4xks | pdb_00004xks
E. coli BFR variant Y45F
Structural highlights
Function[BFR_ECOLI] Iron-storage protein, whose ferroxidase center binds Fe(2+) ions, oxidizes them by dioxygen to Fe(3+), and participates in the subsequent Fe(3+) oxide mineral core formation within the central cavity of the protein complex. The mineralized iron core can contain as many as 2700 iron atoms/24-meric molecule.[1] [2] Publication Abstract from PubMedFerritins are iron storage proteins that overcome the problems of toxicity and poor bioavailability of iron by catalyzing iron oxidation and mineralization through the activity of a diiron ferroxidase site. Unlike in other ferritins, the oxidized di-Fe3+ site of Escherichia coli bacterioferritin (EcBFR) is stable and therefore does not function as a conduit for the transfer of Fe3+ into the storage cavity, but instead acts as a true catalytic cofactor that cycles its oxidation state while driving Fe2+ oxidation in the cavity. Herein, we demonstrate that EcBFR mineralization depends on three aromatic residues near the diiron site, Tyr25, Tyr58, and Trp133, and that a transient radical is formed on Tyr25. The data indicate that the aromatic residues, together with a previously identified inner surface iron site, promote mineralization by ensuring the simultaneous delivery of two electrons, derived from Fe2+ oxidation in the BFR cavity, to the di-ferric catalytic site for safe reduction of O2 . Three Aromatic Residues are Required for Electron Transfer during Iron Mineralization in Bacterioferritin.,Bradley JM, Svistunenko DA, Lawson TL, Hemmings AM, Moore GR, Le Brun NE Angew Chem Int Ed Engl. 2015 Oct 16. doi: 10.1002/anie.201507486. PMID:26474305[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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