Fractionation of proteins synthesized in E. coli exposed to LVFX. Proteins from cultures labeled in the presence of 10 μg/ml LVFX were fractionated as described in Methods and separated by SDS-PAGE (A). The protein samples from untreated cells were run in lanes 1, 3, 5, 7 and 9. The samples from LVFX-treated cells were in lanes 2, 4, 6, 8 and 10. Lanes contain protein fractions as follows: lanes 1 and 2, whole cell lysates; lanes 3 and 4, cytoplasmic and periplasmic protein fractions; lanes 5 and 6, membrane-associated protein fractions. The membrane-associated proteins were solubilized in 1 M NaCl and then dialyzed described in Methods. After centrifugation, the pellets were solubilized in lysis buffer and applied in lanes 7 and 8. The supernatants were applied in lanes 9 and 10. Portions of the protein samples applied in lanes 7 and 8 were also subjected to two-dimensional gel electrophoresis and the results are shown in (B) and (C), respectively.