title: The cydD gene product, component of a heterodimeric ABC transporter, is required for assembly of periplasmic cytochrome c and of cytochrome bd in Escherichia coli.
abstract: The cydD gene of Escherichia coli encodes a protein which, together with the CydC protein, probably constitutes a heterodimeric, ABC-family membrane transporter, necessary for biosynthesis of the cytochrome bd quinol oxidase. Here, we demonstrate that a cydD mutant also fails to synthesise periplasmic c-type cytochrome(s), suggesting that the transporter exports haem or some other component involved in assembly of cytochromes that are found in, or exposed to, the periplasm. The CydDC system appears to be the first example of a transporter required for periplasmic cytochrome assembly processes requiring more than one type of haem. A mutant defective in trxB (adjacent to the cydDC operon, and encoding thioredoxin reductase) was unaffected in cytochrome c or bd assembly.
authors.affiliation: Division of Biochemistry and Molecular Biology, John Curtin School of Medical Research, Australian National University, Canberra City, ACT.
authors.forename: R K
authors.initials: RK
authors.lastname: Poole
authors.forename: F
authors.initials: F
authors.lastname: Gibson
authors.forename: G
authors.initials: G
authors.lastname: Wu
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002451:Cell Compartmentation; D003573:Cytochrome b Group; D003574:Cytochrome c Group / Q000096:biosynthesis*; D003580:Cytochromes / Q000096:biosynthesis*; D045222:Electron Transport Chain Complex Proteins; D004926:Escherichia coli / Q000201:enzymology / Q000378:metabolism*; D029968:Escherichia coli Proteins; D005798:Genes, Bacterial; D009154:Mutation; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000096:biosynthesis*; D013053:Spectrophotometry
chemical_list: D002352:Carrier Proteins; D003573:Cytochrome b Group; D003574:Cytochrome c Group; D003580:Cytochromes; D045222:Electron Transport Chain Complex Proteins; D029968:Escherichia coli Proteins; D010088:Oxidoreductases; C040077:cytochrome bd terminal oxidase complex, E coli; D000251:Adenosine Triphosphatases