Intracellular localization and phenotype of Tat-targeted MBP sandwich fusions. (a) Western blot analysis of periplasmic (per; top panel) and cytoplasmic (cyt; bottom panel) fractions from HS3018 and HS3018 ΔtatC (lane 2 only) cells expressing ssTorA-MBP (lanes 1 and 2) and ssTorA-POI-MBP sandwich fusions of the following POIs: GST, PhoA, Top7, GFP, TrxA, and TraR (lanes 3–8). Western blots were probed with anti-MBP and anti-GroEL primary antibody as indicated. GroEL was used to indicate the quality of each fractionation. (b) Spot plating of cells and constructs described above on M9 minimal agar media supplemented with 0.4% maltose.