FIG. 2.

Protein expression patterns of the wild-type and mutant E. coli strains. (A) Coomassie blue-stained profiles of the total proteins separated on an SDS–12% polyacrylamide gel. (B) Western blot analysis of OmpC expressed in the total bacterial lysates using mouse anti-OmpC antisera. (C) Coomassie blue-stained protein profiles of the outer membrane fractions. The identity of OmpA was confirmed by N-terminal microsequencing. Plasmids pTacOmp(O) and pTacOmp(K) encode OmpC of the O157:H7 origin and that of the K-12 origin, respectively. OmpC/F labels the band containing both OmpC and OmpF that are presumably not separated in these gel systems. Wt, wild-type strain.