Frags2Drugs: A Novel In Silico Fragment-Based Approach to the Discovery of Kinase Inhibitors

<b>Background/Objectives</b>: Fragment-based approaches in the field of drug discovery and design have been widely developed and employed in both academia and industry. We present here an innovative in silico fragment-based drug design approach aimed at designing new inhibitors in the ATP-binding site of protein kinases. <b>Methods</b>: This tool, named Frags2Drugs (F2D), relies on a three-dimensional fragment library obtained from co-crystallized ligands. This library is stored in a graph-oriented database containing the required information to link fragments together. F2D builds every possible molecule that fits into the given cavity on a minute scale. Molecules are then filtered to keep those presenting the best predicted affinity. Several specific molecular filters can be applied, including protein kinase inhibitor-like filters. <b>Results</b>: We validated our method by reconstructing existing co-crystallized ligands and known kinase inhibitors. In this study, we provide several examples of its use to retrieve known or design new type I, type I1/2, type II, and macrocyclic inhibitors on several protein kinases. <b>Conclusions</b>: We have developed an in silico fragment-based ligand design tool able to identify novel kinase inhibitors by growing any scaffolds positioned in the ATP-binding site..