Figure 3: Crystal structures of GPCRs with closely associated cholesterol molecules. (a) The human -adrenergic receptor structure (shown in blue) with bound carazolol (a partial inverse agonist; shown in green) embedded in a lipid bilayer. Cholesterol molecules between two receptor molecules are shown in orange. (b) The crystal structure of human -adrenergic receptor (bound to the partial inverse agonist timolol) highlighting its cholesterol consensus motif (CCM). The side chain positions of the -adrenergic receptor and two bound cholesterol molecules are shown. (c) The crystal structure of the human adenosine receptor (in cyan) with three bound cholesterol molecules (yellow). ((a)–(c)) are reproduced from [36] with permission from Eureka Science Ltd. (d) depicts the dimer interface in the crystal structure of metabotropic glutamate type 1 (mGlu1) receptor. Six bound cholesterol molecules (shown in green) are observed on the extracellular side of helices I and II of two monomers (shown in cyan and orange) of the mGlu1 receptor involved in the dimer formation. Surface and stick presentations of the residues participating in receptor-cholesterol and receptor-receptor interactions are shown. Reproduced from [37], with permission from AAAS. See text for more details.