Western blot analysis of the cytosol, membrane, and inclusion body fractions of E. coli 796 or 797 cells expressing DrrAB at 30 or 42 °C. Wild-type E. coli 796 or E. coli 797 (ftsHts) cells expressing DrrAB (pDX101) were grown at 30 °C to mid-log phase and induced with 0.25 mm IPTG at either 30 or 42 °C for 3 h. Cell fractions were prepared, as described under “Experimental Procedures.” 20 μg of each fraction was loaded onto 12% SDS-PAGE gels, followed by Western blotting against anti-DrrA (upper panel) and anti-DrrB (lower panel) antibodies (m, membrane; c, cytosol; IB, inclusion body). Note that the anti-DrrB antibody is an antipeptide antibody, therefore it shows some cross-reactivity with epitopes in other E. coli proteins, as explained in a previous publication (1).