FIG 5.
Competition of synthetic peptides for in vitro σX degradation. (A) Addition of synthetic peptides X41-68 and X62-76 (2 μM) to the degradation assay mixture. (B) Addition of X41-68 at increasing concentrations (0 to 2 μM) to the degradation assay mixture. In both experiments, σX-Strep (0.6 μM) was incubated with 6His-MecA, -ClpC, and -ClpP, ATP, and the pyruvate kinase/phosphoenolpyruvate (PK/PEP) ATP regeneration system. + or −, presence or absence of a specific compound in the reaction mixture, respectively. σX-Strep was detected by Western blotting. Quantifications by densitometry of the relative amount of σX-Strep using control lane 1 as 100% are shown under the respective Western blots.