Efficient binding of 4/7 α-conotoxins to nicotinic α4β2 receptors is prevented by Arg185 and Pro195 in the α4 subunit

Beissner, Mirko, Dutertre, Sebastien, Schemm, Rudolf, Danker, Timm, Sporning, Annett, Grubmueller, Helmut and Nicke, Annette (2012) Efficient binding of 4/7 α-conotoxins to nicotinic α4β2 receptors is prevented by Arg185 and Pro195 in the α4 subunit. Molecular Pharmacology, 82 4: 711-718. doi:10.1124/mol.112.078683


Author Beissner, Mirko
Dutertre, Sebastien
Schemm, Rudolf
Danker, Timm
Sporning, Annett
Grubmueller, Helmut
Nicke, Annette
Title Efficient binding of 4/7 α-conotoxins to nicotinic α4β2 receptors is prevented by Arg185 and Pro195 in the α4 subunit
Journal name Molecular Pharmacology   Check publisher's open access policy
ISSN 0026-895X
1521-0111
Publication date 2012-10
Sub-type Article (original research)
DOI 10.1124/mol.112.078683
Volume 82
Issue 4
Start page 711
End page 718
Total pages 8
Place of publication Bethesda, MD United States
Publisher American Society for Pharmacology and Experimental Therapeutics
Collection year 2013
Language eng
Formatted abstract
α-Conotoxins are subtype-selective nicotinic acetylcholine receptor (nAChR) antagonists. Although potent α3β2 nAChR-selective α-conotoxins have been identified, currently characterized α-conotoxins show no or only weak affinity for α4β2 nAChRs, which are, besides α7 receptors, the most abundant nAChRs in the mammalian brain. To identify the determinants responsible for this difference, we substituted selected amino acid residues in the ligand-binding domain of the α4 subunit by the corresponding residues in the α3 subunit. Two-electrode voltage clamp analysis of these mutants revealed increased affinity of α-conotoxins MII, TxIA, and [A10L]TxIA at the α4(R185I)β2 receptor. Conversely, α-conotoxin potency was reduced at the reverse α3(I186R)β2 mutant. Replacement of α4Arg185 by alanine, glutamate, and lysine demonstrated that a positive charge in this position prevents α-conotoxin binding. Combination of the R185I mutation with a P195Q mutation outside the binding site but in loop C completely transferred high α-conotoxin potency to the α4β2 receptor. Molecular dynamics simulations of homology models with docked α-conotoxin indicate that these residues control access to the α-conotoxin binding site.
Keyword Acetylcholine Receptor
Antagonist
Residues
Subtypes
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2013 Collection
Institute for Molecular Bioscience - Publications
 
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