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)

A pseudogene, psi nad7, which has significant sequence similarity (66.7% amino acid identity) with the bovine nuclear gene for a 49 kDa subunit of the NADH dehydrogenase (NADH:ubiquinone oxidoreductase, EC 1.6.99.3), has been identified on the mitochondrial genome of the liverwort Marchantia polymorpha. The predicted coding region, which includes six termination codons, is actively transcribed into RNA molecules of 16 and 9.6 kb in length, but RNA splicing products were not detected in the liverwort mitochondria. Genomic DNA blot analysis and RNA blot analysis using poly(A)+ RNA suggest that a structurally related nuclear gene encodes the mitochondrial ND7 polypeptide. These results imply that this psi nad7 is a relic of a gene transfer event from the mitochondrial genome into the nuclear genome during mitochondrial evolution in M. polymorpha.
Mol Gen Genet 1995 Jun 10
PMID:Active transcription of the pseudogene for subunit 7 of the NADH dehydrogenase in Marchantia polymorpha mitochondria. 760 35

In Nicotiana sylvestris, two cytoplasmic male sterile (CMS) mutants obtained by protoplast culture show abnormal developmental features of both vegetative and reproductive organs, and mitochondrial gene reorganization following homologous recombination between 65 bp repeated sequences. A mitochondrial region of 16.2 kb deleted from both CMS mutants was found to contain the last two exons of the nad7 gene coding for a subunit of the mitochondrial respiratory chain complex I, which is encoded in the nucleus in fungi and animals but was recently found to be encoded by the mitochondrial genome in wheat. Although the N. sylvestris nad7 gene shows strong homology with its wheat counterpart, it contains only three introns instead of four. Polymerase chain reaction (PCR) experiments indicated that the parental gene organization, including the complete nad7 gene, is probably maintained at a substoichiometric level in the CMS mutants, but this proportion is too low to have a significant physiological role, as confirmed by expression studies showing the lack of detectable amounts of the NAD7 polypeptide. Consequently, absence of NAD7 is not lethal to plant cells but a deficiency of complex I could be involved in the abnormal CMS phenotype.
Mol Gen Genet 1995 Jul 22
PMID:Deletion of the last two exons of the mitochondrial nad7 gene results in lack of the NAD7 polypeptide in a Nicotiana sylvestris CMS mutant. 765 30

In order to assess the contribution of oxidative metabolism to K+(86Rb+) transport across the lamprey red cell membrane, the effects of various metabolic inhibitors were examined. The influx of K+ was reduced markedly in the presence of 20 mumol/l 2,4-dinitrophenol (2,4-DNP) or rotenone, and to a lesser extent by 1 mmol/l cyanide. Rotenone produced complete inhibition of the K+ active transport and a partial blockade of K+ channels by 28% on the average. Addition of 2,4-DNP to incubation media resulted in a significant reduction of both active transport of K+ (by 47%) and of K+ movement via channels (by 57%). The inhibitory effect of 2,4-DNP on total K+ influx was independent on decreasing extracellular pHe from 7.4 to 6.5. The blocking action of 1 mmol/l Ba2+ on K+ channels was abolished in the red cells incubated at pHe 6.5. Treatment of the red cells with 1 mmol/l cyanide diminished active transport of K+ to about 34% of control values but did not affect K+ channels. The obtained data indicate that in the lamprey red blood cells at least a half of energy needed for the active transport of K+ is supplied with ATP produced by oxidative phosphorylation. It may be suggested that NADH dehydrogenase is the key enzyme required for active transport of K+ in the cells, as rotenone, a selective blocker of this enzyme, causes a complete blockade of the Na+, K(+)-pump.
Gen Physiol Biophys 1994 Dec
PMID:Effect of metabolic inhibitors on K+ transport across the lamprey (Lampetra fluviatilis) erythrocyte membrane. 779 53

The N-terminal amino acid sequence of a 42.5 kDa subunit of the NADH: ubiquinone oxidoreductase (complex I) from potato has been determined by direct protein sequencing. The sequence was found to be homologous to that of the nuclear-encoded 49 kDa complex I subunit of bovine and Neurospora mitochondria and to the sequence deduced from the mitochondrial nad7 gene identified in the mitochondrial (mt) DNA of tryp anosomes and the moss Marchantia. An oligonucleotide probe derived from the potato N-terminal protein sequence hybridized only to the plant mtDNA. Immunoprecipitation of in-organello 35S-labelled potato and wheat mitochondrial translation products with an antibody directed against the Neurospora 49 kDa complex I subunit indicates that at least in these plants the NAD7 protein is synthesized within the organelle. Comparisons of genomic, cDNA and protein sequences of the 5' coding region reveal three codons that are changed by RNA-editing and confirm translation of the edited transcripts in plant mitochondria. The NAD7 protein appears to undergo post-translational processing since the N-terminal methionine residue is absent from the mature mitochondrial protein.
Mol Gen Genet 1994 Jul 08
PMID:The 42.5 kDa subunit of the NADH: ubiquinone oxidoreductase (complex I) in higher plants is encoded by the mitochondrial nad7 gene. 804 59

We have characterized a wheat mitochondrial gene, designated nad7, capable of encoding a 394-amino acid subunit of the respiratory chain NADH dehydrogenase complex. It contains four introns possessing group II features and their positions differ from those in both the liverwort mitochondrial nad7 pseudogene and the nuclear gene encoding the homologous 49 kDa subunit of complex I in Neurospora. The derived amino acid sequence of the wheat nad7 gene is strongly conserved relative to its nuclear or organellar counterparts in other organisms. C-to-U type RNA editing, which is observed at 32 positions within the coding region of wheat nad7 transcripts, strengthens protein sequence similarity. RNA editing is also predicted to improve base-pairing within the domain V/VI regions of all four introns.
Mol Gen Genet 1994 Jul 08
PMID:The NADH dehydrogenase subunit 7 gene is interrupted by four group II introns in the wheat mitochondrial genome. 804 65

The mitochondrial gene coding for subunit 4 of the NADH dehydrogenase complex I (nad4) has been isolated and characterized from lettuce, Lactuca sativa. Analysis of nad4 genes in a number of plants by Southern hybridization had previously suggested that the intron content varied between species. Characterization of the lettuce gene confirms this observation. Lettuce nad4 contains two exons and one group IIA intron, whereas previously sequenced nad4 genes from turnip and wheat contain three group IIA introns. Northern analysis identified a transcript of 1600 nucleotides, which represents the mature nad4 mRNA and a primary transcript of 3200 nucleotides. Sequence analysis of lettuce and turnip nad4 cDNAs was used to confirm the intron/exon border sequences and to examine RNA editing patterns. Editing is observed at the 5' and 3' ends of the lettuce transcript, but is absent from sequences that correspond to exons two, three and the 5' end of exon four in turnip and wheat. In contrast, turnip transcripts are highly edited in this region, suggesting that homologous recombination of an edited and spliced cDNA intermediate was involved in the loss of introns two and three from an ancestral lettuce nad4 gene.
Mol Gen Genet 1994 Apr
PMID:Intron loss from the NADH dehydrogenase subunit 4 gene of lettuce mitochondrial DNA: evidence for homologous recombination of a cDNA intermediate. 819 77

Genes homologous to those encoding mitochondrial NADH dehydrogenase subunits ND4L and ND5 in filamentous fungi were identified in the mitochondrial genome of a budding yeast, Hansenula wingei. The structure and expression of these genes were investigated. The H. wingei ND4L gene is 282 bp long, and potentially codes for a polypeptide of 94 amino acids. The putative ND4L protein sequence shares about 46% homology with the analogous mitochondrial proteins of filamentous fungi. The H. wingei ND5 gene is 1935 bp long, and encodes a 645-residue polypeptide. The derived ND5 protein shares about 38% sequence homology with the analogue in filamentous fungi. The ND4L and ND5 genes have no intervening sequence, and form a gene cluster in the order of 5'-ND4L-ND5-3'. A presumptive mature dicistronic or polycistronic transcript of these genes was detected by Northern blot hybridization. These results strongly indicate that these ND4L and ND5 genes are active. As far as we are aware, this is the first report on the identification of mitochondrially encoded ND genes in yeast.
Mol Gen Genet 1994 May 25
PMID:The mitochondrial genome of yeast Hansenula wingei encodes NADH dehydrogenase subunit genes ND4L and ND5. 820 91

From a sugar beet mitochondrial DNA library, we have isolated an open reading frame (ORF192) showing extensive homology to the gene for the 30 kDa subunit of the bovine mitochondrial complex I (NADH: ubiquinone reductase). The ORF192 was found to be actively transcribed to give an RNA of approximately 1.0 kb. We have designated this gene nad9. Transcripts from the nad9 locus are edited by five C to U transitions, increasing similarity with the amino acid sequence of the corresponding bovine and Neurospora crassa polypeptides. Southern blot hybridization also indicates that nad9 is present in the mitochondrial genomes of a variety of higher plant species.
Mol Gen Genet 1993 Nov
PMID:The sugar beet mitochondrial genome contains an ORF sharing sequence homology with the gene for the 30 kDa subunit of bovine mitochondrial complex I. 824 3

The presence of several NADH dehydrogenase activities associated with cytoplasmic membrane vesicles of chemoheterotrophically grown Rhodobacter capsulatus MT1131 was demonstrated by combining isoelectric focusing with NADH-tetranitrobluetetrazolium activity staining, a procedure that should have general applicability in the analysis of bacterial NADH dehydrogenase activities. Low pI (pI = 5.7), Mid pI (pI = 6.9) and High pI (pI = 8.5) bands were resolved. The Mid pI NADH dehydrogenase activity was purified and identified as a dihydrolipoyl dehydrogenase. Our data indicate that this dihydrolipoyl dehydrogenase is derived from a 2-oxoacid dehydrogenase complex which is associated with the cytoplasmic membrane.
J Gen Microbiol 1993 Aug
PMID:Membrane-associated NADH dehydrogenase activities in Rhodobacter capsulatus: purification of a dihydrolipoyl dehydrogenase. 840 25

The rpl5 ribosomal protein gene was identified in the mitochondrial genome of the higher plant Oenothera berteriana. The gene is present in a unique genomic location upstream of the gene encoding subunit 3 of the NADH dehydrogenase (nad3). Both genes are cotranscribed, and the mRNA is modified at several cytidine residues by RNA editing. Analysis of the editing profiles of both genes by direct cDNA analysis and polymerase chain reaction (PCR) revealed that not all transcripts are fully edited at all sites. Eight of the nine C to U conversions in the rpl5 reading frame are non-silent and change the deduced amino acid sequence. The genes of the prokaryotic-like cistron that includes the rpsl9, rps3, rpl16, rpl5, and rpsl4 genes, which is at least partially conserved in the mitochondrial genomes of other higher and lower plants, are dispersed in the Oenothera mitochondrial genome.
Mol Gen Genet 1993 Sep
PMID:Ribosomal protein gene rpl5 is cotranscribed with the nad3 gene in Oenothera mitochondria. 841 95


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