Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.6.3.14 (ATP synthase)
7,042 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two alloplasmic wheat lines having the same common wheat nucleus but the cytoplasms of Aegilops crassa and Ae. columnaris together with the corresponding normal line (control) were used in the two-dimensional gel electrophoresis of soluble and thylakoid membrane proteins of the chloroplast. Three chloroplast polypeptides: the Rubisco large subunit, the beta subunit of ATP synthase, and an unidentified 31 kDa protein, differed in the common wheat and two Aegilops cytoplasms. Three chloroplast genes, atpB, atpE and trnM, that respectively encode the beta and epsilon subunits of ATP synthase and tRNA(met), were sequenced. The atpB gene differed by two synonymous base substitutions, whereas the other two genes were identical in the two Aegilops cytoplasms. From the predicted amino acid sequences, the beta subunits of the ATP synthase in the Aegilops cytoplasms were assumed to have three amino acid substitutions: Ala by Val, Asp- by Ala, and Gln by Lys+, in contrast to the cytoplasm of common wheat. This accounts for the difference in pI values found for the common wheat and Aegilops cytoplasms. The two base substitutions for the atpE genes of common wheat and the Aegilops cytoplasms were synonymous. The differences detected in the genes encoding the two subunits of ATP synthase do not appear to be ascribable to the differences in phenotypic effects for the common wheat and Aegilops cytoplasms. The base substitution rate of the atpB-atpE-trnM gene cluster was similar to that of the rbcL gene. From the rate for the atpB gene alone, evolutionary divergence of the wheat-Aegilops complex is assumed to have begun ca. 3.0 x 10(6) years ago, as compared to ca. 8.0 x 10(6) years ago for the divergence of the wheat-Aegilops complex and barley.
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PMID:Variations in chloroplast proteins and nucleotide sequences of three chloroplast genes in Triticum and Aegilops. 138 32

Respiratory deficient mutants of Saccharomyces cerevisiae previously assigned to complementation group G59 are pleiotropically deficient in respiratory chain components and in mitochondrial ATPase. This phenotype has been shown to be a consequence of mutations in a nuclear gene coding for mitochondrial leucyl-tRNA synthetase. The structural gene (MSL1) coding for the mitochondrial enzyme has been cloned by transformation of two different G59 mutants with genomic libraries of wild type yeast nuclear DNA. The cloned gene has been sequenced and shown to code for a protein of 894 residues with a molecular weight of 101,936. The amino-terminal sequence (30-40 residues) has a large percentage of basic and hydroxylated residues suggestive of a mitochondrial import signal. The cloned MSL1 gene was used to construct a strain in which 1 kb of the coding sequence was deleted and substituted with the yeast LEU2 gene. Mitochondrial extracts obtained from the mutant carrying the disrupted MSL1::LEU2 allele did not catalyze acylation of mitochondrial leucyl-tRNA even though other tRNAs were normally charged. These results confirmed the correct identification of MSL1 as the structural gene for mitochondrial leucyl-tRNA synthetase. Mutations in MSL1 affect the ability of yeast to grow on nonfermentable substrates but are not lethal indicating that the cytoplasmic leucyl-tRNA synthetase is encoded by a different gene. The primary sequence of yeast mitochondrial leucyl-tRNA synthetase has been compared to other bacterial and eukaryotic synthetases. Significant homology has been found between the yeast enzyme and the methionyl- and isoleucyl-tRNA synthetases of Escherichia coli. The most striking primary sequence homology occurs in the amino-terminal regions of the three proteins encompassing some 150 residues. Several smaller domains in the more internal regions of the polypeptide chains, however, also exhibit homology. These observations have been interpreted to indicate that the three synthetases may represent a related subset of enzymes originating from a common ancestral gene.
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PMID:Homology of yeast mitochondrial leucyl-tRNA synthetase and isoleucyl- and methionyl-tRNA synthetases of Escherichia coli. 282 65

Neurospora mitochondrial DNA is transcribed into long molecules containing the information of several genes. Processing leads to formation of functionally active RNAs. It has been shown previously that when tRNA sequences are present in these transcripts excision of mRNAs occurs at the acceptor stem of these tRNA sequences. We have investigated the processing of precursor RNAs transcribed from a region of the mitochondrial genome devoid of tRNA genes. This region comprises the genes encoding subunit 6 of the mitochondrial ATPase, subunit 2 of cytochrome aa3 and a mitochondrial ATPase proteolipid-like gene. We have proved that a common precursor of the putative mRNAs of these genes exists and we have determined the positions of the 5' and 3' ends of processing intermediates and of the mature mRNAs. We will discuss possible processing routes and secondary structures that substitute for tRNA sequences as processing sites.
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PMID:Processing of precursor RNAs from mitochondria of Neurospora crassa. 295 78

Subunit-specific antisera prepared against each of the four cytoplasmically made subunits (IV, V, VI, and VII) of yeast mitochondrial cytochrome c oxidase (EC 1.9.3.1) were used to precipitate immunoreactive polypeptides that were synthesized either in vitro, in a cell-free protein-synthesizing system programmed with total yeast mRNA, or in vivo, in intact cells and in spheroplasts, under conditions of pulse labeling, pulse-chase labeling, and continuous labeling. Using N-formyl-[35S]Met-rTNA as the only radioactively labeled component in the cell-free system, we demonstrated (i) that each of the four cytoplasmically made subunits is synthesized as a separate entity and not as part of a polyprotein as was claimed by others; (ii) that subunits IV, V, and VI are synthesized as precursors, larger by 1500-3000 daltons than their mature counterparts; in contrast, subunit VII is not synthesized as a larger precursor. Precursor forms of subunits IV, V, and VI identical to those synthesized in vitro were also detected in vivo by pulse-labeling of spheroplasts. The observed disappearance of these larger forms after a chase is compatible with the notion that they represent short-lived precursors that are rapidly converted to their mature counterparts during or shortly after import into mitochondria. Furthermore, using N-formyl-[35S]Met-tRNA, we provide definitive evidence that two of the cytoplasmically made subunits (beta and gamma) of another oligomeric inner mitochondrial membrane protein (F1-ATPase, EC 3.6.1.3) are not synthesized as part of a polyprotein but as individual precursors.
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PMID:The four cytoplasmically made subunits of yeast mitochondrial cytochrome c oxidase are synthesized individually and not as a polyprotein. 625 13

Mitochondrial gene organization was studied in a dimorphic yeast, Yarrowia lipoltica. The gene order in a sequenced 6.6-kilobase region closely resembles that of the human mitochondrial genome in that ATP synthase subunit 8 and 6 genes are followed by genes for cytochrome c oxidase subunit 3 (which contains an intron), NADH-ubiquinone oxidoreductase subunit 4, and ATP synthase subunit 9. This region also contains tRNA genes decoding AUA, UGA, CUN and CCN codons, suggesting a unique mitochondrial translation. All the above genes are transcribed from the same DNA strand into multigenic RNAs, starting from a nonanucleotide sequence, 5'-ATATAAATA-3', similar to other yeast mitochondrial promoters.
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PMID:Organization and transcription of the mitochondrial ATP synthase genes in the yeast Yarrowia lipolytica. 753 57

We have determined the complete nucleotide sequence of a 44 420 bp DNA fragment from chromosome XIV of Saccharomyces cerevisiae. The sequence data revealed 23 open reading frames (ORFs) larger than 300 bp, covering 73.5% of the sequence. The ORFs N2418, N2428, N2441, N2474 and N2480 correspond to previously sequenced S. cerevisiae genes coding respectively for the mitochondrial import protein Mas5, the nucleolar protein Nop2, the outer mitochondrial membrane porin Por1, the cytochrome c oxidase polypeptide VA precursor CoxA and the yeast protein tyrosine phosphatase Msg5. Translation products of three other ORFs N2406, N2411 and N2430 exhibit similarity to previously known S. cerevisiae proteins: the ribosomal protein YL9A, the protein Nca3 involved in the mitochondrial expression of subunits 6 and 8 of the ATP synthase and actin; in addition N2505 presents strong similarity to an ORF of chromosome IX. The predicted protein products of ORFs N2417 and N2403 present similarities with domains from proteins of other organisms: the Candida maltosa cycloheximide-resistance protein, the human interleukin enhancer-binding factor (ILF-2). The 12 remaining ORFs show no significant similarity to known proteins. In addition, we have detected a DNA region very similar to the yeast transposon Ty 1-15 of which insertion has disrupted a tRNA(Asp) gene.
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PMID:The sequence of a 44 420 bp fragment located on the left arm of chromosome XIV from Saccharomyces cerevisiae. 890 43

To obtain a better molecular definition of patients with syndromic retinitis pigmentosa, we screened for mitochondrial DNA (mtDNA) alterations of the two ATPase genes and 22 tRNA-coding sequences in 10 patients whose features resembled NARP (neuropathy, ataxia, and retinitis pigmentosa) syndrome. In two patients, one of whom showed features mimicking Kearns-Sayre syndrome, we identified a heteroplasmic T8993G mutation (average 80%) in the mitochondrial ATPase 6 gene. There was no mutated mtDNA in muscle and leukocytes from the mother of one patient or in leukocytes from his brother, suggesting a rapid segregation of the mutated nucleotide. MtDNA analysis should be considered in the differential diagnosis of patients with syndromic retinitis pigmentosa.
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PMID:Heterogeneous clinical presentation of the mtDNA NARP/T8993G mutation. 922 7

A cDNA encoding subunits 8 and 6 of mitochondrial ATPase of the cephalochordate lancelet (Branchiostoma lanceolatum), a direct ancestor of vertebrates, has been cloned and sequenced. A unique transcript encodes the 8 and 6 subunits. In the course of isolation of the 5' end of the ATPase 8 subunit gene, we also determined the sequence of the 5' adjacent tRNA-Lys gene. The anticodon used by mitochondrial tRNA-Lys is TTT.
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PMID:A unique cDNA coding for subunits 8 and 6 of mitochondrial adenosine triphosphatase of the lancelet Branchiostoma lanceolatum, an ancestor of vertebrates. 933 12

The Escherichia coli rho transcription termination protein is a hexameric helicase, and is believed to function by separating an RNA-DNA hybrid. Unlike hexameric DNA helicases, where a single strand of DNA passes through the central channel, it has been proposed that the RNA wraps around the outside of the ring. We have generated a three-dimensional reconstruction of rho, and localized a tRNA molecule bound to the primary RNA-binding site to the outside of the ring. An atomic structure of the N-terminal domain of rho fits into our reconstruction uniquely, with the residues involved in RNA-binding on the outside of the ring. Although rho shares a common structural core with the F1-ATPase and other hexameric helicases, there has been a divergence in function due to rho's N-terminal domain, which has no homology to other helicases.
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PMID:Three-dimensional reconstruction of transcription termination factor rho: orientation of the N-terminal domain and visualization of an RNA-binding site. 1087 52

Conventional approaches to the diagnosis of mitochondrial respiratory chain diseases, using enzyme assays and histochemistry, are laborious and give limited information concerning the genetic basis of a deficiency. We have evaluated the diagnostic value of 12 monoclonal antibodies to subunits of the four respiratory chain enzyme complexes and F(1)F(0)-ATP synthase. Antibodies were used in immunological studies with skin fibroblast cultures derived from patients with diverse mitochondrial diseases, including patients in which the disease was caused by a nuclear genetic defect and patients known to harbor a heteroplasmic mutation in a mitochondrial tRNA gene. Immunoblotting experiments permitted the identification of specific enzyme assembly deficits and immunocytochemical studies provided clues regarding the genetic origin of the disease. The immunological findings were in agreement with the biochemical and genetic data of the patients. Our study demonstrates that characterization of the fibroblast cultures with the monoclonal antibodies provides a convenient technique to complement biochemical assays and histochemistry in the diagnosis of mitochondrial respiratory chain disorders.
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PMID:Immunological phenotyping of fibroblast cultures from patients with a mitochondrial respiratory chain deficit. 1150 58


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