We performed an all-against-all comparison of the sequence identity within the KLIFS pocket of 85 residues. The sequence identity is defined as the number of identical pocket residues divided by all 85 pocket residues; gap positions are treated as identical if both structures show a gap. If two sequences are identical, the sequence identity is 1; if two sequences do not have a single residue in common, the sequence identity is 0. In order to make these values comparable with the kinase distance matrices, we define distance = 1 -identity.