title: Pancreatic polypeptide is recognized by two hydrophobic domains of the human Y4 receptor binding pocket.
abstract: Structural characterization of the human Y4 receptor (hY4R) interaction with human pancreatic polypeptide (hPP) is crucial, not only for understanding its biological function but also for testing treatment strategies for obesity that target this interaction. Here, the interaction of receptor mutants with pancreatic polypeptide analogs was studied through double-cycle mutagenesis. To guide mutagenesis and interpret results, a three-dimensional comparative model of the hY4R-hPP complex was constructed based on all available class A G protein-coupled receptor crystal structures and refined using experimental data. Our study reveals that residues of the hPP and the hY4R form a complex network consisting of ionic interactions, hydrophobic interactions, and hydrogen binding. Residues Tyr(2.64), Asp(2.68), Asn(6.55), Asn(7.32), and Phe(7.35) of Y4R are found to be important in receptor activation by hPP. Specifically, Tyr(2.64) interacts with Tyr(27) of hPP through hydrophobic contacts. Asn(7.32) is affected by modifications on position Arg(33) of hPP, suggesting a hydrogen bond between these two residues. Likewise, we find that Phe(7.35) is affected by modifications of hPP at positions 33 and 36, indicating interactions between these three amino acids. Taken together, we demonstrate that the top of transmembrane helix 2 (TM2) and the top of transmembrane helices 6 and 7 (TM6-TM7) form the core of the peptide binding pocket. These findings will contribute to the rational design of ligands that bind the receptor more effectively to produce an enhanced agonistic or antagonistic effect.
authors.affiliation: From the Institute of Biochemistry, Faculty of Biosciences, Pharmacy and Psychology, Universität Leipzig, 04103 Leipzig, Germany and.
authors.forename: Xavier
authors.initials: X
authors.lastname: Pedragosa-Badia
authors.forename: Gregory R
authors.initials: GR
authors.lastname: Sliwoski
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Dong Nguyen
authors.forename: Diana
authors.initials: D
authors.lastname: Lindner
authors.forename: Jan
authors.initials: J
authors.lastname: Stichel
authors.forename: Kristian W
authors.initials: KW
authors.lastname: Kaufmann
authors.forename: Jens
authors.initials: J
authors.lastname: Meiler
authors.forename: Annette G
authors.initials: AG
authors.lastname: Beck-Sickinger
mesh_terms: D000818:Animals; D001665:Binding Sites; D019556:COS Cells; D002522:Chlorocebus aethiops; D018360:Crystallography, X-Ray; D057809:HEK293 Cells; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D010191:Pancreatic Polypeptide / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D017476:Receptors, Neuropeptide Y / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D017476:Receptors, Neuropeptide Y; C109491:neuropeptide Y4 receptor; D010191:Pancreatic Polypeptide
keywords: 7-Helix Receptor; Binding Pocket; Comparative Model; Computer Modeling; G Protein-coupled Receptors (GPCR); Molecular Modeling; Neuropeptide; Pancreatic Polypeptide