| Activation of α-keto Acid Dependent Dioxygenases:Application of an {FeNO}7/{FeO2}8 Methodology for Characterizing the Initial Steps of O2 Activation. | |
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MedLine Citation:
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PMID: 21981763 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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The α-keto acid dependent dioxygenases are a major subgroup within the O2-activating mononuclear non-heme iron enzymes. For this class, the resting ferrous, the substrate plus cofactor-bound ferrous, and the Fe(IV)=O sites of the reaction have been well studied. The initial O2-binding and activation steps are experimentally inaccessible and thus are not well understood. In this study, NO is used as an O2 analog to probe the effects of α-keto acid binding in 4-hydroxyphenylpyruvate dioxygenase (HPPD). A combination of EPR, UV-vis absorption, MCD, and VTVH MCD spectroscopies in conjunction with computational models is used to explore the HPPD-NO and HPPD-HPP-NO complexes. New spectroscopic features are observed which result from α-keto acid binding to the {FeNO}7 site. The α-keto acid ligand is a strong donor which promotes the transfer of charge from Fe to NO. The calculations are extended to the O2 reaction coordinate where the strong donation associated with α-keto acid binding promotes a new, S=1 bridged Fe(IV)-peroxy species. These studies provide insight into the effects of a strong donor ligand on O2 binding and activation by Fe(II) in the α-keto acid dependent dioxygenases and are likely relevant to other subgroups in the O2 activating non-heme ferrous enzymes. |
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Authors:
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Adrienne Renee Diebold; Christina D Brown-Marshall; Michael Lee Neidig; June Mallie Brownlee; Graham Rodney Moran; Edward I Solomon |
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Publication Detail:
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Type: JOURNAL ARTICLE Date: 2011-10-8 |
Journal Detail:
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Title: Journal of the American Chemical Society Volume: - ISSN: 1520-5126 ISO Abbreviation: - Publication Date: 2011 Oct |
Date Detail:
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Created Date: 2011-10-10 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 7503056 Medline TA: J Am Chem Soc Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
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