title: The nucleotide sequence of the cyd locus encoding the two subunits of the cytochrome d terminal oxidase complex of Escherichia coli.
abstract: The cytochrome d terminal oxidase complex is one of two terminal oxidases in the aerobic respiratory chain of Escherichia coli. The enzyme is located in the cytoplasmic membrane where it oxidizes ubiquinol-8 in the bilayer and reduces oxygen to water. Enzyme turnover is coupled to the generation of a proton-motive force, resulting in electrogenic translocation across the membrane of one proton per electron passing through the system. The enzyme is an alpha beta heterodimer containing four hemes. The cyd locus, encoding both subunits, has previously been genetically mapped and cloned. This work describes an insertion and deletion analysis of cyd which indicates the direction of transcription, defines the coding regions, and suggests that cyd is an operon. In addition, the complete DNA sequence of the cyd gene is reported. Two open reading frames, separated by 18 base pairs, encode the two subunits of the oxidase complex. Hydropathy profiles of the deduced protein sequence indicate that subunits I and II are each likely to have multiple transmembrane elements. There are only 10 histidines in both subunits, several of which are likely to serve as heme axial ligands.
authors.affiliation: Department of Biochemistry, University of Illinois, Urbana 61801.
authors.forename: G N
authors.initials: GN
authors.lastname: Green
authors.forename: H
authors.initials: H
authors.lastname: Fang
authors.forename: R J
authors.initials: RJ
authors.lastname: Lin
authors.forename: G
authors.initials: G
authors.lastname: Newton
authors.forename: M
authors.initials: M
authors.lastname: Mather
authors.forename: C D
authors.initials: CD
authors.lastname: Georgiou
authors.forename: R B
authors.initials: RB
authors.lastname: Gennis
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002872:Chromosome Deletion; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D003573:Cytochrome b Group; D003580:Cytochromes; D004262:DNA Restriction Enzymes / Q000378:metabolism; D045222:Electron Transport Chain Complex Proteins; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D029968:Escherichia coli Proteins; D007425:Intracellular Membranes / Q000201:enzymology; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000235:genetics*; D010100:Oxygen / Q000378:metabolism; D014451:Ubiquinone / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D003573:Cytochrome b Group; D003580:Cytochromes; D045222:Electron Transport Chain Complex Proteins; D029968:Escherichia coli Proteins; D046911:Macromolecular Substances; D014451:Ubiquinone; D010088:Oxidoreductases; C040077:cytochrome bd terminal oxidase complex, E coli; D004262:DNA Restriction Enzymes; C003741:ubiquinol; D010100:Oxygen