Molecular Modeling of the Human P2Y2 Receptor and Design of a Selective Agonist, 2‘-Amino-2‘-deoxy-2-thiouridine 5‘-Triphosphate
摘要:
A rhodopsin-based homology model of the nucleotide-activated human P2Y(2) 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 Up(4)U demonstrated a shift of conserved cationic Arg3.29 from the UTP gamma position to the delta position of Up(4)U and Up(4) 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 P2Y(2)-selective versus P2Y(4). 2'-Amine acetylation reduced potency, and trifluoroacetylation produced intermediate potency. 5-Amino nucleobase substitution did not enhance P2Y(2) potency through a predicted hydrophilic interaction possibly because of destabilization of the receptor-favored Northern conformation of ribose. This detailed view of P2Y(2) receptor recognition suggests mutations for model validation.
Molecular Modeling of the Human P2Y2 Receptor and Design of a Selective Agonist, 2‘-Amino-2‘-deoxy-2-thiouridine 5‘-Triphosphate
摘要:
A rhodopsin-based homology model of the nucleotide-activated human P2Y(2) 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 Up(4)U demonstrated a shift of conserved cationic Arg3.29 from the UTP gamma position to the delta position of Up(4)U and Up(4) 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 P2Y(2)-selective versus P2Y(4). 2'-Amine acetylation reduced potency, and trifluoroacetylation produced intermediate potency. 5-Amino nucleobase substitution did not enhance P2Y(2) potency through a predicted hydrophilic interaction possibly because of destabilization of the receptor-favored Northern conformation of ribose. This detailed view of P2Y(2) receptor recognition suggests mutations for model validation.