Figure 4. Clp protease is required for degradation of abnormal proteins and SsrA-tagged proteins in mycobacteria.

(A) Growth curves of Msm ptet_clpP2 in growth medium containing low (1 ng/mL) or high (100 ng/mL) concentrations of inducer ATc, in the presence of either no drug, or amikacin (top left, 0.03 µg/mL), streptomycin (top right, 0.125 µg/mL), and chloramphenicol (bottom, 7.5 µg/mL). Data are represented as mean OD₆₀₀ +/− standard deviation. Dashed lines represent assumed growth rates until first measured growth point. (B) Increase in fluorescence (RFU, 485/520) and initial growth curve (OD₆₀₀) of Msm clpP2_ID expressing the fusion construct GFP-SsrA on a constitutively expressing plasmid, in the presence and absence of inducer, ATc. Data are represented as mean RFU or OD₆₀₀ +/− standard deviation. (C) Depletion of ClpP2 and increase in GFP-SsrA in Msm clpP2_ID expressing the fusion construct GFP-SsrA on a constitutively expressing plasmid was tracked by immunoblot. Blots were probed α-GFP, α-myc, α-FLAG, and α-RpoB (loading control).