FIG 4.

Complementation of the wbpZ knockout mutant with site-directed mutants of wbpZ. Top, silver-stained SDS-PAGE gel of extracted LPS; bottom, Western blot using monoclonal antibody (MAb) N1F10, which is specific for CPA LPS. The wbpZ knockout mutant PAO1 wbpZ::Gm lost the ability to synthesize CPA LPS as indicated by the lack of a Western blotting signal. When complemented with wild-type (WT) wbpZ, CPA biosynthesis is restored. The site-directed mutants C26A wbpZ, D174A wbpZ, D253A wbpZ, and D256A wbpZ were also able to restore CPA biosynthesis as indicated by the Western blot. However, the site-directed mutants D172A wbpZ and D254A wbpZ were not able to restore CPA biosynthesis, indicating that these two site-directed mutants were not functional in vivo.