Docking structurally similar analogues: Dealing with the false-positive.

Analogue design forms one of the mainstays of new drug discovery. A fast-follow on approach is commonly used by modern day drug discoverers on the quest of the best in class. Monitoring close structural analogues of the pioneering drug by an algorithm such as docking is fraught with the risk of returning false positives. In this paper, we present the case of two near-pharmacophoric analogues of the JAK3 inhibitor Tasocitinib which give positive docking prediction despite being inactive. Post-processing the docked poses with MM/GBSA and parallel computation of electrostatic potential maps point towards a potential weakening of one of the crucial hydrogen bonds (hinge) within the ATP-binding pocket of JAK3. Perturbing the bound ligands by molecular dynamics (MD) simulations show the complexes to be unstable with the analogues losing their original hold on the protein within 1.2 ns. A short post MD simulation dramatically improves the prediction value of docking runs, especially when dealing with 'me-too' analogues.