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  Mutation of Arg-54 Strongly Influences Heme Composition and Rate and Directionality of Electron Transfer in Paracoccus denitrificans Cytochrome c Oxidase

Kannt, A., Pfitzner, U., Ruitenberg, M., Hellwig, P., Ludwig, B., Mäntele, W., et al. (1999). Mutation of Arg-54 Strongly Influences Heme Composition and Rate and Directionality of Electron Transfer in Paracoccus denitrificans Cytochrome c Oxidase. The Journal of Biological Chemistry, 274(53), 37974-37981. doi:10.1074/jbc.274.53.37974.

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 Creators:
Kannt, Aimo1, Author              
Pfitzner, Ute2, Author
Ruitenberg, Maarten3, Author              
Hellwig, Petra4, Author
Ludwig, Bernd2, Author
Mäntele, Werner4, Author
Fendler, Klaus3, Author              
Michel, Hartmut1, Author              
Affiliations:
1Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, Max Planck Society, ou_2068290              
2Molekulare Genetik, Institut für Biochemie an der Johann-Wolfgang-Goethe-Universität, Marie-Curie-Straße 9, D-60439, ou_persistent22              
3Department of Biophysical Chemistry, Max Planck Institute of Biophysics, Max Planck Society, ou_2068289              
4Institut für Biophysik an der Johann-Wolfgang-Goethe-Universität, Theodor-Stern-Kai 7, Haus 74, D-60590, ou_persistent22              

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 Abstract: he effect of a single site mutation of Arg-54 to methionine in Paracoccus denitrificans cytochromec oxidase was studied using a combination of optical spectroscopy, electrochemical and rapid kinetics techniques, and time-resolved measurements of electrical membrane potential. The mutation resulted in a blue-shift of the heme a α-band by 15 nm and partial occupation of the low-spin heme site by heme O. Additionally, there was a marked decrease in the midpoint potential of the low-spin heme, resulting in slow reduction of this heme species. A stopped-flow investigation of the reaction with ferrocytochromec yielded a kinetic difference spectrum resembling that of heme a3. This observation, and the absence of transient absorbance changes at the corresponding wavelength of the low-spin heme, suggests that, in the mutant enzyme, electron transfer from CuA to the binuclear center may not occur via hemea but that instead direct electron transfer to the high-spin heme is the dominating process. This was supported by charge translocation measurements where Δψ generation was completely inhibited in the presence of KCN. Our results thus provide an example for how the interplay between protein and cofactors can modulate the functional properties of the enzyme complex.

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Language(s): eng - English
 Dates: 1999-09-021999-07-121999-12-31
 Publication Status: Published in print
 Pages: 9
 Publishing info: -
 Table of Contents: -
 Rev. Type: Peer
 Identifiers: DOI: 10.1074/jbc.274.53.37974
PMID: 10608865
 Degree: -

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Title: The Journal of Biological Chemistry
  Other : JBC
Source Genre: Journal
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Publ. Info: Baltimore, etc. : American Society for Biochemistry and Molecular Biology [etc.]
Pages: - Volume / Issue: 274 (53) Sequence Number: - Start / End Page: 37974 - 37981 Identifier: ISSN: 0021-9258
CoNE: https://pure.mpg.de/cone/journals/resource/954925410826_1