title: Common and distinct mechanisms of activation of rhodopsin and other G protein-coupled receptors.
abstract: Detailed and systematic examination of high-resolution structural data is a rational strategy for understanding the function of biological macromolecules. G protein-coupled receptors (GPCRs) are an exceptionally valuable superfamily of proteins for such analysis. The most intriguing question is how a variety of extracellular stimuli evoke structural changes in the intracellular surface of the receptors. The recent active-like crystal structures of GPCRs provide information for uncovering common and distinct mechanisms of light-induced and ligand-induced activation. Based on systematic structural alignment, we have analyzed 3 receptors (rhodopsin, β2 adrenergic receptor, adenosine A2A receptor) and demonstrate that the extracellular movement of helix VI is significantly different between rhodopsin and the other 2 receptors, and that the extracellular side of helix III exhibits distinct features in the 3 receptors. These findings not only emphasize the specialization of rhodopsin as a photoreceptor but also provide insights into the mechanism leading to rearrangement of helix VI.
authors.affiliation: Department of Life Science, Gakushuin University, 1-5-1 Mejiro, Toshima-ku, Tokyo 171-8588, Japan.
authors.forename: Sumire
authors.initials: S
authors.lastname: Nakamura
authors.forename: Takeshi
authors.initials: T
authors.lastname: Itabashi
authors.forename: Daisuke
authors.initials: D
authors.lastname: Ogawa
authors.forename: Tetsuji
authors.initials: T
authors.lastname: Okada
mesh_terms: D003593:Cytoplasm; D006801:Humans; D008024:Ligands; D008958:Models, Molecular; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D043705:Receptor, Adenosine A2A / Q000737:chemistry / Q000378:metabolism*; D018343:Receptors, Adrenergic, beta-2 / Q000737:chemistry / Q000378:metabolism*; D012243:Rhodopsin / Q000737:chemistry / Q000378:metabolism*
chemical_list: D008024:Ligands; D043705:Receptor, Adenosine A2A; D018343:Receptors, Adrenergic, beta-2; D012243:Rhodopsin