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. Does not bind to DNA (By similarity). Dps is important for full resistance to heat and cold shocks and is essential for full virulence of this bacterium. It seems to play a direct or indirect role on the production and/or stability of listeriolysin O. 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 (By similarity). By iron limitation and stationary growth phase. 12 di-nuclear ferroxidase centers are located at the interfaces between subunits related by 2-fold symmetry axes. Belongs to the Dps family.