title: Identification of endogenous surrogate ligands for human P2Y receptors through an in silico search.
abstract: G protein-coupled receptors (GPCRs) are distributed widely throughout the human body, and nearly 50% of current medicines act on a GPCR. GPCRs are considered to consist of seven transmembrane alpha-helices that form an alpha-helical bundle in which agonists and antagonists bind. A 3D structure of the target GPCR is indispensable for designing novel medicines acting on a GPCR. We have previously constructed the 3D structure of human P2Y(1) (hP2Y(1)) receptor, a GPCR, by homology modeling with the 3D structure of bovine rhodopsin as a template. In the present study, we have employed an in silico screening for compounds that could bind to the hP2Y(1)-receptor model using AutoDock 3.0. We selected 21 of the 30 top-ranked compounds, and by measuring intracellular Ca(2+) concentration, we identified 12 compounds that activated or blocked the hP2Y(1) receptor stably expressed in recombinant CHO cells. 5-Phosphoribosyl-1-pyrophosphate (PRPP) was found to activate the hP2Y(1) receptor with a low ED(50) value of 15 nM. The Ca(2+) assays showed it had no significant effect on P2Y(2), P2Y(6), or P2X(2) receptors, but acted as a weak agonist on the P2Y(12) receptor. This is the first study to rationally identify surrogate ligands for the P2Y-receptor family.
authors.affiliation: Laboratory of Pharmcoinformatics, Department of Bioscience and Biotechnology, College of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Hiramoto
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Nonaka
authors.forename: Kazuko
authors.initials: K
authors.lastname: Inoue
authors.forename: Takefumi
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Mariko
authors.initials: M
authors.lastname: Omatsu-Kanbe
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Matsuura
authors.forename: Keigo
authors.initials: K
authors.lastname: Gohda
authors.forename: Norihisa
authors.initials: N
authors.lastname: Fujita
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D016466:CHO Cells; D002118:Calcium / Q000378:metabolism; D006224:Cricetinae; D004305:Dose-Response Relationship, Drug; D006801:Humans; D008024:Ligands; D018048:Receptors, Purinergic P2 / Q000378:metabolism*; D058472:Receptors, Purinergic P2Y1; D017655:Silicon Compounds / Q000737:chemistry / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D008024:Ligands; C546382:P2RY1 protein, human; D018048:Receptors, Purinergic P2; D058472:Receptors, Purinergic P2Y1; D017655:Silicon Compounds; D002118:Calcium