 DOI: 10.3390/molecules23102715] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 10/17/2018] [Accepted: 10/17/2018] [Indexed: 12/14/2022] Open
Abstract
μ-Conotoxins are potent and highly specific peptide blockers of voltage-gated sodium channels. In this study, the solution structure of μ-conotoxin GIIIC was determined using 2D NMR spectroscopy and simulated annealing calculations. Despite high sequence similarity, GIIIC adopts a three-dimensional structure that differs from the previously observed conformation of μ-conotoxins GIIIA and GIIIB due to the presence of a bulky, non-polar leucine residue at position 18. The side chain of L18 is oriented towards the core of the molecule and consequently the N-terminus is re-modeled and located closer to L18. The functional characterization of GIIIC defines it as a canonical μ-conotoxin that displays substantial selectivity towards skeletal muscle sodium channels (NaV), albeit with ~2.5-fold lower potency than GIIIA. GIIIC exhibited a lower potency of inhibition of NaV1.4 channels, but the same NaV selectivity profile when compared to GIIIA. These observations suggest that single amino acid differences that significantly affect the structure of the peptide do in fact alter its functional properties. Our work highlights the importance of structural factors, beyond the disulfide pattern and electrostatic interactions, in the understanding of the functional properties of bioactive peptides. The latter thus needs to be considered when designing analogues for further applications.
Collapse
|
10
|
Wu Y, Ma H, Zhang F, Zhang C, Zou X, Cao Z. Selective Voltage-Gated Sodium Channel Peptide Toxins from Animal Venom: Pharmacological Probes and Analgesic Drug Development. ACS Chem Neurosci 2018; 9:187-197. [PMID: 29161016 DOI: 10.1021/acschemneuro.7b00406] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Voltage-gated sodium channels (Navs) play critical roles in action potential generation and propagation. Nav channelopathy as well as pathological sensitization contribute to allodynia and hyperalgesia. Recent evidence has demonstrated the significant roles of Nav subtypes (Nav1.3, 1.7, 1.8, and 1.9) in nociceptive transduction, and therefore these Navs may represent attractive targets for analgesic drug discovery. Animal toxins are structurally diverse peptides that are highly potent yet selective on ion channel subtypes and therefore represent valuable probes to elucidate the structures, gating properties, and cellular functions of ion channels. In this review, we summarize recent advances on peptide toxins from animal venom that selectively target Nav1.3, 1.7, 1.8, and 1.9, along with their potential in analgesic drug discovery.
Collapse
Affiliation(s)
- Ying Wu
- Jiangsu Provincial Key Laboratory for TCM Evaluation
and Translational Development, China Pharmaceutical University, Nanjing 211198, China
| | - Hui Ma
- Jiangsu Provincial Key Laboratory for TCM Evaluation
and Translational Development, China Pharmaceutical University, Nanjing 211198, China
| | - Fan Zhang
- Jiangsu Provincial Key Laboratory for TCM Evaluation
and Translational Development, China Pharmaceutical University, Nanjing 211198, China
| | - Chunlei Zhang
- Jiangsu Provincial Key Laboratory for TCM Evaluation
and Translational Development, China Pharmaceutical University, Nanjing 211198, China
| | - Xiaohan Zou
- Jiangsu Provincial Key Laboratory for TCM Evaluation
and Translational Development, China Pharmaceutical University, Nanjing 211198, China
| | - Zhengyu Cao
- Jiangsu Provincial Key Laboratory for TCM Evaluation
and Translational Development, China Pharmaceutical University, Nanjing 211198, China
| |
Collapse
|
11
|
Tosti E, Boni R, Gallo A. µ-Conotoxins Modulating Sodium Currents in Pain Perception and Transmission: A Therapeutic Potential. Mar Drugs 2017; 15:E295. [PMID: 28937587 PMCID: PMC5666403 DOI: 10.3390/md15100295] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 09/12/2017] [Accepted: 09/20/2017] [Indexed: 12/27/2022] Open
Abstract
The Conus genus includes around 500 species of marine mollusks with a peculiar production of venomous peptides known as conotoxins (CTX). Each species is able to produce up to 200 different biological active peptides. Common structure of CTX is the low number of amino acids stabilized by disulfide bridges and post-translational modifications that give rise to different isoforms. µ and µO-CTX are two isoforms that specifically target voltage-gated sodium channels. These, by inducing the entrance of sodium ions in the cell, modulate the neuronal excitability by depolarizing plasma membrane and propagating the action potential. Hyperexcitability and mutations of sodium channels are responsible for perception and transmission of inflammatory and neuropathic pain states. In this review, we describe the current knowledge of µ-CTX interacting with the different sodium channels subtypes, the mechanism of action and their potential therapeutic use as analgesic compounds in the clinical management of pain conditions.
Collapse
Affiliation(s)
- Elisabetta Tosti
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy.
| | - Raffaele Boni
- Department of Sciences, University of Basilicata, 75100 Potenza, Italy.
| | - Alessandra Gallo
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy.
| |
Collapse
|
12
|
A novel μ-conotoxin from worm-hunting Conus tessulatus that selectively inhibit rat TTX-resistant sodium currents. Toxicon 2017; 130:11-18. [DOI: 10.1016/j.toxicon.2017.02.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 02/01/2017] [Accepted: 02/16/2017] [Indexed: 12/13/2022]
|
13
|
|
14
|
Han P, Wang K, Dai X, Cao Y, Liu S, Jiang H, Fan C, Wu W, Chen J. The Role of Individual Disulfide Bonds of μ-Conotoxin GIIIA in the Inhibition of Na V1.4. Mar Drugs 2016; 14:md14110213. [PMID: 27869701 PMCID: PMC5128756 DOI: 10.3390/md14110213] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 10/31/2016] [Accepted: 11/11/2016] [Indexed: 12/20/2022] Open
Abstract
μ-Conotoxin GIIIA, a peptide toxin isolated from Conus geographus, preferentially blocks the skeletal muscle sodium channel NaV1.4. GIIIA folds compactly to a pyramidal structure stabilized by three disulfide bonds. To assess the contributions of individual disulfide bonds of GIIIA to the blockade of NaV1.4, seven disulfide-deficient analogues were prepared and characterized, each with one, two, or three pairs of disulfide-bonded Cys residues replaced with Ala. The inhibitory potency of the analogues against NaV1.4 was assayed by whole cell patch-clamp on rNaV1.4, heterologously expressed in HEK293 cells. The corresponding IC50 values were 0.069 ± 0.005 μM for GIIIA, 2.1 ± 0.3 μM for GIIIA-1, 3.3 ± 0.2 μM for GIIIA-2, and 15.8 ± 0.8 μM for GIIIA-3 (-1, -2 and -3 represent the removal of disulfide bridges Cys3–Cys15, Cys4–Cys20 and Cys10–Cys21, respectively). Other analogues were not active enough for IC50 measurement. Our results indicate that all three disulfide bonds of GIIIA are required to produce effective inhibition of NaV1.4, and the removal of any one significantly lowers its sodium channel binding affinity. Cys10–Cys21 is the most important for the NaV1.4 potency.
Collapse
Affiliation(s)
- Penggang Han
- College of Science, National University of Defense Technology, Changsha 410073, Hunan, China.
- Beijing Institute of Pharmaceutical Chemistry, Beijing 102205, China.
| | - Kang Wang
- Beijing Institute of Pharmaceutical Chemistry, Beijing 102205, China.
| | - Xiandong Dai
- Beijing Institute of Pharmaceutical Chemistry, Beijing 102205, China.
| | - Ying Cao
- Beijing Institute of Pharmaceutical Chemistry, Beijing 102205, China.
| | - Shangyi Liu
- Beijing Institute of Pharmaceutical Chemistry, Beijing 102205, China.
| | - Hui Jiang
- Beijing Institute of Pharmaceutical Chemistry, Beijing 102205, China.
| | - Chongxu Fan
- Beijing Institute of Pharmaceutical Chemistry, Beijing 102205, China.
| | - Wenjian Wu
- College of Science, National University of Defense Technology, Changsha 410073, Hunan, China.
| | - Jisheng Chen
- College of Science, National University of Defense Technology, Changsha 410073, Hunan, China.
- Beijing Institute of Pharmaceutical Chemistry, Beijing 102205, China.
| |
Collapse
|
15
|
Munasinghe NR, Christie MJ. Conotoxins That Could Provide Analgesia through Voltage Gated Sodium Channel Inhibition. Toxins (Basel) 2015; 7:5386-407. [PMID: 26690478 PMCID: PMC4690140 DOI: 10.3390/toxins7124890] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 10/23/2015] [Accepted: 11/19/2015] [Indexed: 12/19/2022] Open
Abstract
Chronic pain creates a large socio-economic burden around the world. It is physically and mentally debilitating, and many sufferers are unresponsive to current therapeutics. Many drugs that provide pain relief have adverse side effects and addiction liabilities. Therefore, a great need has risen for alternative treatment strategies. One rich source of potential analgesic compounds that has emerged over the past few decades are conotoxins. These toxins are extremely diverse and display selective activity at ion channels. Voltage gated sodium (NaV) channels are one such group of ion channels that play a significant role in multiple pain pathways. This review will explore the literature around conotoxins that bind NaV channels and determine their analgesic potential.
Collapse
Affiliation(s)
- Nehan R Munasinghe
- Discipline of Pharmacology, The University of Sydney, Sydney, NSW 2006, Australia.
| | - MacDonald J Christie
- Discipline of Pharmacology, The University of Sydney, Sydney, NSW 2006, Australia.
| |
Collapse
|
16
|
Structure and function of μ-conotoxins, peptide-based sodium channel blockers with analgesic activity. Future Med Chem 2015; 6:1677-98. [PMID: 25406007 DOI: 10.4155/fmc.14.107] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
μ-Conotoxins block voltage-gated sodium channels (VGSCs) and compete with tetrodotoxin for binding to the sodium conductance pore. Early efforts identified µ-conotoxins that preferentially blocked the skeletal muscle subtype (NaV1.4). However, the last decade witnessed a significant increase in the number of µ-conotoxins and the range of VGSC subtypes inhibited (NaV1.2, NaV1.3 or NaV1.7). Twenty µ-conotoxin sequences have been identified to date and structure-activity relationship studies of several of these identified key residues responsible for interactions with VGSC subtypes. Efforts to engineer-in subtype specificity are driven by in vivo analgesic and neuromuscular blocking activities. This review summarizes structural and pharmacological studies of µ-conotoxins, which show promise for development of selective blockers of NaV1.2, and perhaps also NaV1.1,1.3 or 1.7.
Collapse
|
17
|
Zhang MM, Gajewiak J, Azam L, Bulaj G, Olivera BM, Yoshikami D. Probing the Redox States of Sodium Channel Cysteines at the Binding Site of μO§-Conotoxin GVIIJ. Biochemistry 2015; 54:3911-20. [DOI: 10.1021/acs.biochem.5b00390] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Min-Min Zhang
- Department
of Biology, University of Utah, Salt Lake City, Utah 84112, United States
| | - Joanna Gajewiak
- Department
of Biology, University of Utah, Salt Lake City, Utah 84112, United States
| | - Layla Azam
- Department
of Biology, University of Utah, Salt Lake City, Utah 84112, United States
| | - Grzegorz Bulaj
- Department
of Medicinal Chemistry, College of Pharmacy, University of Utah, Salt Lake
City, Utah 84108, United States
| | - Baldomero M. Olivera
- Department
of Biology, University of Utah, Salt Lake City, Utah 84112, United States
| | - Doju Yoshikami
- Department
of Biology, University of Utah, Salt Lake City, Utah 84112, United States
| |
Collapse
|
18
|
Systematic study of binding of μ-conotoxins to the sodium channel NaV1.4. Toxins (Basel) 2014; 6:3454-70. [PMID: 25529306 PMCID: PMC4280544 DOI: 10.3390/toxins6123454] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 12/01/2014] [Accepted: 12/10/2014] [Indexed: 01/25/2023] Open
Abstract
Voltage-gated sodium channels (NaV) are fundamental components of the nervous system. Their dysfunction is implicated in a number of neurological disorders, such as chronic pain, making them potential targets for the treatment of such disorders. The prominence of the NaV channels in the nervous system has been exploited by venomous animals for preying purposes, which have developed toxins that can block the NaV channels, thereby disabling their function. Because of their potency, such toxins could provide drug leads for the treatment of neurological disorders associated with NaV channels. However, most toxins lack selectivity for a given target NaV channel, and improving their selectivity profile among the NaV1 isoforms is essential for their development as drug leads. Computational methods will be very useful in the solution of such design problems, provided accurate models of the protein-ligand complex can be constructed. Using docking and molecular dynamics simulations, we have recently constructed a model for the NaV1.4-μ-conotoxin-GIIIA complex and validated it with the ample mutational data available for this complex. Here, we use the validated NaV1.4 model in a systematic study of binding other μ-conotoxins (PIIIA, KIIIA and BuIIIB) to NaV1.4. The binding mode obtained for each complex is shown to be consistent with the available mutation data and binding constants. We compare the binding modes of PIIIA, KIIIA and BuIIIB to that of GIIIA and point out the similarities and differences among them. The detailed information about NaV1.4-μ-conotoxin interactions provided here will be useful in the design of new NaV channel blocking peptides.
Collapse
|
19
|
Green BR, Zhang MM, Chhabra S, Robinson SD, Wilson MJ, Redding A, Olivera BM, Yoshikami D, Bulaj G, Norton RS. Interactions of disulfide-deficient selenocysteine analogs of μ-conotoxin BuIIIB with the α-subunit of the voltage-gated sodium channel subtype 1.3. FEBS J 2014; 281:2885-98. [PMID: 24814369 DOI: 10.1111/febs.12835] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 04/18/2014] [Accepted: 05/05/2014] [Indexed: 12/17/2022]
Abstract
Inhibitors of the α-subunit of the voltage-gated sodium channel subtype 1.3 (NaV 1.3) are of interest as pharmacological tools for the study of neuropathic pain associated with spinal cord injury and have potential therapeutic applications. The recently described μ-conotoxin BuIIIB (μ-BuIIIB) from Conus bullatus was shown to block NaV 1.3 with submicromolar potency (Kd = 0.2 μm), making it one of the most potent peptidic inhibitors of this subtype described to date. However, oxidative folding of μ-BuIIIB results in numerous folding isoforms, making it difficult to obtain sufficient quantities of the active form of the peptide for detailed structure-activity studies. In the present study, we report the synthesis and characterization of μ-BuIIIB analogs incorporating a disulfide-deficient, diselenide-containing scaffold designed to simplify synthesis and facilitate structure-activity studies directed at identifying amino acid residues involved in NaV 1.3 blockade. Our results indicate that, similar to other μ-conotoxins, the C-terminal residues (Trp16, Arg18 and His20) are most crucial for NaV 1 blockade. At the N-terminus, replacement of Glu3 by Ala resulted in an analog with an increased potency for NaV 1.3 (Kd = 0.07 μm), implicating this position as a potential site for modification for increased potency and/or selectivity. Further examination of this position showed that increased negative charge, through γ-carboxyglutamate replacement, decreased potency (Kd = 0.33 μm), whereas replacement with positively-charged 2,4-diamonobutyric acid increased potency (Kd = 0.036 μm). These results provide a foundation for the design and synthesis of μ-BuIIIB-based analogs with increased potency against NaV 1.3.
Collapse
Affiliation(s)
- Brad R Green
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Vic., Australia; Department of Medicinal Chemistry, College of Pharmacy, University of Utah, Salt Lake City, UT, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Abstract
Voltage-gated sodium (Nav) channels are essential contributors to neuronal excitability, making them the most commonly targeted ion channel family by toxins found in animal venoms. These molecules can be used to probe the functional aspects of Nav channels on a molecular level and to explore their physiological role in normal and diseased tissues. This chapter summarizes our existing knowledge of the mechanisms by which animal toxins influence Nav channels as well as their potential application in designing therapeutic drugs.
Collapse
|