Probing the role of the cation-[pi] interaction in the binding sites of GPCRs using unnatural amino acids

We describe a general application of the nonsense suppression methodology for unnatural amino acid incorporation to probe drug - receptor interactions in functional G protein-coupled receptors (GPCRs), evaluating the binding sites of both the M2 muscarinic acetylcholine receptor and the D2 dopamine...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 2009-07, Vol.106 (29), p.11919
Main Authors: Torrice, Michael M, Bower, Kiowa S, Lester, Henry A, Dougherty, Dennis A
Format: Article
Language:English
Subjects:
Amino acids
Binding sites
Frogs
Gene expression
Glycoproteins
T cell receptors
Online Access:Get full text
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Summary:We describe a general application of the nonsense suppression methodology for unnatural amino acid incorporation to probe drug - receptor interactions in functional G protein-coupled receptors (GPCRs), evaluating the binding sites of both the M2 muscarinic acetylcholine receptor and the D2 dopamine receptor. Receptors were expressed in Xenopus oocytes, and activation of a G protein-coupled, inward-rectifying K+ channel (GIRK) provided, after optimization of conditions, a quantitative readout of receptor function. A number of aromatic amino acids thought to be near the agonist-binding site were evaluated. Incorporation of a series of fluorinated tryptophan derivatives at W6.48 of the D2 receptor establishes a cation - ... interaction between the agonist dopamine and W6.48, suggesting a reorientation of W6.48 on agonist binding, consistent with proposed "rotamer switch" models. Interestingly, no comparable cation - ... interaction was found at the aligning residue in the M2 receptor. (ProQuest: ... denotes formulae/symbols omitted.)
ISSN:0027-8424
1091-6490