Fig. 3

Growth of C-A versus T-C-A domain substitution strains. a Structure of pyoverdine from P. aeruginosa PAO1, with the succinimide group highlighted in pink, the chromophore in green, the peptide backbone in red, and the side chains of the threonine residues incorporated by PvdD in blue. The threonine residues incorporated by modules 1 and 2 of PvdD are labelled Thr1 and Thr2, respectively. (b) and (c): Growth of C-A and T-C-A substitution strains on solid King’s B media, either (b) without or (c) with addition of 200 μg.ml⁻¹ EDDHA. Plates were inoculated with the restriction site control (WT), domain substitution strains, and the pvdD deletion mutant (pvdD ⁻), then incubated for 24 h at 37 °C. Photographs were taken under UV light. (d) and (e): Pyoverdine production in liquid media from T-C-A versus C-A domain substitution strains. Values are expressed as a percentage relative to (d) the absorbance (400 nm); or (e) the fluorescence (ex. 400 nm/ em. 440 nm) measured for the CAThr-WT strain, having first been zeroed against the absorbance/fluorescence of the pvdD deletion mutant. Data are the mean of 6 independent replicates, and error bars indicate 1 standard deviation