title: Structural insight into antibody-mediated antagonism of the Glucagon-like peptide-1 Receptor.
abstract: The Glucagon-like peptide-1 receptor (GLP-1R) is a member of the class B G protein-coupled receptor (GPCR) family and a well-established target for the treatment of type 2 diabetes. The N-terminal extracellular domain (ECD) of GLP-1R is important for GLP-1 binding and the crystal structure of the GLP-1/ECD complex was reported previously. The first structure of a class B GPCR transmembrane (TM) domain was solved recently, but the full length receptor structure is still not well understood. Here we describe the molecular details of antibody-mediated antagonism of the GLP-1R using both in vitro pharmacology and x-ray crystallography. We showed that the antibody Fab fragment (Fab 3F52) blocked the GLP-1 binding site of the ECD directly and thereby acts as a competitive antagonist of native GLP-1. Interestingly, Fab 3F52 also blocked a short peptide agonist believed to engage primarily the transmembrane and extracellular loop region of GLP-1R, whereas functionality of an allosteric small-molecule agonist was not inhibited. This study has implications for the structural understanding of the GLP-1R and related class B GPCRs, which is important for the development of new and improved therapeutics targeting these receptors.
authors.affiliation: Incretin Biology, Novo Nordisk, Novo Nordisk Park, DK-2760, Måløv, Denmark.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Hennen
authors.affiliation: Protein &Peptide Chemistry 3, Novo Nordisk, Novo Nordisk Park, DK-2760, Måløv, Denmark.
authors.forename: János T
authors.initials: JT
authors.lastname: Kodra
authors.affiliation: Protein Structure, Novo Nordisk, Novo Nordisk Park, DK-2760, Måløv, Denmark.
authors.forename: Vladyslav
authors.initials: V
authors.lastname: Soroka
authors.affiliation: Yeast Expression Systems, Novo Nordisk, Novo Nordisk Park, DK-2760, Måløv, Denmark.
authors.forename: Berit O
authors.initials: BO
authors.lastname: Krogh
authors.affiliation: Protein Chemistry 1, Novo Nordisk A/S, Novo Nordisk China R&D, Beijing, China.
authors.forename: Xiaoai
authors.initials: X
authors.lastname: Wu
authors.affiliation: Antibody Technology, Novo Nordisk, Novo Nordisk Park, DK-2760, Måløv, Denmark.
authors.forename: Peter
authors.initials: P
authors.lastname: Kaastrup
authors.affiliation: Incretin Biology, Novo Nordisk, Novo Nordisk Park, DK-2760, Måløv, Denmark.
authors.forename: Cathrine
authors.initials: C
authors.lastname: Ørskov
authors.affiliation: Incretin Biology, Novo Nordisk, Novo Nordisk Park, DK-2760, Måløv, Denmark.
authors.forename: Sif G
authors.initials: SG
authors.lastname: Rønn
authors.affiliation: Protein Structure, Novo Nordisk, Novo Nordisk Park, DK-2760, Måløv, Denmark.
authors.forename: Gerd
authors.initials: G
authors.lastname: Schluckebier
authors.affiliation: Protein Structure, Novo Nordisk, Novo Nordisk Park, DK-2760, Måløv, Denmark.
authors.forename: Silvia
authors.initials: S
authors.lastname: Barbateskovic
authors.affiliation: Protein Interaction, Novo Nordisk A/S, Novo Nordisk Park, DK-2760, Måløv, Denmark.
authors.forename: Prafull S
authors.initials: PS
authors.lastname: Gandhi
authors.affiliation: Protein Structure, Novo Nordisk, Novo Nordisk Park, DK-2760, Måløv, Denmark.
authors.forename: Steffen
authors.initials: S
authors.lastname: Reedtz-Runge
mesh_terms: D000906:Antibodies / Q000737:chemistry* / Q000276:immunology*; D001665:Binding Sites; D018360:Crystallography, X-Ray; D000067757:Glucagon-Like Peptide-1 Receptor / Q000037:antagonists & inhibitors* / Q000737:chemistry*; D006801:Humans; D011485:Protein Binding; D011487:Protein Conformation
chemical_list: D000906:Antibodies; D000067757:Glucagon-Like Peptide-1 Receptor