Change search
ReferencesLink to record
Permanent link

Direct link
Oxygen Activation by Rieske Non-Heme Iron Oxygenases, a Theoretical Insight
Stockholm University, Faculty of Science, Department of Physics.
Stockholm University, Faculty of Science, Department of Physics.
Stockholm University, Faculty of Science, Department of Physics.
Stockholm University, Faculty of Science, Department of Physics.
2004 (English)In: Journal of Physical Chemistry B, ISSN 1520-6106, Vol. 108, no 34, 13031-13041 p.Article in journal (Refereed) Published
Abstract [en]

The first steps of dioxygen activation in naphthalene 1,2-dioxygenase have been investigated by means of hybrid density functional theory. Reduction of molecular oxygen by this Rieske dioxygenase occurs in the catalytic domain accommodating a mononuclear non-heme iron(II) complex, and it requires two external electrons ultimately delivered by a Rieske [2Fe−2S] cluster hosted in the neighboring domain. Theoretical tools have been applied to gain insight into the O2-binding step and into the first one-electron-transfer process involving the mononuclear and the Rieske centers, and yielding an iron(II)−superoxo intermediate. The reaction, which is mimicked with a model including both metal sites, is found to be a reversible equilibrium. Although the entropic loss associated with the binding of O2 to iron(II) is not canceled by the corresponding enthalpic binding energy, it is, however, balanced by the exothermicity of the electron transfer process from the Rieske cluster to the dioxygen-bound iron(II) complex. The rationalization for the calculated energetics is related to the values of the ionization potential (IP) of the Rieske cluster and the electron affinity (EA) of the mononuclear iron complex: the latter is computed to be higher than the former, when dioxygen is bound to the metal. The possibility that a second external electron is delivered to the mononuclear site before dioxygenation of the substrate has also been examined. It is shown that, if the second electron is available in the Rieske domain, the electron transfer process is energetically favored. The results acquired with the large model comprising the two metal centers are compared to the corresponding information collected from the study of smaller models, where either the mononuclear iron complex or the Rieske cluster is included.

Place, publisher, year, edition, pages
2004. Vol. 108, no 34, 13031-13041 p.
URN: urn:nbn:se:su:diva-22675DOI: 10.1021/jp048515qOAI: diva2:189251
Part of urn:nbn:se:su:diva-103Available from: 2004-04-15 Created: 2004-04-15 Last updated: 2010-01-18Bibliographically approved
In thesis
1. Theoretical studies of mononuclear non-heme iron active sites
Open this publication in new window or tab >>Theoretical studies of mononuclear non-heme iron active sites
2004 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The quantum chemical investigations presented in this thesis use hybrid density functional theory to shed light on the catalytic mechanisms of mononuclear non-heme iron oxygenases, accommodating a ferrous ion in their active sites. More specifically, the dioxygen activation process and the subsequent oxidative reactions in the following enzymes were studied: tetrahydrobiopterin-dependent hydroxylases, naphthalene 1,2-dioxygenase and α-ketoglutarate-dependent enzymes. In light of many experimental efforts devoted to the functional mimics of non-heme iron oxygenases, the reactivity of functional analogues was also examined.

The computed energetics and the available experimental data served to assess the feasibility of the reaction mechanisms investigated. Dioxygen activation in tetrahydrobiopterin- and α-ketoglutarate-dependent enzymes were found to involve a high-valent iron-oxo species, which was then capable of substrate hydroxylation. In the case of naphthalene 1,2-dioxygenase, the reactivity of an iron(III)-hydroxperoxo species toward the substrate was investigated and compared to the biomimetic counterpart.

Place, publisher, year, edition, pages
Stockholm: Fysikum, 2004. 86 p.
quantum chemistry, enzyme catalysis, iron enzymes
National Category
Theoretical Chemistry
urn:nbn:se:su:diva-103 (URN)91-7265-857-6 (ISBN)
Public defence
2004-05-07, sal FA32, AlbaNova universitetscentrum, Roslagstullsbacken 21, Stockholm, 10:00
Available from: 2004-04-15 Created: 2004-04-15Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Blomberg, Margareta R. A.Siegbahn, Per E. M.
By organisation
Department of Physics
In the same journal
Journal of Physical Chemistry B

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 50 hits
ReferencesLink to record
Permanent link

Direct link