Three aromatic residues are required for electron transfer during iron mineralization in Bacterioferritin

Bradley, Justin M., Svistunenko, Dimitri A., Lawson, Tamara L., Hemmings, Andrew M., Moore, Geoffrey R. and Le Brun, Nick E. (2015) Three aromatic residues are required for electron transfer during iron mineralization in Bacterioferritin. Angewandte Chemie International Edition, 127 (49). 14976–14980. ISSN 1433-7851

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Abstract

Ferritins are iron storage proteins that overcome problems of toxicity and poor bioavailability of iron by catalysing 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. Here we demonstrate that EcBFR mineralization depends on three near-diiron site aromatic residues, 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.

Item Type: Article
Additional Information: © 2015 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Uncontrolled Keywords: bioanorganische chemie,eisen,ferritin,mineralisierung,tyrosylradikale
Faculty \ School: Faculty of Science > School of Chemistry
Faculty of Science > School of Biological Sciences
Depositing User: Pure Connector
Date Deposited: 03 Nov 2015 15:02
Last Modified: 22 Apr 2020 00:31
URI: https://ueaeprints.uea.ac.uk/id/eprint/54992
DOI: 10.1002/ange.201507486

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