Electropositive regions along with moderate section in hit compounds demonstrates that these regions can act as electron donors or acceptors to the active site of the chymase thus making these compounds very reactive. MK-8245 docking results of these compounds also signified the participation of these areas in the imperative interactions with the key active site residues such as Ser195, Gly193, His57, Tyr215 and Phe191 of the enzyme. A deriving pharmacophore model from the three-dimensional structure of a target protein provides helpful information for analyzing protein-ligand interactions and further improvement of ligand binding affinity. While, pharmacophore model derived from already known inhibitors facilitates in the identification of essential chemical features present in experimentally known potent chymase inhibitors. To find novel and potent chymase inhibitors and to provide a new idea for drug design, we used both ligandbased and structure-based methods to perform the virtual screening of commercially available databases. As 912656-34-9 different pharmacophore models generated from different crystal structures may represent different inhibitor binding modes. Therefore, multiple pharmacophore-based virtual screening approach can be more efficient way in identification of potent hits that can bind to various bioactive conformations available in the active site of enzyme. X-ray crystallographic data of chymase in complex with different inhibitors were used to generate four structure�Cbased pharmacophore models. A common feature pharmacophore model was also developed from experimentally known inhibitors. After successful validation of developed pharmacophore models, a smart virtual screening strategy was conducted by employing all pharmacophore models to retrieve hits with novel chemical scaffolds. Drug-like hit compounds were subjected to molecular docking using GOLD and AutoDock to evaluate compounds for important binding site interactions and affinity. Finally four structurally diverse compounds with high GOLD score and binding affinity for several crystal structures of chymase were selected as final hits. Identification of final hits by four different pharmacophore models necessitates the use of multiple pharmacophore- based approach in VS process. Quan
