FIG. 1.
ZntR is a ClpXP and Lon substrate and is stabilized in the presence of added zinc in vivo. Untagged ZntR was expressed from a pBAD promoter in MC4100 (circles in panels B and D) and its clpX::kan (squares in panel B) or lon::kan (diamonds in panel B) derivative. The strains were grown in rich defined medium, and at an OD600 of 0.3, arabinose and ZnSO4 (when specified; closed symbols in panel D) were added. After a 30-min induction, protein synthesis was inhibited by the addition of chloramphenicol, and samples for Western blots (shown in panels A and C) were removed at specific time points. Data obtained from quantitative Western blot analysis are shown in panels B and D. wt, wild type.