Abstract
Computational modeling and its application in ligand screening and ligand receptor interaction studies play important roles in structure-based drug design. A series of sphingosine 1-phosphate (S1P) receptor ligands with varying potencies and receptor selectivities were docked into homology models of the S1P1-5 receptors. These studies provided molecular insights into pharmacological trends both across the receptor family as well as at single receptors. This study identifies ligand recognition features that generalize across the S1P receptor family, features unique to the S1P4 and S1P5 receptors, and suggests significant structural differences of the S1P2 receptor. Docking results reveal a previously unknown sulfur-aromatic interaction between the S1P4 C5.44 sulfur atom and the phenyl ring of benzimidazole as well as π-π interaction between F3.33 of S1P1,4,5 and aromatic ligands. The findings not only confirm the importance of a cation-π interaction between W4.64 and the ammonium of S1P at S1P4 but also predict the same interaction at S1P5. S1P receptor models are validated for pharmacophore development including database mining and new ligand discovery and serve as tools for ligand optimization to improve potency and selectivity.