title: Disruption of the gene encoding the NADH-binding subunit of NADH: ubiquinone oxidoreductase in Neurospora crassa. Formation of a partially assembled enzyme without FMN and the iron-sulphur cluster N-3.
abstract: In this study, the gene of the 51-kDa NADH-binding subunit of the mitochondrial NADH:ubiquinone oxidoreductase (complex I) in Neurospora crassa was inactivated by homologous replacement with a defective gene copy. The resulting mutant, nuo51, lacks the 51-kDa subunit and shows no complex I activity but still grows at one third of the wild-type growth rate. The enzyme activity of the alternative NADH:ubiquinone oxidoreductase(s) is increased twofold while the activities of the other mitochondrial respiratory enzymes are normal. Complex I is almost completely assembled except for the NADH-binding subunit and still possesses three out of the four EPR-detectable iron-sulphur clusters. Since the deleted subunit contains the sequence motif for one tetranuclear iron-sulphur cluster, the missing cluster N-3 is considered to be bound to this subunit.
authors.affiliation: Institut für Biochemie, Heinrich-Heine-Universität Düsseldorf, Germany.
authors.forename: W
authors.initials: W
authors.lastname: Fecke
authors.forename: V D
authors.initials: VD
authors.lastname: Sled
authors.forename: T
authors.initials: T
authors.lastname: Ohnishi
authors.forename: H
authors.initials: H
authors.lastname: Weiss
mesh_terms: D001665:Binding Sites; D002499:Centrifugation, Density Gradient; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D003001:Cloning, Molecular; D004578:Electron Spin Resonance Spectroscopy; D004926:Escherichia coli; D005486:Flavin Mononucleotide / Q000378:metabolism; D005800:Genes, Fungal; D005822:Genetic Vectors; D007506:Iron-Sulfur Proteins / Q000378:metabolism; D046911:Macromolecular Substances; D008928:Mitochondria / Q000201:enzymology; D008970:Molecular Weight; D016296:Mutagenesis; D009243:NAD / Q000378:metabolism; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000096:biosynthesis* / Q000235:genetics* / Q000302:isolation & purification; D009492:Neurospora crassa / Q000201:enzymology* / Q000235:genetics*; D010084:Oxidation-Reduction; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000302:isolation & purification
chemical_list: D007506:Iron-Sulfur Proteins; D046911:Macromolecular Substances; D011994:Recombinant Proteins; D009243:NAD; D005486:Flavin Mononucleotide; D016660:NAD(P)H Dehydrogenase (Quinone)