Out of nearly 1000 screened fragments, 48 were identified to bind to PaFabF (Figure ). Out of those, only 6 fragments bound into or close to one of the two substrate binding sites (Table ). The largest cluster of fragments was found in the dimer interface pocket close to the fatty acid binding site which thus appears to be the most druggable pocket in FabF (Figure ). It remains to be seen if binding into this pocket will lead to enzyme inhibition. Further, because the carboxylate group of platensimycin and its forms hydrogen bonds with the catalytic histidines (Figure ) we had expected to find carboxylate-group bearing fragments to bind into the malonyl-CoA binding site. Only one such ligand was discovered (20). In total, at the time of screening the DSi-Poised library contained 37 carboxylic acids (Table ). Three additional ligands are very similar to 20 and the analogue 56 containing an aromatic carboxylic acid substituted with an acetylated amino group in the 3-position (Z1816233707, Z364321922, and Z364328788). That the latter compounds were not found to bind is unexpected and cannot be explained based on the structure of the binding site.