FIG 5.

DDAH activity is dependent on PA1196. P. aeruginosa PAO1 and the ΔddaH, ΔPA1196, and ΔPA1197 mutants were grown in gluconate-minimal medium to an OD₆₀₀ of 0.3 and then challenged with either no substrate or 1.0 mM ADMA. At 2.0 h after the addition of the substrate, cells were collected by centrifugation, washed, and subsequently lysed via sonication. The lysates were cleared of cellular debris, concentrated, and then assayed for DDAH activity, which is reported in units (U), defined as the formation of l-citrulline (nanomoles hour⁻¹ milligram⁻¹ total protein). Data points represent mean values (n = 2) ± SDs. ANOVA with a Dunnett's post hoc test (α value, 0.05) was done to identify significant differences (P < 0.0001), which are indicated with asterisks.