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)

A cDNA library from Chlamydomonas reinhardtii, constructed in the phage expression vector lambda gt11, was probed with antiserum directed against the nuclear-encoded gamma subunit of the chloroplast H+-transporting ATP synthase [ATP phosphohydrolase (H+-transporting) or chloroplast coupling factors 0 and 1, EC 3.6.1.34] of C. reinhardtii. A cDNA was isolated and transcribed in vitro. The transcript was translated in vitro and immunoprecipitated with anti-gamma-subunit serum to yield a product that coelectrophoresed with the immunoprecipitated product from in vitro-translated polyadenylylated RNA. These proteins were larger than the mature gamma subunit, either immunoprecipitated as chloroplast coupling factor 1 or as the individual subunit. Thus, the gamma subunit is synthesized as a precursor of greater molecular weight in C. reinhardtii. Furthermore, the precursor protein encoded by the cDNA is imported into pea chloroplasts and processed to a lower molecular weight polypeptide that coelectrophoreses with mature C. reinhardtii gamma subunit. The largest cDNA isolated is about the same length as the corresponding mRNA (approximately equal to 1900 bases long) and probably contains the entire coding region. Southern blot analyses revealed restriction fragment length polymorphisms and that the gamma subunit is probably encoded by an intron-containing single-copy gene.
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PMID:Isolation of a cDNA clone for the gamma subunit of the chloroplast ATP synthase of Chlamydomonas reinhardtii: import and cleavage of the precursor protein. 289 28

In contrast to the situation in animals and fungi the alpha-subunit of the mitochondrial F1-ATPase is encoded by two identical mitochondrial genes (ATP A) in male fertile maize (Zea mays L.). Cytoplasmic male sterile (T, C and S) maize mitochondrial genomes only contain a single copy of the gene. Sequence analysis reveals that the uninterrupted coding region of both copies of the gene is 1,524 bp long and encodes a polypeptide of 508 amino acids with a molecular weight of 55,117. The predicted amino acid sequence shares over 60% homology with the nuclear encoded alpha-subunit from yeast and bovine ATPase and approx. 50% with the corresponding chloroplast and bacterial polypeptides.
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PMID:The mitochondrial genome of fertile maize (Zea mays L.) contains two copies of the gene encoding the alpha-subunit of the F1-ATPase. 290 Jun 97

Five protein kinases are shown to serve as specific phosphatases in the absence of ADP. Although the rates of hydrolysis are very slow compared to the forward phosphorylation rates under optimal conditions, they are of the same order as the reverse reaction in the presence of ADP. Because cells contain approximately equal to 3 mM ATP, neither the reverse reaction nor the phosphatase is likely to play a physiological role. beta-casein B phosphorylated by the catalytic subunit of cAMP-dependent protein kinase (protein kinase A) is specifically dephosphorylated by protein kinase A but not by polypeptide-dependent protein kinase (protein kinase P). beta-casein B phosphorylated by protein kinase P is specifically dephosphorylated by protein kinase P but not by protein kinase A. Histone H1 phosphorylated by protein kinase C is dephosphorylated by the same enzyme in the absence of ADP. In all cases tested addition of ADP and F1-ATPase accelerates moderately the rate of dephosphorylation. Native H+-ATPase from yeast plasma membranes is isolated mainly in the phosphorylated form. It is dephosphorylated and rephosphorylated by protein kinase P but not by protein kinase A. Protein-tyrosine kinase of the epidermal growth factor receptor phosphorylates the random synthetic polypeptide poly(Glu80Tyr20). The phosphorylated polymer is specifically dephosphorylated in the absence of ADP by epidermal growth factor receptor preparations but not by insulin receptor preparations. The same polymer phosphorylated by insulin receptor is dephosphorylated by insulin receptor but not by epidermal growth factor receptor preparations. By using a cycle of dephosphorylation-rephosphorylation, it is possible to identify proteins that are phosphorylated by these protein kinases in vivo. Should this method be applicable to additional protein kinases, it should be possible to estimate the quantitative contribution of each protein kinase to a single phosphoprotein.
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PMID:Specific dephosphorylation of phosphoproteins by protein-serine and -tyrosine kinases. 290 Oct 92

A novel DNA sequence coding for subunit 8 of the mitochondrial ATPase of Saccharomyces cerevisiae has been constructed by chemical synthesis. The synthetic gene, termed NAP1, is designed for expression in the yeast nucleus and codes for a 48 amino acid polypeptide identical to that encoded by the mitochondrial aap1 gene of S. cerevisiae. The codons chosen for the NAP1 sequence correspond almost exclusively to those most frequently occurring in highly expressed yeast genes. The NAP1 coding region differs in 31 codons from that of aap1, and is flanked by sequences carrying restriction enzyme sites useful for cloning and for gene expression. A 170 bp double stranded DNA molecule was constructed by assembling 12 oligonucleotides (12 to 45 bases in length) in a single annealing/ligation mixture. This synthetic gene will provide a route for the systematic manipulation, through in vitro mutagenesis, of the structure of a protein normally encoded by mitochondrial DNA.
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PMID:Chemical synthesis of a mitochondrial gene designed for expression in the yeast nucleus. 293 Oct 82

The H+-translocating ATPase located on vacuolar membranes of Neurospora crassa was partially purified by solubilization in two detergents, Triton X-100 and N-hexadecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate, followed by centrifugation on sucrose density gradients. Two polypeptides of Mr approximately equal to 70,000 and approximately equal to 62,000 consistently migrated with activity, along with several minor bands of lower molecular weight. Radioactively labeled inhibitors of ATPase activity, N-[14C]ethylmaleimide and 7-chloro-4-nitro[14C]benzo-2-oxa-1,3-diazole, labeled the Mr approximately equal to 70,000 polypeptide; this labeling was reduced in the presence of ATP. N,N'-[14C]dicyclohexylcarbodiimide labeled a polypeptide of Mr approximately equal to 15,000. Estimation of the functional size of the vacuolar membrane ATPase by radiation inactivation gave a value of Mr 5.2 X 10(5), 10-15% larger than the mitochondrial ATPase. The Neurospora vacuolar ATPase showed no crossreactivity with antiserum to plasma membrane or mitochondrial ATPase but strongly crossreacted with antiserum against a polypeptide of Mr approximately equal to 70,000 associated with the tonoplast ATPase of corn coleoptiles. These results suggest that fungal and plant vacuolar ATPases may be large multisubunit complexes, somewhat similar to, but immunologically distinct from, known F0F1 ATPases.
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PMID:Structural studies of the vacuolar membrane ATPase from Neurospora crassa and comparison with the tonoplast membrane ATPase from Zea mays. 307 3

The genes for the following proteins were localized by hybridization analysis on the cyanelle genome of Cyanophora paradoxa: the alpha and beta subunits of phycocyanin (cpcA and cpcB); the alpha and beta subunits of allophycocyanin (apcA and apcB); the large and small subunits of ribulose-1,5-bisphosphate carboxylase (rbcL and rbcS); the two putative chlorophyll alpha-binding apoproteins of the photosystem I-P700 complex (psaA and psaB); four apoproteins believed to be components of the photosystem II core complex (psbA, psbB, psbC, and psbD); the two apoprotein subunits of cytochrome b-559 which is also found in the core complex of photosystem II (psbE and psbF); three subunits of the ATP synthase complex (atpA and atpBE); and the cytochrome f apoprotein (petA). Eighty-five percent of the genome was cloned as BamHI, BglII, or PstI fragments. These cloned fragments were used to construct a physical map of the cyanelle genome and to localize more precisely some of the genes listed above. The genes for phycocyanin and allophycocyanin were not clustered and were separated by about 25 kilobases. Although the rbcL gene was adjacent to the atpBE genes and the psbC and psbD genes were adjacent, the arrangement of other genes encoding various polypeptide subunits of protein complexes involved in photosynthetic functions was dissimilar to that observed for known chloroplast genomes. These results are consistent with the independent development of this cyanelle from a cyanobacterial endosymbiont.
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PMID:Gene map for the Cyanophora paradoxa cyanelle genome. 393 27

On solubilization with Triton X-100 of sarcoplasmic reticulum vesicles isolated by differential centrifugation, the Ca2+-ATPase is selectively extracted while approximately half of the initial Mg2+-, or 'basal', ATPase remain in the Triton X-100 insoluble residue. The insoluble fraction, which does not contain the 100 000 dalton polypeptide of the Ca2+-ATPase, contains high levels of cytochrome c oxidase. Furthermore, its Mg2+-ATPase activity is inhibited by specific inhibitors of mitochondrial ATPase, indicating that the 'basal' ATPase separated from the Ca2+-ATPase by detergent extraction originates from mitochondrial contaminants. To minimize mitochondrial contamination, sarcoplasmic reticulum vesicles were fractionated by sedimentation in discontinuous sucrose density gradients into four fractions: heavy, intermediate and light, comprising among them 90-95% of the initial sarcoplasmic reticulum protein, and a very light fraction, which contains high levels of Mg2+-ATPase. Only the heavy, intermediate and light fractions originate from sarcoplasmic reticulum; the very light fraction is of surface membrane origin. Each fraction of sarcoplasmic reticulum origin was incubated with calcium phosphate in the presence of ATP and the loaded fractions were separated from the unloaded fractions by sedimentation in discontinuous sucrose density gradients. It was found that vesicles from the intermediate fraction had, after loading, minimal amounts of mitochondrial and surface membrane contamination, and displayed little or no Ca2+-independent basal ATPase activity. This shows conclusively that the basal ATPase is not an intrinsic enzymatic activity of the sarcoplasmic reticulum membrane, but probably originates from variable amounts of mitochondrial and surface membrane contamination in sarcoplasmic reticulum preparations isolated by conventional procedures.
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PMID:Highly purified sarcoplasmic reticulum vesicles are devoid of Ca2+-independent ('basal') ATPase activity. 610 77

Placental polypeptides present in crude preparations of transforming growth factors stimulate glycolysis when added to quiescent 3T3 cells, normal rat kidney, and chick embryo fibroblasts. The stimulation was apparent over a time period of at least 90 min and was seen at glucose concentrations ranging from 1 to 30 mM. Duramycin, an antibiotic isolated from Streptomyces cinnamomeus, inhibits the polypeptide-stimulated and nonstimulated glycolysis of intact cells, since it permeabilizes cells to Pi and nucleotides. However, duramycin also inhibits the Na+-K+-ATPase as well as the ouabain-insensitive Mg2+-ATPase of plasma membranes. Duramycin has no effect on glycolysis catalyzed by cell-free extracts of Ehrlich ascites tumor cells in the presence of mitochondrial ATPase but partially inhibits glycolysis when ADP and Pi are generated by ATPases of plasma membrane preparations.
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PMID:Stimulation of glycolysis by placental polypeptides and inhibition by duramycin. 614 64

Extramitochondrial pools of mitochondrial precursor polypeptides can be detected in yeast spheroplasts which had been pulse-labeled for 3 min in the absence of inhibitors or for 10 min in the presence of an uncoupler of oxidative phosphorylation. In either case, these precursors can be post-translationally converted to the mature forms during a subsequent chase. Post-translational maturation of the precursor to F1-ATPase beta-subunit is accompanied by uptake of the polypeptide into mitochondria. Pools of precursor polypeptides are also found in pulse-labeled intact yeast cells, the pool sizes depending on the metabolic status of the cells. For example, if the rate of protein synthesis is lowered by cycloheximide, the precursor pool size decreases. This indicates that living yeast cells can, and apparently do, import polypeptides into mitochondria post-translationally.
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PMID:Import of proteins into mitochondria. Extramitochondrial pools and post-translational import of mitochondrial protein precursors in vivo. 621 6

We determined that the ATPase activity contained in preparations of neuronal microtubules is associated with a 50,000-dalton polypeptide by four different methods: (a) photoaffinity labeling of the pelletable ATPase fraction with [gamma-32P]-8-azido-ATP; (b) analysis of two-dimensional gels (native gel X SDS slab gel) of an ATPase fraction solubilized by treatment with dichloromethane; (c) ATPase purification by glycerol gradient sedimentation and gel filtration chromatography of a solvent-released ATPase fraction, (d) demonstration of the binding of affinity-purified antibody to the 50-kdalton polypeptide to ATPase activity in vitro. Beginning with preparations of microtubules we have purified the ATPase activity greater than 700-fold and estimate that the purified enzyme has a specific activity of 20 mumol Pi x mg-1 x min-1 and comprises 80-90% of the total ATPase activity associated with neuronal microtubules. With affinity-purified antibody we also demonstrate cross-reactivity to the 50-kdalton subunits of mitochondrial F-1 ATPase and show that the antibody specifically labels mitochondria in PtK-2 cells. Biochemical comparisons of the enzymes reveal similar but not identical subunit composition and sensitivity to mitochondrial ATPase inhibitors. These studies indicate that the principal ATPase activity associated with microtubules is not contained in high molecular weight proteins such as dynein or MAPs and support the hypothesis that the 50-kdalton ATPase is a membrane protein and may be derived from mitochondria or membrane vesicles with F-1-like ATPase activity.
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PMID:Identity and origin of the ATPase activity associated with neuronal microtubules. II. Identification of a 50,000-dalton polypeptide with ATPase activity similar to F-1 ATPase from mitochondria. 622 Oct 23


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