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)

Thyroid hormone regulates the in vivo expression of a selected set of rat nuclear genes encoding mitochondrial inner membrane proteins. Certain mRNAs, such as that for cytochrome c1, are increased as much as 20-50-fold, while others, such as core protein 1 of Complex III and the F1-ATPase beta-subunit do not respond. The promoter region of human cytochrome c1 also supports thyroid hormone induction of a reporter gene in transient transfection experiments. Thus, thyroid hormone regulates only selected genes, even for subunits within the same complex and in widely varying species. By contrast, growth activation of quiescent NIH3T3 cells, a second paradigm used for stimulating mitochondrial biogenesis, does not increase cytochrome c1 mRNA but does increase F1-ATPase beta-subunit mRNA. These findings suggest that nuclear OXPHOS genes are not necessarily expressed in a coordinated manner, and that multiple regulatory circuits might exist which are linked to different physiological stimuli. Analysis of the promoters of several OXPHOS genes reveals a great diversity and heterogeneity of transfactor binding elements. No single regulatory feature exists which could account for a coordinated expression of all OXPHOS genes. The potential diversity for regulating expression of nuclear OXPHOS genes raises the possibility for the existence of disease states linked to regulatory defects.
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PMID:The role of thyroid hormone and promoter diversity in the regulation of nuclear encoded mitochondrial proteins. 759 31

Some analytical and functional parameters of rat heart mitochondrial have been investigated at six different periods of ageing from 2 to 26 months. The fatty acid composition of the mitochondrial membranes reveals a percentage increase of polyunsaturated fatty acids (20:4 n-6, 22:6 n-3) up to 12 months, followed by a decrease; however, fluorescence polarization of the membrane probe diphenylhexatriene is not changed, revealing that membrane fluidity is not significantly affected. No major change in ubiquinone-9 and in cytochrome content is apparent, indicating that the relative ratio of the respiratory chain components is unmodified. Nevertheless, significant changes in enzyme specific activities are detected: NADH cytochrome c reductase and cytochrome oxidase activities increase up to 12 months, then decrease at 18-26 months; ubiquinol cytochrome c reductase exhibits a peak at 18 months, followed by a decrease. All these activities follow a similar trend during the whole life span of the rat, even though the 'maximum' is different. No significant changes have been found in ATP synthase. Succinate-cytochrome c reductase steadily increases over the whole life span. The results, showing activity decreases in the respiratory enzymes having subunits encoded by mitochondrial DNA, are compatible with the 'mitochondrial' theory of ageing.
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PMID:Mitochondrial activities of rat heart during ageing. 788 68

The genes encoding cytochrome b6 of the chloroplast cytochrome b6/f complex (petB) and the ATP synthase CF1-beta subunit (atpB) and epsilon-subunit (atpE) were identified on the EcoD fragment of the Euglena gracilis chloroplast genome. The complete nucleotide sequence of these three genes was determined. The petB-atpB-atpE genes are cotranscribed as a tricistronic operon. This gene organization differs from that of land plants in which atpB-atpE form a discistronic operon, and petB is within the psbB-ycf8-psbH-petB-petD operon. Euglena cytochrome b6 and the beta-subunit of the chloroplast ATP synthase are very similar in derived amino acid sequence to the corresponding gene products from other organisms. The epsilon-subunit of the chloroplast ATP synthase complex is more divergent. In Euglena, the petB-atpB-atpE genes contain introns, including two twintrons, at eight different positions. All of the intron positions were confirmed by analysis of cDNAs. Two independent intercistronic RNA processing events and 11 splicing reactions lead to the accumulation of the mature petB, atpB and atpE monocistronic mRNAs.
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PMID:Gene structure and expression of a novel Euglena gracilis chloroplast operon encoding cytochrome b6 and the beta and epsilon subunits of the H(+)-ATP synthase complex. 792 15

Cytosol-synthesized chloroplast and mitochondrial precursor proteins are proteolytically processed after import by highly specific, metal-dependent soluble enzymes: the stromal processing peptidase (SPP) and the matrix processing peptidase (MPP), respectively. We have used in vitro processing assays to compare the reaction specificities of highly purified preparations of pea SPP and Neurospora crassa MPP, both of which are unable to cleave a variety of 'foreign' proteins. We show that SPP can cleave all five mitochondrial precursor proteins tested, namely cyclophilin, the beta subunit of the F1-ATPase complex, the Rieske FeS protein, the alpha-MPP subunit and cytochrome b2. In contrast, MPP is unable to cleave any chloroplast precursor proteins tested. Several of the mitochondrial precursor proteins are cleaved more efficiently by SPP than are many authentic chloroplast precursor proteins but, in each case, cleavage takes place at a site or sites which are N-terminal to the authentic MPP site; pre-cyclophilin is cleaved 5 residues upstream of the MPP site and the precursor of the beta subunit of the F1-ATPase complex is cleaved at sites 5 and 12 residues upstream. We discuss the implications of these data for the SPP reaction mechanism.
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PMID:Efficient but aberrant cleavage of mitochondrial precursor proteins by the chloroplast stromal processing peptidase. 816 39

ATP synthase was isolated from beef heart mitochondria by extraction with N,N-bis-(3-D-gluconamidopropyl)deoxycholamide or by traditional cholate extraction. The enzyme was purified subsequently by ion-exchange and gel-permeation chromatographies in the presence of glycerol and the protease inhibitor diisopropylfluorophosphate. The ATP synthase consisted of 12-14 subunits and contained three tightly bound nucleotides. The co-reconstitution of crude or purified ATP synthase with monomeric bacteriorhodopsin by the method of detergent incubation of liposomes yielded proteoliposomes capable of light-driven ATP synthesis, as detected with a luciferase system for at least 30 min. The reaction was suppressed by the inhibitors oligomycin (> 90%) and dicyclohexylcarbodiimide (85%) and by the uncoupler carbonylcyanide-p-trifluormethoxyphenylhydrazone (> 95%). The purified ATP synthase was apparently free of cytochrome impurities and of adenylate kinase activity, i.e. the enzyme exhibited light-driven ATP synthesis without the dark reaction. For the first time, this is demonstrated with purified ATP synthase from beef heart mitochondria.
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PMID:Purification of ATP synthase from beef heart mitochondria (F0F1) and co-reconstitution with monomeric bacteriorhodopsin into liposomes capable of light-driven ATP synthesis. 826 26

Mitochondria were isolated from biopsies of the biceps femoris muscle of Danish landrace pigs. Three groups of animals were compared: (1) normal pigs; (2) pigs that were homozygous with respect to the gene Hal(n)/Hal(n) coding for the porcine malignant hyperthermia syndrome; and (3) heterozygote animals. A newly developed micro-method for preparation and assaying of small quantities of intact mitochondria was employed. With this technique mitochondria from biopsies weighing less than 100 mg were examined with respect to cytochrome content as well as phosphorylating and respiratory activities, including the nonphosphorylating exo-NADH oxidase activity. The mitochondria, prepared in a yield of 48%, showed high respiratory activities with tricarboxylic acid-cycle intermediates and pyruvate, and somewhat lower activity with palmitoyl-carnitine as substrate. The ATP synthase activity was about 1000 micromol ATP/min per g of protein and the maximal respiratory activity approx. 700 micromol of O2/min per g of protein. No differences among the three groups of animals were detected, except for the exo-NADH oxidase activities, which were 43, 78 and 107 micromol of O2/min per g of protein in the groups of normal, heterozygous and homozygous animals respectively. It is concluded that the exo-NADH oxidase activity may be a genetic manifestation of malignant hyperthermia and may play a significant role in the heat production characteristic of the syndrome.
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PMID:Characterization of mitochondria from pig muscle: higher activity of exo-NADH oxidase in animals suffering from malignant hyperthermia. 861 44

Thyroid hormone (T3) modulates the mRNA levels for cytochrome c and the adenine nucleotide translocator-2 (ANT2) in adult rat liver. Here we show that T3 activates expression of a reporter gene driven from the human cytochrome c1 and ANT2 promoters transfected into human choriocarcinoma JEG3 cells. By contrast, the human F1-ATPase beta-subunit promoter responded marginally, thus providing a pattern of differential expression similar to that earlier observed in rats in vivo. T3-activation is dependent on co-expression of the thyroid hormone receptor (TR alpha1). Co-expression of both the TR and RXR receptors had no additional effect. Transient transfection of deletion constructs showed that T3 activation is retained by the proximal regions of the cytochrome c1 and ANT2 promoters, and, in the case of cytochrome c1, is lost upon removal of a fragment containing the transcription initiator ((nucleotides) (nt) + 1 to + 100). The promoter regions supporting T3-activation of the reporter genes appear to lack strong DNA binding sites for TR and retinoid X receptor (RXR).
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PMID:Thyroid hormone activates transcription from the promoter regions of some human nuclear-encoded genes of the oxidative phosphorylation system. 914 77

Employing isoelectric focusing on immobilized pH gradients followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) we have obtained a map of C. elegans proteins, from a mixed culture containing all developmental stages, presenting over 2000 spots within the window of isoelectric points (pI) 3.5-9 and a molecular mass of 10-200 kDa. Edman microsequencing yielded successful results in 12 out of 24 analyzed spots. All but one of the N-terminal sequences retrieved C. elegans sequences in cosmid and/or expressed sequence tag clones. Structurally related protein sequences found in data banks included enzymes in energy metabolism (cytochrome oxydase, ATP synthase, enolase), a fatty acid-binding protein, a translationally controlled tumor protein, an unknown C. elegans protein, an acidic ribosomal protein, a titin-like protein, a G-protein beta chain, cyclophilin, and cathepsin D. Experimental determination of N-termini allowed us to define sites of signal cleavage providing further information on the physiological role of the newly found C. elegans proteins. This report demonstrates the possibility of two-dimensional gel electrophoresis and Edman microsequencing in the elucidation of C. elegans proteome.
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PMID:Two-dimensional gel electrophoresis of Caenorhabditis elegans homogenates and identification of protein spots by microsequencing. 915 Sep 41

From a cDNA library, constructed from mushroom primordia, nine cDNAs were isolated which were either induced or specifically expressed during fruit body development and maturation of the basidiomycete Agaricus bisporus. These cDNAs varied in size from 372 to 1019 bp and hybridized to transcripts of 400-1600 nt. Four of the cDNAs were only expressed in the generative phase of the life cycle while the other five cDNAs were strongly induced but had low steady-state mRNA levels in vegetatively grown mycelium of the hybrid strain Horst U1. An apparent full-length cDNA could be identified by sequence analysis and specified a putative protein homologous to the delta-subunit of the mitochondrial ATP synthase complex of Saccharomyces cerevisiae and Neurospora crassa. For one of the partial cDNAs, significant homology was found with a family of cell division control proteins, while another partial cDNA appeared to encode a cytochrome P450. All cDNAs, except the presumed cytochrome-P450-specifying cDNA (cypA), hybridized with single copy genes scattered over the Agaricus genome. For the cypA gene, the presence of several additional copies was shown by heterologous hybridizations. Based on changes in expression levels of the fruit-body-induced genes during development coinciding with alterations in morphological appearance of mushrooms, four stages of development were distinguished during growth and maturation of A. bisporus fruit bodies.
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PMID:Isolation of developmentally regulated genes from the edible mushroom Agaricus bisporus. 920 75

Nuclear-encoded mitochondrial precursor proteins are proteolytically processed inside the mitochondrion after import. The general mitochondrial processing activity in plant mitochondria has been shown to be integrated into the cytochrome bc1 complex of the respiratory chain. Here we investigate the occurrence of an additional, matrix-located processing activity by incubation of the precursors of the soybean mitochondrial proteins, alternative oxidase, the FAd subunit of the ATP synthetase and the tobacco F1 beta subunit of the ATP synthase, with the membrane and soluble components of mitochondria isolated from soybean cotyledons and spinach leaves. A matrix-located peptidase specifically processed the precursors to the predicted mature form in a reaction which was sensitive to orthophenanthroline, a characteristic inhibitor of mitochondrial processing peptidase (MPP). The specificity of the matrix peptidase was illustrated by the inhibition of processing of the alternative oxidase precursor in both soybean and spinach matrix extracts upon altering a single amino acid residue in the targeting presequence (-2 Arg to Gly). Additionally, there was no evidence for general proteolysis of precursor proteins incubated with the matrix. The purity of the matrix fractions was ascertained by spectrophotometric and immunological analyses. The results demonstrate that there is a specific processing activity in the matrix of soybean and spinach in addition to the previously well characterized membrane-bound MPP integrated into the cytochrome bcl complex of the respiratory chain.
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PMID:A matrix-located processing peptidase of plant mitochondria. 948 72


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