Please use this identifier to cite or link to this item: https://hdl.handle.net/20.500.14279/2202
Title: Direct detection of Fe(IV)=O intermediates in the cytochrome aa3 oxidase from Paracoccus denitrificans[H2O2 reaction
Authors: Pinakoulaki, Eftychia 
Pfitzner, Ute 
Varotsis, Constantinos 
metadata.dc.contributor.other: Πινακουλάκη, Ευτυχία
Βαρώτσης, Κωνσταντίνος
Major Field of Science: Engineering and Technology
Field Category: Environmental Engineering
Keywords: Biochemistry;Amino acids;Denitrification;Iron;Oxygen;Cytochrome oxidase;Copper;Heme;Raman spectrometry
Issue Date: 25-Feb-2003
Source: Journal of biological chemistry, 2003, vol. 278, no. 21, pp.18761-18766
Volume: 278
Issue: 21
Start page: 18761
End page: 18766
Journal: Journal of Biological Chemistry 
Abstract: We report the first evidence for the formation of the "607- and 580-nm forms" in the cytochrome oxidase aa3/H2O2 reaction without the involvement of tyrosine 280. The pKa of the 607-580-nm transition is 7.5. The 607-nm form is also formed in the mixed valence cytochrome oxidase/O2 reaction in the absence of tyrosine 280. Steady-state resonance Raman characterization of the reaction products of both the wild-type and Y280H cytochrome aa3 from Paracoccus denitrificans indicate the formation of six-coordinate low spin species, and do not support, in contrast to previous reports, the formation of a porphyrin π-cation radical. We observe three oxygen isotope-sensitive Raman bands in the oxidized wild-type aa3/H2O2 reaction at 804, 790, and 358 cm-1. The former two are assigned to the Fe(IV)=O stretching mode of the 607- and 580-nm forms, respectively. The 14 cm-1 frequency difference between the oxoferryl species is attributed to variations in the basicity of the proximal to heme a3 His-411, induced by the oxoferryl conformations of the heme a3-CuB pocket during the 607-580-nm transition. We suggest that the 804-790 cm-1 oxoferryl transition triggers distal conformational changes that are subsequently communicated to the proximal His-411 heme a3 site. The 358 cm-1 mode has been found for the first time to accumulate with the 804 cm-1 mode in the peroxide reaction. These results indicate that the mechanism of oxygen reduction must be reexamined
URI: https://hdl.handle.net/20.500.14279/2202
ISSN: 00219258
DOI: 10.1074/jbc.M211925200
Rights: © The American Society for Biochemistry and Molecular Biology, Inc.
Attribution-NonCommercial-NoDerivs 3.0 United States
Type: Article
Affiliation: University of Crete 
Affiliation : University of Crete 
Publication Type: Peer Reviewed
Appears in Collections:Άρθρα/Articles

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