Small molecule antivirulents targeting the iron-regulated heme oxygenase (HemO) of P. aeruginosa

Bacteria require iron for survival and virulence and employ several mechanisms including utilization of the host heme containing proteins. The final step in releasing iron is the oxidative cleavage of heme by HemO. A recent computer aided drug design (CADD) study identified several inhibitors of the bacterial HemOs. Herein we report the near complete HN, N, CO, Cα, and Cβ chemical shift assignment of the P. aeruginosa HemO in the absence and presence of inhibitors (E)-3-(4-(phenylamino)phenylcarbamoyl)acrylic acid (3) and (E)-N'-(4-(dimethylamino)benzylidene) diazenecarboximidhydrazide (5). The NMR data confirm that the inhibitors bind within the heme pocket of HemO consistent with in silico molecular dynamic simulations. Both inhibitors and the phenoxy derivative of 3 have activity against P. aeruginosa clinical isolates. Furthermore, 5 showed antimicrobial activity in the in vivo C. elegans curing assay. Thus, targeting virulence mechanisms required within the host is a viable antimicrobial strategy for the development of novel antivirulants.