Fig. 4.

TF antagonizes the DnaK/DnaJ chaperone machine at low temperatures. (A) Growth of MC4100 and its isogenic Δtig, dnaJ::Tn10-42, and Δtig dnaJ::Tn10-42 mutant derivatives following incubation on LB agar plates at the indicated temperatures. (B) The dnaJ::Tn10-42 mutant allele was introduced by phage P1 transduction into either the ΔsecB or ΔsecB Δtig mutant derivatives in the presence of the various p29SEN-based constructs. −, vector; B, SecB; J, DnaJ. The results of a representative P1 transduction experiment performed at 30°C on LB-tetracycline-ampicillin agar plates supplemented with 10 μM IPTG are shown. (C) Intracellular protein aggregation at 30°C after a 3-h depletion of DnaK/DnaJ in the presence (wt) or in the absence (ΔsecB) of chromosomally encoded SecB. + indicates the presence of 0.5% l-arabinose, and − indicates the absence of l-arabinose and the presence of 0.4% glucose. Western blot analysis of the resulting steady-state levels of DnaK after the 3-h depletion is shown. The nature of the aggregates is shown in SI Table 1 and Fig. 7.