Crystal structure of the endogenous agonist-bound prostanoid receptor EP3

Prostanoids are a series of bioactive lipid metabolites that function in an autacoid manner via activation of cognate G-protein-coupled receptors (GPCRs). Here, we report the crystal structure of human prostaglandin (PG) E receptor subtype EP3 bound to endogenous ligand PGE(2) at 2.90 angstrom resolution. The structure reveals important insights into the activation mechanism of prostanoid receptors and provides a molecular basis for the binding modes of endogenous ligands.