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ToolsBou-Abdallah, Fadi, Lewin, Allison C., Le Brun, Nick E., Moore, Geoffrey R. and Chasteen, N. Dennis (2002) Iron detoxification properties of Escherichia coli bacterioferritin. Attenuation of oxyradical chemistry. Journal of Biological Chemistry, 277 (40). pp. 37064-37069. ISSN 0021-9258
Full text not available from this repository.Abstract
Bacterioferritin (EcBFR) of Escherichia coli is an iron-mineralizing hemoprotein composed of 24 identical subunits, each containing a dinuclear metal-binding site known as the "ferroxidase center." The chemistry of Fe(II) binding and oxidation and Fe(III) hydrolysis using H2O2 as oxidant was studied by electrode oximetry, pH-stat, UV-visible spectrophotometry, and electron paramagnetic resonance spin trapping experiments. Absorption spectroscopy data demonstrate the oxidation of two Fe(II) per H2O2 at the ferroxidase center, thus avoiding hydroxyl radical production via Fenton chemistry. The oxidation reaction with H2O2 corresponds to [Fe(II)2-P]Z + H2O2 → [Fe(III)2O-P]Z + H2O, where [Fe(II)2-P]Z represents a diferrous ferroxidase center complex of the protein P with net charge Z and [Fe(III)2O-P]Z a μ-oxo-bridged diferric ferroxidase complex. The mineralization reaction is given by 2Fe2+ + H2O2 + 2H2O → 2FeOOH(core) + 4H+, where two Fe(II) are again oxidized by one H2O2. Hydrogen peroxide is shown to be an intermediate product of dioxygen reduction when O2 is used as the oxidant in both the ferroxidation and mineralization reactions. Most of the H2O2 produced from O2 is rapidly consumed in a subsequent ferroxidase reaction with Fe(II) to produce H2O. EPR spin trapping experiments show that the presence of EcBFR greatly attenuates the production of hydroxyl radical during Fe(II) oxidation by H2O2, consistent with the ability of the bacterioferritin to facilitate the pair-wise oxidation of Fe(II) by H2O2, thus avoiding odd electron reduction products of oxygen and therefore oxidative damage to the protein and cellular components through oxygen radical chemistry.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | biochemistry,molecular biology,cell biology ,/dk/atira/pure/subjectarea/asjc/1300/1303 |
| Faculty \ School: | Faculty of Science > School of Chemical Sciences and Pharmacy (former - to 2009) 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 |
| Related URLs: | |
| Depositing User: | LivePure Connector |
| Date Deposited: | 18 Jun 2025 09:30 |
| Last Modified: | 23 Jun 2025 10:30 |
| URI: | https://ueaeprints.uea.ac.uk/id/eprint/99603 |
| DOI: | 10.1074/jbc.M205712200 |
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