During stationary phase, binds the chromosome non-specifically, forming a highly ordered and stable dps-DNA co-crystal within which chromosomal DNA is condensed and protected from diverse damages. It protects DNA from oxidative damage by sequestering intracellular Fe(2+) ion and storing it in the form of Fe(3+) oxyhydroxide mineral, which can be released after reduction. One hydrogen peroxide oxidizes two Fe(2+) ions, which prevents hydroxyl radical production by the Fenton reaction. Dps also protects the cell from UV and gamma irradiation, iron and copper toxicity, thermal stress and acid and base shocks. Also shows a weak catalase activity. 2 Fe(2+) + 2 H(+) + H2O2 = 2 Fe(3+) + 2 H2O Homododecamer. The 12 subunits form a hollow sphere into which the mineral iron core of up to 500 Fe(3+) can be deposited. Belongs to the Dps family.