Predicted Structure of Agonist-Bound Glucagon-Like Peptide 1 Receptor, a Class B G Protein-Coupled Receptor

Proc Natl Acad Sci U S A. 2012 Dec 4;109(49):19988-93. doi: 10.1073/pnas.1218051109. Epub 2012 Nov 19.

Abstract

The glucagon-like peptide 1 receptor (GLP1R) is a G protein-coupled receptor (GPCR) involved in insulin synthesis and regulation; therefore, it is an important drug target for treatment of diabetes. However, GLP1R is a member of the class B1 family of GPCRs for which there are no experimental structures. To provide a structural basis for drug design and to probe class B GPCR activation, we predicted the transmembrane (TM) bundle structure of GLP1R bound to the peptide Exendin-4 (Exe4; a GLP1R agonist on the market for treating diabetes) using the MembStruk method for scanning TM bundle conformations. We used protein-protein docking methods to combine the TM bundle with the X-ray crystal structure of the 143-aa N terminus coupled to the Exe4 peptide. This complex was subjected to 28 ns of full-solvent, full-lipid molecular dynamics. We find 14 strong polar interactions of Exe4 with GLP1R, of which 8 interactions are in the TM bundle (2 interactions confirmed by mutation studies) and 6 interactions involve the N terminus (3 interactions found in the crystal structure). We also find 10 important hydrophobic interactions, of which 4 interactions are in the TM bundle (2 interactions confirmed by mutation studies) and 6 interactions are in the N terminus (6 interactions present in the crystal structure). Thus, our predicted structure agrees with available mutagenesis studies. We suggest a number of mutation experiments to further validate our predicted structure. The structure should be useful for guiding drug design and can provide a structural basis for understanding ligand binding and receptor activation of GLP1R and other class B1 GPCRs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Drug Design
  • Exenatide
  • Glucagon-Like Peptide-1 Receptor
  • Hydrophobic and Hydrophilic Interactions
  • Models, Molecular*
  • Peptides / metabolism*
  • Protein Conformation*
  • Protein Interaction Domains and Motifs / genetics
  • Receptors, Glucagon / agonists*
  • Receptors, Glucagon / chemistry*
  • Venoms / metabolism*

Substances

  • Glucagon-Like Peptide-1 Receptor
  • Peptides
  • Receptors, Glucagon
  • Venoms
  • Exenatide