GPCR Engineering Yields High-Resolution Structural Insights into β₂-Adrenergic Receptor Function

• Published in: Science (American Association for the Advancement of Science) Vol. 318; no. 5854; pp. 1266 - 1273
• Main Authors: Rosenbaum, Daniel M, Cherezov, Vadim, Hanson, Michael A, Rasmussen, Søren G.F, Thian, Foon Sun, Kobilka, Tong Sun, Choi, Hee-Jung, Yao, Xiao-Jie, Weis, William I, Stevens, Raymond C, Kobilka, Brian K
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 23.11.2007
• Subjects: Agonists; Amino acids; Biological and medical sciences; Cell receptors; Cell structures and functions; Crystal structure; Crystallization; Crystals; Drug interactions; Fundamental and applied biological sciences. Psychology; Ligands; Molecular and cellular biology; Molecules; Monoamines receptors (catecholamine, serotonine, histamine, acetylcholine); Proteins; Receptors; β2-Adrenergic receptor; High resolution
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1150609

The β₂-adrenergic receptor (β₂AR) is a well-studied prototype for heterotrimeric guanine nucleotide-binding protein (G protein)-coupled receptors (GPCRs) that respond to diffusible hormones and neurotransmitters. To overcome the structural flexibility of the β₂AR and to facilitate its crystallization, we engineered a β₂AR fusion protein in which T4 lysozyme (T4L) replaces most of the third intracellular loop of the GPCR ("β₂AR-T4L") and showed that this protein retains near-native pharmacologic properties. Analysis of adrenergic receptor ligand-binding mutants within the context of the reported high-resolution structure of β₂AR-T4L provides insights into inverse-agonist binding and the structural changes required to accommodate catecholamine agonists. Amino acids known to regulate receptor function are linked through packing interactions and a network of hydrogen bonds, suggesting a conformational pathway from the ligand-binding pocket to regions that interact with G proteins.