| Fe-O versus O-O bond cleavage in reactive iron peroxide intermediates of superoxide reductase. | |
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MedLine Citation:
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PMID: 23135387 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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It is generally accepted that the catalytic cycles of superoxide reductases (SORs) and cytochromes P450 involve a ferric hydroperoxo intermediate at a mononuclear iron center with a coordination sphere consisting of four equatorial nitrogen ligands and one axial cysteine thiolate trans to the hydroperoxide. However, although SORs and P450s have similar intermediates, SORs selectively cleave the Fe-O bond and liberate peroxide, whereas P450s cleave the O-O bond to yield a high-valent iron center. This difference has attracted the interest of researchers, and is further explored here. Meta hybrid DFT (M06-2X) results for the reactivity of the putative peroxo/hydroperoxo reaction intermediates in the catalytic cycle of SORs were found to indicate a high-spin preference in all cases. An exploration of the energy profiles for Fe-O and O-O bond cleavage in all spin states in both ferric and ferrous models revealed that Fe-O bond cleavage always occurs more easily than O-O bond cleavage. While O-O bond cleavage appears to be thermodynamically and kinetically unfeasible in ferric hydrogen peroxide complexes, it could occur as a minor (significantly disfavored) side reaction in the interaction of ferrous SOR with hydrogen peroxide. |
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Authors:
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Amr Ali Ahmed Ali Attia; Daniela Cioloboc; Alexandru Lupan; Radu Silaghi-Dumitrescu |
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Publication Detail:
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Type: JOURNAL ARTICLE Date: 2012-11-8 |
Journal Detail:
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Title: Journal of biological inorganic chemistry : JBIC : a publication of the Society of Biological Inorganic Chemistry Volume: - ISSN: 1432-1327 ISO Abbreviation: J. Biol. Inorg. Chem. Publication Date: 2012 Nov |
Date Detail:
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Created Date: 2012-11-8 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 9616326 Medline TA: J Biol Inorg Chem Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Affiliation:
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Department of Chemistry and Chemical Engineering, "Babes-Bolyai" University, 1 Mihail Kogălniceanu str, 400084, Cluj-Napoca, Romania. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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