title: Molecular modeling of the human P2Y2 receptor and design of a selective agonist, 2'-amino-2'-deoxy-2-thiouridine 5'-triphosphate.
abstract: A rhodopsin-based homology model of the nucleotide-activated human P2Y2 receptor, including loops, termini, and phospholipids, was optimized with the Monte Carlo multiple minimum conformational search routine. Docked uridine 5'-triphosphate (UTP) formed a nucleobase pi-pi complex with conserved Phe3.32. Selectivity-enhancing 2'-amino-2'-deoxy substitution interacted through pi-hydrogen-bonding with aromatic Phe6.51 and Tyr3.33. A "sequential ligand composition" approach for docking the flexible dinucleotide agonist Up4U demonstrated a shift of conserved cationic Arg3.29 from the UTP gamma position to the delta position of Up4U and Up4 ribose. Synthesized nucleotides were tested as agonists at human P2Y receptors expressed in 1321N1 astrocytoma cells. 2'-Amino and 2-thio modifications were synergized to enhance potency and selectivity; compound 8 (EC50 = 8 nM) was 300-fold P2Y2-selective versus P2Y4. 2'-Amine acetylation reduced potency, and trifluoroacetylation produced intermediate potency. 5-Amino nucleobase substitution did not enhance P2Y2 potency through a predicted hydrophilic interaction possibly because of destabilization of the receptor-favored Northern conformation of ribose. This detailed view of P2Y2 receptor recognition suggests mutations for model validation.
authors.affiliation: Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
authors.forename: Andrei A
authors.initials: AA
authors.lastname: Ivanov
authors.forename: Hyojin
authors.initials: H
authors.lastname: Ko
authors.forename: Liesbet
authors.initials: L
authors.lastname: Cosyn
authors.forename: Savitri
authors.initials: S
authors.lastname: Maddileti
authors.forename: Pedro
authors.initials: P
authors.lastname: Besada
authors.forename: Ingrid
authors.initials: I
authors.lastname: Fricks
authors.forename: Stefano
authors.initials: S
authors.lastname: Costanzi
authors.forename: T Kendall
authors.initials: TK
authors.lastname: Harden
authors.forename: Serge Van
authors.initials: SV
authors.lastname: Calenbergh
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Jacobson
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry; D001665:Binding Sites; D045744:Cell Line, Tumor; D015195:Drug Design; D006801:Humans; D008958:Models, Molecular; D009010:Monte Carlo Method; D011487:Protein Conformation; D058910:Purinergic P2 Receptor Agonists; D021281:Quantitative Structure-Activity Relationship; D018048:Receptors, Purinergic P2 / Q000737:chemistry*; D058473:Receptors, Purinergic P2Y2; D014544:Uridine Triphosphate / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology
chemical_list: C519096:2'-amino-2'-deoxy-2-thiouridine 5'-triphosphate; C546385:P2RY2 protein, human; D058910:Purinergic P2 Receptor Agonists; D018048:Receptors, Purinergic P2; D058473:Receptors, Purinergic P2Y2; D000255:Adenosine Triphosphate; D014544:Uridine Triphosphate