Regulation of the Escherichia coli HipBA Toxin-Antitoxin System by Proteolysis
Figure 4
The 16 C-terminal amino acid residues of HipB are required for degradation.
(A) Degradation of HipB72 in vivo. HipB72 was expressed from a pBRlacitac promoter in BW25113 (KLE905) and its lon::kan derivate (KLE906). Both strains were grown in LB medium, and at an OD600 of 0.3 1 mM IPTG was added. After 1 h of induction, protein synthesis was inhibited by the addition of 100 µg/ml Cam, and samples for Western blots were removed over the course of 30 min. (B) Degradation of HipB 72 in vitro. His6-HipB72 was purified and added to the Lon degradation assay. At least 3 independent experiments were performed to calculate HipB72 turnover.