Figure 4.

Characterization of enzymatic and bacterial inhibition by BM01D09, BT06F11 and BT08F04. IC₅₀ values for the inhibitory potency of BM01D09 (A), BT06F11 (B), and BT08F04 (C) against the aminoacylation activity of P. aeruginosa LysRS were 17 μM, 30 μM, and 27 μM, respectively. The compounds were serially diluted from 200 μM to 0.4 μM into aminoacylation assays containing P. aeruginosa LysRS at 0.01 μM. “% Positive” indicates the percentage of activity observed relative to activity in assays in which only DMSO was added to the assay in the absence of compound. The curve fits and IC₅₀ values were determined using the sigmoidal dose-response model in XLfit 5.3 (IDBS). The activity of the hit compounds against the growth of cultures containing (D) S. aureus and (E) M. catarrhalis bacteria were determined using broth microdilution susceptibility testing. Compounds were added to bacterial cultures at 4×minimum inhibitory concentration. Samples were analyzed by plating and determination of colony-forming units at 0, 2, 4, 6, and 24 h. Open circles (○) represent cultures containing BM01D09, filled squares (◼) represent cultures containing BT06F11, and filled triangles (▲) represent cultures containing BT08F04. Filled circles (●) represent the growth of control cultures containing only DMSO in the absence of compound.