LmPTR1 tetramer (PDB-ID 5l4n) as the searching model (all non-protein atoms were excluded). Models were refined using REFMAC5 (CCP4 suite). Visual inspection and manual rebuilding of missing atoms was performed using Coot. Water molecules were added with the automated standard procedures implemented in the software ARP/wARP and checked with Coot. In the higher resolution complexes of TbPTR1 with compounds 2a and 2e, all atoms were refined anisotropically in the final refinement cycles and hydrogen atoms were added in the calculated positions.