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:3.6.1.3 (ATPase)
65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Deuterium Fourier transform nuclear magnetic resonance (NMR) spectra at 34 MHz (corresponding to a magnetic field strength of 5.2 T) have been obtained of a variety of protein-lipid systems containing specifically deuterated phospholipids. The following systems were investigated as a function of temperature: sarcoplasmic reticulum ATPase (ATP phosphohydrolase, EC 3.6.1.3) complexed with 1-myristoyl-2-(14,14,14-trideuteriomyristoyl)-sn-glycero-3-phosphocholine (DMPC-d3) or 1,2-bis(16,16,16-trideuteriopalmitoyl)-sn-glycero-3-phosphocholine (DPPC-k6); human brain lipophilin complexed with DPPC-d6 or 1,2-bis(6,6-dideuteriopalmitoyl)-sn-glycero-3-phosphocholine (DPPC-6,6-d4); beef brain myelin proteolipid apoprotein (PLA) reconstituted with DMPC labeled as CD2 (or CD3) at one or more of positions 3, 4, 6, 8, 10, 12, or 14 of the sn-2 chain. For purposes of comparison, spectra were also obtained for bilayers containing cholesterol (CHOL). The results show that proteins either disorder or have little effect on hydrocarbon chain order in membranes above the gel to liquid-crystal phase transition temperature (Tc) of the pure lipids. Cholesterol, however, causes a very large ordering of the hydrocarbon chains above Tc, but both cholesterol and protein prevent chain crystallization (by effectively disordering chain packing) immediately below Tc. No evidence for any ordered "boundary lipid" in association with protein was found above Tc, perhaps due to the rough nature of protein surfaces. Above Tc, exchange between free bilayer and protein associated lipid is fast on the time scale of the deuterium NMR experiment (greater than or similar to 10(3) s-1). We have also obtained proton-decoupled phosphorus-31 nuclear magnetic resonance spectra at 60.7 MHz (corresponding to a magnetic field strength of 3.5 T) of DMPC, DMPC-AT-Pase, and DMPC-CHOL complexes. The results indicate that ATPase and CHOL CAUSE SMALL DECREASES IN 31P chemical shielding anisotropies but that in addition ATPase causes a four- to fivefold increase in 31P spin-lattice and Carr-Purcell spin-spin relaxation rates, suggesting the possibility of polar group protein-lipid interaction leading to increased correlation times in the region of the lipid phosphate head group.
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PMID:Protein-lipid interactions. A nuclear magnetic resonance study of sarcoplasmic reticulum Ca2,Mg2+-ATPase, lipophilin, and proteolipid apoprotein-lecithin systems and a comparison with the effects of cholesterol. 16 Feb 47

Plasma membrane proteolipid (plasmolipin), which was originally isolated from kidney membranes, has also been shown to be present in brain. In this study, we examined the distribution of plasmolipin in brain regions, myelin, and oligodendroglial membranes. Immunoblot analysis of different brain regions revealed that plasmolipin levels were higher in regions rich in white matter. Plasmolipin was also detected in myelin, myelin subfractions, and oligodendroglial membranes. Immunocytochemical analysis of the cerebellum revealed that plasmolipin was localized in the myelinated tracts. Plasmolipin levels in myelin were enriched during five successive cycles of myelin purification, similar to the enrichment of myelin proteolipid apoprotein (PLP) and myelin basic protein (MBP). In contrast, levels of Na+,K(+)-ATPase and a 70-kDa protein were decreased. When myelin or white matter was extracted with chloroform/methanol, it contained, in addition to PLP, a significant amount of plasmolipin. Quantitative immunoblot analysis suggested that plasmolipin constitutes in the range of 2.2-4.8% of total myelin protein. Plasmolipin, purified from kidney membranes, was detected by silver stain on gels at 18 kDa and did not show immunological cross-reactivity with either PLP or MBP. Thus, it is concluded that plasmolipin is present in myelin, possibly as a component of the oligodendroglial plasma membrane, but is structurally and immunologically different from the previously characterized myelin proteolipids.
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PMID:Presence of the plasma membrane proteolipid (plasmolipin) in myelin. 169 42

We analyse recent ESR measurements on Ca2+ ATPase and Myelin proteolipid apoprotein reconstituted in phosphatidylcholine bilayer membranes. Our intention is to discover whether the measurements indicate significant protein-protein repulsive or attractive interactions. In order to do so we have studied a model of a lipid bilayer membrane containing transbilayer proteins. It represents the proteins by hexagons moving on a triangular lattice interacting via an energy E0 which can be attractive, repulsive or zero. The last-named represents that all of the Ca2+ ATPase data is best described either by the "random" model or, possibly, by one in which there is a small repulsive interaction, but not by the "annulus" model or one in which there is always at least one layer of lipid chains between every pair of proteins. We find that all of the Myelin PLA data is best described by a "random" distribution of hexamers and not by an "annulus" model of hexamers. We suggest measurements that can be done in order to unambiguously settle the question of whether these systems are best described by a "random"-type model or an "annulus"-type model.
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PMID:Protein lateral distribution in lipid bilayer membranes. Applications to ESR studies. 299 20

Polyadenylated mRNA was isolated from aged slices of sweet potato root tissue and translated in a wheat germ cell-free system. The synthesis of apoprotein of the flavoprotein subunit of succinate dehydrogenase and two of the subunits of mitochondrial adenosine triphosphatase were detected by indirect immunoprecipitation. The molecular weights of the immunologically identified products were 3,000 and 8,000-9,000 daltons larger than the mature flavoprotein subunit of succinate dehydrogenase and the mature subunits of adenosine triphosphatase, respectively.
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PMID:Cell-free synthesis of succinate dehydrogenase and mitochondrial adenosine triphosphatase of sweet potato. 613 26

The effects of the mitochondrial protein synthesis inhibitor chloramphenicol and the mitochondrial F0 adenosine triphosphatase inhibitor oligomycin on the synthesis of nucleus-encoded cytochrome c protein were studied. Both inhibitors stimulated cytochrome c protein synthesis in the derepressed state (growth in media containing 2% raffinose) but had no effect on the synthesis of the cytochrome c protein in the repressed state (growth in media containing 5% glucose). Oligomycin uncoupled the synthesis of the apoprotein from its processing into the hemoprotein. Neither antibiotic had a significant effect on the rate of glucose repression of cytochrome protein synthesis. The kinetics of cytochrome c derepression and the effects of these two antibiotics on these kinetics were also studied. Cells were derepressed by transfer from glucose- to faffinose-containing media, and the rate of cytochrome c synthesis increased from the repressed to the derepressed level during the second hour of derepression. Chloramphenicol delayed this derepression, but after 5 h the rate of cytochrome c protein synthesis increased to twice the rate of synthesis in uninhibited cells. On the other hand, oligomycin inhibited derepression of cytochrome c. These results are discussed with respect to the effects of mitochondrial function in the derepressed and repressed states and during the processes of repression and derepression of cytochrome c.
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PMID:Effect of mitochondrial functions on synthesis of yeast cytochrome c. 624 23

Mitochondrial adenosine triphosphatase isolated from a double mutant of Saccharomyces cerevisiae lacking cytochrome b apoprotein and subunit II of cytochrome oxidase does not contain the mitochondrial translation product (approximate molecular weight, 32,000) previously suggested to be a subunit of the enzyme complex.
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PMID:The largest mitochondrial translation product copurifying with the mitochondrial adenosine triphosphatase of Saccharomyces cerevisiae is not a subunit of the enzyme complex. 626 Jul 57

Late in gestation, the prenatal fetal alveolar epithelium switches from fluid secretion to resorption of salt and water via apical sodium channels and basal Na-K-ATPase. The amounts of lung sodium pump activity protein and mRNA increase in the lung just before birth. Because maternal glucocorticoids (GC) may promote maturation of the alveolar epithelium and augment fetal surfactant apoprotein levels, we hypothesized that GC increase the fetal lung Na-K-ATPase alpha- and beta-subunit gene expression in development. Timed-pregnant Sprague-Dawley rats were injected daily with intraperitoneal dexamethasone (1 mg/kg) or saline for 1, 3, or 5 days before death at fetal day (FD) 17 or 19. Maternal GC treatment altered the fetal lung wet to dry weight, decreasing it at FD17 and increasing it at FD19. Northern analysis of total lung RNA for the alpha1- and beta1-pump subunits demonstrated differential regulation of the mRNA in response to GC. At FD17, beta1-mRNA increased after 1 (FD16) or 3 days (FD14-FD16) of GC treatment, whereas alpha1-mRNA was not altered. There were accompanying increases in beta1-, but not alpha1-, protein. At FD19, GC treatment for 5 days (FD14-FD18) increased beta1- and decreased alpha1-mRNA levels, but treatment for 1 (FD18) or 3 days (FD16-FD18) had no effect. In all groups, the alpha1-Na-K-ATPase protein was predominantly on the basolateral surface of airspace epithelium by immunofluorescence. In summary, maternal dexamethasone differentially affected the fetal lung mRNA levels of the two sodium pump subunits in a complex manner, with increased beta1-mRNA levels dependent on duration of treatment and fetal age.
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PMID:Developmental changes of fetal rat lung Na-K-ATPase after maternal treatment with dexamethasone. 914 40

Increased resistance to blood flow in arteries is built up by blockade of transport of saturated fatty acids of triglycerides in VLDL to cell through apoE/B-100 receptor endocytosis (active transport). This way does not affect the structure of cell membrane. Blockade of the active transport stimulates the compensating activation of lipolysis increasing the level of free saturated fatty acids in the blood. These fatty acids are included into the cell membrane via passive transport. In the membrane fatty acids form local domains with unregulated permeability and nonspecific ion transport: Na+ and Ca2+ enter into cell without any control and K+ and Mg2+ leak out. Responding cells activate Na+, K(+)- and Ca(2+)-ATPase and cholesterol synthesis. Ion pumps activate Na+ and Ca2+ out-fluxes; cholesterol blocks nonspecific ion permeability, but increases membrane microviscosity and inhibits secondary activity of ion pumps, thus forming vicious circle of hypernatriemia and hypercalciemia disturbing functions of loose connective tissue. They increase cell size, promote synthesis and secretion of collagen and elastin. It has led to wail thickening, elasticity drop and artety clear cross section narrowing. The increase of sensitivity to contractility of smooth muscle cells, hyperreactivity towards pressor regulators and resistance to depressor regulators cause artery spasm, peripheral resistance increases and starts up pathogenesis of essential hypertension.
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PMID:[Disruption of saturated fatty acids in cells in the pathogenesis of essential hypertension]. 984 18

The MutL DNA mismatch repair protein has recently been shown to be an ATPase and to belong to an emerging ATPase superfamily that includes DNA topoisomerase II and Hsp90. We report here the crystal structures of a 40 kDa ATPase fragment of E. coli MutL (LN40) complexed with a substrate analog, ADPnP, and with product ADP. More than 60 residues that are disordered in the apoprotein structure become ordered and contribute to both ADPnP binding and dimerization of LN40. Hydrolysis of ATP, signified by subsequent release of the gamma-phosphate, releases two key loops and leads to dissociation of the LN40 dimer. Dimerization of the LN40 region is required for and is the rate-limiting step in ATP hydrolysis by MutL. The ATPase activity of MutL is stimulated by DNA and likely acts as a switch to coordinate DNA mismatch repair.
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PMID:Transformation of MutL by ATP binding and hydrolysis: a switch in DNA mismatch repair. 1019 5

Apoaequorin was targeted to the cytosol, nucleus, and endoplasmic reticulum of HeLa cells in order to determine the effect of Ca(2+) release from the ER on protein degradation. In resting cells apoaequorin had a rapid half-life (ca. 20-30 min) in the cytosol or nucleus, but was relatively stable for up to 24 h in the ER (t(1/2) > 24 h). However, release of Ca(2+) from the ER, initiated by the addition of inhibitors of the ER Ca(2+)/Mg(2+) ATPase such as 2 microM thapsigargin or 1 microM ionomycin, initiated rapid loss of apoaequorin in the ER, but had no detectable effect on apoaequorin turnover in the cytosol nor the nucleus. This loss of apoprotein was not the result of secretion into the external fluid, and could not be inhibited by inhibitors of protein degradation by proteosomes. Proteolysis of apoaequorin in cell extracts (t(1/2) < 20 min) was completely inhibited in the presence of 1 mM Ca(2+), and this effect was independent of the ER retention signal KDEL at the C-terminus. Proteolysis was unaffected by the presence of selected serine protease inhibitors, or 10 microM Zn(2+), a known caspase-3 inhibitor. The results show that apoaequorin can monitor proteolysis of ER proteins activated by loss of ER Ca(2+). Several Ca(2+)-binding proteins exist in the ER, acting as the Ca(2+) store and chaperones. Our results have important implications both for the role of ER Ca(2+) in cell activation and stress and when using aequorin for monitoring free ER Ca(2+) over long time periods.
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PMID:Apoaequorin monitors degradation of endoplasmic reticulum (ER) proteins initiated by loss of ER Ca(2+). 1067 70


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