1. Key Determinants of Nucleotide-Activated G Protein-Coupled P2Y2 Receptor Function Revealed by Chemical and Pharmacological Experiments, Mutagenesis and Homology Modeling
- Author
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Ivar Von Kügelgen, Christa E. Müller, Geun Yung Ko, Petra Hillmann, Andreas Spinrath, Robert A. Nicholas, Hans Dieter Höltje, Evi Kostenis, Samuel C. Wolff, and Alexandra Raulf
- Subjects
Models, Molecular ,Agonist ,G protein ,medicine.drug_class ,Molecular Sequence Data ,Gene Expression ,Enzyme-Linked Immunosorbent Assay ,Ligands ,Partial agonist ,Protein Structure, Secondary ,Cell Line ,Receptors, Purinergic P2Y2 ,Drug Discovery ,medicine ,Animals ,Humans ,Amino Acid Sequence ,Disulfides ,Amino Acids ,Binding site ,Site-directed mutagenesis ,Receptor ,G protein-coupled receptor ,Sequence Homology, Amino Acid ,Nucleotides ,Receptors, Purinergic P2 ,Chemistry ,Biochemistry ,Drug Design ,Mutagenesis, Site-Directed ,Molecular Medicine ,Signal transduction ,Extracellular Space ,Oxidation-Reduction - Abstract
The P2Y(2) receptor, which is activated by UTP, ATP, and dinucleotides, was studied as a prototypical nucleotide-activated GPCR. A combination of receptor mutagenesis, determination of its effects on potency and efficacy of agonists and antagonists, homology modeling, and chemical experiments was applied. R272 (extracellular loop EL3) was found to play a gatekeeper role, presumably responsible for recognition and orientation of the nucleotides. R272 is also directly involved in binding of dinucleotides, which behaved as partial agonists. Y118A (3.37) mutation led to dramatically reduced efficacy of agonists; it is part of the entry channel as well as the triphosphate binding site. While the Y114A (3.33) mutation did not have any effect on agonist activities, the antagonist Reactive Blue 2 (6) was completely inactive at that mutant. The disulfide bridge Cys25-Cys278 was found to be important for agonist potency but neither for agonist efficacy nor for antagonist potency.
- Published
- 2009
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