In the following, the fragment similarity was analyzed within each subpocket to assess if certain subpockets are occupied by more similar ligands than others. Overall, the intrasubpocket fragment similarity does not differ largely between the subpockets and is generally rather low (Figure .B, Table ). The highest average intra-subpocket similarity was observed in AP with a mean of 0.14, the lowest in B1 (0.07), B2 (0.09), and FP (0.09). A higher similarity in AP can be explained by the lower flexibility of this kinase region and the targeted design of chemical moieties interacting specifically with the hinge region. The low average similarity within FP might be observed due to the larger space around the FP center compared to the other subpockets, allowing a higher diversity in FP fragments. The low similarity in B1 and B2 is probably the result of the small amount of data available for these subpockets.