FIG 6.

The LbcA N-terminal extension is essential for the protease activity of CtpA. (a) CtpA pulldown assay using various N-terminal and C-terminal deletion mutants of LbcA. Lane 2 is the CtpA input control (C). Lane 3 is the background binding of CtpA to nickel beads. (b) In vitro substrate (PA1198) degradation assay. (c) Substrate degradation in vivo. Plasmids encoding wild-type LbcA (WT), LbcA(ΔN84), or LbcA(ΔN165) were transformed into a P. aeruginosa ΔlbcA mutant. None = empty plasmid vector control. The LbcA proteins and accumulation of the PA1198 substrate were detected by immunoblot analysis with polyclonal antisera.