FIG 5.
ElsL is active against tetrapeptides in Tetra and TetraTetra. (A) Western blot analysis with anti-ElsL and anti-RpoA antisera. ElsL is 18.97 kDa, while RpoA is 37.27 kDa. WCLs, whole-cell lysates; SP, spheroplast; C, cytoplasm; PP, periplasm; TM, total membrane fraction. (B) Recombinant ElsL or the active-site mutant ElsLC13S was incubated with PG isolated from E. coli strain BW25113 (tetrapeptide rich) (top) or strain CS703-1 (pentapeptide rich) (bottom). ElsL was active against tetrapeptides but not pentapeptides. (C) Tn-seq analysis of ampD::Tn insertions relative to the wild type 12 h after meropenem treatment. (D) Meropenem tolerance assay in the ΔampD mutant, which encodes a well-conserved cytoplasmic enzyme required for PG recycling. Error bars represent the averages from 3 technical replicates ± SD from the means.