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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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