Modeling the diiron(II) ferroxidase complex in human H ferritin

► A complete structure for the diiron(II) ferroxidase complex in human H ferritin has been obtained. ► The structure of the complex matches closely the experimental structure of its dizinc counterpart. ► The high-spin and broken symmetry spin coupling approximations yield similar structures. ► The structure of the diiron(II) complex advances research on the diiron(III) intermediate.