Clustering was performed by iterating through the list of sequences and iteratively checking if the sequence has satisfied the criteria listed above. If it satisfied these criteria, it would be added. If not, a new cluster containing just that sequence would be created. A total of 21 clusters were identified to contain more than one sequence. The sequence from each cluster with the best resolution in angstroms (i.e. the smallest value) was selected by default. If a cluster contains a native version of the enzyme and versions with inhibitors, the native version was selected as the representative member from the cluster. PDB entries 3m6v and 3m6w were included due to being in different space groups as specified by their authors.