FIG. 6.

⁵⁵Fe uptake by TbpB-HA mutants. Iron-stressed gonococci were incubated with ⁵⁵Fe-labeled Tf. ⁵⁵Fe uptake was measured as a percentage of wild type. Each bar represents the mean of three independent experiments. Each bar is labeled according to strain name with the HA epitope insertion number in parentheses. FA19 and FA6815 (TbpA⁻ TbpB⁻) serve as the wild-type and negative controls, respectively. FA6905 serves as a TbpB⁻ control strain. Standard deviations are represented by error bars. *, P ≤ 0.05 in comparison to wild type; **, P ≤ 0.05 in comparison to both wild type and FA6905.