FIG. 4.

Changes in C4BP binding seen with HepI LOS mutants are not related to differences in Por expression levels. (A) Strains MS11, 1291, their lgtE and lgtF mutants, and 1291 PorMS11 lgtE were incubated with 1% NHS. Following extensive washing, bacterial lysates were subjected to electrophoresis and Western blotting. Control lanes included bacteria alone (no NHS in reaction mixture). With the 50-kDa marker used as a guide, the blot was cut horizontally; the upper portion (proteins of >50 kDa) was probed with polyclonal anti-human C4BP, and the lower portion (proteins of <50 kDa) was stained with Coomassie blue. The location of the 70-kDa C4BP α chain is shown. The positions of the ∼37-kDa MS11 and 1291 Por1B molecules are indicated on the Coomassie-stained blots by black dots and asterisks, respectively. (B) C4BP binding and Por expression on MS11, F62 PorMS11, and their lgtE and lgtF mutants was examined. As described above, bacteria were incubated with NHS and Western blotting was performed. Proteins of >50 kDa were probed with anti-C4BP, and proteins of <50 kDa were probed with anti-MS11 Por1B MAb 5.51.