FIG 1.

Stereochemistry scan of cyclic peptomers results in a more potent derivative, 4EpDN. (A) Structures of 1EpDN stereoisomers. Isomers were generated from different combinations of four side chains at positions 3 to 6. Numbers preceding compounds were used to distinguish the different isomers and the conformation of the four side chains. The d-amino acid side chain is shown in red. (B) WT P. aeruginosa PA103 was grown under T3SS-inducing conditions with increasing concentrations of cyclic peptomer isomers. Secretion of T3SS cargo into the culture supernatant was assessed by precipitating secreted proteins and visualizing them with Coomassie blue. ExoU band intensities were quantified and normalized to that of the DMSO control. The results are from at least two independent experiments. Nonlinear curve fitting is shown to depict the trend of inhibition. Error bars are standard errors of the mean.