Fig. 3.

TatB suppressors support export of a Tat substrate with its native signal peptide. E. coli strains producing native levels of TatA, TatC, and the indicated TatB variants, and overproducing His-tagged CueO with a wild-type (Upper) or KK-substituted (Lower) signal peptide were fractionated into whole cell (W), spheroplast (S), and periplasm (P) fractions. Equivalent amounts of each fraction were separated by SDS/PAGE and analyzed by Western blot with antibodies against CueO and the cytosolic marker DnaK.