3c59
From Proteopedia
Crystal structure of the ligand-bound glucagon-like peptide-1 receptor extracellular domain
Structural highlights
Function[GLP1R_HUMAN] This is a receptor for glucagon-like peptide 1. The activity of this receptor is mediated by G proteins which activate adenylyl cyclase. [EXE4_HELSU] Venom protein that mimics the incretin hormone glucagon-like peptide 1 (GLP-1). It stimulates insulin synthesis and secretion, protects against beta-cell apoptosis in response to different insults, and promotes beta-cell proliferation. It also promotes satiety, reduces food intake, reduces fat deposition, reduces body weight and inhibits gastric emptying. Interacts with GLP-1 receptor (GLP1R). Induces hypotension that is mediated by relaxation of cardiac smooth muscle.[1] [2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe glucagon-like peptide-1 receptor (GLP-1R) belongs to Family B1 of the seven-transmembrane G protein-coupled receptors, and its natural agonist ligand is the peptide hormone glucagon-like peptide-1 (GLP-1). GLP-1 is involved in glucose homeostasis, and activation of GLP-1R in the plasma membrane of pancreatic beta-cells potentiates glucose-dependent insulin secretion. The N-terminal extracellular domain (nGLP-1R) is an important ligand binding domain that binds GLP-1 and the homologous peptide Exendin-4 with differential affinity. Exendin-4 has a C-terminal extension of nine amino acid residues known as the "Trp cage", which is absent in GLP-1. The Trp cage was believed to interact with nGLP-1R and thereby explain the superior affinity of Exendin-4. However, the molecular details that govern ligand binding and specificity of nGLP-1R remain undefined. Here we report the crystal structure of human nGLP-1R in complex with the antagonist Exendin-4(9-39) solved by the multiwavelength anomalous dispersion method to 2.2A resolution. The structure reveals that Exendin-4(9-39) is an amphipathic alpha-helix forming both hydrophobic and hydrophilic interactions with nGLP-1R. The Trp cage of Exendin-4 is not involved in binding to nGLP-1R. The hydrophobic binding site of nGLP-1R is defined by discontinuous segments including primarily a well defined alpha-helix in the N terminus of nGLP-1R and a loop between two antiparallel beta-strands. The structure provides for the first time detailed molecular insight into ligand binding of the human GLP-1 receptor, an established target for treatment of type 2 diabetes. Crystal structure of the ligand-bound glucagon-like peptide-1 receptor extracellular domain.,Runge S, Thogersen H, Madsen K, Lau J, Rudolph R J Biol Chem. 2008 Apr 25;283(17):11340-7. Epub 2008 Feb 20. PMID:18287102[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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