UNIGE document Scientific Article
previous document  unige:5107  next document
add to browser collection

Interaction of alpha-conotoxin ImII and its analogs with nicotinic receptors and acetylcholine-binding proteins: additional binding sites on Torpedo receptor

Kasheverov, Igor E.
Zhmak, Maxim N.
Fish, Alexander
Rucktooa, Prakash
Khruschov, Alexey Yu
Osipov, Alexey V.
Ziganshin, Rustam H.
D'hoedt, Dieter
show hidden authors show all authors [1 - 12]
Published in Journal of neurochemistry. 2009, vol. 111, no. 4, p. 934-44
Abstract alpha-Conotoxins interact with nicotinic acetylcholine receptors (nAChRs) and acetylcholine-binding proteins (AChBPs) at the sites for agonists/competitive antagonists. alpha-Conotoxins blocking muscle-type or alpha7 nAChRs compete with alpha-bungarotoxin. However, alpha-conotoxin ImII, a close homolog of the alpha7 nAChR-targeting alpha-conotoxin ImI, blocked alpha7 and muscle nAChRs without displacing alpha-bungarotoxin (Ellison et al. 2003, 2004), suggesting binding at a different site. We synthesized alpha-conotoxin ImII, its ribbon isomer (ImIIiso), 'mutant' ImII(W10Y) and found similar potencies in blocking human alpha7 and muscle nAChRs in Xenopus oocytes. Both isomers displaced [(125)I]-alpha-bungarotoxin from human alpha7 nAChRs in the cell line GH(4)C(1) (IC(50) 17 and 23 microM, respectively) and from Lymnaea stagnalis and Aplysia californica AChBPs (IC(50) 2.0-9.0 microM). According to SPR measurements, both isomers bound to immobilized AChBPs and competed with AChBP for immobilized alpha-bungarotoxin (K(d) and IC(50) 2.5-8.2 microM). On Torpedo nAChR, alpha-conotoxin [(125)I]-ImII(W10Y) revealed specific binding (K(d) 1.5-6.1 microM) and could be displaced by alpha-conotoxin ImII, ImIIiso and ImII(W10Y) with IC(50) 2.7, 2.2 and 3.1 microM, respectively. As alpha-cobratoxin and alpha-conotoxin ImI displaced [(125)I]-ImII(W10Y) only at higher concentrations (IC(50)> or = 90 microM), our results indicate that alpha-conotoxin ImII and its congeners have an additional binding site on Torpedo nAChR distinct from the site for agonists/competitive antagonists.
Keywords Acetylcholine/pharmacologyAmino Acid SequenceAnimalsAplysiaBinding Sites/drug effects/physiologyBinding, Competitive/drug effectsBungarotoxins/metabolismCarrier Proteins/metabolismConotoxins/chemistry/metabolismDose-Response Relationship, DrugHumansInhibitory Concentration 50Iodine Isotopes/metabolismMolecular Sequence DataOocytesRadioligand Assay/methodsReceptors, Nicotinic/genetics/metabolismSerine EndopeptidasesSpectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methodsSurface Plasmon Resonance/methodsTorpedo/metabolismXenopus laevis
PMID: 19712060
Full text
Article (Published version) (967 Kb) - document accessible for UNIGE members only Limited access to UNIGE
(ISO format)
KASHEVEROV, Igor E. et al. Interaction of alpha-conotoxin ImII and its analogs with nicotinic receptors and acetylcholine-binding proteins: additional binding sites on Torpedo receptor. In: Journal of Neurochemistry, 2009, vol. 111, n° 4, p. 934-44. doi: 10.1111/j.1471-4159.2009.06359.x https://archive-ouverte.unige.ch/unige:5107

449 hits



Deposited on : 2010-02-02

Export document
Format :
Citation style :