Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.6.5.3 (complex I)
 8,901 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The amino acid sequence of the 10 kDa subunit of the flavoprotein (FP) fragment of complex I from bovine heart mitochondria has been determined by protein sequence analysis, thereby completing the sequence of the FP fragment. The calculated molecular weight of the 10 kDa subunit agrees exactly with the value of 8438 determined by electrospray mass spectrometry, and further confirmation of the sequence has been obtained by sequencing cDNAs amplified from total bovine heart cDNA by the polymerase chain reaction, using mixed oligonucleotides based upon the protein sequence as primers and hybridization probes. The sequence of the 10 kDa subunit is not related to that of any known protein. Being devoid of cysteine residues, it has none of the characteristic features of known iron-sulfur proteins and it is improbable that it is involved in liganding Fe-S centers in the FP fragment.
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PMID:NADH:ubiquinone oxidoreductase from bovine heart mitochondria. Complementary DNA sequence of the import precursor of the 10 kDa subunit of the flavoprotein fragment. 190 1

The NADH dehydrogenase complex isolated from Paracoccus denitrificans is composed of approximately 10 unlike polypeptides and contains noncovalently bound FMN, non-heme iron, and acid-labile sulfide [Yagi, T. (1986) Arch. Biochem. Biophys. 250, 302-311]. The NADH-binding subunit (Mr = 50,000) of this enzyme complex was identified by direct photoaffinity labeling with [32P]NADH [Yagi, T., & Dinh, T.M. (1990) Biochemistry 29, 5515-5520]. Primers were synthesized on the basis of the N-terminal amino acid sequence of this polypeptide, and these primers were used to synthesize an oligonucleotide probe by the polymerase chain reaction. This probe was utilized to isolate the gene encoding the NADH-binding subunit from a genomic library of P. denitrificans. The nucleotide sequence of the gene and the deduced amino acid sequence of the entire NADH-binding subunit were determined. The NADH-binding subunit has 431 amino acid residues and a calculated molecular weight of 47,191. The encoded protein contains a putative NAD(H)-binding and an iron-sulfur cluster-binding consensus sequence. The deduced amino acid sequence of the Paracoccus NADH-binding subunit shows remarkable similarity to the alpha subunit of the NAD-linked hydrogenase of Alcaligenes eutrophus H16. When partial DNA sequencing of the regions surrounding the gene encoding the NADH-binding subunit was carried out, sequences homologous to the 24-, 49-, and 75-kDa polypeptides of bovine complex I were detected, suggesting that the structural genes of the Paracoccus NADH dehydrogenase complex constitute a gene cluster.
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PMID:The NADH-binding subunit of the energy-transducing NADH-ubiquinone oxidoreductase of Paracoccus denitrificans: gene cloning and deduced primary structure. 190 52

Mitochondrial NADH:ubiquinone oxidoreductase (complex I) is the most complicated system in the respiratory chain. It consists of many subunits, some of which hold iron-sulfur clusters, but structural information is still limited. The amino acid sequences of two 13 kDa polypeptides, 13 kDa-A and 13 kDa-B polypeptides, of iron-sulfur protein fraction (IP) of bovine heart mitochondrial complex I were determined by a combination of protease digestion, Edman degradation, and carboxypeptidase digestion. The 13 kDa-A polypeptide was composed of 96 amino acids with a molecular weight of 10,536. The 13 kDa-B polypeptide consisted of 114 amino acids and had an acetylated amino terminus. The molecular weight of this protein was calculated to be 13,130 including the acetyl group. These proteins had no obvious sequence similarity to other known proteins. The partial amino acid sequence of 30 kDa-B polypeptide of IP was also determined to reveal a characteristic arrangement of cysteine residues that could be involved in iron-sulfur cluster formation.
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PMID:The amino acid sequences of two 13 kDa polypeptides and partial amino acid sequence of 30 kDa polypeptide of complex I from bovine heart mitochondria: possible location of iron-sulfur clusters. 190 66

The NADH dehydrogenase complex isolated from Paracoccus denitrificans is composed of approximately 10 unlike polypeptides [Yagi, T. (1986) Arch. Biochem. Biophys. 250, 302-311]. Structural genes encoding the subunits of this enzyme complex constitute at least one gene cluster [Xu, X., Matsuno-Yagi, A., & Yagi, T. (1991) Biochemistry 30, 6422-6428]. The 25-kDa subunit (NQO2), which has been isolated from sodium dodecyl sulfate-polyacrylamide gels, is a polypeptide of this enzyme complex. The partial N-terminal amino acid sequence and amino acid composition of the NQO2 subunit have been determined. On the basis of the amino acid sequence, the NQO2 gene was found to be located 1.7 kilobase pairs upstream of the gene for NADH-binding subunit (NQO1). The complete nucleotide sequence of the NQO2 gene was determined. It is composed of 717 base pairs and codes for 239 amino acid residues with a calculated molecular weight of 26,122. The NQO2 subunit is homologous to the Mr 24,000 subunit of the mammalian mitochondrial NADH-ubiquinone oxidoreductase which bears an electron paramagnetic resonance-visible binuclear iron-sulfur cluster (probably cluster N1b). Comparison of the predicted amino acid sequence of the Paracoccus NQO2 subunit with those of its mammalian counterparts suggests putative binding sites for the iron-sulfur cluster. In addition, nucleotide sequencing shows the presence of two unidentified reading frames between the NQO1 and NQO2 genes. These are designated URF1 and URF2 and are composed of 261 and 642 base pairs, respectively. The possible function of the protein coded for the URF2 is discussed.
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PMID:Characterization of the 25-kilodalton subunit of the energy-transducing NADH-ubiquinone oxidoreductase of Paracoccus denitrificans: sequence similarity to the 24-kilodalton subunit of the flavoprotein fraction of mammalian complex I. 190 71

A lambda gt10 bovine brain and a lambda gt11 bovine heart cDNA library were screened with oligonucleotide probes corresponding to partial protein sequences directly determined from the isolated 51-kDa subunit of the bovine respiratory-chain NADH dehydrogenase. Clones were isolated that encode a protein of 464 amino acids containing all the 11 partial tryptic peptide sequences determined from the 51-kDa subunit. The size and amino acid composition of this protein agree with those determined for the purified 51-kDa subunit. Furthermore, this protein contains a putative NADH-binding domain, a possible FMN-binding site, and a putative binding site for an iron-sulfur cluster. The above evidence indicates that the cloned protein is the 51-kDa subunit or its precursor. A search for sequence similarity with proteins in the Protein Identification Resource data base has revealed that the 51-kDa subunit has 32% amino acid sequence identity with a major portion of the alpha subunit of the soluble NAD(+)-reducing hydrogenase from Alcaligenes eutrophus. In particular, there are three segments of high sequence similarity (70-88%) between the two proteins which correspond to the three ligand-binding sites.
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PMID:cDNA-derived amino acid sequence of the NADH-binding 51-kDa subunit of the bovine respiratory NADH dehydrogenase reveals striking similarities to a bacterial NAD(+)-reducing hydrogenase. 203 66

A systematic study of the effects of the synthetic glucocorticoid, methylprednisolone (MP), on respiration and energy coupling in tightly-coupled mitochondria isolated from rat tissues has been initiated. In intact rat skeletal muscle, liver and heart mitochondria, incubation, in vitro, with greater than or equal to 0.1 mM MP caused inhibition of the state 3 respiratory rates with succinate and NAD-linked substrates. In skeletal muscle and heart mitochondria, the oxidation of succinate was significantly more sensitive to MP than was that of the NAD-linked substrates. No effects were seen at low concentrations (less than 0.02 mM) of MP. In all three tissues, these data together with analysis of the partial reactions of the electron transport chain and steady-state kinetic analysis of cytochrome reduction indicated that in isolated mitochondria high concentrations of MP: (a) inhibit the oxidation of NAD-linked substrates at the level of the respiratory chain between the primary NADH dehydrogenase flavoprotein and coenzyme Q, most likely at the iron-sulfur centers or coenzyme Q-binding proteins of complex I; and (b) inhibit succinate oxidation in intact (but not disrupted) mitochondria, not by inhibiting electron transfer along the respiratory chain, but possibly at the level of succinate transport into the mitochondria. The results of these studies suggest that the therapeutic effects of MP in mitochondrial disease result from indirect effects rather than direct effects on the mitochondrial membrane. More importantly, the absence of an effect at low MP concentrations provides the baseline information needed for further studies to be carried out in vivo.
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PMID:In vitro effects of glucocorticoid on mitochondrial energy metabolism. 204 73

The NADH-quinone oxidoreductases of the bacterial respiratory chain could be divided in two groups depending on whether they bear an energy-coupling site. Those enzymes that bear the coupling site are designated as NADH dehydrogenase 1 (NDH-1) and those that do not as NADH dehydrogenase 2 (NDH-2). All members of the NDH-1 group analyzed to date are multiple polypeptide enzymes and contain noncovalently bound FMN and iron-sulfur clusters as prosthetic groups. The NADH-ubiquinone-1 reductase activities of NDH-1 are inhibited by rotenone, capsaicin, and dicyclohexylcarbodiimide. The NDH-2 enzymes are generally single polypeptides and contain noncovalently bound FAD and no iron-sulfur clusters. The enzymatic activities of the NDH-2 are not affected by the above inhibitors for NDH-1. Recently, it has been found that both of these types of the NADH-quinone oxidoreductase are present in a single strain of bacteria. The significance of the occurrence of these two types of enzymes in a single organism has been discussed in this review.
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PMID:Bacterial NADH-quinone oxidoreductases. 205 Jun 55

The NADH dehydrogenase complex isolated from Paracoccus denitrificans is composed of approximately 10 unlike polypeptides and contains noncovalently bound FMN, non-heme iron, and acid-labile sulfide [Yagi, T. (1986) Arch. Biochem. Biophys. 250, 302-311]. When the Paracoccus NADH dehydrogenase complex was irradiated by UV light in the presence of [adenylate-32P]NAD, radioactivity was incorporated exclusively into one of three polypeptides of Mr approximately 50,000. Similar results were obtained when [adenylate-32P]NADH was used. The labeling of the Mr 50,000 polypeptide was diminished when UV irradiation of the enzyme with [adenylate-32P]NAD was performed in the presence of NADH, but not in the presence of NADP(H). The labeled polypeptide was isolated by preparative sodium dodecyl sulfate gel electrophoresis and was shown to cross-react with antiserum to the NADH-binding subunit (Mr = 51,000) of bovine NADH-ubiquinone oxidoreductase. Its amino acid composition was also very similar to that of the bovine NADH-binding subunit. These chemical and immunological results indicate that the Mr 50,000 polypeptide is an NADH-binding subunit of the Paracoccus NADH dehydrogenase complex.
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PMID:Identification of the NADH-binding subunit of NADH-ubiquinone oxidoreductase of Paracoccus denitrificans. 211 69

NADH:ubiquinone reductase, the respiratory chain complex I of mitochondria, consists of some 25 nuclear-encoded and seven mitochondrially encoded subunits, and contains as redox groups one FMN, probably one internal ubiquinone and at least four iron-sulphur clusters. We are studying the assembly of the enzyme in Neurospora crassa. The flux of radioactivity in cells that were pulse-labelled with [35S]methionine was followed through immunoprecipitable assembly intermediates into the holoenzyme. Labelled polypeptides were observed to accumulate transiently in a Mr 350,000 intermediate complex. This complex contains all mitochondrially encoded subunits of the enzyme as well as subunits encoded in the nucleus that have no homologous counterparts in a small, merely nuclear-encoded form of the NADH:ubiquinone reductase made by Neurospora crassa cells poisoned with chloramphenicol. With regard to their subunit compositions, the assembly intermediate and small NADH:ubiquinone reductase complement each other almost perfectly to give the subunit composition of the large complex I. These results suggest that two pathways exist in the assembly of complex I that independently lead to the preassembly of two major parts, which subsequently join to form the complex. One preassembled part is related to the small form of NADH:ubiquinone reductase and contributes most of the nuclear-encoded subunits, FMN, three iron-sulphur clusters and the site for the internal ubiquinone. The other part is the assembly intermediate and contributes all mitochondrially encoded subunits, one iron-sulphur cluster and the catalytic site for the substrate ubiquinone. We discuss the results with regard to the evolution of the electron pathway through complex I.
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PMID:Assembly of NADH: ubiquinone reductase (complex I) in Neurospora mitochondria. Independent pathways of nuclear-encoded and mitochondrially encoded subunits. 214 52

The respiratory chain NADH:ubiquinone oxidoreductase (NADH dehydrogenase or Complex I) of mitochondria comprises some 30 different subunits, and one FMN and 4 or 5 iron-sulfur clusters as internal redox groups. The bacterial glucose dehydrogenase, which oxidizes glucose to gluconolactone in the periplasmatic space and transfers the electrons to ubiquinone, is a single polypeptide chain with pyrolloquinoline quinone as the only redox group. We report here that the two different enzymes have the same ubiquinone binding domain motif and we discuss the predicted membrane folding of this domain with regard to its role in the proton translocating function of the two enzymes.
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PMID:The same domain motif for ubiquinone reduction in mitochondrial or chloroplast NADH dehydrogenase and bacterial glucose dehydrogenase. 214 3


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