Figure 1.

(A) Cellular content of TF, unlike that of GroEL, increases as growth temperature decreases. C600 cells were grown in LB medium at different temperatures to the same optical density (A₆₀₀ = 0.5). Equal aliquots were taken, and cells collected by centrifugation. Cell proteins were resolved by SDS/PAGE, and the relative amounts of TF and GroEL measured by Western blot analysis with an anti-TF or anti-GroEL antibody and ¹²⁵I-protein A. (B) TF content decreases at 4°C. C600 cells were grown in LB medium to A₆₀₀ = 0.5 at 37°C and transferred to 4°C. Equal aliquots were taken from the cell culture before and 48 hr after the temperature shift, and TF content was measured as described above.