title: Protein chaperones mediating copper insertion into the CuA site of the aa3-type cytochrome c oxidase of Paracoccus denitrificans.
abstract: The biogenesis of the mitochondrial cytochrome c oxidase is a complex process involving the stepwise assembly of its multiple subunits encoded by two genetic systems. Moreover, several chaperones are required to recruit and insert the redox-active metal centers into subunits I and II, two a-type hemes and a total of three copper ions, two of which form the CuA center located in a hydrophilic domain of subunit II. The copper-binding Sco protein(s) have been implicated with the metallation of this site in various model organisms. Here we analyze the role of the two Sco homologues termed ScoA and ScoB, along with two other copper chaperones, on the biogenesis of the cytochrome c oxidase in the bacterium Paracoccus denitrificans by deleting each of the four genes individually or pairwise, followed by assessing the functionality of the assembled oxidase both in intact membranes and in the purified enzyme complex. Copper starvation leads to a drastic decrease of oxidase activity in membranes from strains involving the scoB deletion. This loss is shown to be of dual origin, (i) a severe drop in steady-state oxidase levels in membranes, and (ii) a diminished enzymatic activity of the remaining oxidase complex, traced back to a lower copper content, specifically in the CuA site of the enzyme. Neither of the other proteins addressed here, ScoA or the two PCu proteins, exhibit a direct effect on the metallation of the CuA site in P. denitrificans, but are discussed as potential interaction partners of ScoB.
authors.affiliation: Institute of Biochemistry, Molecular Genetics, Goethe University, D-60438 Frankfurt, Germany.
authors.forename: Banaja Priyadarshini
authors.initials: BP
authors.lastname: Dash
authors.affiliation: Institute of Biochemistry, Molecular Genetics, Goethe University, D-60438 Frankfurt, Germany.
authors.forename: Melanie
authors.initials: M
authors.lastname: Alles
authors.affiliation: Institute of Biochemistry, Molecular Genetics, Goethe University, D-60438 Frankfurt, Germany.
authors.forename: Freya Alena
authors.initials: FA
authors.lastname: Bundschuh
authors.affiliation: Institute of Biochemistry, Molecular Genetics, Goethe University, D-60438 Frankfurt, Germany.
authors.forename: Oliver-M H
authors.initials: OH
authors.lastname: Richter
authors.affiliation: Institute of Biochemistry, Molecular Genetics, Goethe University, D-60438 Frankfurt, Germany. Electronic address: ludwig@em.uni-frankfurt.de.
authors.forename: Bernd
authors.initials: B
authors.lastname: Ludwig
mesh_terms: D001483:Base Sequence; D001665:Binding Sites; D002352:Carrier Proteins / Q000502:physiology*; D003300:Copper / Q000378:metabolism*; D003576:Electron Transport Complex IV / Q000737:chemistry*; D018832:Molecular Chaperones / Q000502:physiology*; D008969:Molecular Sequence Data; D010231:Paracoccus denitrificans / Q000201:enzymology*
chemical_list: D002352:Carrier Proteins; D018832:Molecular Chaperones; C023548:copper-binding protein; D003300:Copper; D003576:Electron Transport Complex IV
keywords: Copper chaperone; Cu(A) center; Oxidase biogenesis; Respiratory chain; Sco1