title: Receptor subtype-specific docking of Asp6.59 with C-terminal arginine residues in Y receptor ligands.
abstract: Y receptors (YRs) are G protein-coupled receptors whose Y(1)R, Y(2)R, and Y(5)R subtypes preferentially bind neuropeptide Y (NPY) and peptide YY, whereas mammalian Y(4)Rs show a higher affinity for pancreatic polypeptide (PP). Comparison of YR orthologs and paralogs revealed Asp(6.59) to be fully conserved throughout all of the YRs reported so far. By replacing this conserved aspartic acid residue with alanine, asparagine, glutamate, and arginine, we now show that this residue plays a crucial role in binding and signal transduction of NPY/PP at all YRs. Sensitivity to distinct replacements is, however, receptor subtype-specific. Next, we performed a complementary mutagenesis approach to identify the contact site of the ligand. Surprisingly, this conserved residue interacts with two different ligand arginine residues by ionic interactions; although in Y(2)R and Y(5)R, Arg(33) is the binding partner of Asp(6.59), in Y(1)R and Y(4)R, Arg(35) of human PP and NPY interacts with Asp(6.59). Furthermore, Arg(25) of PP and NPY is involved in ligand binding only at Y(2)R and Y(5)R. This suggests significant differences in the docking of YR ligands between Y(1/4)R and Y(2/5)R and provides new insights into the molecular binding mode of peptide agonists at GPCRs. Furthermore, the proposed model of a subtype-specific binding mode is in agreement with the evolution of YRs.
authors.affiliation: Institute of Biochemistry, Faculty of Bioscience, Pharmacy and Psychology, University of Leipzig, Brüderstrasse 34, 04103 Leipzig, Germany.
authors.forename: Nicole
authors.initials: N
authors.lastname: Merten
authors.forename: Diana
authors.initials: D
authors.lastname: Lindner
authors.forename: Nadine
authors.initials: N
authors.lastname: Rabe
authors.forename: Holger
authors.initials: H
authors.lastname: Römpler
authors.forename: Karin
authors.initials: K
authors.lastname: Mörl
authors.forename: Torsten
authors.initials: T
authors.lastname: Schöneberg
authors.forename: Annette G
authors.initials: AG
authors.lastname: Beck-Sickinger
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001120:Arginine; D019556:COS Cells; D002522:Chlorocebus aethiops; D017124:Conserved Sequence; D006224:Cricetinae; D006801:Humans; D008024:Ligands; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009478:Neuropeptide Y / Q000737:chemistry*; D010191:Pancreatic Polypeptide / Q000737:chemistry*; D017476:Receptors, Neuropeptide Y / Q000737:chemistry* / Q000145:classification
chemical_list: D008024:Ligands; D009478:Neuropeptide Y; D017476:Receptors, Neuropeptide Y; D010191:Pancreatic Polypeptide; D001120:Arginine