Investigating the binding mechanism of novel 6-aminonicotinate-based antagonists with P2Y12 by 3D-QSAR, docking and molecular dynamics simulations.

P2Y12 receptor is an attractive target for the anti-platelet therapies, treating various thrombotic diseases. In this work, a total of 107 6-aminonicotinate-based compounds as potent P2Y12 antagonists were studies by a molecular modeling study combining three-dimensional quantitative structure-activity relationship (3D-QSAR), molecular docking and molecular dynamics (MD) simulations to explore the decisive binding conformations of these antagonists with P2Y12 and the structural features for the activity. The optimum CoMFA and CoMSIA models identified satisfactory robustness and good predictive ability, with R2 = .983, q2 = .805, [Formula: see text] = .881 for CoMFA model, and R2 = .935, q2 = .762, [Formula: see text] = .690 for CoMSIA model, respectively. The probable binding modes of compounds and key amino acid residues were revealed by molecular docking. MD simulations and MM/GBSA free energy calculations were further performed to validate the rationality of docking results and to compare the binding modes of several compound pairs with different activities, and the key residues (Val102, Tyr105, Tyr109, His187, Val190, Asn191, Phe252, His253, Arg256, Tyr259, Thr260, Val279, and Lys280) for the higher activity were pointed out. The binding energy decomposition indicated that the hydrophobic and hydrogen bond interactions play important roles for the binding of compounds to P2Y12. We hope these results could be helpful in design of potent and selective P2Y12 antagonists.

Studies of N(9)-arenthenyl purines as novel DFG-in and DFG-out dual Src/Abl inhibitors using 3D-QSAR, docking and molecular dynamics simulations.

Recently, the development of Src/Abl (c-Src/Bcr-Abl tyrosine kinases) dual inhibitors has attracted considerable attention from the research community for treatment of malignancies. In order to explore the different structural features impacting the Src and Abl inhibitory activities of N(9)-arenethenyl purines and to investigate the molecular mechanisms of ligand-receptor interactions, a molecular modeling study combining the three-dimensional quantitative structure-activity relationship (3D-QSAR), molecular docking and molecular dynamics (MD) simulations was performed. The obtained CoMFA (comparative molecular field analysis) models exhibited satisfactory internal and external predictability. The plots of the CoMFA fields could be used to investigate the structural differences between DFG-in (targeting the active enzyme conformation) and DFG-out (targeting the inactive enzyme conformation) inhibitors. The key amino acid residues were identified by docking studies, and the detailed binding modes of the compounds with different activities were determined by MD simulations. The binding free energies gave a good correlation with the experimental determined activities. In an energetic analysis, the MM-PBSA (molecular mechanics Poisson-Boltzmann surface) energy decomposition revealed that the van der Waals interactions were the major driving force for the binding of the DFG-in and DFG-out compounds to Src and Abl, especially the hydrophobic interactions between ligands and residues Ala403/380, Asp404/381, and Phe405/382 in DFG-out Src and Abl complexes. They also help to stabilize the DFG-out conformations. These results can offer useful references for designing novel potential DFG-in and DFG-out dual Src/Abl inhibitors.