FIG 3.

DegP removes the ECT to permit degradation of the prodomain by CtpA. (A) Linear schematic of FhaB_HA-PRR, a version of FhaB that contains an HA tag (black wedge) inserted N-terminal to the proline rich region (PRR). The HA tag at this location is not disruptive to normal FhaB processing. FhaB_ΔECT lacks the C-terminal 98 amino acids (ECT). FhaB_CT-HA has the HA tag located at the C terminus. (B) Western blot analysis of WCLs from strains grown for 4 h in BvgAS-activating medium after overnight growth in BvgAS-inactivating medium. Full-length molecules (FhaB_HA-PRR and FhaB_CT-HA appear yellow due to recognition by both α-MCD (green) and α-HA (red) antibodies. The intermediate polypeptide FhaB^CP and final product FHA appear green due to loss of the HA tag. In the absence of CtpA, a 275 kDa polypeptide, FHA²⁷⁵, is created rather than FHA′.