Crystal structure of oligomeric β1-adrenergic G protein-coupled receptors in ligand-free basal state

Nat Struct Mol Biol. 2013 Apr;20(4):419-25. doi: 10.1038/nsmb.2504. Epub 2013 Feb 24.


G protein-coupled receptors (GPCRs) mediate transmembrane signaling. Before ligand binding, GPCRs exist in a basal state. Crystal structures of several GPCRs bound with antagonists or agonists have been solved. However, the crystal structure of the ligand-free basal state of a GPCR, the starting point of GPCR activation and function, had not yet been determined. Here we report the X-ray crystal structure of the ligand-free basal state of a GPCR in a lipid membrane-like environment. Oligomeric turkey β1-adrenergic receptors display two dimer interfaces. One interface involves the transmembrane domain (TM) 1, TM2, the C-terminal H8 and extracellular loop 1. The other interface engages residues from TM4, TM5, intracellular loop 2 and extracellular loop 2. Structural comparisons show that this ligand-free state is in an inactive conformation. This provides the structural basis of GPCR dimerization and oligomerization.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Biopolymers
  • Dimerization
  • Disulfides / chemistry
  • Ligands
  • Models, Molecular
  • Receptors, Adrenergic, beta-1 / chemistry*
  • Receptors, G-Protein-Coupled / chemistry*


  • Biopolymers
  • Disulfides
  • Ligands
  • Receptors, Adrenergic, beta-1
  • Receptors, G-Protein-Coupled

Associated data

  • PDB/4GPO