Initial diffraction **data** were collected at the Diamond Light Source, Didcot, UK. Diffraction **data** for the deposited structures were collected at the European Synchrotron Radiation Facility, Grenoble, France. Data were processed with XDS (25) and scaled with AIMLESS (26). The structures were solved by molecular replacement with Phaser (27), the AadA-ATP structure with Protein Data Bank (PDB) code 5g4a (12) as search model and the antibiotic complexes with AadA-ATP as search model. All structures had two molecules in the asymmetric unit. The structures were refined by reciprocal-space refinement in Phenix (28) and model building and real-space refinement in Coot (29). Statistics for **data** processing and refinement are shown in Table 2. The structure factors and refined coordinates have been deposited in the PDB.