Publication Date:
2011-10-28
Description:
Oxygen-containing mononuclear iron species--iron(III)-peroxo, iron(III)-hydroperoxo and iron(IV)-oxo--are key intermediates in the catalytic activation of dioxygen by iron-containing metalloenzymes. It has been difficult to generate synthetic analogues of these three active iron-oxygen species in identical host complexes, which is necessary to elucidate changes to the structure of the iron centre during catalysis and the factors that control their chemical reactivities with substrates. Here we report the high-resolution crystal structure of a mononuclear non-haem side-on iron(III)-peroxo complex, [Fe(III)(TMC)(OO)](+). We also report a series of chemical reactions in which this iron(III)-peroxo complex is cleanly converted to the iron(III)-hydroperoxo complex, [Fe(III)(TMC)(OOH)](2+), via a short-lived intermediate on protonation. This iron(III)-hydroperoxo complex then cleanly converts to the ferryl complex, [Fe(IV)(TMC)(O)](2+), via homolytic O-O bond cleavage of the iron(III)-hydroperoxo species. All three of these iron species--the three most biologically relevant iron-oxygen intermediates--have been spectroscopically characterized; we note that they have been obtained using a simple macrocyclic ligand. We have performed relative reactivity studies on these three iron species which reveal that the iron(III)-hydroperoxo complex is the most reactive of the three in the deformylation of aldehydes and that it has a similar reactivity to the iron(IV)-oxo complex in C-H bond activation of alkylaromatics. These reactivity results demonstrate that iron(III)-hydroperoxo species are viable oxidants in both nucleophilic and electrophilic reactions by iron-containing enzymes.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3306242/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉 〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3306242/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Cho, Jaeheung -- Jeon, Sujin -- Wilson, Samuel A -- Liu, Lei V -- Kang, Eun A -- Braymer, Joseph J -- Lim, Mi Hee -- Hedman, Britt -- Hodgson, Keith O -- Valentine, Joan Selverstone -- Solomon, Edward I -- Nam, Wonwoo -- 5P41RR001209/RR/NCRR NIH HHS/ -- GM 40392/GM/NIGMS NIH HHS/ -- P41 RR001209/RR/NCRR NIH HHS/ -- P41 RR001209-31/RR/NCRR NIH HHS/ -- R01 GM040392/GM/NIGMS NIH HHS/ -- R01 GM040392-25/GM/NIGMS NIH HHS/ -- RR-001209/RR/NCRR NIH HHS/ -- England -- Nature. 2011 Oct 26;478(7370):502-5. doi: 10.1038/nature10535.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Bioinspired Science, Ewha Womans University, Seoul 120-750, Korea.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22031443" target="_blank"〉PubMed〈/a〉
Keywords:
Aldehydes/metabolism
;
Crystallography, X-Ray
;
Enzymes/chemistry/metabolism
;
Hydrogen Peroxide/*chemistry/metabolism
;
Iron/*chemistry/metabolism
;
Ligands
;
Models, Molecular
;
Nonheme Iron Proteins/chemistry/metabolism
;
Oxygen/chemistry/metabolism
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
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