FIG. 5.
IcsA expression and secretion into the culture supernatant in the skp mutant and other strains. Western blot analysis of whole-cell proteins in pellets (P) and of proteins in culture supernatants (S) of strains used in this study. (A) Representative blot, probed with antibody to IcsA, showing full-length mature IcsA (IcsA53-1102) and the IcsP-cleaved fragment of IcsA (IcsA53-757). (B) Blot probed with antibody to Skp. (C) Densitometry of bands corresponding to IcsA53-1102 or IcsA53-757; the number reported is the mean value for densitometry of bands on multiple blots, with values normalized to the wild-type strain. Since protein loading for the pellets was not directly proportional to that for the supernatants, values were normalized separately for pellets and supernatants (values of 1.00 for the wild type are shown in italics). n.d., not done. Molecular size markers are indicated in kilodaltons to the left of the blots.