FIG 5.

Truncation of the C termini of MepM and PA1199 protects them from degradation by CtpA in vitro. (A) His₆-MepM (WT) or His₆–MepM-Δ7 proteins were incubated with LbcA-His₆ and either active CtpA-His₆ (CtpA) or inactive CtpA-S302A–His₆ (CtpA-S302A) for 1 h or 3 h. Samples were separated by 10% SDS-PAGE and stained with ProtoBlue Safe (National Diagnostics). (B) His₆-PA1199 (WT) or His₆-PA1199-Δ7 proteins were incubated with LbcA-His₆ and either active CtpA-His₆ (CtpA) or inactive CtpA-S302A–His₆ (CtpA-S302A) for 0.5 h or 1 h. Samples were analyzed on a single 16% SDS-PAGE gel, but the order of the left- and right-hand sides of the gel was reversed to construct the image, indicated by the vertical black line. For both panels, approximate sizes of molecular-mass marker proteins (M), in kilodaltons, are indicated on the left-hand side. Gels are single representatives of several replicate experiments.