title: Identification and primary structure of five human NADH-ubiquinone oxidoreductase subunits.
abstract: The multi-subunit NADH-ubiquinone oxidoreductase (complex I) is the first enzyme complex in the electron transport chain of mitochondria. A small number of NADH-ubiquinone oxidoreductase subunits are the products of mitochondrial genes (subunits 1-7), while the remainder are nuclear encoded and imported from the cytoplasm. We have isolated and sequenced five subunits of the human complex I from a human heart lambda ZAP Express cDNA library. Comparison of the deduced amino acid sequences of the human subunits with the corresponding bovine sequences revealed greater than 80% amino acid identity. The high degree of similarity between human and bovine sequences suggests functional conservation of these subunits in the complex I. In silico Northern analysis revealed that two of the subunits were expressed ubiquitously while the remainder may have more restricted patterns of expression.
authors.affiliation: Department of Laboratory Medicine & Pathobiology, University of Toronto, Toronto Hospital, Ontario, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Ton
authors.forename: D M
authors.initials: DM
authors.lastname: Hwang
authors.forename: A A
authors.initials: AA
authors.lastname: Dempsey
authors.forename: C C
authors.initials: CC
authors.lastname: Liew
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002467:Cell Nucleus / Q000235:genetics; D017124:Conserved Sequence; D018076:DNA, Complementary / Q000235:genetics; D004579:Electron Transport; D042967:Electron Transport Complex I; D015723:Gene Library; D006801:Humans; D008929:Mitochondria, Heart / Q000201:enzymology; D008969:Molecular Sequence Data; D009247:NADH, NADPH Oxidoreductases / Q000235:genetics*; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D014018:Tissue Distribution
chemical_list: D018076:DNA, Complementary; D009247:NADH, NADPH Oxidoreductases; D042967:Electron Transport Complex I