title: Isolation and characterization of a new class of cytochrome d terminal oxidase mutants of Escherichia coli.
abstract: Cytochrome d terminal oxidase mutants were isolated by using hydroxylamine mutagenesis of pNG2, a pBR322-derived plasmid containing the wild-type cyd operon. The mutagenized plasmid was transformed into a cyo cyd recA strain, and the transformants were screened for the inability to confer aerobic growth on nonfermentable carbon sources. Western blot analysis and visible-light spectroscopy were performed to characterize three independent mutants grown both aerobically and anaerobically. The mutational variants of the cytochrome d complex were stabilized under anaerobic growth conditions. All three mutations perturb the b595 and d heme components of the complex. These mutations were mapped and sequenced and are shown to be located in the N-terminal third of subunit II of the cytochrome d complex. It is proposed that the N terminus of subunit II may interact with subunit I to form an interface that binds the b595 and d heme centers.
authors.affiliation: Department of Chemistry, School of Chemical Sciences, University of Illinois, Urbana 61801.
authors.forename: K L
authors.initials: KL
authors.lastname: Oden
authors.forename: R B
authors.initials: RB
authors.lastname: Gennis
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003573:Cytochrome b Group; D017937:Cytochrome d Group; D003580:Cytochromes / Q000235:genetics; D045222:Electron Transport Chain Complex Proteins; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D029968:Escherichia coli Proteins; D015870:Gene Expression; D005819:Genetic Markers; D008969:Molecular Sequence Data; D016296:Mutagenesis; D010088:Oxidoreductases / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D010957:Plasmids
chemical_list: D003573:Cytochrome b Group; D003580:Cytochromes; D045222:Electron Transport Chain Complex Proteins; D029968:Escherichia coli Proteins; D005819:Genetic Markers; D017937:Cytochrome d Group; D010088:Oxidoreductases; C040077:cytochrome bd terminal oxidase complex, E coli