title: Two variants of the assembly factor Surf1 target specific terminal oxidases in Paracoccus denitrificans.
abstract: Biogenesis of cytochrome c oxidase (COX) relies on a large number of assembly proteins, one of them being Surf1. In humans, the loss of Surf1 function is associated with Leigh syndrome, a fatal neurodegenerative disorder. In the soil bacterium Paracoccus denitrificans, homologous genes specifying Surf1 have been identified and located in two operons of terminal oxidases: surf1q is the last gene of the qox operon (coding for a ba(3)-type ubiquinol oxidase), and surf1c is found at the end of the cta operon (encoding subunits of the aa(3)-type cytochrome c oxidase). We introduced chromosomal single and double deletions for both surf1 genes, leading to significantly reduced oxidase activities in membrane. Our experiments on P. denitrificans surf1 single deletion strains show that both Surf1c and Surf1q are functional and act independently for the aa(3)-type cytochrome c oxidase and the ba(3)-type quinol oxidase, respectively. This is the first direct experimental evidence for the involvement of a Surf1 protein in the assembly of a quinol oxidase. Analyzing the heme content of purified cytochrome c oxidase, we conclude that Surf1, though not indispensable for oxidase assembly, is involved in an early step of cofactor insertion into subunit I.
authors.affiliation: Institut für Biochemie, Abteilung Molekulare Genetik, Johann Wolfgang Goethe-Universität, Frankfurt am Main, Germany. Freya@em.uni-frankfurt.de
authors.forename: Freya A
authors.initials: FA
authors.lastname: Bundschuh
authors.forename: Klaus
authors.initials: K
authors.lastname: Hoffmeier
authors.forename: Bernd
authors.initials: B
authors.lastname: Ludwig
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003576:Electron Transport Complex IV / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008928:Mitochondria / Q000201:enzymology; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010231:Paracoccus denitrificans / Q000378:metabolism*; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism*; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D020033:Protein Isoforms; D021122:Protein Subunits; C092928:Surf-1 protein; D003576:Electron Transport Complex IV