Orthosteric and/or Allosteric Binding of α-Conotoxins to Nicotinic Acetylcholine Receptors and Their Models
α-Conotoxins from <i>Conus</i> snails are capable of distinguishing muscle and neuronal nicotinic acetylcholine receptors (nAChRs). α-Conotoxin RgIA and αO-conotoxin GeXIVA, blocking neuronal α9α10 nAChR, are potential analgesics. Typically, &...
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doaj-4baca4d9b0c5468eb3e26107218a6f962020-11-24T21:23:00ZengMDPI AGMarine Drugs1660-33972018-11-01161246010.3390/md16120460md16120460Orthosteric and/or Allosteric Binding of α-Conotoxins to Nicotinic Acetylcholine Receptors and Their ModelsElena V. Kryukova0Igor A. Ivanov1Dmitry S. Lebedev2Ekaterina N. Spirova3Natalia S. Egorova4Marios Zouridakis5Igor E. Kasheverov6Socrates J. Tzartos7Victor I. Tsetlin8Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya Street, 16/10, 117997 Moscow, RussiaShemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya Street, 16/10, 117997 Moscow, RussiaShemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya Street, 16/10, 117997 Moscow, RussiaShemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya Street, 16/10, 117997 Moscow, RussiaShemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya Street, 16/10, 117997 Moscow, RussiaDepartment of Neurobiology, Hellenic Pasteur Institute, 127, Vas. Sofias ave., Athens 115 21, GreeceShemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya Street, 16/10, 117997 Moscow, RussiaDepartment of Neurobiology, Hellenic Pasteur Institute, 127, Vas. Sofias ave., Athens 115 21, GreeceShemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya Street, 16/10, 117997 Moscow, Russiaα-Conotoxins from <i>Conus</i> snails are capable of distinguishing muscle and neuronal nicotinic acetylcholine receptors (nAChRs). α-Conotoxin RgIA and αO-conotoxin GeXIVA, blocking neuronal α9α10 nAChR, are potential analgesics. Typically, α-conotoxins bind to the orthosteric sites for agonists/competitive antagonists, but αO-conotoxin GeXIVA was proposed to attach allosterically, judging by electrophysiological experiments on α9α10 nAChR. We decided to verify this conclusion by radioligand analysis in competition with α-bungarotoxin (αBgt) on the ligand-binding domain of the nAChR α9 subunit (α9 LBD), where, from the X-ray analysis, αBgt binds at the orthosteric site. A competition with αBgt was registered for GeXIVA and RgIA, IC<sub>50</sub> values being in the micromolar range. However, high nonspecific binding of conotoxins (detected with their radioiodinated derivatives) to His<sub>6</sub>-resin attaching α9 LBD did not allow us to accurately measure IC<sub>50</sub>s. However, IC<sub>50</sub>s were measured for binding to <i>Aplysia californica</i> AChBP: the RgIA globular isomer, known to be active against α9α10 nAChR, was more efficient than the ribbon one, whereas all three GeXIVA isomers had similar potencies at low µM. Thus, radioligand analysis indicated that both conotoxins can attach to the orthosteric sites in these nAChR models, which should be taken into account in the design of analgesics on the basis of these conotoxins.https://www.mdpi.com/1660-3397/16/12/460conotoxinsnicotinic acetylcholine receptorsligand-binding domainacetylcholine-binding proteinbinding siteradioligand analysis |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Elena V. Kryukova Igor A. Ivanov Dmitry S. Lebedev Ekaterina N. Spirova Natalia S. Egorova Marios Zouridakis Igor E. Kasheverov Socrates J. Tzartos Victor I. Tsetlin |
spellingShingle |
Elena V. Kryukova Igor A. Ivanov Dmitry S. Lebedev Ekaterina N. Spirova Natalia S. Egorova Marios Zouridakis Igor E. Kasheverov Socrates J. Tzartos Victor I. Tsetlin Orthosteric and/or Allosteric Binding of α-Conotoxins to Nicotinic Acetylcholine Receptors and Their Models Marine Drugs conotoxins nicotinic acetylcholine receptors ligand-binding domain acetylcholine-binding protein binding site radioligand analysis |
author_facet |
Elena V. Kryukova Igor A. Ivanov Dmitry S. Lebedev Ekaterina N. Spirova Natalia S. Egorova Marios Zouridakis Igor E. Kasheverov Socrates J. Tzartos Victor I. Tsetlin |
author_sort |
Elena V. Kryukova |
title |
Orthosteric and/or Allosteric Binding of α-Conotoxins to Nicotinic Acetylcholine Receptors and Their Models |
title_short |
Orthosteric and/or Allosteric Binding of α-Conotoxins to Nicotinic Acetylcholine Receptors and Their Models |
title_full |
Orthosteric and/or Allosteric Binding of α-Conotoxins to Nicotinic Acetylcholine Receptors and Their Models |
title_fullStr |
Orthosteric and/or Allosteric Binding of α-Conotoxins to Nicotinic Acetylcholine Receptors and Their Models |
title_full_unstemmed |
Orthosteric and/or Allosteric Binding of α-Conotoxins to Nicotinic Acetylcholine Receptors and Their Models |
title_sort |
orthosteric and/or allosteric binding of α-conotoxins to nicotinic acetylcholine receptors and their models |
publisher |
MDPI AG |
series |
Marine Drugs |
issn |
1660-3397 |
publishDate |
2018-11-01 |
description |
α-Conotoxins from <i>Conus</i> snails are capable of distinguishing muscle and neuronal nicotinic acetylcholine receptors (nAChRs). α-Conotoxin RgIA and αO-conotoxin GeXIVA, blocking neuronal α9α10 nAChR, are potential analgesics. Typically, α-conotoxins bind to the orthosteric sites for agonists/competitive antagonists, but αO-conotoxin GeXIVA was proposed to attach allosterically, judging by electrophysiological experiments on α9α10 nAChR. We decided to verify this conclusion by radioligand analysis in competition with α-bungarotoxin (αBgt) on the ligand-binding domain of the nAChR α9 subunit (α9 LBD), where, from the X-ray analysis, αBgt binds at the orthosteric site. A competition with αBgt was registered for GeXIVA and RgIA, IC<sub>50</sub> values being in the micromolar range. However, high nonspecific binding of conotoxins (detected with their radioiodinated derivatives) to His<sub>6</sub>-resin attaching α9 LBD did not allow us to accurately measure IC<sub>50</sub>s. However, IC<sub>50</sub>s were measured for binding to <i>Aplysia californica</i> AChBP: the RgIA globular isomer, known to be active against α9α10 nAChR, was more efficient than the ribbon one, whereas all three GeXIVA isomers had similar potencies at low µM. Thus, radioligand analysis indicated that both conotoxins can attach to the orthosteric sites in these nAChR models, which should be taken into account in the design of analgesics on the basis of these conotoxins. |
topic |
conotoxins nicotinic acetylcholine receptors ligand-binding domain acetylcholine-binding protein binding site radioligand analysis |
url |
https://www.mdpi.com/1660-3397/16/12/460 |
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