Structural Insights into the Reaction between Hydrogen Peroxide and Di-iron Complexes at the Ferroxidase Center of Ferritin.

The Fe(II) oxidation mechanism in the ferroxidase center of heavy chain ferritin has been studied extensively. However, the actual production of H 2 O 2 was found to be substantially lower than expected at low flux of Fe(II) to ferritin subunits. Here, we demonstrated that H 2 O 2 could interact with the di-iron nuclear center, leading to the production of hydroxyl radicals and oxygen. Two reaction intermediates were captured in the ferroxidase center by using the time-lapse crystallographic techniques in a shellfish ferritin. The crystal structures revealed the binding of H 2 O 2 as a μ -1,2-peroxo-diferric species and the binding of O 2 to the diferric structure. This investigation sheds light on the reaction between the di-iron nuclear center and H 2 O 2 and provides insights for the exploitation of metalloenzymes.