Fig. 5.

TF modulates both SecA and ribosome association with IMs. (A) Western blot analysis of either whole-cell or IM preparations showing SecA, L4, S3, YidC, and FtsA levels from cells grown at 37°C. The MC4100 wild type and its Δtig mutant derivative, as well as the Δtig mutant transformed with either p29SEN vector or p29SEN-TF are shown. Expression of TF from p29SEN-TF was induced with 100 μM IPTG for 1 h. Comparison of cytoplasmic and whole membrane fractions observed under such conditions is shown in SI Fig. 9. (B) Complementation of the Cs phenotype of MC4100 ΔsecB by p29SEN vector or p29SEN-SecA. Fresh transformants were serially diluted 10-fold and spotted on LB-ampicillin agar plates in the presence of 100 μM IPTG and incubated at the indicated temperatures. (C) SecA expression levels in these transformants at 37°C after 2-h induction with 100 μM IPTG. (D) Suppression of the OppA export defect of MC4100 ΔsecB by p29SEN vector or p29SEN-SecA at 23°C in the presence of 100 μM IPTG.