FIG. 3.

Expression of BfpE-LacZ fusion proteins. Whole-cell extracts were prepared from plasmid-bearing derivatives of E. coli CC118 and separated by SDS-PAGE on a 6% polyacrylamide gel. The fusion proteins were detected with an anti-β-galactosidase antibody. The positions of molecular mass markers are displayed to the left of the blot. The first three lanes display samples from strains carrying control plasmids pTEB65 (no LacZ), pTrclacZ (no BfpE), and pTEB42 (substrate for exonuclease III digestion). The remaining lanes display samples from strains carrying plasmids with bfpE′::′lacZ fusion genes. The number of the terminal amino acid in the BfpE portion of the fusion protein is noted above each lane. The arrow to the right of the blot indicates a prominent degradation product of many of the fusions that is similar in size to β-galactosidase (LacZ).