Structural insight into antibody-mediated antagonism of the Glucagon-like peptide-1 Receptor

  • Sci Rep. 2016 May 19;6:26236. doi: 10.1038/srep26236.
Stephanie Hennen  1 ,  János T Kodra  2 ,  Vladyslav Soroka  3 ,  Berit O Krogh  4 ,  Xiaoai Wu  5 ,  Peter Kaastrup  6 ,  Cathrine Ørskov  1 ,  Sif G Rønn  1 ,  Gerd Schluckebier  3 ,  Silvia Barbateskovic  3 ,  Prafull S Gandhi  7 ,  Steffen Reedtz-Runge  3
Affiliations
  • 1. Incretin Biology, Novo Nordisk, Novo Nordisk Park, DK-2760, Måløv, Denmark.
  • 2. Protein &Peptide Chemistry 3, Novo Nordisk, Novo Nordisk Park, DK-2760, Måløv, Denmark.
  • 3. Protein Structure, Novo Nordisk, Novo Nordisk Park, DK-2760, Måløv, Denmark.
  • 4. Yeast Expression Systems, Novo Nordisk, Novo Nordisk Park, DK-2760, Måløv, Denmark.
  • 5. Protein Chemistry 1, Novo Nordisk A/S, Novo Nordisk China R&D, Beijing, China.
  • 6. Antibody Technology, Novo Nordisk, Novo Nordisk Park, DK-2760, Måløv, Denmark.
  • 7. Protein Interaction, Novo Nordisk A/S, Novo Nordisk Park, DK-2760, Måløv, Denmark.
PMID: 27196125 DOI: 10.1038/srep26236
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.