Figure 4. Iron-binding assays using monomeric HbpS and furter mutants with exchanged E by D or A (within the internal E₇₈XXE₈₁ motif) or Y by A or F (from the adjacent Y77).

Relative iron-binding activities of the wild-type as well as of the mutants H28A (building only monomers), E78D, E81D, E78D/E81D, E78A/E81A, Y77A and Y77F previously incubated with iron ions are shown. The activity of the wild-type sample without previous incubation with iron is also shown (WT-).