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Zavarzina II, Kuzmenkov AI, Dobrokhotov NA, Maleeva EE, Korolkova YV, Peigneur S, Tytgat J, Krylov NA, Vassilevski AA, Chugunov AO. The scorpion toxin BeKm-1 blocks hERG cardiac potassium channels using an indispensable arginine residue. FEBS Lett 2024; 598:889-901. [PMID: 38563123 DOI: 10.1002/1873-3468.14850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 02/07/2024] [Accepted: 02/20/2024] [Indexed: 04/04/2024]
Abstract
BeKm-1 is a peptide toxin from scorpion venom that blocks the pore of the potassium channel hERG (Kv11.1) in the human heart. Although individual protein structures have been resolved, the structure of the complex between hERG and BeKm-1 is unknown. Here, we used molecular dynamics and ensemble docking, guided by previous double-mutant cycle analysis data, to obtain an in silico model of the hERG-BeKm-1 complex. Adding to the previous mutagenesis study of BeKm-1, our model uncovers the key role of residue Arg20, which forms three interactions (a salt bridge and hydrogen bonds) with the channel vestibule simultaneously. Replacement of this residue even by lysine weakens the interactions significantly. In accordance, the recombinantly produced BeKm-1R20K mutant exhibited dramatically decreased activity on hERG. Our model may be useful for future drug design attempts.
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Affiliation(s)
- Iana I Zavarzina
- Moscow Institute of Physics and Technology (State University), Dolgoprudny, Russia
| | | | - Nikita A Dobrokhotov
- Moscow Institute of Physics and Technology (State University), Dolgoprudny, Russia
| | | | | | | | - Jan Tytgat
- Toxicology and Pharmacology, KU Leuven, Belgium
| | - Nikolay A Krylov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia
| | - Alexander A Vassilevski
- Moscow Institute of Physics and Technology (State University), Dolgoprudny, Russia
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia
| | - Anton O Chugunov
- Moscow Institute of Physics and Technology (State University), Dolgoprudny, Russia
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia
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2
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Pei S, Xu C, Tan Y, Wang M, Yu J, Zhangsun D, Zhu X, Luo S. Synthesis, Activity, and Application of Fluorescent Analogs of [D1G, Δ14Q]LvIC Targeting α6β4 Nicotinic Acetylcholine Receptor. Bioconjug Chem 2023; 34:2194-2204. [PMID: 37748043 DOI: 10.1021/acs.bioconjchem.3c00283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/27/2023]
Abstract
α6β4* nicotinic acetylcholine receptor (nAChR) (* represents the possible presence of additional subunits) is mainly distributed in the central and peripheral nervous system and is associated with neurological diseases, such as neuropathic pain; however, the ability to explore its function and distribution is limited due to the lack of pharmacological tools. As one of the analogs of α-conotoxin (α-CTx) LvIC from Conus lividus, [D1G, Δ14Q]LvIC (Lv) selectively and potently blocks α6/α3β4 nAChR (α6/α3 represents a chimera). Here, we synthesized three fluorescent analogs of Lv by connecting fluorescent molecules 6-carboxytetramethylrhodamine succinimidyl ester (6-TAMRA-SE, R), Cy3 NHS ester (Cy3, C) and BODIPY-FL NHS ester (BDP, B) to the N-terminus of the peptide and obtained Lv-R, Lv-C, and Lv-B, respectively. The potency and selectivity of three fluorescent peptides were evaluated using two-electrode voltage-clamp recording on nAChR subtypes expressed in Xenopus laevis oocytes, and the potency and selectivity of Lv-B were almost maintained with the half-maximal inhibition (IC50) of 64 nM. Then, we explored the stability of Lv-B in artificial cerebrospinal fluid and stained rat brain slices with Lv-B. The results indicated that the stability of Lv-B was slightly improved compared to that of native Lv. Additionally, we detected the distribution of the α6β4* nAChR subtype in the cerebral cortex using green fluorescently labeled peptide and fluorescence microscopy. Our findings not only provide a visualized pharmacological tool for exploring the distribution of the α6β4* nAChR subtype in various situ tissues and organs but also extend the application of α-CTx [D1G, Δ14Q]LvIC to demonstrate the involvement of α6β4 nAChR function in pathophysiology and pharmacology.
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Affiliation(s)
- Shengrong Pei
- Guangxi Key Laboratory of Special Biomedicine; School of Medicine, Guangxi University, Nanning 530004, China
| | - Chenxing Xu
- Guangxi Key Laboratory of Special Biomedicine; School of Medicine, Guangxi University, Nanning 530004, China
| | - Yao Tan
- Guangxi Key Laboratory of Special Biomedicine; School of Medicine, Guangxi University, Nanning 530004, China
| | - Meiting Wang
- Guangxi Key Laboratory of Special Biomedicine; School of Medicine, Guangxi University, Nanning 530004, China
| | - Jinpeng Yu
- Guangxi Key Laboratory of Special Biomedicine; School of Medicine, Guangxi University, Nanning 530004, China
| | - Dongting Zhangsun
- Guangxi Key Laboratory of Special Biomedicine; School of Medicine, Guangxi University, Nanning 530004, China
- Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou 570228, China
| | - Xiaopeng Zhu
- Guangxi Key Laboratory of Special Biomedicine; School of Medicine, Guangxi University, Nanning 530004, China
| | - Sulan Luo
- Guangxi Key Laboratory of Special Biomedicine; School of Medicine, Guangxi University, Nanning 530004, China
- Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou 570228, China
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3
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Krylov NA, Tabakmakher VM, Yureva DA, Vassilevski AA, Kuzmenkov AI. Kalium 3.0 is a comprehensive depository of natural, artificial, and labeled polypeptides acting on potassium channels. Protein Sci 2023; 32:e4776. [PMID: 37682529 PMCID: PMC10578113 DOI: 10.1002/pro.4776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 09/04/2023] [Accepted: 09/06/2023] [Indexed: 09/09/2023]
Abstract
Here, we introduce the third release of Kalium database (http://kaliumdb.org/), a manually curated comprehensive depository that accumulates data on polypeptide ligands of potassium channels. The major goal of this amplitudinous update is to summarize findings for natural polypeptide ligands of K+ channels, as well as data for the artificial derivatives of these substances obtained over the decades of exploration. We manually analyzed more than 700 original manuscripts and systematized the information on mutagenesis, production of radio- and fluorescently labeled derivatives, and the molecular pharmacology of K+ channel ligands. As a result, data on more than 1200 substances were processed and added enriching the database content fivefold. We also included the electrophysiological data obtained on the understudied and neglected K+ channels including the heteromeric and concatenated channels. We associated target channels in Kalium with corresponding entries in the official database of the International Union of Basic and Clinical Pharmacology. Kalium was supplemented with an adaptive Statistics page, where users are able to obtain actual data output. Several other improvements were introduced, such as a color code to distinguish the range of ligand activity concentrations and advanced tools for filtration and sorting. Kalium is a fully open-access database, crosslinked to other databases of interest. It can be utilized as a convenient resource containing ample up-to-date information about polypeptide ligands of K+ channels.
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Affiliation(s)
- Nikolay A. Krylov
- Shemyakin‐Ovchinnikov Institute of Bioorganic ChemistryRussian Academy of SciencesMoscowRussia
| | - Valentin M. Tabakmakher
- Shemyakin‐Ovchinnikov Institute of Bioorganic ChemistryRussian Academy of SciencesMoscowRussia
- Institute of Life Sciences and BiomedicineFar Eastern Federal UniversityVladivostokRussia
| | - Daria A. Yureva
- Shemyakin‐Ovchinnikov Institute of Bioorganic ChemistryRussian Academy of SciencesMoscowRussia
| | - Alexander A. Vassilevski
- Shemyakin‐Ovchinnikov Institute of Bioorganic ChemistryRussian Academy of SciencesMoscowRussia
- Moscow Institute of Physics and Technology (State University)MoscowRussia
| | - Alexey I. Kuzmenkov
- Shemyakin‐Ovchinnikov Institute of Bioorganic ChemistryRussian Academy of SciencesMoscowRussia
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4
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Ergen PH, Shorter S, Ntziachristos V, Ovsepian SV. Neurotoxin-Derived Optical Probes for Biological and Medical Imaging. Mol Imaging Biol 2023; 25:799-814. [PMID: 37468801 PMCID: PMC10598172 DOI: 10.1007/s11307-023-01838-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 07/04/2023] [Accepted: 07/05/2023] [Indexed: 07/21/2023]
Abstract
The superb specificity and potency of biological toxins targeting various ion channels and receptors are of major interest for the delivery of therapeutics to distinct cell types and subcellular compartments. Fused with reporter proteins or labelled with fluorophores and nanocomposites, animal toxins and their detoxified variants also offer expanding opportunities for visualisation of a range of molecular processes and functions in preclinical models, as well as clinical studies. This article presents state-of-the-art optical probes derived from neurotoxins targeting ion channels, with discussions of their applications in basic and translational biomedical research. It describes the design and production of probes and reviews their applications with advantages and limitations, with prospects for future improvements. Given the advances in imaging tools and expanding research areas benefiting from the use of optical probes, described here resources should assist the discovery process and facilitate high-precision interrogation and therapeutic interventions.
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Affiliation(s)
- Pinar Helin Ergen
- Faculty of Engineering and Science, University of Greenwich London, Chatham Maritime, Kent, ME4 4TB, United Kingdom
| | - Susan Shorter
- Faculty of Engineering and Science, University of Greenwich London, Chatham Maritime, Kent, ME4 4TB, United Kingdom
| | - Vasilis Ntziachristos
- Chair of Biological Imaging at the Central Institute for Translational Cancer Research (TranslaTUM), School of Medicine, Technical University of Munich, 81675, Munich, Germany
- Institute of Biological and Medical Imaging, Helmholtz Zentrum München (GmbH), 85764, Neuherberg, Germany
- Munich Institute of Robotics and Machine Intelligence (MIRMI), Technical University of Munich, 80992, Munich, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Munich Heart Alliance, Munich, Germany
| | - Saak Victor Ovsepian
- Faculty of Engineering and Science, University of Greenwich London, Chatham Maritime, Kent, ME4 4TB, United Kingdom.
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Tsetlin V, Shelukhina I, Kozlov S, Kasheverov I. Fifty Years of Animal Toxin Research at the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS. Int J Mol Sci 2023; 24:13884. [PMID: 37762187 PMCID: PMC10530976 DOI: 10.3390/ijms241813884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 09/04/2023] [Accepted: 09/06/2023] [Indexed: 09/29/2023] Open
Abstract
This review covers briefly the work carried out at our institute (IBCh), in many cases in collaboration with other Russian and foreign laboratories, for the last 50 years. It discusses the discoveries and studies of various animal toxins, including protein and peptide neurotoxins acting on the nicotinic acetylcholine receptors (nAChRs) and on other ion channels. Among the achievements are the determination of the primary structures of the α-bungarotoxin-like three-finger toxins (TFTs), covalently bound dimeric TFTs, glycosylated cytotoxin, inhibitory cystine knot toxins (ICK), modular ICKs, and such giant molecules as latrotoxins and peptide neurotoxins from the snake, as well as from other animal venoms. For a number of toxins, spatial structures were determined, mostly by 1H-NMR spectroscopy. Using this method in combination with molecular modeling, the molecular mechanisms of the interactions of several toxins with lipid membranes were established. In more detail are presented the results of recent years, among which are the discovery of α-bungarotoxin analogs distinguishing the two binding sites in the muscle-type nAChR, long-chain α-neurotoxins interacting with α9α10 nAChRs and with GABA-A receptors, and the strong antiviral effects of dimeric phospholipases A2. A summary of the toxins obtained from arthropod venoms includes only highly cited works describing the molecules' success story, which is associated with IBCh. In marine animals, versatile toxins in terms of structure and molecular targets were discovered, and careful work on α-conotoxins differing in specificity for individual nAChR subtypes gave information about their binding sites.
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Affiliation(s)
- Victor Tsetlin
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklay Str., 117997 Moscow, Russia; (I.S.); (I.K.)
| | - Irina Shelukhina
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklay Str., 117997 Moscow, Russia; (I.S.); (I.K.)
| | - Sergey Kozlov
- Department of Molecular Neurobiology, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklay Str., 117997 Moscow, Russia;
| | - Igor Kasheverov
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklay Str., 117997 Moscow, Russia; (I.S.); (I.K.)
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6
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Orlov NA, Kryukova EV, Efremenko AV, Yakimov SA, Toporova VA, Kirpichnikov MP, Nekrasova OV, Feofanov AV. Interactions of the Kv1.1 Channel with Peptide Pore Blockers: A Fluorescent Analysis on Mammalian Cells. MEMBRANES 2023; 13:645. [PMID: 37505011 PMCID: PMC10383195 DOI: 10.3390/membranes13070645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 06/23/2023] [Accepted: 06/27/2023] [Indexed: 07/29/2023]
Abstract
The voltage-gated potassium channel Kv1.1, which is abundant in the CNS and peripheral nervous system, controls neuronal excitability and neuromuscular transmission and mediates a number of physiological functions in non-excitable cells. The development of some diseases is accompanied by changes in the expression level and/or activity of the channels in particular types of cells. To meet the requirements of studies related to the expression and localization of the Kv1.1 channels, we report on the subnanomolar affinity of hongotoxin 1 N-terminally labeled with Atto 488 fluorophore (A-HgTx) for the Kv1.1 channel and its applicability for fluorescent imaging of the channel in living cells. Taking into consideration the pharmacological potential of the Kv1.1 channel, a fluorescence-based analytical system was developed for the study of peptide ligands that block the ion conductivity of Kv1.1 and are potentially able to correct abnormal activity of the channel. The system is based on analysis of the competitive binding of the studied compounds and A-HgTx to the mKate2-tagged human Kv1.1 (S369T) channel, expressed in the plasma membrane of Neuro2a cells. The system was validated by measuring the affinities of the known Kv1.1-channel peptide blockers, such as agitoxin 2, kaliotoxin 1, hongotoxin 1, and margatoxin. Peptide pore blocker Ce1, from the venom of the scorpion Centruroides elegans, was shown to possess a nanomolar affinity for the Kv1.1 channel. It is reported that interactions of the Kv1.1 channel with the studied peptide blockers are not affected by the transition of the channel from the closed to open state. The conclusion is made that the structural rearrangements accompanying the channel transition into the open state do not change the conformation of the P-loop (including the selectivity filter) involved in the formation of the binding site of the peptide pore blockers.
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Affiliation(s)
- Nikita A Orlov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Elena V Kryukova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Anastasia V Efremenko
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Sergey A Yakimov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Victoria A Toporova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Mikhail P Kirpichnikov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Oksana V Nekrasova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Alexey V Feofanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
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7
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Primak AL, Orlov NA, Peigneur S, Tytgat J, Ignatova AA, Denisova KR, Yakimov SA, Kirpichnikov MP, Nekrasova OV, Feofanov AV. AgTx2-GFP, Fluorescent Blocker Targeting Pharmacologically Important K v1.x (x = 1, 3, 6) Channels. Toxins (Basel) 2023; 15:toxins15030229. [PMID: 36977120 PMCID: PMC10056440 DOI: 10.3390/toxins15030229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/14/2023] [Accepted: 03/16/2023] [Indexed: 03/30/2023] Open
Abstract
The growing interest in potassium channels as pharmacological targets has stimulated the development of their fluorescent ligands (including genetically encoded peptide toxins fused with fluorescent proteins) for analytical and imaging applications. We report on the properties of agitoxin 2 C-terminally fused with enhanced GFP (AgTx2-GFP) as one of the most active genetically encoded fluorescent ligands of potassium voltage-gated Kv1.x (x = 1, 3, 6) channels. AgTx2-GFP possesses subnanomolar affinities for hybrid KcsA-Kv1.x (x = 3, 6) channels and a low nanomolar affinity to KcsA-Kv1.1 with moderate dependence on pH in the 7.0-8.0 range. Electrophysiological studies on oocytes showed a pore-blocking activity of AgTx2-GFP at low nanomolar concentrations for Kv1.x (x = 1, 3, 6) channels and at micromolar concentrations for Kv1.2. AgTx2-GFP bound to Kv1.3 at the membranes of mammalian cells with a dissociation constant of 3.4 ± 0.8 nM, providing fluorescent imaging of the channel membranous distribution, and this binding depended weakly on the channel state (open or closed). AgTx2-GFP can be used in combination with hybrid KcsA-Kv1.x (x = 1, 3, 6) channels on the membranes of E. coli spheroplasts or with Kv1.3 channels on the membranes of mammalian cells for the search and study of nonlabeled peptide pore blockers, including measurement of their affinity.
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Affiliation(s)
- Alexandra L Primak
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Nikita A Orlov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Steve Peigneur
- Toxicology and Pharmacology, Campus Gasthuisberg O&N2, University of Leuven (KU Leuven), Herestraat 49, P.O. Box 922, B-3000 Leuven, Belgium
| | - Jan Tytgat
- Toxicology and Pharmacology, Campus Gasthuisberg O&N2, University of Leuven (KU Leuven), Herestraat 49, P.O. Box 922, B-3000 Leuven, Belgium
| | - Anastasia A Ignatova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Kristina R Denisova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Sergey A Yakimov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Mikhail P Kirpichnikov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Oksana V Nekrasova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Alexey V Feofanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
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8
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Combining mKate2-Kv1.3 Channel and Atto488-Hongotoxin for the Studies of Peptide Pore Blockers on Living Eukaryotic Cells. Toxins (Basel) 2022; 14:toxins14120858. [PMID: 36548755 PMCID: PMC9780825 DOI: 10.3390/toxins14120858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/01/2022] [Accepted: 12/02/2022] [Indexed: 12/12/2022] Open
Abstract
The voltage-gated potassium Kv1.3 channel is an essential component of vital cellular processes which is also involved in the pathogenesis of some autoimmune, neuroinflammatory and oncological diseases. Pore blockers of the Kv1.3 channel are considered as potential drugs and are used to study Kv1 channels' structure and functions. Screening and study of the blockers require the assessment of their ability to bind the channel. Expanding the variety of methods used for this, we report on the development of the fluorescent competitive binding assay for measuring affinities of pore blockers to Kv1.3 at the membrane of mammalian cells. The assay constituents are hongotoxin 1 conjugated with Atto488, fluorescent mKate2-tagged Kv1.3 channel, which was designed to improve membrane expression of the channel in mammalian cells, confocal microscopy, and a special protocol of image processing. The assay is implemented in the "mix and measure", format and allows the screening of Kv1.3 blockers, such as peptide toxins, that bind to the extracellular vestibule of the K+-conducting pore, and analyzing their affinity.
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Wai DCC, Naseem MU, Mocsár G, Babu Reddiar S, Pan Y, Csoti A, Hajdu P, Nowell C, Nicolazzo JA, Panyi G, Norton RS. Fluorescent Peptide Toxin for Selective Visualization of the Voltage-Gated Potassium Channel K V1.3. Bioconjug Chem 2022; 33:2197-2212. [DOI: 10.1021/acs.bioconjchem.2c00436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Dorothy C. C. Wai
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria3052, Australia
| | - Muhammad Umair Naseem
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen4032, Hungary
| | - Gábor Mocsár
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen4032, Hungary
- Damjanovich Cell Analysis Core Facility, Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen4032, Hungary
| | - Sanjeevini Babu Reddiar
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria3052, Australia
| | - Yijun Pan
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria3052, Australia
| | - Agota Csoti
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen4032, Hungary
| | - Peter Hajdu
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen4032, Hungary
- Department of Dental Biochemistry, Faculty of Dentistry, University of Debrecen, Debrecen4032, Hungary
| | - Cameron Nowell
- Imaging, FACS and Analysis Core, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria3052, Australia
| | - Joseph A. Nicolazzo
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria3052, Australia
| | - Gyorgy Panyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen4032, Hungary
| | - Raymond S. Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria3052, Australia
- ARC Centre for Fragment-Based Design, Monash University, Parkville, Victoria3052, Australia
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10
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Characterising ion channel structure and dynamics using fluorescence spectroscopy techniques. Biochem Soc Trans 2022; 50:1427-1445. [DOI: 10.1042/bst20220605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 09/21/2022] [Accepted: 10/04/2022] [Indexed: 11/17/2022]
Abstract
Ion channels undergo major conformational changes that lead to channel opening and ion conductance. Deciphering these structure-function relationships is paramount to understanding channel physiology and pathophysiology. Cryo-electron microscopy, crystallography and computer modelling provide atomic-scale snapshots of channel conformations in non-cellular environments but lack dynamic information that can be linked to functional results. Biophysical techniques such as electrophysiology, on the other hand, provide functional data with no structural information of the processes involved. Fluorescence spectroscopy techniques help bridge this gap in simultaneously obtaining structure-function correlates. These include voltage-clamp fluorometry, Förster resonance energy transfer, ligand binding assays, single molecule fluorescence and their variations. These techniques can be employed to unearth several features of ion channel behaviour. For instance, they provide real time information on local and global rearrangements that are inherent to channel properties. They also lend insights in trafficking, expression, and assembly of ion channels on the membrane surface. These methods have the advantage that they can be carried out in either native or heterologous systems. In this review, we briefly explain the principles of fluorescence and how these have been translated to study ion channel function. We also report several recent advances in fluorescence spectroscopy that has helped address and improve our understanding of the biophysical behaviours of different ion channel families.
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11
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Fuest S, Post C, Balbach ST, Jabar S, Neumann I, Schimmelpfennig S, Sargin S, Nass E, Budde T, Kailayangiri S, Altvater B, Ranft A, Hartmann W, Dirksen U, Rössig C, Schwab A, Pethő Z. Relevance of Abnormal KCNN1 Expression and Osmotic Hypersensitivity in Ewing Sarcoma. Cancers (Basel) 2022; 14:cancers14194819. [PMID: 36230742 PMCID: PMC9564116 DOI: 10.3390/cancers14194819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 09/27/2022] [Accepted: 09/29/2022] [Indexed: 12/02/2022] Open
Abstract
Simple Summary The main oncogene in Ewing sarcoma directly drives a high expression of a previously unknown variant KCNN1 (encoding the KCa2.1 channel) that we also verified in samples from >200 patients. Yet, we found that the channel is not functional and does not modulate Ewing sarcoma cell behavior. We could explain this lack of functional impact by the surprising absence of any KCa2.1-carried K+ current in Ewing sarcoma cells. However, we show in a proof-of-principle study that the essential lack of a K+ conductance can be exploited by applying hypoosmotic stress and effectively and selectively killing the Ewing sarcoma cells. Abstract Ewing sarcoma (EwS) is a rare and highly malignant bone tumor occurring mainly in childhood and adolescence. Physiologically, the bone is a central hub for Ca2+ homeostasis, which is severely disturbed by osteolytic processes in EwS. Therefore, we aimed to investigate how ion transport proteins involved in Ca2+ homeostasis affect EwS pathophysiology. We characterized the expression of 22 candidate genes of Ca2+-permeable or Ca2+-regulated ion channels in three EwS cell lines and found the Ca2+-activated K+ channel KCa2.1 (KCNN1) to be exceptionally highly expressed. We revealed that KCNN1 expression is directly regulated by the disease-driving oncoprotein EWSR1-FL1. Due to its consistent overexpression in EwS, KCNN1 mRNA could be a prognostic marker in EwS. In a large cohort of EwS patients, however, KCNN1 mRNA quantity does not correlate with clinical parameters. Several functional studies including patch clamp electrophysiology revealed no evidence for KCa2.1 function in EwS cells. Thus, elevated KCNN1 expression is not translated to KCa2.1 channel activity in EwS cells. However, we found that the low K+ conductance of EwS cells renders them susceptible to hypoosmotic solutions. The absence of a relevant K+ conductance in EwS thereby provides an opportunity for hypoosmotic therapy that can be exploited during tumor surgery.
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Affiliation(s)
- Sebastian Fuest
- Institute of Physiology II, University Münster, 48149 Münster, Germany
| | - Christoph Post
- Institute of Physiology II, University Münster, 48149 Münster, Germany
| | - Sebastian T. Balbach
- Department of Pediatric Hematology and Oncology, University Children’s Hospital Münster, 48149 Münster, Germany
| | - Susanne Jabar
- Pediatrics III, University Hospital Essen, 45147 Essen, Germany
| | - Ilka Neumann
- Institute of Physiology II, University Münster, 48149 Münster, Germany
| | | | - Sarah Sargin
- Institute of Physiology II, University Münster, 48149 Münster, Germany
| | - Elke Nass
- Institute of Physiology I, University Münster, 48149 Münster, Germany
| | - Thomas Budde
- Institute of Physiology I, University Münster, 48149 Münster, Germany
| | - Sareetha Kailayangiri
- Department of Pediatric Hematology and Oncology, University Children’s Hospital Münster, 48149 Münster, Germany
| | - Bianca Altvater
- Department of Pediatric Hematology and Oncology, University Children’s Hospital Münster, 48149 Münster, Germany
| | - Andreas Ranft
- Pediatrics III, University Hospital Essen, 45147 Essen, Germany
| | - Wolfgang Hartmann
- Division of Translational Pathology, Gerhard-Domagk-Institute of Pathology, University Münster, 48149 Münster, Germany
| | - Uta Dirksen
- Pediatrics III, University Hospital Essen, 45147 Essen, Germany
| | - Claudia Rössig
- Department of Pediatric Hematology and Oncology, University Children’s Hospital Münster, 48149 Münster, Germany
| | - Albrecht Schwab
- Institute of Physiology II, University Münster, 48149 Münster, Germany
| | - Zoltán Pethő
- Institute of Physiology II, University Münster, 48149 Münster, Germany
- Correspondence:
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12
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Sarkar D, Mishra S, Nisal R, Majhi S, Shrivas R, Singh Y, Anusree VS, Kalia J. Site-Specific Fluorescent Labeling of the Cysteine-Rich Toxin, DkTx, for TRPV1 Ion Channel Imaging and Membrane Binding Studies. Bioconjug Chem 2022; 33:1761-1770. [PMID: 36073164 DOI: 10.1021/acs.bioconjchem.2c00355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Peptide toxins secreted by venomous animals bind to mammalian ion channel proteins and modulate their function. The high specificity of these toxins for their target ion channels enables them to serve as powerful tools for ion channel biology. Toxins labeled with fluorescent dyes are employed for the cellular imaging of channels and also for studying toxin-channel and toxin-membrane interactions. Several of these toxins are cysteine-rich, rendering the production of properly folded fluorescently labeled toxins technically challenging. Herein, we evaluate a variety of site-specific protein bioconjugation approaches for producing fluorescently labeled double-knot toxin (DkTx), a potent TRPV1 ion channel agonist that contains an uncommonly large number of cysteines (12 out of a total of 75 amino acids present in the protein). We find that popular cysteine-mediated bioconjugation approaches are unsuccessful as the introduction of a non-native cysteine residue for thiol modification leads to the formation of misfolded toxin species. Moreover, N-terminal aldehyde-mediated bioconjugation approaches are also not suitable as the resultant labeled toxin lacks activity. In contrast to these approaches, C-terminal bioconjugation of DkTx via the sortase bioconjugation technology yields functionally active fluorescently labeled DkTx. We employ this labeled toxin for imaging rat TRPV1 heterologously expressed in Xenopus laevis oocytes, as well as for performing membrane binding studies on giant unilamellar vesicles composed of different lipid compositions. Our studies set the stage for using fluorescent DkTx as a tool for TRPV1 biology and provide an informative blueprint for labeling cysteine-rich proteins.
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Affiliation(s)
- Debayan Sarkar
- Department of Biology, Indian Institute of Science Education and Research (IISER) Pune, Dr. Homi Bhabha Road, Pashan, Pune, Maharashtra 411008, India.,Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal Bypass Road, Bhauri, Bhopal, Madhya Pradesh 462066, India
| | - Satyajit Mishra
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal Bypass Road, Bhauri, Bhopal, Madhya Pradesh 462066, India
| | - Rahul Nisal
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Pune, Dr. Homi Bhabha Road, Pashan, Pune, Maharashtra 411008, India
| | - Sumita Majhi
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal Bypass Road, Bhauri, Bhopal, Madhya Pradesh 462066, India
| | - Rohit Shrivas
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal Bypass Road, Bhauri, Bhopal, Madhya Pradesh 462066, India
| | - Yashaswi Singh
- Department of Biology, Indian Institute of Science Education and Research (IISER) Pune, Dr. Homi Bhabha Road, Pashan, Pune, Maharashtra 411008, India.,Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal Bypass Road, Bhauri, Bhopal, Madhya Pradesh 462066, India
| | - V S Anusree
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal Bypass Road, Bhauri, Bhopal, Madhya Pradesh 462066, India
| | - Jeet Kalia
- Department of Biology, Indian Institute of Science Education and Research (IISER) Pune, Dr. Homi Bhabha Road, Pashan, Pune, Maharashtra 411008, India.,Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal Bypass Road, Bhauri, Bhopal, Madhya Pradesh 462066, India.,Department of Chemistry, Indian Institute of Science Education and Research (IISER) Pune, Dr. Homi Bhabha Road, Pashan, Pune, Maharashtra 411008, India.,Department of Chemistry, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal Bypass Road, Bhauri, Bhopal, Madhya Pradesh 462066, India
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13
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Denisova KR, Orlov NA, Yakimov SA, Kirpichnikov MP, Feofanov AV, Nekrasova OV. Atto488-Agitoxin 2—A Fluorescent Ligand with Increased Selectivity for Kv1.3 Channel Binding Site. Bioengineering (Basel) 2022; 9:bioengineering9070295. [PMID: 35877346 PMCID: PMC9312206 DOI: 10.3390/bioengineering9070295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 06/29/2022] [Accepted: 06/30/2022] [Indexed: 11/16/2022] Open
Abstract
Fluorescently labeled peptide blockers of ion channels are useful probes in studying the localization and functioning of the channels and in the performance of a search for new channel ligands with bioengineering screening systems. Here, we report on the properties of Atto488-agitoxin 2 (A-AgTx2), a derivative of the Kv1 channel blocker agitoxin 2 (AgTx2), which was N-terminally labeled with Atto 488 fluorophore. The interactions of A-AgTx2 with the outer binding sites of the potassium voltage-gated Kv1.x (x = 1, 3, 6) channels were studied using bioengineered hybrid KcsA–Kv1.x (x = 1, 3, 6) channels. In contrast to AgTx2, A-AgTx2 was shown to lose affinity for the Kv1.1 and Kv1.6 binding sites but to preserve it for the Kv1.3 site. Thus, Atto488 introduces two new functionalities to AgTx2: fluorescence and the selective targeting of the Kv1.3 channel, which is known for its pharmacological significance. In the case of A-AgTx2, fluorescent labeling served as an alternative to site-directed mutagenesis in modulating the pharmacological profile of the channel blocker. Although the affinity of A-AgTx2 for the Kv1.3 binding site was decreased as compared to the unlabeled AgTx2, its dissociation constant value was within a low nanomolar range (4.0 nM). The properties of A-AgTx2 allow one to use it for the search and study of Kv1.3 channel blockers as well as to consider it for the imaging of the Kv1.3 channel in cells and tissues.
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Affiliation(s)
- Kristina R. Denisova
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia; (K.R.D.); (N.A.O.); (M.P.K.)
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia; (S.A.Y.); (O.V.N.)
| | - Nikita A. Orlov
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia; (K.R.D.); (N.A.O.); (M.P.K.)
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia; (S.A.Y.); (O.V.N.)
| | - Sergey A. Yakimov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia; (S.A.Y.); (O.V.N.)
| | - Mikhail P. Kirpichnikov
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia; (K.R.D.); (N.A.O.); (M.P.K.)
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia; (S.A.Y.); (O.V.N.)
| | - Alexey V. Feofanov
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia; (K.R.D.); (N.A.O.); (M.P.K.)
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia; (S.A.Y.); (O.V.N.)
- Correspondence:
| | - Oksana V. Nekrasova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia; (S.A.Y.); (O.V.N.)
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14
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GFP-Margatoxin, a Genetically Encoded Fluorescent Ligand to Probe Affinity of Kv1.3 Channel Blockers. Int J Mol Sci 2022; 23:ijms23031724. [PMID: 35163644 PMCID: PMC8835862 DOI: 10.3390/ijms23031724] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 01/30/2022] [Accepted: 01/31/2022] [Indexed: 02/01/2023] Open
Abstract
Peptide pore blockers and their fluorescent derivatives are useful molecular probes to study the structure and functions of the voltage-gated potassium Kv1.3 channel, which is considered as a pharmacological target in the treatment of autoimmune and neurological disorders. We present Kv1.3 fluorescent ligand, GFP-MgTx, constructed on the basis of green fluorescent protein (GFP) and margatoxin (MgTx), the peptide, which is widely used in physiological studies of Kv1.3. Expression of the fluorescent ligand in E. coli cells resulted in correctly folded and functionally active GFP-MgTx with a yield of 30 mg per 1 L of culture. Complex of GFP-MgTx with the Kv1.3 binding site is reported to have the dissociation constant of 11 ± 2 nM. GFP-MgTx as a component of an analytical system based on the hybrid KcsA-Kv1.3 channel is shown to be applicable to recognize Kv1.3 pore blockers of peptide origin and to evaluate their affinities to Kv1.3. GFP-MgTx can be used in screening and pre-selection of Kv1.3 channel blockers as potential drug candidates.
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15
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Rivera-de-Torre E, Rimbault C, Jenkins TP, Sørensen CV, Damsbo A, Saez NJ, Duhoo Y, Hackney CM, Ellgaard L, Laustsen AH. Strategies for Heterologous Expression, Synthesis, and Purification of Animal Venom Toxins. Front Bioeng Biotechnol 2022; 9:811905. [PMID: 35127675 PMCID: PMC8811309 DOI: 10.3389/fbioe.2021.811905] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 12/24/2021] [Indexed: 11/13/2022] Open
Abstract
Animal venoms are complex mixtures containing peptides and proteins known as toxins, which are responsible for the deleterious effect of envenomations. Across the animal Kingdom, toxin diversity is enormous, and the ability to understand the biochemical mechanisms governing toxicity is not only relevant for the development of better envenomation therapies, but also for exploiting toxin bioactivities for therapeutic or biotechnological purposes. Most of toxinology research has relied on obtaining the toxins from crude venoms; however, some toxins are difficult to obtain because the venomous animal is endangered, does not thrive in captivity, produces only a small amount of venom, is difficult to milk, or only produces low amounts of the toxin of interest. Heterologous expression of toxins enables the production of sufficient amounts to unlock the biotechnological potential of these bioactive proteins. Moreover, heterologous expression ensures homogeneity, avoids cross-contamination with other venom components, and circumvents the use of crude venom. Heterologous expression is also not only restricted to natural toxins, but allows for the design of toxins with special properties or can take advantage of the increasing amount of transcriptomics and genomics data, enabling the expression of dormant toxin genes. The main challenge when producing toxins is obtaining properly folded proteins with a correct disulfide pattern that ensures the activity of the toxin of interest. This review presents the strategies that can be used to express toxins in bacteria, yeast, insect cells, or mammalian cells, as well as synthetic approaches that do not involve cells, such as cell-free biosynthesis and peptide synthesis. This is accompanied by an overview of the main advantages and drawbacks of these different systems for producing toxins, as well as a discussion of the biosafety considerations that need to be made when working with highly bioactive proteins.
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Affiliation(s)
- Esperanza Rivera-de-Torre
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
- *Correspondence: Esperanza Rivera-de-Torre, ; Andreas H. Laustsen,
| | - Charlotte Rimbault
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Timothy P. Jenkins
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Christoffer V. Sørensen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Anna Damsbo
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Natalie J. Saez
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, Australia
| | - Yoan Duhoo
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, Australia
| | - Celeste Menuet Hackney
- Department of Biology, Linderstrøm-Lang Centre for Protein Science, University of Copenhagen, Copenhagen, Denmark
| | - Lars Ellgaard
- Department of Biology, Linderstrøm-Lang Centre for Protein Science, University of Copenhagen, Copenhagen, Denmark
| | - Andreas H. Laustsen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
- *Correspondence: Esperanza Rivera-de-Torre, ; Andreas H. Laustsen,
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16
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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] [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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17
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Bioengineered System for High Throughput Screening of Kv1 Ion Channel Blockers. Bioengineering (Basel) 2021; 8:bioengineering8110187. [PMID: 34821753 PMCID: PMC8614864 DOI: 10.3390/bioengineering8110187] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/03/2021] [Accepted: 11/10/2021] [Indexed: 12/12/2022] Open
Abstract
Screening drug candidates for their affinity and selectivity for a certain binding site is a crucial step in developing targeted therapy. Here, we created a screening assay for receptor binding that can be easily scaled up and automated for the high throughput screening of Kv channel blockers. It is based on the expression of the KcsA-Kv1 hybrid channel tagged with a fluorescent protein in the E. coli membrane. In order to make this channel accessible for the soluble compounds, E. coli were transformed into spheroplasts by disruption of the cellular peptidoglycan envelope. The assay was evaluated using a hybrid KcsA-Kv1.3 potassium channel tagged with a red fluorescent protein (TagRFP). The binding of Kv1.3 channel blockers was measured by flow cytometry either by using their fluorescent conjugates or by determining the ability of unconjugated compounds to displace fluorescently labeled blockers with a known affinity. A fraction of the occupied receptor was calculated with a dedicated pipeline available as a Jupyter notebook. Measured binding constants for agitoxin-2, charybdotoxin and kaliotoxin were in firm agreement with the earlier published data. By using a mid-range flow cytometer with manual sample handling, we measured and analyzed up to ten titration curves (eight data points each) in one day. Finally, we considered possibilities for multiplexing, scaling and automation of the assay.
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Kudryashova KS, Nekrasova OV, Kirpichnikov MP, Feofanov AV. Chimeras of KcsA and Kv1 as a bioengineering tool to study voltage-gated potassium channels and their ligands. Biochem Pharmacol 2021; 190:114646. [PMID: 34090876 DOI: 10.1016/j.bcp.2021.114646] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 05/31/2021] [Accepted: 06/01/2021] [Indexed: 11/28/2022]
Abstract
Chimeric potassium channels KcsA-Kv1, which are among the most intensively studied hybrid membrane proteins to date, were constructed by replacing a part of the pore domain of bacterial potassium channel KcsA (K channel of streptomyces A) with corresponding regions of the mammalian voltage-gated potassium channels belonging to the Kv1 subfamily. In this way, the pore blocker binding site of Kv1 channels was transferred to KcsA, opening up possibility to use the obtained hybrids as receptors of Kv1-channel pore blockers of different origin. In this review the recent progress in KcsA-Kv1 channel design and applications is discussed with a focus on the development of new assays for studying interactions of pore blockers with the channels. A summary of experimental data is presented demonstrating that hybrid channels reproduce the blocker-binding profiles of parental Kv1 channels. It is overviewed how the KcsA-Kv1 chimeras are used to get new insight into the structure of potassium channels, to determine molecular basis for high affinity and selectivity of binding of peptide blockers to Kv1 channels, as well as to identify new peptide ligands.
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Affiliation(s)
- Ksenia S Kudryashova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia
| | - Oksana V Nekrasova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia.
| | - Mikhail P Kirpichnikov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia; Biological Faculty, Lomonosov Moscow State University, Leninskie Gory 1, 119992 Moscow, Russia
| | - Alexey V Feofanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia; Biological Faculty, Lomonosov Moscow State University, Leninskie Gory 1, 119992 Moscow, Russia
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19
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Primak AL, Skutel MA, Nekrasova OV, Arseniev AS, Kirpichnikov MP, Feofanov AV. Kv1 Potassium Channel Ligands Based on Hongotoxin 1 and Red Fluorescent Protein. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2020. [DOI: 10.1134/s1068162020060266] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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20
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N-Terminal Tagging with GFP Enhances Selectivity of Agitoxin 2 to Kv1.3-Channel Binding Site. Toxins (Basel) 2020; 12:toxins12120802. [PMID: 33339256 PMCID: PMC7766132 DOI: 10.3390/toxins12120802] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 11/26/2020] [Accepted: 12/15/2020] [Indexed: 01/03/2023] Open
Abstract
Recently developed fluorescent protein-scorpion toxin chimeras (FP-Tx) show blocking activities for potassium voltage-gated channels of Kv1 family and retain almost fully pharmacological profiles of the parental peptide toxins (Kuzmenkov et al., Sci Rep. 2016, 6, 33314). Here we report on N-terminally green fluorescent protein (GFP)-tagged agitoxin 2 (GFP-L2-AgTx2) with high affinity and selectivity for the binding site of Kv1.3 channel involved in the pathogenesis of various (primarily of autoimmune origin) diseases. The basis for this selectivity relates to N-terminal location of GFP, since transposition of GFP to the C-terminus of AgTx2 recovered specific interactions with the Kv1.1 and Kv1.6 binding sites. Competitive binding experiments revealed that the binding site of GFP-L2-AgTx2 overlaps that of charybdotoxin, kaliotoxin 1, and agitoxin 2, the known Kv1.3-channel pore blockers. GFP-L2-AgTx2 was demonstrated to be applicable as a fluorescent probe to search for Kv1.3 pore blockers among individual compounds and in complex mixtures, to measure blocker affinities, and to visualize Kv1.3 distribution at the plasma membrane of Kv1.3-expressing HEK293 cells. Our studies show that definite combinations of fluorescent proteins and peptide blockers can result in considerable modulation of the natural blocker-channel binding profile yielding selective fluorescent ligands of certain channels.
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21
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Das B, Patra A, Mukherjee AK. Correlation of Venom Toxinome Composition of Indian Red Scorpion ( Mesobuthus tamulus) with Clinical Manifestations of Scorpion Stings: Failure of Commercial Antivenom to Immune-Recognize the Abundance of Low Molecular Mass Toxins of This Venom. J Proteome Res 2020; 19:1847-1856. [PMID: 32125869 DOI: 10.1021/acs.jproteome.0c00120] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The Indian red scorpion (Mesobuthus tamulus), with its life-threatening sting, is the world's most dangerous species of scorpion. The toxinome composition of M. tamulus venom was determined by tandem mass spectrometry (MS) analysis of venom protein bands separated by SDS-PAGE. A total of 110 venom toxins were identified from searching the MS data against the Buthidae family (taxid: 6855) of toxin entries in nonredundant protein databases. The Na+ and K+ ion channel toxins taken together are the most abundant toxins (76.7%) giving rise to the neurotoxic nature of this venom. The other minor toxin classes in the M. tamulus venom proteome are serine protease-like protein (2.9%), serine protease inhibitor (2.2%), antimicrobial peptide (2.3%), hyaluronidase (2.2%), makatoxin (2.1%), lipolysis potentiating peptides (1.2%), neurotoxin affecting Cl- channel (1%), parabutoporin (0.6%), Ca2+ channel toxins (0.8%), bradykinin potentiating peptides (0.2%), HMG CoA reductase inhibitor (0.1%), and other toxins with unknown pharmacological activity (7.7%). Several of these toxins have been shown to be promising drug candidates. M. tamulus venom does not show enzymatic activity (phospholipase A2, l-amino acid oxidase, adenosine tri-, di-, and monophosphatase, hyaluronidase, metalloproteinase, and fibrinogenolytic), in vitro hemolytic activity, interference with blood coagulation, or platelet modulation properties. The clinical manifestations post M. tamulus sting have been described in the literature and are well correlated with its venom proteome composition. An abundance of low molecular mass toxins (3-15 kDa) are responsible for exerting the major pharmacological effects of M. tamulus venom, though they are poorly immune-recognized by commercial scorpion antivenom. This is a major concern for the development of effective antivenom therapy against scorpion stings.
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Affiliation(s)
- Bhabana Das
- Microbial Biotechnology and Protein Research Laboratory, Department of Molecular Biology and Biotechnology, School of Sciences, Tezpur University, Tezpur 784028, Assam, India
| | - Aparup Patra
- Microbial Biotechnology and Protein Research Laboratory, Department of Molecular Biology and Biotechnology, School of Sciences, Tezpur University, Tezpur 784028, Assam, India
| | - Ashis Kumar Mukherjee
- Microbial Biotechnology and Protein Research Laboratory, Department of Molecular Biology and Biotechnology, School of Sciences, Tezpur University, Tezpur 784028, Assam, India
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Reshetniak S, Rizzoli SO. Interrogating Synaptic Architecture: Approaches for Labeling Organelles and Cytoskeleton Components. Front Synaptic Neurosci 2019; 11:23. [PMID: 31507402 PMCID: PMC6716447 DOI: 10.3389/fnsyn.2019.00023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 08/02/2019] [Indexed: 01/06/2023] Open
Abstract
Synaptic transmission has been studied for decades, as a fundamental step in brain function. The structure of the synapse, and its changes during activity, turned out to be key aspects not only in the transfer of information between neurons, but also in cognitive processes such as learning and memory. The overall synaptic morphology has traditionally been studied by electron microscopy, which enables the visualization of synaptic structure in great detail. The changes in the organization of easily identified structures, such as the presynaptic active zone, or the postsynaptic density, are optimally studied via electron microscopy. However, few reliable methods are available for labeling individual organelles or protein complexes in electron microscopy. For such targets one typically relies either on combination of electron and fluorescence microscopy, or on super-resolution fluorescence microscopy. This review focuses on approaches and techniques used to specifically reveal synaptic organelles and protein complexes, such as cytoskeletal assemblies. We place the strongest emphasis on methods detecting the targets of interest by affinity binding, and we discuss the advantages and limitations of each method.
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Affiliation(s)
- Sofiia Reshetniak
- Institute for Neuro- and Sensory Physiology, Center for Biostructural Imaging of Neurodegeneration (BIN), University Medical Center Göttingen, Göttingen, Germany
- International Max Planck Research School for Molecular Biology, Göttingen, Germany
| | - Silvio O. Rizzoli
- Institute for Neuro- and Sensory Physiology, Center for Biostructural Imaging of Neurodegeneration (BIN), University Medical Center Göttingen, Göttingen, Germany
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Anti-tumoral effect of scorpion peptides: Emerging new cellular targets and signaling pathways. Cell Calcium 2019; 80:160-174. [DOI: 10.1016/j.ceca.2019.05.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 05/10/2019] [Accepted: 05/10/2019] [Indexed: 12/31/2022]
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Vasseur L, Chavanieu A, Combemale S, Caumes C, Béroud R, De Waard M, Ducrot P, Boutin JA, Ferry G, Cens T. Fluorescent analogues of BeKm-1 with high and specific activity against the hERG channel. Toxicon X 2019; 2:100010. [PMID: 32550567 PMCID: PMC7285999 DOI: 10.1016/j.toxcx.2019.100010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 01/30/2019] [Accepted: 02/13/2019] [Indexed: 12/30/2022] Open
Abstract
Peptidic toxins that target specifically mammalian channels and receptors can be found in the venom of animals. These toxins are rarely used directly as tools for biochemical experiments, and need to be modified via the attachment of chemical groups (e.g., radioactive or fluorescent moieties). Ideally, such modifications should maintain the toxin specificity and affinity for its target. With the goal of obtaining fluorescent derivatives of BeKm-1, a toxin from the scorpion species Buthus eupeus that selectively inhibits the voltage-gated potassium ion channel hERG, we produced four active analogues using a model of BeKm-1 docking to the outer mouth of the channel. In these BeKm-1 analogues, the natural peptide was linked to the fluorescent cyanine 5 (Cy5) probe via four different linkers at Arg1 or Arg/Lys27. All analogues retained their specificity towards the hERG channel in electrophysiological experiments but displayed a lesser affinity. These results validate our strategy for designing toxin analogues and demonstrate that different chemical groups can be attached to different residues of BeKm-1. Recent structural data on the hERG ion channel allow modeling BeKm-1 docking to the outer mouth of the channel. The docking model identified solvent-exposed residues in BeKm-1 sequence for the attachment of chemical groups. Four BeKm-1 analogues were produced by labeling with a fluorescent dye the end of four different linkers. Electrophysiological recordings demonstrated that BeKm-1 analogues retain the toxin affinity and specificity towards hERG.
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Affiliation(s)
- Lucie Vasseur
- Institut des Biomolécules Max Mousseron, Université de Montpellier, Montpellier, France
| | - Alain Chavanieu
- Institut des Biomolécules Max Mousseron, Université de Montpellier, Montpellier, France
| | | | | | | | - Michel De Waard
- Smartox Biotechnology, Saint-Egrève, France.,Institut du Thorax, Inserm UMR 1087/CNRS UMR 6291, LabEx « Ion Channels, Science & Therapeutics », Nantes, France
| | - Pierre Ducrot
- Pole d'expertise Biotechnologie, Chimie, Biologie, Institut de Recherches Servier, Croissy-sur-Seine, France
| | - Jean A Boutin
- Pole d'expertise Biotechnologie, Chimie, Biologie, Institut de Recherches Servier, Croissy-sur-Seine, France
| | - Gilles Ferry
- Pole d'expertise Biotechnologie, Chimie, Biologie, Institut de Recherches Servier, Croissy-sur-Seine, France
| | - Thierry Cens
- Institut des Biomolécules Max Mousseron, Université de Montpellier, Montpellier, France
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Kuzmenkov AI, Vassilevski AA. Labelled animal toxins as selective molecular markers of ion channels: Applications in neurobiology and beyond. Neurosci Lett 2018; 679:15-23. [DOI: 10.1016/j.neulet.2017.10.050] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 10/23/2017] [Accepted: 10/25/2017] [Indexed: 12/12/2022]
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