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Szekér P, Bodó T, Klima K, Csóti Á, Hanh NN, Murányi J, Hajdara A, Szántó TG, Panyi G, Megyeri M, Péterfi Z, Farkas S, Gyöngyösi N, Hornyák P. KcsA-Kv1.x chimeras with complete ligand-binding sites provide improved predictivity for screening selective Kv1.x blockers. J Biol Chem 2024; 300:107155. [PMID: 38479597 PMCID: PMC11002876 DOI: 10.1016/j.jbc.2024.107155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 02/12/2024] [Accepted: 03/06/2024] [Indexed: 04/08/2024] Open
Abstract
Despite significant advances in the development of therapeutic interventions targeting autoimmune diseases and chronic inflammatory conditions, lack of effective treatment still poses a high unmet need. Modulating chronically activated T cells through the blockade of the Kv1.3 potassium channel is a promising therapeutic approach; however, developing selective Kv1.3 inhibitors is still an arduous task. Phage display-based high throughput peptide library screening is a rapid and robust approach to develop promising drug candidates; however, it requires solid-phase immobilization of target proteins with their binding site preserved. Historically, the KcsA bacterial channel chimera harboring only the turret region of the human Kv1.3 channel was used for screening campaigns. Nevertheless, literature data suggest that binding to this type of chimera does not correlate well with blocking potency on the native Kv1.3 channels. Therefore, we designed and successfully produced advanced KcsA-Kv1.3, KcsA-Kv1.1, and KcsA-Kv1.2 chimeric proteins in which both the turret and part of the filter regions of the human Kv1.x channels were transferred. These T+F (turret-filter) chimeras showed superior peptide ligand-binding predictivity compared to their T-only versions in novel phage ELISA assays. Phage ELISA binding and competition results supported with electrophysiological data confirmed that the filter region of KcsA-Kv1.x is essential for establishing adequate relative affinity order among selected peptide toxins (Vm24 toxin, Hongotoxin-1, Kaliotoxin-1, Maurotoxin, Stichodactyla toxin) and consequently obtaining more reliable selectivity data. These new findings provide a better screening tool for future drug development efforts and offer insight into the target-ligand interactions of these therapeutically relevant ion channels.
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Affiliation(s)
| | | | | | | | | | | | | | - Tibor Gábor Szántó
- Faculty of Medicine, Department of Biophysics and Cell Biology, University of Debrecen, Debrecen, Hungary
| | - György Panyi
- Faculty of Medicine, Department of Biophysics and Cell Biology, University of Debrecen, Debrecen, Hungary
| | | | | | | | - Norbert Gyöngyösi
- Department of Molecular Biology, Semmelweis University, Budapest, Hungary
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Kranzler M, Walser V, Stark TD, Ehling-Schulz M. A poisonous cocktail: interplay of cereulide toxin and its structural isomers in emetic Bacillus cereus. Front Cell Infect Microbiol 2024; 14:1337952. [PMID: 38596651 PMCID: PMC11002159 DOI: 10.3389/fcimb.2024.1337952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 03/11/2024] [Indexed: 04/11/2024] Open
Abstract
Food intoxications evoked by emetic Bacillus cereus strains constitute a serious threat to public health, leading to emesis and severe organ failure. The emetic peptide toxin cereulide, assembled by the non-ribosomal peptide synthetase CesNRPS, cannot be eradicated from contaminated food by usual hygienic measures due to its molecular size and structural stability. Next to cereulide, diverse chemical variants have been described recently that are produced concurrently with cereulide by CesNRPS. However, the contribution of these isocereulides to the actual toxicity of emetic B. cereus, which produces a cocktail of these toxins in a certain ratio, is still elusive. Since cereulide isoforms have already been detected in food remnants from foodborne outbreaks, we aimed to gain insights into the composition of isocereulides and their impact on the overall toxicity of emetic B. cereus. The amounts and ratios of cereulide and isocereulides were determined in B. cereus grown under standard laboratory conditions and in a contaminated sample of fried rice balls responsible for one of the most severe food outbreaks caused by emetic B. cereus in recent years. The ratios of variants were determined as robust, produced either under laboratory or natural, food-poisoning conditions. Examination of their actual toxicity in human epithelial HEp2-cells revealed that isocereulides A-N, although accounting for only 10% of the total cereulide toxins, were responsible for about 40% of the total cytotoxicity. An this despite the fact that some of the isocereulides were less cytotoxic than cereulide when tested individually for cytotoxicity. To estimate the additive, synergistic or antagonistic effects of the single variants, each cereulide variant was mixed with cereulide in a 1:9 and 1:1 binary blend, respectively, and tested on human cells. The results showed additive and synergistic impacts of single variants, highlighting the importance of including not only cereulide but also the isocereulides in routine food and clinical diagnostics to achieve a realistic toxicity evaluation of emetic B. cereus in contaminated food as well as in patient samples linked to foodborne outbreaks. Since the individual isoforms confer different cell toxicity both alone and in association with cereulide, further investigations are needed to fully understand their cocktail effect.
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Affiliation(s)
- Markus Kranzler
- Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine, Vienna, Austria
| | - Veronika Walser
- Food Chemistry and Molecular and Sensory Science, Technical University of Munich, Freising, Germany
| | - Timo D. Stark
- Food Chemistry and Molecular and Sensory Science, Technical University of Munich, Freising, Germany
| | - Monika Ehling-Schulz
- Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine, Vienna, Austria
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Beloborodov E, Iurova E, Sugak D, Rastorgueva E, Pogodina E, Fomin A, Viktorov D, Slesarev S, Saenko Y. Stabilizing Scaffold for Short Peptides Based on Knottins. Curr Cancer Drug Targets 2024; 24:CCDT-EPUB-138494. [PMID: 38357956 DOI: 10.2174/0115680096285288240118090050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 12/23/2023] [Accepted: 01/09/2024] [Indexed: 02/16/2024]
Abstract
BACKGROUND Bombesin (BBN) is a short peptide with a high affinity for receptors that are expressed on the surface of various types of cancer cells. However, a full length BBN molecule has low in vivo stability. OBJECTIVE In our study, we propose the use of peptide toxins, derived from animal and plant toxins, as scaffold molecules to enhance the bioavailability and stability of bombesin. These peptides possess a unique structure known as an inhibitory cystine knot. METHODS We synthesized structures in which short bombesin was incorporated into various domains of arthropod and plant toxins using solid-phase peptide synthesis. The stability under different conditions was assessed through high-performance liquid chromatography, and binding to cell cultures expressing the bombesin receptor was analyzed. Additionally, toxicity to cell cultures was evaluated using fluorescence microscopy. RESULTS The data obtained demonstrated that placing the short peptide between the first and second cysteine residues in arachnid toxins results in increased in vitro stability and bioavailability, as well as low cytotoxicity. CONCLUSION Arachnid toxins with an inhibitory cystine knot can be considered as a scaffold for increasing the stability of therapeutic peptides.
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Affiliation(s)
- Evgenii Beloborodov
- Laboratory of Research and Development of Peptide Drugs and Vaccines, S.P. Kapitsa Technological Research Institute, Ulyanovsk State University, Ulyanovsk, Russia
| | - Elena Iurova
- Laboratory of Research and Development of Peptide Drugs and Vaccines, S.P. Kapitsa Technological Research Institute, Ulyanovsk State University, Ulyanovsk, Russia
| | - Dmitrii Sugak
- Laboratory of Research and Development of Peptide Drugs and Vaccines, S.P. Kapitsa Technological Research Institute, Ulyanovsk State University, Ulyanovsk, Russia
| | - Eugenia Rastorgueva
- Laboratory of Research and Development of Peptide Drugs and Vaccines, S.P. Kapitsa Technological Research Institute, Ulyanovsk State University, Ulyanovsk, Russia
- Department of General and Clinical Pharmacology and Microbiology, Faculty of Medicine, Ulyanovsk State University, Ulyanovsk, Russia
| | - Evgeniya Pogodina
- Laboratory of Research and Development of Peptide Drugs and Vaccines, S.P. Kapitsa Technological Research Institute, Ulyanovsk State University, Ulyanovsk, Russia
| | - Aleksandr Fomin
- Laboratory of Research and Development of Peptide Drugs and Vaccines, S.P. Kapitsa Technological Research Institute, Ulyanovsk State University, Ulyanovsk, Russia
| | - Denis Viktorov
- Laboratory of Research and Development of Peptide Drugs and Vaccines, S.P. Kapitsa Technological Research Institute, Ulyanovsk State University, Ulyanovsk, Russia
| | - Sergei Slesarev
- Department of Biology, Ecology and Natural Resources Management, Faculty of Ecology, Ulyanovsk State University, Ulyanovsk, Russia
| | - Yury Saenko
- Laboratory of Research and Development of Peptide Drugs and Vaccines, S.P. Kapitsa Technological Research Institute, Ulyanovsk State University, Ulyanovsk, Russia
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Chandy KG, Sanches K, Norton RS. Structure of the voltage-gated potassium channel K V1.3: Insights into the inactivated conformation and binding to therapeutic leads. Channels (Austin) 2023; 17:2253104. [PMID: 37695839 PMCID: PMC10496531 DOI: 10.1080/19336950.2023.2253104] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 08/23/2023] [Accepted: 08/24/2023] [Indexed: 09/13/2023] Open
Abstract
The voltage-gated potassium channel KV1.3 is an important therapeutic target for the treatment of autoimmune and neuroinflammatory diseases. The recent structures of KV1.3, Shaker-IR (wild-type and inactivating W434F mutant) and an inactivating mutant of rat KV1.2-KV2.1 paddle chimera (KVChim-W362F+S367T+V377T) reveal that the transition of voltage-gated potassium channels from the open-conducting conformation into the non-conducting inactivated conformation involves the rupture of a key intra-subunit hydrogen bond that tethers the selectivity filter to the pore helix. Breakage of this bond allows the side chains of residues at the external end of the selectivity filter (Tyr447 and Asp449 in KV1.3) to rotate outwards, dilating the outer pore and disrupting ion permeation. Binding of the peptide dalazatide (ShK-186) and an antibody-ShK fusion to the external vestibule of KV1.3 narrows and stabilizes the selectivity filter in the open-conducting conformation, although K+ efflux is blocked by the peptide occluding the pore through the interaction of ShK-Lys22 with the backbone carbonyl of KV1.3-Tyr447 in the selectivity filter. Electrophysiological studies on ShK and the closely-related peptide HmK show that ShK blocks KV1.3 with significantly higher potency, even though molecular dynamics simulations show that ShK is more flexible than HmK. Binding of the anti-KV1.3 nanobody A0194009G09 to the turret and residues in the external loops of the voltage-sensing domain enhances the dilation of the outer selectivity filter in an exaggerated inactivated conformation. These studies lay the foundation to further define the mechanism of slow inactivation in KV channels and can help guide the development of future KV1.3-targeted immuno-therapeutics.
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Affiliation(s)
- K. George Chandy
- LKCMedicine-ICESing Ion Channel Platform, Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, Singapore, Singapore
| | - Karoline Sanches
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
- ARC Centre for Fragment-Based Design, Monash University, Parkville, Victoria, Australia
| | - Raymond S. Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
- ARC Centre for Fragment-Based Design, Monash University, Parkville, Victoria, Australia
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Walker AA, Perkins LE, Battisti A, Zalucki MP, King GF. Proteome of urticating setae of Ochrogaster lunifer, a processionary caterpillar of medical and veterinary importance, including primary structures of putative toxins. Proteomics 2023; 23:e2300204. [PMID: 37528493 DOI: 10.1002/pmic.202300204] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 06/09/2023] [Accepted: 06/14/2023] [Indexed: 08/03/2023]
Abstract
Ochrogaster lunifer (Lepidoptera: Notodontidae) is an Australian processionary caterpillar with detachable urticating setae that have a defensive function. These true setae induce inflammation when they contact human skin, and equine foetal loss syndrome if they are accidentally ingested by gravid horses. We used transcriptomics and proteomics to identify proteins and peptides present in and on urticating setae, which may include toxins that contribute to inflammation and/or foetal loss syndromes. This process identified 37 putative toxins, including multiple homologues of the honeybee venom peptide secapin, and proteins with similarity to odorant binding proteins, arylphorins, and the insect immune modulator Diedel. This work identifies candidate molecules that may contribute to the adverse effects of processionary caterpillar setae on human and animal health.
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Affiliation(s)
- Andrew A Walker
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland, Australia
- Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, St Lucia, Queensland, Australia
| | - Lynda E Perkins
- School of Biological Sciences, The University of Queensland, St Lucia, Queensland, Australia
| | - Andrea Battisti
- Department of Agronomy, Food, Natural Resources, Animals and the Environment, University of Padova, Padova, Italy
| | - Myron P Zalucki
- School of Biological Sciences, The University of Queensland, St Lucia, Queensland, Australia
| | - Glenn F King
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland, Australia
- Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, St Lucia, Queensland, Australia
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Iurova E, Rastorgueva E, Beloborodov E, Pogodina E, Fomin A, Sugak D, Viktorov D, Tumozov I, Saenko Y. Protective Effect of Peptide Calcium Channel Blocker Omega-Hexatoxin-Hv1a on Epithelial Cell during Ischemia-Reperfusion Injury. Pharmaceuticals (Basel) 2023; 16:1314. [PMID: 37765122 PMCID: PMC10538190 DOI: 10.3390/ph16091314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 08/25/2023] [Accepted: 09/01/2023] [Indexed: 09/29/2023] Open
Abstract
Ischemia-reperfusion injury (IRI) is a common phenomenon that develops both from natural causes and during major operations. Many intracellular processes mediated by calcium ions are involved in the development of IRI. Currently, chemical calcium channel blockers are used but they have a number of limitations. In this article, we study the effect of the omega-hexatoxin-Hv1a peptide toxin, an alternative to chemical calcium channel blockers, on the mechanisms of IRI development in epithelial cell culture. The toxin was produced using solid phase peptide synthesis. IRI was caused by deprivation of glucose, serum and oxygen. The data obtained demonstrate that the omega-hexatoxin-Hv1a toxin in nanomolar concentrations is able to prevent the development of apoptosis and necrosis in epithelial cells by reducing the concentration of calcium, sodium and potassium ions, as well as by delaying rapid normalization of the pH level, affecting the mitochondrial potential and oxidative stress. This toxin can be used as an alternative to chemical calcium channel blockers for preventing tissue and organ IRI due to its low-dose requirement and high bioavailability.
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Affiliation(s)
- Elena Iurova
- Laboratory of Research and Development of Peptide Drugs and Vaccines, S. P. Kapitsa Technological Research Institute, Ulyanovsk State University, 432017 Ulyanovsk, Russia; (E.I.); (E.R.); (E.B.); (E.P.); (A.F.); (D.S.); (D.V.); (I.T.)
| | - Eugenia Rastorgueva
- Laboratory of Research and Development of Peptide Drugs and Vaccines, S. P. Kapitsa Technological Research Institute, Ulyanovsk State University, 432017 Ulyanovsk, Russia; (E.I.); (E.R.); (E.B.); (E.P.); (A.F.); (D.S.); (D.V.); (I.T.)
- Department of General and Clinical Pharmacology and Microbiology, Faculty of Medicine, Ulyanovsk State University, 432017 Ulyanovsk, Russia
| | - Evgenii Beloborodov
- Laboratory of Research and Development of Peptide Drugs and Vaccines, S. P. Kapitsa Technological Research Institute, Ulyanovsk State University, 432017 Ulyanovsk, Russia; (E.I.); (E.R.); (E.B.); (E.P.); (A.F.); (D.S.); (D.V.); (I.T.)
| | - Evgeniya Pogodina
- Laboratory of Research and Development of Peptide Drugs and Vaccines, S. P. Kapitsa Technological Research Institute, Ulyanovsk State University, 432017 Ulyanovsk, Russia; (E.I.); (E.R.); (E.B.); (E.P.); (A.F.); (D.S.); (D.V.); (I.T.)
| | - Aleksandr Fomin
- Laboratory of Research and Development of Peptide Drugs and Vaccines, S. P. Kapitsa Technological Research Institute, Ulyanovsk State University, 432017 Ulyanovsk, Russia; (E.I.); (E.R.); (E.B.); (E.P.); (A.F.); (D.S.); (D.V.); (I.T.)
| | - Dmitrii Sugak
- Laboratory of Research and Development of Peptide Drugs and Vaccines, S. P. Kapitsa Technological Research Institute, Ulyanovsk State University, 432017 Ulyanovsk, Russia; (E.I.); (E.R.); (E.B.); (E.P.); (A.F.); (D.S.); (D.V.); (I.T.)
| | - Denis Viktorov
- Laboratory of Research and Development of Peptide Drugs and Vaccines, S. P. Kapitsa Technological Research Institute, Ulyanovsk State University, 432017 Ulyanovsk, Russia; (E.I.); (E.R.); (E.B.); (E.P.); (A.F.); (D.S.); (D.V.); (I.T.)
| | - Ivan Tumozov
- Laboratory of Research and Development of Peptide Drugs and Vaccines, S. P. Kapitsa Technological Research Institute, Ulyanovsk State University, 432017 Ulyanovsk, Russia; (E.I.); (E.R.); (E.B.); (E.P.); (A.F.); (D.S.); (D.V.); (I.T.)
| | - Yury Saenko
- Laboratory of Research and Development of Peptide Drugs and Vaccines, S. P. Kapitsa Technological Research Institute, Ulyanovsk State University, 432017 Ulyanovsk, Russia; (E.I.); (E.R.); (E.B.); (E.P.); (A.F.); (D.S.); (D.V.); (I.T.)
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Ngo K, Mateos DL, Han Y, Rouen KC, Ahn SH, Wulff H, Clancy CE, Yarov-Yarovoy V, Vorobyov I. Elucidating Molecular Mechanisms of Protoxin-2 State-specific Binding to the Human Na V1.7 Channel. bioRxiv 2023:2023.02.27.530360. [PMID: 36909474 PMCID: PMC10002706 DOI: 10.1101/2023.02.27.530360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
Abstract
Human voltage-gated sodium (hNaV) channels are responsible for initiating and propagating action potentials in excitable cells and mutations have been associated with numerous cardiac and neurological disorders. hNaV1.7 channels are expressed in peripheral neurons and are promising targets for pain therapy. The tarantula venom peptide protoxin-2 (PTx2) has high selectivity for hNaV1.7 and serves as a valuable scaffold to design novel therapeutics to treat pain. Here, we used computational modeling to study the molecular mechanisms of the state-dependent binding of PTx2 to hNaV1.7 voltage-sensing domains (VSDs). Using Rosetta structural modeling methods, we constructed atomistic models of the hNaV1.7 VSD II and IV in the activated and deactivated states with docked PTx2. We then performed microsecond-long all-atom molecular dynamics (MD) simulations of the systems in hydrated lipid bilayers. Our simulations revealed that PTx2 binds most favorably to the deactivated VSD II and activated VSD IV. These state-specific interactions are mediated primarily by PTx2's residues R22, K26, K27, K28, and W30 with VSD as well as the surrounding membrane lipids. Our work revealed important protein-protein and protein-lipid contacts that contribute to high-affinity state-dependent toxin interaction with the channel. The workflow presented will prove useful for designing novel peptides with improved selectivity and potency for more effective and safe treatment of pain.
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Affiliation(s)
- Khoa Ngo
- Biophysics Graduate Group, University of California, Davis
- Department of Physiology and Membrane Biology, University of California, Davis
| | - Diego Lopez Mateos
- Biophysics Graduate Group, University of California, Davis
- Department of Physiology and Membrane Biology, University of California, Davis
| | - Yanxiao Han
- Department of Physiology and Membrane Biology, University of California, Davis
| | - Kyle C. Rouen
- Biophysics Graduate Group, University of California, Davis
- Department of Physiology and Membrane Biology, University of California, Davis
| | - Surl-Hee Ahn
- Department of Chemical Engineering, University of California, Davis
| | - Heike Wulff
- Department of Pharmacology, University of California, Davis
| | - Colleen E. Clancy
- Department of Physiology and Membrane Biology, University of California, Davis
- Department of Pharmacology, University of California, Davis
- Center for Precision Medicine and Data Science, University of California, Davis
| | - Vladimir Yarov-Yarovoy
- Department of Physiology and Membrane Biology, University of California, Davis
- Department of Anesthesiology and Pain Medicine, University of California, Davis
| | - Igor Vorobyov
- Department of Physiology and Membrane Biology, University of California, Davis
- Department of Pharmacology, University of California, Davis
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Wu X, Chen Y, Liu H, Kong X, Liang X, Zhang Y, Tang C, Liu Z. The Molecular Composition of Peptide Toxins in the Venom of Spider Lycosa coelestis as Revealed by cDNA Library and Transcriptomic Sequencing. Toxins (Basel) 2023; 15. [PMID: 36828457 DOI: 10.3390/toxins15020143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Revised: 02/02/2023] [Accepted: 02/08/2023] [Indexed: 02/12/2023] Open
Abstract
In the so-called "struggle for existence" competition, the venomous animals developed a smart and effective strategy, envenomation, for predation and defense. Biochemical analysis revealed that animal venoms are chemical pools of proteinase, peptide toxins, and small organic molecules with various biological activities. Of them, peptide toxins are of great molecular diversity and possess the capacity to modulate the activity of ion channels, the second largest group of drug targets expressed on the cell membrane, which makes them a rich resource for developing peptide drug pioneers. The spider Lycosa coelestis (L. coelestis) commonly found in farmland in China is a dominant natural enemy of agricultural pests; however, its venom composition and activity were never explored. Herein, we conducted cDNA library and transcriptomic sequencing of the venom gland of L. coelestis, which identified 1131 high-quality expressed sequence tags (ESTs), grouped into three categories denoted as toxin-like ESTs (597, 52.79%), cellular component ESTs (357, 31.56%), and non-matched ESTs (177, 15.65%). These toxin-like ESTs encode 98 non-reductant toxins, which are artificially divided into 11 families based on their sequence homology and cysteine frameworks (2-14 cysteines forming 1-7 disulfide bonds to stabilize the toxin structure). Furthermore, RP-HPLC purification combined with off-line MALDI-TOF analysis have detected 147 different peptides physically existing in the venom of L. coelestis. Electrophysiology analysis confirmed that the venom preferably inhibits the voltage-gated calcium channels in rat dorsal root ganglion neurons. Altogether, the present study has added a great lot of new members to the spider toxin superfamily and built the foundation for characterizing novel active peptides in the L. coelestis venom.
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Mateos DL, Yarov-Yarovoy V. Structural modeling of peptide toxin-ion channel interactions using RosettaDock. Proteins 2023. [PMID: 36729043 DOI: 10.1002/prot.26474] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 12/09/2022] [Accepted: 01/30/2023] [Indexed: 02/03/2023]
Abstract
Voltage-gated ion channels play essential physiological roles in action potential generation and propagation. Peptidic toxins from animal venoms target ion channels and provide useful scaffolds for the rational design of novel channel modulators with enhanced potency and subtype selectivity. Despite recent progress in obtaining experimental structures of peptide toxin-ion channel complexes, structural determination of peptide toxins bound to ion channels in physiologically important states remains challenging. Here we describe an application of RosettaDock approach to the structural modeling of peptide toxins interactions with ion channels. We tested this approach on 10 structures of peptide toxin-ion channel complexes and demonstrated that it can sample near-native structures in all tested cases. Our approach will be useful for improving the understanding of the molecular mechanism of natural peptide toxin modulation of ion channel gating and for the structural modeling of novel peptide-based ion channel modulators.
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Affiliation(s)
- Diego Lopez Mateos
- Department of Physiology and Membrane Biology, University of California Davis, Davis, California, USA.,Biophysics Graduate Group, University of California Davis, Davis, California, USA
| | - Vladimir Yarov-Yarovoy
- Department of Physiology and Membrane Biology, University of California Davis, Davis, California, USA.,Biophysics Graduate Group, University of California Davis, Davis, California, USA.,Department of Anesthesiology and Pain Medicine, University of California Davis, Davis, California, USA
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Mogavero S, Höfs S, Lauer AN, Müller R, Brunke S, Allert S, Gerwien F, Groth S, Dolk E, Wilson D, Gutsmann T, Hube B. Candidalysin Is the Hemolytic Factor of Candida albicans. Toxins (Basel) 2022; 14. [PMID: 36548771 DOI: 10.3390/toxins14120874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 12/07/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
Candida albicans produces an important virulence factor, the hypha-associated Ece1-derived secreted peptide toxin candidalysin, which is crucial for the establishment of mucosal and systemic infections. C. albicans has also long been known to be hemolytic, yet the hemolytic factor has not been clearly identified. Here, we show that candidalysin is the hemolytic factor of C. albicans. Its hemolytic activity is modulated by fragments of another Ece1 peptide, P7. Hemolysis by candidalysin can be neutralized by the purinergic receptor antagonist pyridoxal-phosphate-6-azophenyl-2',4'-disulfonic acid (PPADS). PPADS also affects candidalysin's ability to intercalate into synthetic membranes. We also describe the neutralization potential of two anti-candidalysin nanobodies, which are promising candidates for future anti-Candida therapy. This work provides evidence that the historically proposed hemolytic factor of C. albicans is in fact candidalysin and sheds more light on the complex roles of this toxin in C. albicans biology and pathogenicity.
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Chu Y, Zhang H, Zhang L. Function Prediction of Peptide Toxins with Sequence-Based Multi-Tasking PU Learning Method. Toxins (Basel) 2022; 14. [PMID: 36422985 DOI: 10.3390/toxins14110811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 10/28/2022] [Accepted: 11/14/2022] [Indexed: 11/24/2022] Open
Abstract
Peptide toxins generally have extreme pharmacological activities and provide a rich source for the discovery of drug leads. However, determining the optimal activity of a new peptide can be a long and expensive process. In this study, peptide toxins were retrieved from Uniprot; three positive-unlabeled (PU) learning schemes, adaptive basis classifier, two-step method, and PU bagging were adopted to develop models for predicting the biological function of new peptide toxins. All three schemes were embedded with 14 machine learning classifiers. The prediction results of the adaptive base classifier and the two-step method were highly consistent. The models with top comprehensive performances were further optimized by feature selection and hyperparameter tuning, and the models were validated by making predictions for 61 three-finger toxins or the external HemoPI dataset. Biological functions that can be identified by these models include cardiotoxicity, vasoactivity, lipid binding, hemolysis, neurotoxicity, postsynaptic neurotoxicity, hypotension, and cytolysis, with relatively weak predictions for hemostasis and presynaptic neurotoxicity. These models are discovery-prediction tools for active peptide toxins and are expected to accelerate the development of peptide toxins as drugs.
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12
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Richardson JP, Brown R, Kichik N, Lee S, Priest E, Mogavero S, Maufrais C, Wickramasinghe DN, Tsavou A, Kotowicz NK, Hepworth OW, Gallego-Cortés A, Ponde NO, Ho J, Moyes DL, Wilson D, D'Enfert C, Hube B, Naglik JR. Candidalysins Are a New Family of Cytolytic Fungal Peptide Toxins. mBio 2022; 13:e0351021. [PMID: 35073742 DOI: 10.1128/mbio.03510-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Candidalysin is the first cytolytic peptide toxin identified in any human fungal pathogen. Candidalysin is secreted by Candida albicans and is critical for driving infection and host immune responses in several model systems. However, Candida infections are also caused by non-C. albicans species. Here, we identify and characterize orthologs of C. albicans candidalysin in C. dubliniensis and C. tropicalis. The candidalysins have different amino acid sequences, are amphipathic, and adopt a predominantly α-helical secondary structure in solution. Comparative functional analysis demonstrates that each candidalysin causes epithelial damage and calcium influx and activates intracellular signaling pathways and cytokine secretion. Importantly, C. dubliniensis and C. tropicalis candidalysins have higher damaging and activation potential than C. albicans candidalysin and exhibit more rapid membrane binding and disruption, although both fungal species cause less damage to epithelial cells than C. albicans. This study identifies the first family of peptide cytolysins in human-pathogenic fungi. IMPORTANCE Pathogenic fungi kill an estimated 1.5 million people every year. Recently, we discovered that the fungal pathogen Candida albicans secretes a peptide toxin called candidalysin during mucosal infection. Candidalysin causes damage to host cells, a process that supports disease progression. However, fungal infections are also caused by Candida species other than C. albicans. In this work, we identify and characterize two additional candidalysin toxins present in the related fungal pathogens C. dubliniensis and C. tropicalis. While the three candidalysins have different amino acid sequences, all three toxins are α-helical and amphipathic. Notably, the candidalysins from C. dubliniensis and C. tropicalis are more potent at inducing cell damage, calcium influx, mitogen-activated protein kinase signaling, and cytokine responses than C. albicans candidalysin, with the C. dubliniensis candidalysin having the most rapid membrane binding kinetics. These observations identify the candidalysins as the first family of peptide toxins in human-pathogenic fungi.
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13
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Nguyen PT, Yarov-Yarovoy V. Towards Structure-Guided Development of Pain Therapeutics Targeting Voltage-Gated Sodium Channels. Front Pharmacol 2022; 13:842032. [PMID: 35153801 PMCID: PMC8830516 DOI: 10.3389/fphar.2022.842032] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 01/12/2022] [Indexed: 12/19/2022] Open
Abstract
Voltage-gated sodium (NaV) channels are critical molecular determinants of action potential generation and propagation in excitable cells. Normal NaV channel function disruption can affect physiological neuronal signaling and lead to increased sensitivity to pain, congenital indifference to pain, uncoordinated movement, seizures, or paralysis. Human genetic studies have identified human NaV1.7 (hNaV1.7), hNaV1.8, and hNaV1.9 channel subtypes as crucial players in pain signaling. The premise that subtype selective NaV inhibitors can reduce pain has been reinforced through intensive target validation and therapeutic development efforts. However, an ideal therapeutic has yet to emerge. This review is focused on recent progress, current challenges, and future opportunities to develop NaV channel targeting small molecules and peptides as non-addictive therapeutics to treat pain.
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Affiliation(s)
- Phuong T Nguyen
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, United States
| | - Vladimir Yarov-Yarovoy
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, United States.,Department of Anesthesiology and Pain Medicine, University of California, Davis, Davis, CA, United States
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14
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Kasheverov IE, Kuzmenkov AI, Kudryavtsev DS, Chudetskiy IS, Shelukhina IV, Barykin EP, Ivanov IA, Siniavin AE, Ziganshin RH, Baranov MS, Tsetlin VI, Vassilevski AA, Utkin YN. Snake Toxins Labeled by Green Fluorescent Protein or Its Synthetic Chromophore are New Probes for Nicotinic acetylcholine Receptors. Front Mol Biosci 2021; 8:753283. [PMID: 34926576 PMCID: PMC8671107 DOI: 10.3389/fmolb.2021.753283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 11/10/2021] [Indexed: 11/25/2022] Open
Abstract
Fluorescence can be exploited to monitor intermolecular interactions in real time and at a resolution up to a single molecule. It is a method of choice to study ligand-receptor interactions. However, at least one of the interacting molecules should possess good fluorescence characteristics, which can be achieved by the introduction of a fluorescent label. Gene constructs with green fluorescent protein (GFP) are widely used to follow the expression of the respective fusion proteins and monitor their function. Recently, a small synthetic analogue of GFP chromophore (p-HOBDI-BF2) was successfully used for tagging DNA molecules, so we decided to test its applicability as a potential fluorescent label for proteins and peptides. This was done on α-cobratoxin (α-CbTx), a three-finger protein used as a molecular marker of muscle-type, neuronal α7 and α9/α10 nicotinic acetylcholine receptors (nAChRs), as well as on azemiopsin, a linear peptide neurotoxin selectively inhibiting muscle-type nAChRs. An activated N-hydroxysuccinimide ester of p-HOBDI-BF2 was prepared and utilized for toxin labeling. For comparison we used a recombinant α-CbTx fused with a full-length GFP prepared by expression of a chimeric gene. The structure of modified toxins was confirmed by mass spectrometry and their activity was characterized by competition with iodinated α-bungarotoxin in radioligand assay with respective receptor preparations, as well as by thermophoresis. With the tested protein and peptide neurotoxins, introduction of the synthetic GFP chromophore induced considerably lower decrease in their affinity for the receptors as compared with full-length GFP attachment. The obtained fluorescent derivatives were used for nAChR visualization in tissue slices and cell cultures.
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Affiliation(s)
- Igor E Kasheverov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Alexey I Kuzmenkov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Denis S Kudryavtsev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Ivan S Chudetskiy
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Irina V Shelukhina
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Evgeny P Barykin
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
| | - Igor A Ivanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Andrei E Siniavin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Rustam H Ziganshin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Mikhail S Baranov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Victor I Tsetlin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Alexander A Vassilevski
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia.,Moscow Institute of Physics and Technology, Moscow Region, Russia
| | - Yuri N Utkin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
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15
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Schroder RV, Cohen LS, Wang P, Arizala JD, Poget SF. Expression, Purification and Refolding of a Human Na V1.7 Voltage Sensing Domain with Native-like Toxin Binding Properties. Toxins (Basel) 2021; 13:toxins13100722. [PMID: 34679015 PMCID: PMC8541342 DOI: 10.3390/toxins13100722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 10/04/2021] [Accepted: 10/04/2021] [Indexed: 01/28/2023] Open
Abstract
The voltage-gated sodium channel NaV1.7 is an important target for drug development due to its role in pain perception. Recombinant expression of full-length channels and their use for biophysical characterization of interactions with potential drug candidates is challenging due to the protein size and complexity. To overcome this issue, we developed a protocol for the recombinant expression in E. coli and refolding into lipids of the isolated voltage sensing domain (VSD) of repeat II of NaV1.7, obtaining yields of about 2 mg of refolded VSD from 1 L bacterial cell culture. This VSD is known to be involved in the binding of a number of gating-modifier toxins, including the tarantula toxins ProTx-II and GpTx-I. Binding studies using microscale thermophoresis showed that recombinant refolded VSD binds both of these toxins with dissociation constants in the high nM range, and their relative binding affinities reflect the relative IC50 values of these toxins for full-channel inhibition. Additionally, we expressed mutant VSDs incorporating single amino acid substitutions that had previously been shown to affect the activity of ProTx-II on full channel. We found decreases in GpTx-I binding affinity for these mutants, consistent with a similar binding mechanism for GpTx-I as compared to that of ProTx-II. Therefore, this recombinant VSD captures many of the native interactions between NaV1.7 and tarantula gating-modifier toxins and represents a valuable tool for elucidating details of toxin binding and specificity that could help in the design of non-addictive pain medication acting through NaV1.7 inhibition.
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Affiliation(s)
- Ryan V. Schroder
- Department of Chemistry, College of Staten Island, University of New York, 2800 Victory Blvd., Staten Island, NY 10314, USA; (R.V.S.); (L.S.C.); (P.W.); (J.D.A.)
- The Ph.D. Program in Biochemistry, The Graduate Center of the City University of New York, 365 Fifth Avenue, New York, NY 10016, USA
| | - Leah S. Cohen
- Department of Chemistry, College of Staten Island, University of New York, 2800 Victory Blvd., Staten Island, NY 10314, USA; (R.V.S.); (L.S.C.); (P.W.); (J.D.A.)
| | - Ping Wang
- Department of Chemistry, College of Staten Island, University of New York, 2800 Victory Blvd., Staten Island, NY 10314, USA; (R.V.S.); (L.S.C.); (P.W.); (J.D.A.)
| | - Joekeem D. Arizala
- Department of Chemistry, College of Staten Island, University of New York, 2800 Victory Blvd., Staten Island, NY 10314, USA; (R.V.S.); (L.S.C.); (P.W.); (J.D.A.)
- The Ph.D. Program in Biochemistry, The Graduate Center of the City University of New York, 365 Fifth Avenue, New York, NY 10016, USA
| | - Sébastien F. Poget
- Department of Chemistry, College of Staten Island, University of New York, 2800 Victory Blvd., Staten Island, NY 10314, USA; (R.V.S.); (L.S.C.); (P.W.); (J.D.A.)
- The Ph.D. Program in Biochemistry, The Graduate Center of the City University of New York, 365 Fifth Avenue, New York, NY 10016, USA
- The Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, 365 Fifth Avenue, New York, NY 10016, USA
- Correspondence:
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16
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Naranjo D, Díaz-Franulic I. Binding of κ-Conotoxin-PVIIA to Open and Closed Shaker K-Channels Are Differentially Affected by the Ionic Strength. Mar Drugs 2020; 18:E533. [PMID: 33114777 PMCID: PMC7694074 DOI: 10.3390/md18110533] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 09/10/2020] [Accepted: 09/13/2020] [Indexed: 01/01/2023] Open
Abstract
κ-Conotoxin-PVIIA (κ-PVIIA) is a potassium-channel blocking peptide from the venom of the fish-hunting snail, Conus purpurascens, which is essential for quick prey's excitotoxic immobilization. Binding of one κ-PVIIA to Shaker K-channels occludes the K+-conduction pore without additional conformational effects. Because this 27-residue toxin is +4-charged at neutral pH, we asked if electrostatic interactions play a role in binding. With Voltage-Clamp electrophysiology, we tested how ionic strength (IS) affects κ-PVIIA blockade to Shaker. When IS varied from ~0.06 to ~0.16 M, the dissociation constant for open and closed channels increased by ~5- and ~16-fold, respectively. While the association rates decreased equally, by ~4-fold, in open and closed channels, the dissociation rates increased 4-5-fold in closed channels but was IS-insensitive in open channels. To explain this differential IS-dependency, we propose that the bound κ-PVIIA wobbles, so that in open channels the intracellular environment, via ion-conduction pore, buffers the imposed IS-changes in the toxin-channel interface. A Brønsted-Bjerrum analysis on the rates predicts that if, instead of fish, the snail preyed on organisms with seawater-like lymph ionic composition, a severely harmless toxin, with >100-fold diminished affinity, would result. Thus, considerations of the native ionic environment are essential for conotoxins evaluation as pharmacological leads.
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Affiliation(s)
- David Naranjo
- Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360103, Chile
| | - Ignacio Díaz-Franulic
- Center for Bioinformatics and Integrative Biology, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago 8370146, Chile;
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360103, Chile
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17
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Shah B, Sindhikara D, Borrelli K, Leffler AE. Water Thermodynamics of Peptide Toxin Binding Sites on Ion Channels. Toxins (Basel) 2020; 12:toxins12100652. [PMID: 33053750 PMCID: PMC7599640 DOI: 10.3390/toxins12100652] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 09/21/2020] [Accepted: 10/09/2020] [Indexed: 12/20/2022] Open
Abstract
Peptide toxins isolated from venomous creatures, long prized as research tools due to their innate potency for ion channels, are emerging as drugs as well. However, it remains challenging to understand why peptide toxins bind with high potency to ion channels, to identify residues that are key for activity, and to improve their affinities via mutagenesis. We use WaterMap, a molecular dynamics simulation-based method, to gain computational insight into these three questions by calculating the locations and thermodynamic properties of water molecules in the peptide toxin binding sites of five ion channels. These include an acid-sensing ion channel, voltage-gated potassium channel, sodium channel in activated and deactivated states, transient-receptor potential channel, and a nicotinic receptor whose structures were recently determined by crystallography and cryo-electron microscopy (cryo-EM). All channels had water sites in the peptide toxin binding site, and an average of 75% of these sites were stable (low-energy), and 25% were unstable (medium or high energy). For the sodium channel, more unstable water sites were present in the deactivated state structure than the activated. Additionally, for each channel, unstable water sites coincided with the positions of peptide toxin residues that previous mutagenesis experiments had shown were important for activity. Finally, for the sodium channel in the deactivated state, unstable water sites were present in the peptide toxin binding pocket but did not overlap with the peptide toxin, suggesting that future experimental efforts could focus on targeting these sites to optimize potency.
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Affiliation(s)
- Binita Shah
- Schrödinger, Inc. 120 W. 45th St, New York, NY 10036, USA; (B.S.); (D.S.); (K.B.)
- PhD Program in Biological and Biomedical Sciences, Division of Medical Sciences, Harvard Medical School, Boston, MA 02115, USA
| | - Dan Sindhikara
- Schrödinger, Inc. 120 W. 45th St, New York, NY 10036, USA; (B.S.); (D.S.); (K.B.)
| | - Ken Borrelli
- Schrödinger, Inc. 120 W. 45th St, New York, NY 10036, USA; (B.S.); (D.S.); (K.B.)
| | - Abba E. Leffler
- Schrödinger, Inc. 120 W. 45th St, New York, NY 10036, USA; (B.S.); (D.S.); (K.B.)
- Correspondence:
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18
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Ma H, Qiu P, Harvey PJ, Li X, Zhang Z, Xu Q, Liang J, Kaas Q, Craik DJ, Yang J, Jiang T, Bi X, Yu R. In Silico Design of MDM2-Targeting Peptides from a Naturally Occurring Constrained Peptide. ChemMedChem 2019; 14:1710-1716. [PMID: 31444979 DOI: 10.1002/cmdc.201900366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 08/20/2019] [Indexed: 01/10/2023]
Abstract
Naturally occurring constrained peptides are frequently used as scaffolds for bioactive peptide grating due to their high stability. Here, we used in silico methods to design several constrained peptides comprising a scorpion toxin scaffold, a MDM2 binding epitope, and a cluster of positively charged residues. The designed peptides displayed varied binding affinity to MDM2 despite differing by only one or two residues. One of the peptides, SC426, had nanomolar binding affinity (KD =6.6±2.6 nm) to MDM2, and exhibited stronger inhibitory activity on the proliferation of HCT116 cells (p53-wild type) and SW480 cells (p53-mutant) than that of nutlin-3a. Binding mode analysis of the designed peptide at MDM2 suggests that the conserved "FWL" epitope was buried in the hydrophobic binding pocket, and the residues located at the periphery of the binding site contributed to the high binding affinity of SC426. Overall, in silico design of miniproteins with therapeutic potential through epitope grafting to the naturally occurring constrained peptide is an effective strategy.
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Affiliation(s)
- He Ma
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao, 266003, China.,Laboratory for Marine Drugs and Bioproducts, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266003, China.,Innovation Center for Marine Drug Screening and Evaluation, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266003, China
| | - Peiju Qiu
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao, 266003, China.,Laboratory for Marine Drugs and Bioproducts, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266003, China.,Innovation Center for Marine Drug Screening and Evaluation, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266003, China
| | - Peta J Harvey
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Xiao Li
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao, 266003, China.,Laboratory for Marine Drugs and Bioproducts, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266003, China
| | - Zheyu Zhang
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao, 266003, China.,Laboratory for Marine Drugs and Bioproducts, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266003, China.,Innovation Center for Marine Drug Screening and Evaluation, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266003, China
| | - Qingliang Xu
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao, 266003, China.,Laboratory for Marine Drugs and Bioproducts, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266003, China
| | - Jiazhen Liang
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao, 266003, China.,Laboratory for Marine Drugs and Bioproducts, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266003, China
| | - Quentin Kaas
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - David J Craik
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Jinbo Yang
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao, 266003, China.,Laboratory for Marine Drugs and Bioproducts, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266003, China.,Innovation Center for Marine Drug Screening and Evaluation, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266003, China
| | - Tao Jiang
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao, 266003, China.,Laboratory for Marine Drugs and Bioproducts, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266003, China.,Innovation Center for Marine Drug Screening and Evaluation, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266003, China
| | - Xiaolin Bi
- Department of Nutrition, Affiliated Hospital of Qingdao University, Qingdao, 266003, China
| | - Rilei Yu
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao, 266003, China.,Laboratory for Marine Drugs and Bioproducts, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266003, China.,Innovation Center for Marine Drug Screening and Evaluation, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266003, China
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19
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Juichi H, Miyashita M, Nakagawa Y, Miyagawa H. Isolation and characterization of the insecticidal, two-domain toxin LaIT3 from the Liocheles australasiae scorpion venom. Biosci Biotechnol Biochem 2019; 83:2183-2189. [PMID: 31448688 DOI: 10.1080/09168451.2019.1654849] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
A novel insecticidal peptide (LaIT3) was isolated from the Liocheles australasiae venom. The primary structure of LaIT3 was determined by a combination of Edman degradation and MS/MS de novo sequencing analysis. Discrimination between Leu and Ile in MS/MS analysis was achieved based on the difference in side chain fragmentation assisted by chemical derivatization. LaIT3 was determined to be an 84-residue peptide with three intrachain disulfide bonds. The sequence similarity search revealed that LaIT3 belongs to the scorpine-like peptides consisting of two structural domains: an N-terminal α-helical domain and a C-terminal cystine-stabilized domain. As observed for most of the scorpine-like peptides, LaIT3 showed significant antibacterial activity against Escherichia coli, which is likely to be caused by its membrane-disrupting property.
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Affiliation(s)
- Hironori Juichi
- Graduate School of Agriculture, Kyoto University, Kyoto, Japan
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20
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Heep J, Klaus A, Kessel T, Seip M, Vilcinskas A, Skaljac M. Proteomic Analysis of the Venom from the Ruby Ant Myrmica rubra and the Isolation of a Novel Insecticidal Decapeptide. Insects 2019; 10:E42. [PMID: 30717163 DOI: 10.3390/insects10020042] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 01/21/2019] [Accepted: 01/24/2019] [Indexed: 11/24/2022]
Abstract
Ants are a biodiverse group of insects that have evolved toxic venom containing many undiscovered bioactive molecules. In this study, we found that the venom of the ruby ant Myrmica rubra is a rich source of peptides. LC-MS analysis revealed the presence of 142 different peptides varying in molecular weight, sequence length, and hydrophobicity. One of the most abundant peaks was selected for further biochemical and functional characterization. Combined Edman degradation and de novo peptide sequencing revealed the presence of a novel decapeptide (myrmicitoxin) with the amino acid sequence NH2-IDPKLLESLA-CONH2. The decapeptide was named U-MYRTX-MRArub1 and verified against a synthetic standard. The amidated peptide was tested in a synthetic form to determine the antimicrobial activity towards the bacterial pathogens and insecticidal potential against pea aphids (Acyrthosiphon pisum). This peptide did not show antimicrobial activity but it significantly reduced the survival of aphids. It also increased the sensitivity of the aphids to two commonly used chemical insecticides (imidacloprid and methomyl). Since ant venom research is still in its infancy, the findings of this first study on venom peptides derived from M. rubra highlight these insects as an important and rich source for discovery of novel lead structures with potential application in pest control.
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21
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Yun YB, Han JH, Kim YK. Characterization of Phage-Resistant Strains Derived from Pseudomonas tolaasii 6264, which Causes Brown Blotch Disease. J Microbiol Biotechnol 2018; 28:2064-2070. [PMID: 30301322 DOI: 10.4014/jmb.1809.09023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
Pseudomonas tolaasii 6264 is a representative strain that causes bacterial blotch disease on the cultivated oyster mushroom, Pleurotus ostreatus. Bacteriophages are able to sterilize the pathogenic P. tolaasii strains, and therefore, they can be applied in creating disease-free mushroom cultivation farms, through a method known as "phage therapy". For successful phage therapy, the characterization of phage-resistant strains is necessary, since they are frequently induced from the original pathogenic bacteria in the presence of phages. When 10 different phages were incubated with P. tolaasii 6264, their corresponding phage-resistant strains were obtained. In this study, changes in pathogenic, genetic, and biochemical characteristics as well as the acquired phage resistance of these strains were investigated. In the phylogenetic analyses, all phage-resistant strains were identical to the original parent strain based on the sequence comparison of 16S rRNA genes. When various phage-resistant strains were examined by three different methods, pitting test, white line test, and hemolytic activity, they were divided into three groups: strains showing all positive results in three tests, two positive in the first two tests, and all negative. Nevertheless, all phage-resistant strains showed that their pathogenic activities were reduced or completely lost.
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Affiliation(s)
- Yeong-Bae Yun
- Department of Environmental and Biological Chemistry, Chungbuk National University, Cheongju 28644, Republic of Korea
| | - Ji-Hye Han
- Department of Environmental and Biological Chemistry, Chungbuk National University, Cheongju 28644, Republic of Korea
| | - Young-Kee Kim
- Department of Environmental and Biological Chemistry, Chungbuk National University, Cheongju 28644, Republic of Korea
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22
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Peigneur S, Cheneval O, Maiti M, Leipold E, Heinemann SH, Lescrinier E, Herdewijn P, De Lima ME, Craik DJ, Schroeder CI, Tytgat J. Where cone snails and spiders meet: design of small cyclic sodium-channel inhibitors. FASEB J 2018; 33:3693-3703. [PMID: 30509130 DOI: 10.1096/fj.201801909r] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A 13 aa residue voltage-gated sodium (NaV) channel inhibitor peptide, Pn, containing 2 disulfide bridges was designed by using a chimeric approach. This approach was based on a common pharmacophore deduced from sequence and secondary structural homology of 2 NaV inhibitors: Conus kinoshitai toxin IIIA, a 14 residue cone snail peptide with 3 disulfide bonds, and Phoneutria nigriventer toxin 1, a 78 residue spider toxin with 7 disulfide bonds. As with the parent peptides, this novel NaV channel inhibitor was active on NaV1.2. Through the generation of 3 series of peptide mutants, we investigated the role of key residues and cyclization and their influence on NaV inhibition and subtype selectivity. Cyclic PnCS1, a 10 residue peptide cyclized via a disulfide bond, exhibited increased inhibitory activity toward therapeutically relevant NaV channel subtypes, including NaV1.7 and NaV1.9, while displaying remarkable serum stability. These peptides represent the first and the smallest cyclic peptide NaV modulators to date and are promising templates for the development of toxin-based therapeutic agents.-Peigneur, S., Cheneval, O., Maiti, M., Leipold, E., Heinemann, S. H., Lescrinier, E., Herdewijn, P., De Lima, M. E., Craik, D. J., Schroeder, C. I., Tytgat, J. Where cone snails and spiders meet: design of small cyclic sodium-channel inhibitors.
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Affiliation(s)
- Steve Peigneur
- Toxicology and Pharmacology, Katholieke Universiteit (KU) Leuven, Campus Gasthuisberg, Leuven, Belgium.,Department de Bioquímica e Imunologia, Laboratório de Venenos e Toxinas Animais, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo-Horizonte, Brazil
| | - Olivier Cheneval
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Mohitosh Maiti
- Laboratory of Medicinal Chemistry, Rega Institute for Medical Research, Katholieke Universiteit (KU) Leuven, Leuven, Belgium
| | - Enrico Leipold
- Department of Biophysics, Center for Molecular Biomedicine, Jena University Hospital, Friedrich Schiller University Jena, Germany
| | - Stefan H Heinemann
- Department of Biophysics, Center for Molecular Biomedicine, Jena University Hospital, Friedrich Schiller University Jena, Germany
| | - Eveline Lescrinier
- Laboratory of Medicinal Chemistry, Rega Institute for Medical Research, Katholieke Universiteit (KU) Leuven, Leuven, Belgium
| | - Piet Herdewijn
- Laboratory of Medicinal Chemistry, Rega Institute for Medical Research, Katholieke Universiteit (KU) Leuven, Leuven, Belgium
| | - Maria Elena De Lima
- Department de Bioquímica e Imunologia, Laboratório de Venenos e Toxinas Animais, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo-Horizonte, Brazil.,Programa de Pós-Graduação em Ciências da Saúde, Biomedicina e Medicina, Instituto de Ensino e Pesquisa da Santa Casa de Belo Horizonte, Grupo Santa Casa de Belo Horizonte, Belo Horizonte, Brazil
| | - David J Craik
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Christina I Schroeder
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Jan Tytgat
- Toxicology and Pharmacology, Katholieke Universiteit (KU) Leuven, Campus Gasthuisberg, Leuven, Belgium
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23
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Zhang Y, Peng D, Huang B, Yang Q, Zhang Q, Chen M, Rong M, Liu Z. Discovery of a Novel Na v1.7 Inhibitor From Cyriopagopus albostriatus Venom With Potent Analgesic Efficacy. Front Pharmacol 2018; 9:1158. [PMID: 30386239 PMCID: PMC6198068 DOI: 10.3389/fphar.2018.01158] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 09/24/2018] [Indexed: 01/15/2023] Open
Abstract
Spider venoms contain a vast array of bioactive peptides targeting ion channels. A large number of peptides have high potency and selectivity toward sodium channels. Nav1.7 contributes to action potential generation and propagation and participates in pain signaling pathway. In this study, we describe the identification of μ-TRTX-Ca2a (Ca2a), a novel 35-residue peptide from the venom of Vietnam spider Cyriopagopus albostriatus (C. albostriatus) that potently inhibits Nav1.7 (IC50 = 98.1 ± 3.3 nM) with high selectivity against skeletal muscle isoform Nav1.4 (IC50 > 10 μM) and cardiac muscle isoform Nav1.5 (IC50 > 10 μM). Ca2a did not significantly alter the voltage-dependent activation or fast inactivation of Nav1.7, but it hyperpolarized the slow inactivation. Site-directed mutagenesis analysis indicated that Ca2a bound with Nav1.7 at the extracellular S3–S4 linker of domain II. Meanwhile, Ca2a dose-dependently attenuated pain behaviors in rodent models of formalin-induced paw licking, hot plate test, and acetic acid-induced writhing. This study indicates that Ca2a is a potential lead molecule for drug development of novel analgesics.
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Affiliation(s)
- Yunxiao Zhang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Dezheng Peng
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Biao Huang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Qiuchu Yang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Qingfeng Zhang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Minzhi Chen
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Mingqiang Rong
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Zhonghua Liu
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
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24
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Zhang J, Tang D, Liu S, Hu H, Liang S, Tang C, Liu Z. Purification and Characterization of JZTx-14, a Potent Antagonist of Mammalian and Prokaryotic Voltage-Gated Sodium Channels. Toxins (Basel) 2018; 10:toxins10100408. [PMID: 30308978 PMCID: PMC6215091 DOI: 10.3390/toxins10100408] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 10/04/2018] [Accepted: 10/06/2018] [Indexed: 12/19/2022] Open
Abstract
Exploring the interaction of ligands with voltage-gated sodium channels (NaVs) has advanced our understanding of their pharmacology. Herein, we report the purification and characterization of a novel non-selective mammalian and bacterial NaVs toxin, JZTx-14, from the venom of the spider Chilobrachys jingzhao. This toxin potently inhibited the peak currents of mammalian NaV1.2–1.8 channels and the bacterial NaChBac channel with low IC50 values (<1 µM), and it mainly inhibited the fast inactivation of the NaV1.9 channel. Analysis of NaV1.5/NaV1.9 chimeric channel showed that the NaV1.5 domain II S3–4 loop is involved in toxin association. Kinetics data obtained from studying toxin–NaV1.2 channel interaction showed that JZTx-14 was a gating modifier that possibly trapped the channel in resting state; however, it differed from site 4 toxin HNTx-III by irreversibly blocking NaV currents and showing state-independent binding with the channel. JZTx-14 might stably bind to a conserved toxin pocket deep within the NaV1.2–1.8 domain II voltage sensor regardless of channel conformation change, and its effect on NaVs requires the toxin to trap the S3–4 loop in its resting state. For the NaChBac channel, JZTx-14 positively shifted its conductance-voltage (G–V) and steady-state inactivation relationships. An alanine scan analysis of the NaChBac S3–4 loop revealed that the 108th phenylalanine (F108) was the key residue determining the JZTx-14–NaChBac interaction. In summary, this study provided JZTx-14 with potent but promiscuous inhibitory activity on both the ancestor bacterial NaVs and the highly evolved descendant mammalian NaVs, and it is a useful probe to understand the pharmacology of NaVs.
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Affiliation(s)
- Jie Zhang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410081, China.
| | - Dongfang Tang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410081, China.
| | - Shuangyu Liu
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410081, China.
| | - Haoliang Hu
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410081, China.
| | - Songping Liang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410081, China.
| | - Cheng Tang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410081, China.
| | - Zhonghua Liu
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410081, China.
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25
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Zeng X, Li P, Chen B, Huang J, Lai R, Liu J, Rong M. Selective Closed-State Nav1.7 Blocker JZTX-34 Exhibits Analgesic Effects against Pain. Toxins (Basel) 2018; 10:toxins10020064. [PMID: 29393892 PMCID: PMC5848165 DOI: 10.3390/toxins10020064] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 01/26/2018] [Accepted: 01/31/2018] [Indexed: 12/11/2022] Open
Abstract
Jingzhaotoxin-34 (JZTX-34) is a selective inhibitor of tetrodotoxin-sensitive (TTX-S) sodium channels. In this study, we found that JZTX-34 selectively acted on Nav1.7 with little effect on other sodium channel subtypes including Nav1.5. If the DIIS3-S4 linker of Nav1.5 is substituted by the correspond linker of Nav1.7, the sensitivity of Nav1.5 to JZTX-34 extremely increases to 1.05 µM. Meanwhile, a mutant D816R in the DIIS3-S4 linker of Nav1.7 decreases binding affinity of Nav1.7 to JZTX-34 about 32-fold. The reverse mutant R800D at the corresponding position in Nav1.5 greatly increased its binding affinity to JZTX-34. This implies that JZTX-34 binds to DIIS3-S4 linker of Nav1.7 and the critical residue of Nav1.7 is D816. Unlike β-scorpion toxin trapping sodium channel in an open state, activity of JZTX-34 requires the sodium channel to be in a resting state. JZTX-34 exhibits an obvious analgesic effect in a rodent pain model. Especially, it shows a longer duration and is more effective than morphine in hot pain models. In a formalin-induced pain model, JZTX-34 at dose of 2 mg/kg is equipotent with morphine (5 mg/kg) in the first phase and several-fold more effective than morphine in second phase. Taken together, our data indicate that JZTX-34 releases pain by selectively binding to the domain II voltage sensor of Nav1.7 in a closed configuration.
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Affiliation(s)
- Xiongzhi Zeng
- The National & Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410081, Hunan, China.
- The Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha 410081, Hunan, China.
| | - Pengpeng Li
- Life Sciences College of Nanjing Agricultural University, 210095, Jiangsu, China.
| | - Bo Chen
- The National & Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410081, Hunan, China.
- The Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha 410081, Hunan, China.
| | - Juan Huang
- The National & Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410081, Hunan, China.
- The Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha 410081, Hunan, China.
| | - Ren Lai
- Life Sciences College of Nanjing Agricultural University, 210095, Jiangsu, China.
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming 650223, Yunnan, China.
| | - Jingze Liu
- Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Science, Hebei Normal University, Shijiazhuang 050024, Hebei, China.
| | - Mingqiang Rong
- The National & Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410081, Hunan, China.
- The Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha 410081, Hunan, China.
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26
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Tang C, Zhou X, Nguyen PT, Zhang Y, Hu Z, Zhang C, Yarov-Yarovoy V, DeCaen PG, Liang S, Liu Z. A novel tarantula toxin stabilizes the deactivated voltage sensor of bacterial sodium channel. FASEB J 2017; 31:3167-3178. [PMID: 28400471 DOI: 10.1096/fj.201600882r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 03/27/2017] [Indexed: 01/18/2023]
Abstract
Voltage-gated sodium channels (NaVs) are activated by transiting the voltage sensor from the deactivated to the activated state. The crystal structures of several bacterial NaVs have captured the voltage sensor module (VSM) in an activated state, but structure of the deactivated voltage sensor remains elusive. In this study, we sought to identify peptide toxins stabilizing the deactivated VSM of bacterial NaVs. We screened fractions from several venoms and characterized a cystine knot toxin called JZTx-27 from the venom of tarantula Chilobrachys jingzhao as a high-affinity antagonist of the prokaryotic NaVs NsVBa (nonselective voltage-gated Bacillus alcalophilus) and NaChBac (bacterial sodium channel from Bacillus halodurans) (IC50 = 112 nM and 30 nM, respectively). JZTx-27 was more efficacious at weaker depolarizing voltages and significantly slowed the activation but accelerated the deactivation of NsVBa, whereas the local anesthetic drug lidocaine was shown to antagonize NsVBa without affecting channel gating. Mutation analysis confirmed that JZTx-27 bound to S3-4 linker of NsVBa, with F98 being the critical residue in determining toxin affinity. All electrophysiological data and in silico analysis suggested that JZTx-27 trapped VSM of NsVBa in one of the deactivated states. In mammalian NaVs, JZTx-27 preferably inhibited the inactivation of NaV1.5 by targeting the fourth transmembrane domain. To our knowledge, this is the first report of peptide antagonist for prokaryotic NaVs. More important, we proposed that JZTx-27 stabilized the NsVBa VSM in the deactivated state and may be used as a probe to determine the structure of the deactivated VSM of NaVs.-Tang, C., Zhou, X., Nguyen, P. T., Zhang, Y., Hu, Z., Zhang, C., Yarov-Yarovoy, V., DeCaen, P. G., Liang, S., Liu, Z. A novel tarantula toxin stabilizes the deactivated voltage sensor of bacterial sodium channel.
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Affiliation(s)
- Cheng Tang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Xi Zhou
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Phuong Tran Nguyen
- Department of Physiology and Membrane Biology, University of California Davis, Davis, California, USA
| | - Yunxiao Zhang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Zhaotun Hu
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Changxin Zhang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Vladimir Yarov-Yarovoy
- Department of Physiology and Membrane Biology, University of California Davis, Davis, California, USA
| | - Paul G DeCaen
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Songping Liang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China;
| | - Zhonghua Liu
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China;
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27
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Thapa P, Cabalteja CC, Philips EE, Espiritu MJ, Peigneur S, Mille BG, Tytgat J, Cummins TR, Bingham JP. t-boc synthesis of huwentoxin-i through native chemical ligation incorporating a trifluoromethanesulfonic acid cleavage strategy. Biopolymers 2017; 106:737-45. [PMID: 27271997 DOI: 10.1002/bip.22887] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 05/24/2016] [Accepted: 05/31/2016] [Indexed: 11/10/2022]
Abstract
Tert-butyloxycarbonyl (t-Boc)-based native chemical ligation (NCL) techniques commonly employ hydrogen fluoride (HF) to create the thioester fragment required for the ligation process. Our research aimed to assess the replacement of HF with Trifluoromethanesulfonic acid (TFMSA). Here we examined a 33 amino acid test peptide, Huwentoxin-I (HwTx-I) as a novel candidate for our TFMSA cleavage protocol. Structurally HwTx-I has an X-Cys(16) -Cys(17) -X sequence mid-region, which makes it an ideal candidate for NCL. Experiments determined that the best yields (16.8%) obtained for 50 mg of a thioester support resin were achieved with a TFMSA volume of 100 μL with a 0.5-h incubation on ice, followed by 2.0 h at room temperature. RP-HPLC/UV and mass spectra indicated the appropriate parent mass and retention of the cleaved HwTx-I N-terminal thioester fragment (Ala(1) -Cys(16) ), which was used in preparation for NCL. The resulting chemically ligated HwTx-I was oxidized/folded, purified, and then assessed for pharmacological target selectivity. Native-like HwTx-I produced by this method yielded an EC50 value of 340.5 ± 26.8 nM for Nav 1.2 and an EC50 value of 504.1 ± 81.3 nM for Nav 1.3, this being similar to previous literature results using native material. This article represents the first NCL based synthesis of this potent sodium channel blocker. Our illustrated approach removes potential restrictions in the advancement of NCL as a common peptide laboratory technique with minimal investment, and removes the hazards associated with HF usage. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 737-745, 2016.
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Affiliation(s)
- Parashar Thapa
- Department of Molecular Biosciences and Bioengineering, College of Tropical Agriculture and Human Resources, University of Hawaii, Honolulu, HI, 96822
| | - Chino C Cabalteja
- Department of Molecular Biosciences and Bioengineering, College of Tropical Agriculture and Human Resources, University of Hawaii, Honolulu, HI, 96822
| | - Edwin E Philips
- Department of Molecular Biosciences and Bioengineering, College of Tropical Agriculture and Human Resources, University of Hawaii, Honolulu, HI, 96822
| | - Michael J Espiritu
- Department of Molecular Biosciences and Bioengineering, College of Tropical Agriculture and Human Resources, University of Hawaii, Honolulu, HI, 96822
| | - Steve Peigneur
- Department of Toxicology and Pharmacology, University of Leuven (KU Leuven), Campus Gasthuisberg O&N II, Leuven, 3000, Belgium
| | - Bea G Mille
- Department of Toxicology and Pharmacology, University of Leuven (KU Leuven), Campus Gasthuisberg O&N II, Leuven, 3000, Belgium
| | - Jan Tytgat
- Department of Toxicology and Pharmacology, University of Leuven (KU Leuven), Campus Gasthuisberg O&N II, Leuven, 3000, Belgium
| | - Theodore R Cummins
- Department of Pharmacology and Toxicology, Indiana University, Indianapolis, IN.,Department of Pharmacology and Toxicology, Stark Neurosciences Research Institute, 320 West 25th Street, NB-414F, Indianapolis, IN, 46202-2266
| | - Jon-Paul Bingham
- Department of Molecular Biosciences and Bioengineering, College of Tropical Agriculture and Human Resources, University of Hawaii, Honolulu, HI, 96822.
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28
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Huang C, Morlighem JÉR, Zhou H, Lima ÉP, Gomes PB, Cai J, Lou I, Pérez CD, Lee SM, Rádis-Baptista G. The Transcriptome of the Zoanthid Protopalythoa variabilis (Cnidaria, Anthozoa) Predicts a Basal Repertoire of Toxin-like and Venom-Auxiliary Polypeptides. Genome Biol Evol 2016; 8:3045-3064. [PMID: 27566758 PMCID: PMC5630949 DOI: 10.1093/gbe/evw204] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/20/2016] [Indexed: 12/12/2022] Open
Abstract
Protopalythoa is a zoanthid that, together with thousands of predominantly marine species, such as hydra, jellyfish, and sea anemones, composes the oldest eumetazoan phylum, i.e., the Cnidaria. Some of these species, such as sea wasps and sea anemones, are highly venomous organisms that can produce deadly toxins for preying, for defense or for territorial disputes. Despite the fact that hundreds of organic and polypeptide toxins have been characterized from sea anemones and jellyfish, practically nothing is known about the toxin repertoire in zoanthids. Here, based on a transcriptome analysis of the zoanthid Protopalythoa variabilis, numerous predicted polypeptides with canonical venom protein features are identified. These polypeptides comprise putative proteins from different toxin families: neurotoxic peptides, hemostatic and hemorrhagic toxins, membrane-active (pore-forming) proteins, protease inhibitors, mixed-function venom enzymes, and venom auxiliary proteins. The synthesis and functional analysis of two of these predicted toxin products, one related to the ShK/Aurelin family and the other to a recently discovered anthozoan toxin, displayed potent in vivo neurotoxicity that impaired swimming in larval zebrafish. Altogether, the complex array of venom-related transcripts that are identified in P. variabilis, some of which are first reported in Cnidaria, provides novel insight into the toxin distribution among species and might contribute to the understanding of composition and evolution of venom polypeptides in toxiferous animals.
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Affiliation(s)
- Chen Huang
- State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Macau, China
| | - Jean-Étienne Rl Morlighem
- Northeast Biotechnology Network (RENORBIO), Post-graduation program in Biotechnology, Federal University of Ceará, Fortaleza, Brazil Laboratory of Biochemistry and Biotechnology, Institute for Marine Sciences, Federal University of Ceará, Fortaleza, Brazil
| | - Hefeng Zhou
- State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Macau, China
| | - Érica P Lima
- Centro Acadêmico de Vitoria, Universidade Federal de Pernambuco, Vitória de Santo Antão, Brazil
| | - Paula B Gomes
- Departamento de Biologia, Universidade Federal Rural de Pernambuco, Recife, Brazil
| | - Jing Cai
- Faculty of Science and Technology, Department of Civil and Environmental Engineering, University of Macau, Macau, China
| | - Inchio Lou
- Faculty of Science and Technology, Department of Civil and Environmental Engineering, University of Macau, Macau, China
| | - Carlos D Pérez
- Centro Acadêmico de Vitoria, Universidade Federal de Pernambuco, Vitória de Santo Antão, Brazil
| | - Simon Ming Lee
- State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Macau, China
| | - Gandhi Rádis-Baptista
- Laboratory of Biochemistry and Biotechnology, Institute for Marine Sciences, Federal University of Ceará, Fortaleza, Brazil
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29
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Abstract
Solitary wasps paralyze insects or spiders with stinging venom and feed the paralyzed preys to their larva. Accordingly, the venoms should contain a variety of constituents acting on nervous systems. However, only a few solitary wasp venoms have been chemically studied despite thousands of species inhabiting the planet. We have surveyed bioactive substances in solitary wasp venoms found in Japan and discovered a variety of novel bioactive peptides. Pompilidotoxins (PMTXs), in the venoms of the pompilid wasps Anoplius samariensis and Batozonellus maculifrons, are small peptides consisting of 13 amino acids without a disulfide bond. PMTXs slowed Na⁺ channel inactivation, in particular against neuronal type Na⁺ channels, and were rather selective to the Nav1.6 channel. Mastoparan-like cytolytic and antimicrobial peptides are the major components of eumenine wasp venoms. They are rich in hydrophobic and basic amino acids, adopting a α-helical secondary structure, and showing mast cell degranulating, antimicrobial and hemolytic activities. The venom of the spider wasp Cyphononyx fulvognathus contained four bradykinin-related peptides. They are hyperalgesic and, dependent on the structure, differently associated with B₁ or B₂ receptors. Further survey led to the isolation of leucomyosuppressin-like FMRFamide peptides from the venoms of the digger wasps Sphex argentatus and Isodontia harmandi. These results of peptide toxins in solitary wasp venoms from our studies are summarized.
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Hakim MA, Jiang W, Luo L, Li B, Yang S, Song Y, Lai R. Scorpion Toxin, BmP01, Induces Pain by Targeting TRPV1 Channel. Toxins (Basel) 2015; 7:3671-87. [PMID: 26389953 DOI: 10.3390/toxins7093671] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 09/01/2015] [Accepted: 09/07/2015] [Indexed: 01/17/2023] Open
Abstract
The intense pain induced by scorpion sting is a frequent clinical manifestation. To date, there is no established protocol with significant efficacy to alleviate the pain induced by scorpion envenomation. One of the important reasons is that, little information on pain-inducing compound from scorpion venoms is available. Here, a pain-inducing peptide (BmP01) has been identified and characterized from the venoms of scorpion (Mesobuthus martensii). In an animal model, intraplantar injection of BmP01 in mouse hind paw showed significant acute pain in wild type (WT) mice but not in TRPV1 knock-out (TRPV1 KO) mice during 30 min recording. BmP01 evoked currents in WT dorsal root ganglion (DRG) neurons but had no effect on DRG neurons of TRPV1 KO mice. Furthermore, OPEN ACCESS Toxins 2015, 7 3672 BmP01 evoked currents on TRPV1-expressed HEK293T cells, but not on HEK293T cells without TRPV1. These results suggest that (1) BmP01 is one of the pain-inducing agents in scorpion venoms; and (2) BmP01 induces pain by acting on TRPV1. To our knowledge, this is the first report about a scorpion toxin that produces pain by targeting TRPV1. Identification of a pain-inducing compound may facilitate treating pain induced by scorpion envenomation.
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Sachkova MY, Slavokhotova AA, Grishin EV, Vassilevski AA. Structure of the yellow sac spider Cheiracanthium punctorium genes provides clues to evolution of insecticidal two-domain knottin toxins. Insect Mol Biol 2014; 23:527-538. [PMID: 24717175 DOI: 10.1111/imb.12097] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Yellow sac spiders (Cheiracanthium punctorium, family Miturgidae) are unique in terms of venom composition, because, as we show here, two-domain toxins have replaced the usual one-domain peptides as the major constituents. We report the structure of the two-domain Che. punctorium toxins (CpTx), along with the corresponding cDNA and genomic DNA sequences. At least three groups of insecticidal CpTx were identified, each consisting of several members. Unlike many cone snail and snake toxins, accelerated evolution is not typical of cptx genes, which instead appear to be under the pressure of purifying selection. Both CpTx modules present the inhibitor cystine knot (ICK), or knottin signature; however, the sequence similarity between the domains is low. Conversely, notable similarity was found between separate domains of CpTx and one-domain toxins from spiders of the Lycosidae family. The observed chimerism is a landmark of exon shuffling events, but in contrast to many families of multidomain protein genes no introns were found in the cptx genes. Considering the possible scenarios, we suggest that an early transcription-mediated fusion event between two related one-domain toxin genes led to the emergence of a primordial cptx-like sequence. We conclude that evolution of toxin variability in spiders appears to be quite different from other venomous animals.
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Affiliation(s)
- M Y Sachkova
- M.M. Shemyakin and Yu.A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russian Federation
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Blanchard MG, Rash LD, Kellenberger S. Inhibition of voltage-gated Na(+) currents in sensory neurones by the sea anemone toxin APETx2. Br J Pharmacol 2012; 165:2167-77. [PMID: 21943094 PMCID: PMC3413854 DOI: 10.1111/j.1476-5381.2011.01674.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Revised: 09/07/2011] [Accepted: 09/08/2011] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND AND PURPOSE APETx2, a toxin from the sea anemone Anthropleura elegantissima, inhibits acid-sensing ion channel 3 (ASIC3)-containing homo- and heterotrimeric channels with IC(50) values < 100 nM and 0.1-2 µM respectively. ASIC3 channels mediate acute acid-induced and inflammatory pain response and APETx2 has been used as a selective pharmacological tool in animal studies. Toxins from sea anemones also modulate voltage-gated Na(+) channel (Na(v) ) function. Here we tested the effects of APETx2 on Na(v) function in sensory neurones. EXPERIMENTAL APPROACH Effects of APETx2 on Na(v) function were studied in rat dorsal root ganglion (DRG) neurones by whole-cell patch clamp. KEY RESULTS APETx2 inhibited the tetrodotoxin (TTX)-resistant Na(v) 1.8 currents of DRG neurones (IC(50) , 2.6 µM). TTX-sensitive currents were less inhibited. The inhibition of Na(v) 1.8 currents was due to a rightward shift in the voltage dependence of activation and a reduction of the maximal macroscopic conductance. The inhibition of Na(v) 1.8 currents by APETx2 was confirmed with cloned channels expressed in Xenopus oocytes. In current-clamp experiments in DRG neurones, the number of action potentials induced by injection of a current ramp was reduced by APETx2. CONCLUSIONS AND IMPLICATIONS APETx2 inhibited Na(v) 1.8 channels, in addition to ASIC3 channels, at concentrations used in in vivo studies. The limited specificity of this toxin should be taken into account when using APETx2 as a pharmacological tool. Its dual action will be an advantage for the use of APETx2 or its derivatives as analgesic drugs.
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Affiliation(s)
- Maxime G Blanchard
- Département de Pharmacologie et Toxicologie, Université de LausanneLausanne, Switzerland
| | - Lachlan D Rash
- Institute for Molecular Bioscience, The University of QueenslandSt Lucia, Queensland, Australia
| | - Stephan Kellenberger
- Département de Pharmacologie et Toxicologie, Université de LausanneLausanne, Switzerland
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Takacs Z, Toups M, Kollewe A, Johnson E, Cuello LG, Driessens G, Biancalana M, Koide A, Ponte CG, Perozo E, Gajewski TF, Suarez-Kurtz G, Koide S, Goldstein SAN. A designer ligand specific for Kv1.3 channels from a scorpion neurotoxin-based library. Proc Natl Acad Sci U S A 2009; 106:22211-6. [PMID: 20007782 PMCID: PMC2799710 DOI: 10.1073/pnas.0910123106] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Indexed: 02/03/2023] Open
Abstract
Venomous animals immobilize prey using protein toxins that act on ion channels and other targets of biological importance. Broad use of toxins for biomedical research, diagnosis, and therapy has been limited by inadequate target discrimination, for example, among ion channel subtypes. Here, a synthetic toxin is produced by a new strategy to be specific for human Kv1.3 channels, critical regulators of immune T cells. A phage display library of 11,200 de novo proteins is designed using the alpha-KTx scaffold of 31 scorpion toxin sequences known or predicted to bind to potassium channels. Mokatoxin-1 (moka1) is isolated by affinity selection on purified target. Moka1 blocks Kv1.3 at nanomolar levels that do not inhibit Kv1.1, Kv1.2, or KCa1.1. As a result, moka1 suppresses CD3/28-induced cytokine secretion by T cells without cross-reactive gastrointestinal hyperactivity. The 3D structure of moka1 rationalizes its specificity and validates the engineering approach, revealing a unique interaction surface supported on an alpha-KTx scaffold. This scaffold-based/target-biased strategy overcomes many obstacles to production of selective toxins.
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Affiliation(s)
- Zoltan Takacs
- Department of Pediatrics and Institute of Molecular Pediatric Sciences
| | - Megan Toups
- Department of Pediatrics and Institute of Molecular Pediatric Sciences
| | - Astrid Kollewe
- Department of Pediatrics and Institute of Molecular Pediatric Sciences
| | - Erik Johnson
- Department of Pediatrics and Institute of Molecular Pediatric Sciences
| | | | - Gregory Driessens
- Departments of Pathology and Medicine, Pritzker School of Medicine, University of Chicago, Chicago, IL 60637
| | | | - Akiko Koide
- Department of Biochemistry and Molecular Biology, and
| | - Cristiano G. Ponte
- Coordenação de Biotecnologia, Instituto Federal do Rio de Janeiro, Rio de Janeiro, 20270-021, Brazil; and
| | | | - Thomas F. Gajewski
- Departments of Pathology and Medicine, Pritzker School of Medicine, University of Chicago, Chicago, IL 60637
| | - Guilherme Suarez-Kurtz
- Divisão de Farmacologia, Instituto Nacional de Câncer, Rio de Janeiro, 20231-050, Brazil
| | - Shohei Koide
- Department of Biochemistry and Molecular Biology, and
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Abstract
Sea anemones are a rich source of two classes of peptide toxins, sodium channel toxins and potassium channel toxins, which have been or will be useful tools for studying the structure and function of specific ion channels. Most of the known sodium channel toxins delay channel inactivation by binding to the receptor site 3 and most of the known potassium channel toxins selectively inhibit Kv1 channels. The following peptide toxins are functionally unique among the known sodium or potassium channel toxins: APETx2, which inhibits acid-sensing ion channels in sensory neurons; BDS-I and II, which show selectivity for Kv3.4 channels and APETx1, which inhibits human ether-a-go-go-related gene potassium channels. In addition, structurally novel peptide toxins, such as an epidermal growth factor (EGF)-like toxin (gigantoxin I), have also been isolated from some sea anemones although their functions remain to be clarified.
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Affiliation(s)
- Tomohiro Honma
- Department of Food Science and Technology, Tokyo University of Marine Science and Technology, Konan-4, Minato-ku, Tokyo, 108-8477 Japan
| | - Kazuo Shiomi
- Department of Food Science and Technology, Tokyo University of Marine Science and Technology, Konan-4, Minato-ku, Tokyo, 108-8477 Japan
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