title: Topology and function of CcmD in cytochrome c maturation.
abstract: The system I cytochrome c biogenesis pathway requires CcmD, a small polypeptide of 69 residues in Escherichia coli. Here it is shown that CcmD is a component of the CcmABC ATP-binding cassette transporter complex. CcmD is not necessary for the CcmC-dependent transfer of heme to CcmE in the periplasm or for interaction of CcmE with CcmABC. CcmD is absolutely required for the release of holo-CcmE from the CcmABCD complex. Evidence is presented that the topology of CcmD in the cytoplasmic membrane is the N terminus outside and the C terminus inside with one transmembrane domain.
authors.affiliation: Department of Biology, Washington University, Campus Box 1137, 1 Brookings Drive, St. Louis, MO 63130, USA.
authors.forename: Cynthia L
authors.initials: CL
authors.lastname: Richard-Fogal
authors.forename: Elaine R
authors.initials: ER
authors.lastname: Frawley
authors.forename: Robert G
authors.initials: RG
authors.lastname: Kranz
mesh_terms: D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D001692:Biological Transport; D002462:Cell Membrane; D045304:Cytochromes c / Q000096:biosynthesis* / Q000737:chemistry / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D005798:Genes, Bacterial; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
chemical_list: D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; C116246:CcmC protein, bacteria; C415989:CcmD protein, E coli; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; D045304:Cytochromes c