H Size-exclusion profiles for apo and iron-loaded forms of DJA6. 1 mM EDTA, purified DJA6 after incubated with EDTA at a final concentration of 1 mM; 20 μM or 100 μM Ferrous, apo-DJA6 after incubated with Fe(NH4)2(SO4)2 at a final concentration of 20 μM or 100 μM, respectively. Positions of theoretical tetramer and dimer are indicated by dotted lines. Images of the Coomassie Brilliant Blue-stained gel after SEC elution are shown. 