Protects DNA from oxidative damage by sequestering intracellular Fe(2+) ion and storing it in the form of Fe(3+) oxyhydroxide mineral. One hydrogen peroxide oxidizes two Fe(2+) ions, which prevents hydroxyl radical production by the Fenton reaction (By similarity). It efficiently oxidizes Fe(2+) in the presence of hydrogen peroxide and stores it. 2 Fe(2+) + 2 H(+) + H2O2 = 2 Fe(3+) + 2 H2O Homododecamer. The 12 identical subunits form a holow sphere unto which the mineral iron core of up to 300 Fe(3+) can be deposited. Belongs to the Dps family.