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

---

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

We have examined the structure of the vacuolar ATPase of Neurospora crassa using negatively stained preparations of vacuolar membranes and of detergent-solubilized and gradient-purified ATPase complexes. We also examined the peripheral sector (V1) of the enzyme after it had been removed and purified. Using different stains, vacuolar membranes displayed ball-and-stalk structures similar to those of the intact mitochondrial ATPase. However, the vacuolar ATPase was clearly different from the mitochondrial ATPase in both size and structural features. The vacuolar enzyme had a much larger head domain with a distinct cleft down the middle of the complex. This domain was held above the membrane by a prominent stalk. Most intriguing was the presence of basal components. These structures appeared to project from the vacuolar membrane near the base of the stalks. Detergent-solubilized, gradient-purified ATPases displayed the same head, stalk, and basal features as those found with the intact enzyme on vacuolar membranes. The mitochondrial ATPase was significantly smaller, and no clefted head domains or basal components were observed. When V1 and F1 particles were directly compared, a significant difference in size and shape between these two soluble ATPase sectors was apparent. V1 retained all of the features seen in the globular head of the intact complex: V-shaped, triangular, and square forms around a stain-filled core.
...
PMID:Structure of the vacuolar ATPase from Neurospora crassa as determined by electron microscopy. 138 58

Secretory vesicles that accumulate in the temperature-sensitive sec6-4 strain of yeast have been shown to contain a vanadate-sensitive ATPase, presumably en route to the plasma membrane (Walworth, N. C., and Novick, P. J. (1987) J. Cell Biol. 105, 163-174). We have now established this enzyme to be a fully functional form of the PMA1 [H+]ATPase, identical in its catalytic properties to that found in the plasma membrane. In addition, the secretory vesicles are sealed tightly enough to permit the measurement of ATP-dependent proton pumping with fluorescent probes. We have gone on to exploit the vesicles as an expression system for site-directed mutants of the ATPase. For this purpose, a sec6-4 strain has been constructed in which the chromosomal PMA1 gene is under control of the GAL1 promoter; the mutant pma1 allele to be studied is introduced on a centromeric plasmid under the control of a novel heat shock promoter. In galactose medium at 23 degrees C, the wild-type ATPase is produced and supports normal vegetative growth. When the cells are switched to glucose medium at 37 degrees C, however, the wild-type gene turns off, the mutant gene turns on, and secretory vesicles accumulate. The vesicles contain a substantial amount of newly synthesized, plasmid-encoded ATPase (5-10% of total vesicle protein), but only traces of residual wild-type PMA1 ATPase and no detectable mitochondrial ATPase, vacuolar ATPase, or acid or alkaline phosphatase. To test the expression strategy, we have made use of pma1-105 (Ser368----Phe), a vanadate-resistant mutant previously characterized by standard methods (Perlin, D. S., Harris, S. L., Seto-Young, D., and Haber, J. E. (1989) J. Biol. Chem. 264, 21857-21864). In secretory vesicles, as expected, the plasmid-borne pma1-105 allele gives rise to a mutant enzyme with a reduced rate of ATP hydrolysis and a 100-fold increase in Ki for vanadate. Proton pumping is similarly resistant to vanadate. Thus, the vesicles appear well suited for the production and characterization of mutant forms of the PMA1 [H+]ATPase. They should also aid the study of other yeast membrane proteins that are essential for growth as well as heterologous proteins whose appearance in the plasma membrane may be toxic to the cell.
...
PMID:Expression of the yeast plasma membrane [H+]ATPase in secretory vesicles. A new strategy for directed mutagenesis. 182 8

The head piece of the A-type ATP synthase in an extremely halophilic archaebacterium, namely Halobacterium salinarium (halobium), is composed of two kinds of subunit, alpha and beta, and is associated with ATP-hydrolyzing activity. The genes encoding these subunits with hydrolytic activity have been cloned and sequenced. The putative amino acid sequences of the alpha and beta subunits deduced from the nucleotide sequences of the genomic DNA consist of 585 and 471 residues, respectively. The amino acid sequence of the alpha subunit of the halobacterial ATPase is 63 and 49% identical to the alpha subunits of ATPases from two other archaebacteria, Methanosarcina barkeri and Sulfolobus acidocaldarius, respectively. The sequence of the beta subunit is 66 and 55% identical to the beta subunits from these respective organisms. The homology between the alpha and beta subunits is around 30%. In contrast, the sequences of the halobacterial ATPase is less than 30% identical to F1 ATPase when any combination of subunits is considered. However, they are greater than 50% identical to a eukaryotic vacuolar ATPase when alpha and a, beta and b combinations are considered. These data fully confirm the first demonstration of this kind of relationship which was achieved by immunoblotting with an antibody raised against the halobacterial ATPase. We concluded that the archaebacterial ATP synthase is an A-type and not an F-type ATPase. This classification is also demonstrated by a "rooted" phylogenetic tree where halobacteria locate close to other archaebacteria and eukaryotes and distant from eubacteria.
...
PMID:The ATP synthase of Halobacterium salinarium (halobium) is an archaebacterial type as revealed from the amino acid sequences of its two major subunits. 183 29

Immunological cross-reactivity among three types of H(+)-ATPases, that is, three archaebacterial ATPases, the F1-ATPase from thermophilic bacterium PS3 (TF1) and the vacuolar membrane ATPase from Saccharomyces cerevisiae, was examined by means of immunoblot analyses. The three archaebacterial ATPases were very similar in immunological cross-reactivity, suggesting that they belong to the same family of ATPases. Cross-reaction was also observed between the ATPase from Sulfolobus acidocaldarius, one of the three archaebacteria, and TF1. S. cerevisiae vacuolar ATPase reacted with the antibodies prepared against each of the three archaebacterial ATPases, but did not react with the antibody against TF1. Electron microscopic examination revealed that the oligomeric structure of Sulfolobus ATPase was very similar to that of F1-ATPase. These results, taken together, suggest that the archaebacterial ATPases share close structural similarities with the vacuolar ATPases, and, to a lesser degree, with the F0F1-ATPases.
...
PMID:Archaebacterial ATPases: relationship to other ion-translocating ATPase families examined in terms of immunological cross-reactivity. 196 31

We have measured the uptake of arginine into vacuolar membrane vesicles from Neurospora crassa. Arginine transport was found to be dependent on ATP hydrolysis, Mg2+, time, and vesicle protein with transported arginine remaining unmodified after entry into the vesicles. The Mg2+ concentration required for optimal arginine transport varied with the ATP concentration so that maximal transport occurred when the MgATP2- concentration was at a maximum and the concentrations of free ATP and Mg2+ were at a minimum. Arginine transport exhibited Michaelis-Menten kinetics when the arginine concentration was varied (Km = 0.4 mM). In contrast, arginine transport did not follow Michaelis-Menten kinetics when the MgATP2-concentration was varied (S0.5 = 0.12 mM). There was no inhibition of arginine transport when glutamine, ornithine, or lysine were included in the assay mixture. In contrast, arginine transport was inhibited 43% when D-arginine was present at a concentration 16-fold higher than that of L-arginine. Measurements of the internal vesicle volume established that arginine is concentrated 14-fold relative to the external concentration. Arginine transport was inhibited by dicyclohexylcarbodiimide, carbonyl cyanide m-chlorophenyl-hydrazone, and potassium nitrate (an inhibitor of vacuolar ATPase activity). Inhibitors of the plasma membrane or mitochondrial ATPase such as sodium vanadate or sodium azide did not affect arginine transport activity. In addition, arginine transport had a nucleoside triphosphate specificity similar to that of the vacuolar ATPase. These results suggest that arginine transport is dependent on vacuolar ATPase activity and an intact proton channel and proton gradient.
...
PMID:The properties of arginine transport in vacuolar membrane vesicles of Neurospora crassa. 294 21

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.
...
PMID:Structural studies of the vacuolar membrane ATPase from Neurospora crassa and comparison with the tonoplast membrane ATPase from Zea mays. 307 3

The vacuolar membrane ATPase of Neurospora crassa closely resembles the mitochondrial ATPase in its substrate specificity, substrate affinity, and sensitivity to the inhibitor N,N'-dicyclohexylcarbodiimide. Three different mutants with altered mitochondrial ATPase activity, exhibited as 1) resistance to N,N'-dicyclohexylcarbodiimide, 2) enhanced sensitivity to N,N'-dicyclohexylcarbodiimide, and 3) very low specific activity, were found to be unaltered in the vacuolar membrane ATPase. The vacuolar membrane ATPase was similar to the mitochondrial ATPase and approximately 10-fold more sensitive than the plasma membrane ATPase in its sensitivity to the inhibitors 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole, 2',3'-O-(2,4,6-trinitrophenyl) adenosine 5'-triphosphate, and 5'-adenylylimidodiphosphate. By contrast, the vacuolar ATPase resembled the plasma membrane ATPase in its response to quercetin (both 10-fold more sensitive than the mitochondrial ATPase); it was unique in its sensitivity to KNO3. A N,N'-dicyclohexylcarbodiimide-binding protein, migrating between molecular weight markers of 14,400 and 21,500, was identified as a putative component of the vacuolar membrane ATPase. Taken together, these findings support the argument that the vacuolar membrane ATPase is a distinct enzyme, more like the mitochondrial F0F1 ATPase than the plasma membrane ATPase.
...
PMID:Comparison of the vacuolar membrane ATPase of Neurospora crassa with the mitochondrial and plasma membrane ATPases. 622 53

Using vacuolar membranes from Neurospora crassa, we observed that sulfite prevented the loss of vacuolar ATPase activity that otherwise occurred during 36 h at room temperature. Sulfite neither activated nor changed the kinetic behavior of the enzyme. Further, in the presence of sulfite, the vacuolar ATPase was not inhibited by nitrate. We tested the hypothesis that sulfite acts as a reducing agent to stabilize the enzyme, while nitrate acts as an oxidizing agent, inhibiting the enzyme by promoting the formation of disulfide bonds. All reducing agents tested, dithionite, selenite, thiophosphate, dithiothreitol and glutathione, prevented the loss of ATPase activity. On the other hand, all oxidizing agents tested, bromate, iodate, arsenite, perchlorate, and hydrogen peroxide, were potent inhibitors of ATPase activity. The inhibitory effect of the oxidizing agents was specific for the vacuolar ATPase. The mitochondrial ATPase, assayed under identical conditions, was not inhibited by any of the oxidizing agents. Analysis of proteins with two-dimensional gel electrophoresis indicated that nitrate can promote the formation of disufide bonds between proteins in the vacuolar membrane. These data suggest a mechanism to explain why nitrate specifically inhibits vacuolar ATPases, and they support the proposal by Feng and Forgac (Feng, Y., and Forgac, M. (1994) J. Biol. Chem. 269, 13244-13230) that oxidation and reduction of critical cysteine residues may regulate the activity of vacuolar ATPases in vivo.
...
PMID:The vacuolar ATPase: sulfite stabilization and the mechanism of nitrate inactivation. 782 84

The neuronal ceroid-lipofuscinoses (NCL, Batten disease) are fatal inherited neurodegenerative diseases of children characterized by retinal and brain atrophy and the accumulation of electron-dense storage bodies in cells. Mutations in different genes underlie different major forms. The infantile disease (CLN-1, McKusick 256730) is distinguished by the storage of the sphingolipid activator proteins (SAPs) A and D in distinctive granular osmiophilic deposits (GRODs). This contrasts with the other major forms, where subunit c of mitochondrial ATP synthase is stored in various multilamellar profiles. Ceroid-lipofuscinoses also occur in dogs, including a form in miniature Schnauzers with distinctive granular osmiophilic deposit-like storage bodies. Antisera to SAPs A and D reacted to these storage bodies in situ. The presence of SAP D was confirmed by Western blotting and of SAP A by protein sequencing. Neither subunit c of mitochondrial ATP synthase nor of vacuolar ATPase is stored. This suggests that there are two families of ceroid-lipofuscinoses, the subunit c-storing forms, and those in which SAPs A and D, and perhaps other proteins, accumulate. Further work is required to determine whether other forms with granular osmiophilic deposits belong to the latter class and the genetic relationships between them and the human infantile disease.
...
PMID:Accumulation of sphingolipid activator proteins (SAPs) A and D in granular osmiophilic deposits in miniature Schnauzer dogs with ceroid-lipofuscinosis. 906 71

Since the discovery of mitochondrial ATP synthase subunit c storage in different forms of neuronal ceroid lipofuscinosis (NCL, Batten disease), it has been found that other hydrophobic proteins also accumulate in different forms. Costorage of subunit c of vacuolar ATPase is observed in "mnd/mnd" mice and in English Setters, Border Collies and Tibetan Terriers. A small amount is stored in the ovine disease and none in the human late-infantile disease. It is a storage body matrix component. An additional 8 kDa component immunoreactive to vacuolar ATPase subunit c antibodies is found in brain-derived storage bodies. The sphingolipid activator proteins, SAPs A and D, are stored in the human infantile disease and a form in Miniature Schnauzer dogs, but neither of the c subunits are. These results suggest two classes of NCL, the subunit c-storing diseases, related by a series of lesions in a subunit c-turnover pathway, and the SAP-storing diseases.
...
PMID:Different patterns of hydrophobic protein storage in different forms of neuronal ceroid lipofuscinosis (NCL, Batten disease). 915 21


1 2 3 Next >>

---