title: NMR structure of an intracellular loop peptide derived from prostaglandin EP3alpha receptor.
abstract: We found that a peptide (EP3a: TIKALVSRCRAKAAV) corresponding to the N-terminal site of the intracellular third loop of human prostaglandin EP3alpha receptor could activate G protein alpha-subunit directly. The activity was almost same as Mastoparan-X, a G protein activating peptide from wasp venom. The three-dimensional molecular structure of the peptide in SDS-d(25) micelles was determined by 2D (1)H NMR spectroscopy. The structure of EP3a consists of a positive charge cluster on the C-terminal helical site. The cluster was also found in several corresponding receptor peptides. Therefore, the positive charge cluster on the helical structure might play a crucial role in activation of G protein.
authors.affiliation: Faculty of Pharmaceutical Sciences, Chiba Institute of Science, Choshi, Chiba 288-0025, Japan.
authors.forename: Tatsuhiko
authors.initials: T
authors.lastname: Kikkou
authors.forename: Osamu
authors.initials: O
authors.lastname: Matsumoto
authors.forename: Tadayasu
authors.initials: T
authors.lastname: Ohkubo
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Gozoh
authors.initials: G
authors.lastname: Tsujimoto
mesh_terms: D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000737:chemistry; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008958:Models, Molecular; D008968:Molecular Conformation; D010455:Peptides / Q000737:chemistry; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D018078:Receptors, Prostaglandin E / Q000737:chemistry* / Q000378:metabolism*; D058308:Receptors, Prostaglandin E, EP3 Subtype
chemical_list: C545647:PTGER3 protein, human; D010455:Peptides; D018078:Receptors, Prostaglandin E; D058308:Receptors, Prostaglandin E, EP3 Subtype; D016244:Guanosine 5'-O-(3-Thiotriphosphate)