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Studies of the Structure of the N‐Terminal Domain from the Y4 Receptor—a G Protein‐Coupled Receptor—and its Interaction with Hormones from the NPY Family
Author(s) -
Zou Chao,
Kumaran Sowmini,
Markovic Stefan,
Walser Reto,
Zerbe Oliver
Publication year - 2008
Publication title -
chembiochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.05
H-Index - 126
eISSN - 1439-7633
pISSN - 1439-4227
DOI - 10.1002/cbic.200800221
Subject(s) - peptide yy , chemistry , neuropeptide y receptor , receptor , g protein coupled receptor , peptide , binding site , ligand (biochemistry) , peptide hormone , biophysics , stereochemistry , biochemistry , neuropeptide , biology
Binding of peptide hormones to G protein‐coupled receptors is believed to be mediated through formation of contacts of the ligands with residues of the extracellular loops of family 1 GPCRs. Here we have investigated whether additional binding sites exist within the N‐terminal domain, as studied in the form of binding of peptides from the neuropeptide Y (NPY) family to the N terminus of the Y4 receptor (N‐Y4). The N‐terminal domain of the Y4 receptor has been expressed in isotopically enriched form and studied by solution NMR spectroscopy. The peptide is unstructured in solution, whereas a micelle‐associated helical segment is formed in the presence of dodecylphosphocholine (DPC) or sodium dodecylsulfate (SDS). As measured by surface plasmon resonance (SPR) spectroscopy, N‐Y4 binds with approximately 50 μ M affinity to the pancreatic polypeptide (PP), a high‐affinity ligand to the Y4 receptor, whereas binding to neuropeptide Y (NPY) and peptide YY (PYY) is much weaker. Residues critical for binding in PP and in N‐Y4 have been identified by site‐directed mutagenesis. The data indicate that electrostatic interactions dominate and that this interaction is mediated by acidic ligand and basic receptor residues. Residues of N‐Y4 are likely to contribute to the binding of PP, and in addition might possibly also help to transfer the hormone from the membrane‐bound state into the receptor binding pocket.