Iron oxidation in Escherichia coli bacterioferritin ferroxidase centre, a site designed to react rapidly with H2O2 but slowly with O2

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Pullin, Jacob, Wilson, Michael T., Clémancey, Martin, Blondin, Geneviève, Bradley, Justin M., Moore, Geoffrey R., Le Brun, Nick E. ORCID: https://orcid.org/0000-0001-9780-4061, Lučić, Marina, Worrall, Jonathan A. R. and Svistunenko, Dimitri A. (2021) Iron oxidation in Escherichia coli bacterioferritin ferroxidase centre, a site designed to react rapidly with H2O2 but slowly with O2. Angewandte Chemie-International Edition, 60 (15). pp. 8361-8369. ISSN 1433-7851

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Abstract

Both O2 and H2O2 can oxidize iron at the ferroxidase center (FC) of Escherichia coli bacterioferritin (EcBfr) but mechanistic details of the two reactions need clarification. UV/Vis, EPR, and Mössbauer spectroscopies have been used to follow the reactions when apo‐EcBfr, pre‐loaded anaerobically with Fe2+, was exposed to O2 or H2O2. We show that O2 binds di‐Fe2+ FC reversibly, two Fe2+ ions are oxidized in concert and a H2O2 molecule is formed and released to the solution. This peroxide molecule further oxidizes another di‐Fe2+ FC, at a rate circa 1000 faster than O2, ensuring an overall 1:4 stoichiometry of iron oxidation by O2. Initially formed Fe3+ can further react with H2O2 (producing protein bound radicals) but relaxes within seconds to an H2O2‐unreactive di‐Fe3+ form. The data obtained suggest that the primary role of EcBfr in vivo may be to detoxify H2O2 rather than sequester iron.

Item Type: Article
Faculty \ School: Faculty of Science > School of Chemistry (former - to 2024)
UEA Research Groups: Faculty of Science > Research Centres > Centre for Molecular and Structural Biochemistry
Faculty of Science > Research Groups > Chemistry of Life Processes
Depositing User: LivePure Connector
Date Deposited: 29 Jan 2021 01:01
Last Modified: 21 Dec 2024 00:59
URI: https://ueaeprints.uea.ac.uk/id/eprint/78314
DOI: 10.1002/anie.202015964

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