Abstract
A high-valent Fe(IV) species is proposed to be generated from the decay of a peroxodiferric intermediate in the catalytic cycle at the di-iron cofactor center of dioxygen-activating enzymes such as methane monooxygenase. However, it is believed that this intermediate is not formed in the di-iron substrate site of ferritin, where oxidation of Fe(II) substrate to Fe(III) (the ferroxidase reaction) occurs also via a peroxodiferric intermediate. In opposition to this generally accepted view, here we present evidence for the occurrence of a high-valent Fe(IV) in the ferroxidase reaction of an archaeal ferritin, which is based on trapped intermediates obtained with the freeze-quench technique and combination of spectroscopic characterization. We hypothesize that a Fe(IV) intermediate catalyzes oxidation of excess Fe(II) nearby the ferroxidase center.
Original language | English |
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Pages (from-to) | 1712-1719 |
Number of pages | 8 |
Journal | FEBS Letters |
Volume | 591 |
Issue number | 12 |
DOIs | |
Publication status | Published - 1 Jun 2017 |
Keywords
- Fe(IV)
- ferritin
- ferroxidase
- peroxodiferric
- tyrosine radical