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          Institute: MPI für Biophysik     Collection: Abt. Molekulare Membranbiologie     Display Documents

ID: 579656.0, MPI für Biophysik / Abt. Molekulare Membranbiologie
Interconversions of P and F intermediates of cytochrome c oxidase from Paracoccus denitrificans
Authors:von der Hocht, Iris; van Wonderen, Jessica H.; Hilbers, Florian; Angerer, Heike; MacMillan, Fraser; Michel, Hartmut
Date of Publication (YYYY-MM-DD):2011-03-08
Title of Journal:Proceedings of the National Academy of Sciences of the United States of America
Journal Abbrev.:Proc. Natl. Acad. Sci. USA (PNAS)
Issue / Number:10
Start Page:3964
End Page:3969
Review Status:Peer-review
Audience:Experts Only
Abstract / Description:Cytochrome c oxidase (CcO) is the terminal enzyme of the respiratory chain. This redox-driven proton pump catalyzes the fourelectron reduction of molecular oxygen to water, one of the most fundamental processes in biology. Elucidation of the intermediate structures in the catalytic cycle is crucial for understanding both the mechanism of oxygen reduction and its coupling to proton pumping. Using CcO from Paracoccus denitrificans, we demonstrate that the artificial F state, classically generated by reaction with an excess of hydrogen peroxide, can be converted into a new P state (in contradiction to the conventional direction of the catalytic cycle) by addition of ammonia at pH 9. We suggest that ammonia coordinates directly to CuB in the binuclear active center in this P state and discuss the chemical structures of both oxoferryl intermediates F and P. Our results are compatible with a superoxide bound to CuB in the F state.
Free Keywords:artificial intermediates; catalase activity; electron paramagnetic resonance spectroscopy; optical difference spectroscopy
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Biophysik/Abteilung Molekulare Membranbiologie
External Affiliations:Henry Wellcome Unit for Biological Electron Paramagnetic Resonance Spectroscopy, School of Chemistry, University of East Anglia, Norwich NR4 7TJ, United Kingdom
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