Olfactory receptors (ORs), which comprise the largest G protein-coupled receptor (GPCR) family, play a pivotal role in recognizing a variety of odorants in the vertebrate olfactory system. 1-4 Genome-wide repertoires of the OR family have become available in a variety of vertebrate species, such as human (~350 intact ORs) 5-7 and mouse (1300 to 1500 intact ORs), 8,9 as well as in invertebrates, including fruit fly (62 ORs), 10-12 nematode (~500 chemosensory receptors), 13,14 and mosquito (79 ORs) 15 (0.5 to 4% of the predicted proteomes). The vertebrate OR sequences can be separated into two classes: the Class I family, which was first found in fish and was therefore predicted to recognize water-soluble odorant molecules, such as amino acids and carboxylic acids; and the Class II family, which was not found in fish, and was therefore thought to have appeared during the transition from an aquatic to a terrestrial lifestyle. 16,17 Conserved motifs of five to 10 amino acids have been found that can identify ORs and distinguish them from other GPCRs. In addition, variable regions are found within transmembrane domains of ORs. As in other GPCRs, these might function as the ligand-binding site. 18-20 Across the OR family, the amino acid similarity is 37% on average, with an identity ranging from less than 20% to over 90%. 4.
|ホスト出版物のタイトル||G Protein-Coupled Receptors|
|ホスト出版物のサブタイトル||Structure, Function, and Ligand Screening|
|出版ステータス||出版済み - 1 1 2005|
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