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. Author manuscript; available in PMC: 2012 May 1.
Published in final edited form as: Traffic. 2011 Feb 25;12(5):543–548. doi: 10.1111/j.1600-0854.2011.01168.x

Figure 2.

Figure 2

(a) The periplasmic mGFP, mCherry and sfGFP bacterial expression constructs contain an optimized MBP signal sequence and the cytoplasmic sfGFP and mCherry constructs do not. (b) The epifluorescent micrographs (63X) of E. coli expressing peri-mCherry (750ms), cyt-mCherry (12ms), cyt-sfGFP (100ms) or peri-sfGFP (500ms) indicates peri-sfGFP localized to the periplasm and is much brighter than peri-mCherry. (c) GFP in peri-mGFP is not fluorescent (2s exposure) in either the periplasm or the cytoplasm. However, it is made and accumulates in the cytoplasm similar to reports by others (27). Scale bars are 10μm. (d) Each of our constructs is present in the expected E. coli fractions, except for peri-mGFP, which is only detected by immunoblot in the cytoplasm. We used anti-GroEL and anti-β-lactamase to label the cytoplasmic and periplasmic fractions, respectively. (e) Fluorimeter measurements of the periplasmic and cytoplasmic fractions of peri-sfGFP expressing E. coli. The majority of fluorescence activity was in the periplasmic fraction of peri-sfGFP as denoted by the much higher peak at approximately 510nm.