FIG. 4.

Increased npg2 and npg3 immunoreactivity at high pH and in pglI mutants. Immunoblotting of whole-cell lysates of wild-type strains, pglI mutants, and high-pH-treated wild-type strains revealed increased reactivity with the npg2 and npg3 monoclonal antibodies due to the lack of an O-acetyl group in pglI mutants or with the high-pH treatment. The extraneous band that appeared during high-pH treatment is PilE (as determined by immunoblotting with SM1 [data not shown]). This band was not present with the 4/3/1 background, in which pilE was conditionally repressed. The strains used were KS100 (N400 wt), KS144 (N400 pglI), KS104 (N400 pglC), KS101 (4/3/1 wt), KS300 (FA1090 wt), KS303 (FA1090 pglI), and KS301 (FA1090 pglC). wt, wild type.