Summary of removed ligands during fragmentation. During the fragmentation procedure, some complexes were discarded due to the following reasons (Table ): (B.1) A few kinase structures were missing required atom positions, thus, their subpocket centers could not be calculated. (B.2) Some ligands, such as staurosporine are not suitable for fragmentation, as they contain large, unfragmentable portions. Thus, structures with BRICS fragment(s) with more than 22 heavy atoms were discarded. (B.3) Ligands not occupying AP were excluded from the fragment library, as this work focuses on ligands targeting the ATP binding site and most kinase inhibitors developed so far bind in the AP subpocket. (B.4) Ligands displaying unwanted subpocket connections were discarded. Consequently, 2,553 ligands remained and their fragments were included in the fragment library (available at ).