title: Subunit CcoQ is involved in the assembly of the Cbb3-type cytochrome c oxidases from Pseudomonas stutzeri ZoBell but not required for their activity.
abstract: The Cbb3-type cytochrome c oxidases (Cbb3-CcOs), the second most abundant CcOs, catalyze the reduction of molecular oxygen to water, even at micromolar oxygen concentrations. In Pseudomonas stutzeri ZoBell, two tandemly organized cbb3-operons encode the isoforms Cbb3-1 and Cbb3-2 both possessing subunits CcoN, CcoO and CcoP. However, only the cbb3-2 operon contains an additional ccoQ gene. CcoQ consists of 62 amino acids and is predicted to possess one transmembrane spanning helix. The physiological role of CcoQ was investigated based on a CcoQ-deletion mutant and wild-type Cbb3-2 crystals not containing subunit CcoQ. Cbb3-2 isolated from the deletion mutant is inactive and appears as a dispersed band on blue native-PAGE gels. Surprisingly, in the absence of ccoQ, Cbb3-1 also shows a strongly reduced activity. Our data suggest that CcoQ primarily functions as an assembly factor for Cbb3-2 but is also required for correct assembly of Cbb3-1. In contrast, once correctly assembled, Cbb3-1 and Cbb3-2 possess a full enzymatic activity even in the absence of CcoQ.
authors.affiliation: Max Planck Institute of Biophysics, Department of Molecular Membrane Biology, Max-von-Laue-Str. 3, D-60438 Frankfurt am Main, Germany. Electronic address: martin.kohlstaedt@biophys.mpg.de.
authors.forename: Martin
authors.initials: M
authors.lastname: Kohlstaedt
authors.affiliation: Max Planck Institute of Biophysics, Department of Molecular Membrane Biology, Max-von-Laue-Str. 3, D-60438 Frankfurt am Main, Germany. Electronic address: sabine.buschmann@biophys.mpg.de.
authors.forename: Sabine
authors.initials: S
authors.lastname: Buschmann
authors.affiliation: Max Planck Institute of Biophysics, Department of Molecular Membrane Biology, Max-von-Laue-Str. 3, D-60438 Frankfurt am Main, Germany. Electronic address: julian.langer@biophys.mpg.de.
authors.forename: Julian D
authors.initials: JD
authors.lastname: Langer
authors.affiliation: Max Planck Institute of Biophysics, Department of Molecular Membrane Biology, Max-von-Laue-Str. 3, D-60438 Frankfurt am Main, Germany. Electronic address: hao.xie@biophys.mpg.de.
authors.forename: Hao
authors.initials: H
authors.lastname: Xie
authors.affiliation: Max Planck Institute of Biophysics, Department of Molecular Membrane Biology, Max-von-Laue-Str. 3, D-60438 Frankfurt am Main, Germany. Electronic address: hartmut.michel@biophys.mpg.de.
authors.forename: Hartmut
authors.initials: H
authors.lastname: Michel
mesh_terms: D000595:Amino Acid Sequence / Q000235:genetics; D003576:Electron Transport Complex IV / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009876:Operon / Q000235:genetics; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism*; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D044223:Pseudomonas stutzeri / Q000201:enzymology; D017384:Sequence Deletion / Q000235:genetics
chemical_list: D020033:Protein Isoforms; D021122:Protein Subunits; C414443:cbb3 oxidase; D003576:Electron Transport Complex IV; D010100:Oxygen
keywords: Assembly; Cbb3; Cytochrome c oxidase; Knockout mutant; Pseudomonas stutzeri; Subunit CcoQ