FIG. 1.
Inverse relationship between steady-state levels of SRP and heat shock proteins. MC4100 and HDB45 (Ptrc-ffh ffh::kan) were grown overnight in LB containing 10 μM IPTG. Cells were washed and diluted to an OD550 of 0.0002 in LB containing 0, 1, 2, 5, or 10 μM IPTG. At late log phase (OD550, 0.8 to 1.0) samples were removed from each culture and proteins were precipitated with 10% TCA. The concentrations of Ffh, DnaK, and GroEL were measured by Western blotting. Lane 1: MC4100; lanes 2 to 6: HDB45 grown in the presence of the indicated amount of IPTG.