Figure 4

Soluble Vif and CBF-β proteins can be efficiently produced only in the presence of EloB/C. E. coli BL21 (DE3) cells containing appropriate pST39 constructs were induced, harvested, homogenized by sonication and then clarified by centrifugation. For solubility analysis, the supernatant and the pellet were subjected to SDS–PAGE. All proteins were untagged. (A) Solubility of Vif, expressed alone or co-expressed with CBF-β, EloB, EloC, CBF-β + EloB, CBF-β + EloC, EloB + EloC or CBF-β + EloB + EloC, was determined by visualization with Coomassie staining. Tot, total cell lysate; S, supernatant; P, pellet. (B) Fractions in (A) were visualized by immunoblotting using appropriate antibodies. (C) Quantification of band intensities of Vif in (B). All experiments were repeated three times.