CHIR-090 is from International Patent WO 2004/062601 A2 (31). The slow, tight-binding inhibitory activity of CHIR-090 against E. coli and A. aeolicus LpxC was established in the present study. The structures of L-161,240, TU-514 and BB 78485, as well as their estimated Kis versus LpxC of E. coli and A. aeolicus, are from the literature (8, 10, 11).