FIG 6 .
Hydrophobic variants of the SufI signal peptide mediate binding to TatBC and TatBCF94D. Cells of strain DADE-P coproducing C-terminally FLAG-tagged SufI with its native signal peptide (WT SufI) or harboring the indicated leucine substitutions, alongside TatB and C-terminally His-tagged TatC or TatCF94D, were lysed and incubated with digitonin, and His-tagged TatC was isolated with Ni-charged beads. Following elution of bound TatC-His, equivalent volumes of the eluate from each sample were analyzed by Western blotting with anti-His, anti-TatB, or anti-FLAG antibodies as indicated. DADE-P coproducing C-terminally FLAG-tagged SufI with its native signal peptide alongside TatB and nontagged TatC (lane annotated “No Histag”) was used as a negative control. Equivalent volumes of sample were loaded in each lane. WT, wild type.