title: Genetically encoded chemical probes in cells reveal the binding path of urocortin-I to CRF class B GPCR.
abstract: Molecular determinants regulating the activation of class B G-protein-coupled receptors (GPCRs) by native peptide agonists are largely unknown. We have investigated here the interaction between the corticotropin releasing factor receptor type 1 (CRF1R) and its native 40-mer peptide ligand Urocortin-I directly in mammalian cells. By incorporating unnatural amino acid photochemical and new click-chemical probes into the intact receptor expressed in the native membrane of live cells, 44 intermolecular spatial constraints have been derived for the ligand-receptor interaction. The data were analyzed in the context of the recently resolved crystal structure of CRF1R transmembrane domain and existing extracellular domain structures, yielding a complete conformational model for the peptide-receptor complex. Structural features of the receptor-ligand complex yield molecular insights on the mechanism of receptor activation and the basis for discrimination between agonist and antagonist function.
authors.affiliation: Jack H. Skirball Center for Chemical Biology and Proteomics, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
authors.forename: Irene
authors.initials: I
authors.lastname: Coin
authors.forename: Vsevolod
authors.initials: V
authors.lastname: Katritch
authors.forename: Tingting
authors.initials: T
authors.lastname: Sun
authors.forename: Zheng
authors.initials: Z
authors.lastname: Xiang
authors.forename: Fai Yiu
authors.initials: FY
authors.lastname: Siu
authors.forename: Michael
authors.initials: M
authors.lastname: Beyermann
authors.forename: Raymond C
authors.initials: RC
authors.lastname: Stevens
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D057930:Click Chemistry / Q000379:methods; D003432:Cross-Linking Reagents / Q000378:metabolism; D006801:Humans; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D051381:Rats; D018019:Receptors, Corticotropin-Releasing Hormone / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D054832:Urocortins / Q000737:chemistry* / Q000378:metabolism*; D000099052:CRF Receptor, Type 1
chemical_list: D003432:Cross-Linking Reagents; D018019:Receptors, Corticotropin-Releasing Hormone; C576814:UCN protein, human; D054832:Urocortins; D000099052:CRF Receptor, Type 1