Fig 5. Iron storage capacities of BfrA and BfrB.

Purified proteins were incubated separately with increasing amounts of iron for 2 hours at room temperature to facilitate the storage of iron as ferric mineral and determine the iron storing capacity of the protein. The residual unbound excess iron was detected by the addition of ferrozine reagent which complexes with free ferrous present in the solution forming a purple coloured product that is analyzed at 570 nm. (a) The figure depicts the percentage of iron incorporated by the protein at increasing iron:protein molar ratios. (b) Rate of iron oxidation was monitored by measuring the absorbance at 310 nm by incubating protein and iron in a ratio of 1:500. Rate was calculated as change in absorbance per unit time for both the proteins and was found to be similar. These experiments were performed twice, however, the figure shown is representative of one experiment.