FIG. 1.
Map of the narK1K2GHJI operon of Pseudomonas aeruginosa. The map shows the narK1 and narK2 genes to be upstream of the structural genes of nitrate reductase (narGHJI). Relevant restriction sites used to create deletions are shown. The endogenous promoter for the operon is shown as Pnar. The direction of transcription of both the operon and the gentamicin cassette (Gm) is shown with the help of arrows. The orientation of the Gm cassette in the gene disruptions was always positive with respect to the gene, as shown in the figure. The figure is not drawn to scale. The ΔnarK1::Gm mutant was created by blunt-ending the Gm cassette into the NcoI-SalI deletion site. The ΔnarK2::Gm mutant was created by blunt-ending the Gm cassette into the XhoI-ApaI deletion site. The ΔnarK1K2::Gm mutant was created by blunt-ending the Gm cassette into the NotI-ApaI deletion site.