For hit optimization, we focused on the two fragments binding close to the catalytic residues of FabF (hits 20 and 21, Figure and Figure ). Hundreds of analogues of the two hits were identified from online compound catalogues. Virtual libraries of these analogues were docked into the PaFabF C164Q binding site using FlexX as implemented in SeeSAR whereas docking was guided by defining the binding modes of the hits as templates. To select compounds for purchasing and experimental screening, priority was given to compounds which were readily available for purchase and which contained only small changes compared to the original hit compounds to allow SAR exploration around the hits. Furthermore, the predicted binding modes and docking scores were also considered when selecting compounds.