Change search
ReferencesLink to record
Permanent link

Direct link
Electronic Structural Flexibility of Heterobimetallic Mn/Fe Cofactors: R2lox and R2c Proteins
Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
Stockholm University, Faculty of Science, Department of Physics.
Show others and affiliations
2014 (English)In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 136, no 38, 13399-13409 p.Article in journal (Refereed) Published
Abstract [en]

The electronic structure of the Mn/Fe cofactor identified in a new class of oxidases (R2lox) described by Andersson and Hogbom [Proc. Natl. Acad. Sci. U.S.A. 2009, 106, 5633] is reported. The R2lox protein is homologous to the small subunit of class Ic ribonucleotide reductase (R2c) but has a completely different in vivo function. Using multifrequency EPR and related pulse techniques, it is shown that the cofactor of R2lox represents an antiferromagnetically coupled Mn-III/Fe-III dimer linked by a mu-hydroxo/bis-mu-carboxylato bridging network. The Mn-III ion is coordinated by a single water ligand. The R2lox cofactor is photoactive, converting into a second form (R2lox(photo)) upon visible illumination at cryogenic temperatures (77 K) that completely decays upon warming. This second, unstable form of the cofactor more closely resembles the Mn-III/Fe-III cofactor seen in R2c. It is shown that the two forms of the R2lox cofactor differ primarily in terms of the local site geometry and electronic state of the Mn-III ion, as best evidenced by a reorientation of its unique Mn-55 hyperfine axis. Analysis of the metal hyperfine tensors in combination with density functional theory (DFT) calculations suggests that this change is triggered by deprotonation of the mu-hydroxo bridge. These results have important consequences for the mixed-metal R2c cofactor and the divergent chemistry R2lox and R2c perform.

Place, publisher, year, edition, pages
2014. Vol. 136, no 38, 13399-13409 p.
National Category
Chemical Sciences
URN: urn:nbn:se:su:diva-108534DOI: 10.1021/ja507435tISI: 000342328200057OAI: diva2:764651


Available from: 2014-11-20 Created: 2014-10-29 Last updated: 2014-11-20Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Griese, Julia J.Gräslund, AstridHögbom, Martin
By organisation
Department of Biochemistry and BiophysicsDepartment of Physics
In the same journal
Journal of the American Chemical Society
Chemical Sciences

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: 23 hits
ReferencesLink to record
Permanent link

Direct link