In this work, the kinase binding site was divided into six subpockets, which were selected based on their location and function in known kinase-inhibitor structures. Each subpocket is described by the geometric center of the Cα atoms of newly identified anchor residues from the 85 binding site residues defined by KLIFS. The respective subpocket spanning anchor residues (Table ) were selected manually after visual inspection of several structures with the aim to define a location that overlays with important parts of known kinase ligands and to provide a good distribution of centers within the pocket. As one example, the subpocket centers within the binding site of the epidermal growth factor receptor (EGFR) kinase are shown in Figure .B. Later, fragments will be assigned to the closest subpocket, by measuring their distance to the subpocket centers, and stored in subpocket-specific library pools (subpocket pools). In the following, the residue numbering refers to the numbering used in KLIFS.