FIG. 6.

Overproduction of DnaK1, DnaK2, and DnaK3 proteins in E. coli. E. coli MC4100 cells harboring the dnaK expression plasmids pTrcDK1 (lanes 1 and 2), pTrcDK2 (lanes 3 and 4), and pTrcDK3 (lanes 5 and 6) were grown at 37°C in the presence (lanes 2, 4, and 6) or absence (lanes 1, 3, and 5) of 1 mM IPTG. After incubation for 5 h, cultures were sampled and cells were harvested by centrifugation. Cells were suspended in SDS sample buffer and subjected to SDS-PAGE on 10% polyacrylamide gels, followed by Coomassie blue staining. The positions of molecular size standards are indicated on the left. Arrows indicate the positions of the DnaK proteins.