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)

The mitochondrial F1-ATPase is a multimeric enzyme, comprised of 3alpha, 3beta, gamma, delta and epsilon subunits, that is primarily responsible for the synthesis of ATP in eukaryotic cells. Recent work has shown that the F1 complex of the petite-negative yeast Kluyveromyces lactis, with specific mutations in the alpha, beta or gamma subunits, has a novel function that suppresses lethality caused by loss of mtDNA. Previously, genes for the four largest subunits of K. lactis F1 have been identified and characterised. In this study the gene coding for the epsilon-subunit of F1, KlATPepsilon, has been isolated and found to encode a polypeptide of 61 amino acids with only 32 residues identical to those in the protein from Sacharomyces cerevisiae. Strains carrying a null mutation of KlATPepsilon are respiratory deficient while the introduction of ATPepsilon from S. cerevisiae restores growth on non-fermentable carbon sources. In contrast to S. cerevisiae, K. lactis disrupted in ATPepsilon does not have a detectable F1-related mitochondrial ATP hydrolysis activity, suggesting that the epsilon-subunit plays a critical role in the formation of the catalytic sector of F1. With a disrupted KlATPepsilon, the rho degrees-lethality suppressor function of F1 carrying the atp2-1 and atp1-6 alleles is abolished. However, inactivation of the epsilon subunit does not eliminate the rho degrees-viable phenotype of the atp1-1, atp2-9, atp3-2 mutants. It is suggested that the absence of epsilon may effect the assembly or stability of F in the wild-type, atp 2-1 and atp1-6 strains, whereas the defect can be suppressed by the atp1-1, atp2-9 and atp3-2 mutations in the alpha, beta and gamma subunits respectively.
...
PMID:Absence of F1-ATPase activity in Kluyveromyces lactis lacking the epsilon subunit. 1095 75

The central stalk in ATP synthase, made of gamma, delta and epsilon subunits in the mitochondrial enzyme, is the key rotary element in the enzyme's catalytic mechanism. The gamma subunit penetrates the catalytic (alpha beta)(3) domain and protrudes beneath it, interacting with a ring of c subunits in the membrane that drives rotation of the stalk during ATP synthesis. In other crystals of F(1)-ATPase, the protrusion was disordered, but with crystals of F(1)-ATPase inhibited with dicyclohexylcarbodiimide, the complete structure was revealed. The delta and epsilon subunits interact with a Rossmann fold in the gamma subunit, forming a foot. In ATP synthase, this foot interacts with the c-ring and couples the transmembrane proton motive force to catalysis in the (alpha beta)(3) domain.
...
PMID:The structure of the central stalk in bovine F(1)-ATPase at 2.4 A resolution. 1106 50

This introductory article briefly summarizes how our views about the structural features of ATP synthases (F0F1) have evolved over the past 30 years and also reviews some of our current views in the year 2000 about the structures of these remarkably unique enzyme complexes. Suffice it to say that as we approach the end of the first year of this new millinium, we can be conservatively confident that we have a reasonably good grasp of the overall "low-resolution" structural features of ATP synthases. Electron microscopy techniques, combined with the tools of biochemistry, molecular biology, and immunology, have played the leading role here by identifying the headpiece, basepiece, central stalk, side stalk, cap, and in the mitochondrial enzyme, the collar around the central stalk. We can be reasonably confident also that we have a fairly good grasp of much of the "high-resolution" structural features of both the F1 moiety comprised of fives subunit types (alpha, beta, gamma, delta, and epsilon) and parts of the F0 moiety comprised of either three (E. coli) or at least ten (mitochondria) subunit types. This information acquired in several different laboratories, either by X-ray crystallography or NMR spectroscopy, includes details about the active site and subunit relationships. Moreover, it is consistent with recently reported data that the F1 moiety may be an ATP driven motor, which, during ATP synthesis, is driven in reverse by the electrochemical proton gradient generated by the electron transport chain. The real structural challenges of the future are to acquire at high resolution "complete" ATP synthase complexes representative of different stages of the catalytic cycle during ATP synthesis and representative also of key regulatory states.
...
PMID:ATP synthases in the year 2000: evolving views about the structures of these remarkable enzyme complexes. 1176 93

We describe here purification and biochemical characterization of the F(1)F(o)-ATP synthase from the thermoalkaliphilic organism Bacillus sp. strain TA2.A1. The purified enzyme produced the typical subunit pattern of an F(1)F(o)-ATP synthase on a sodium dodecyl sulfate-polyacrylamide gel, with F(1) subunits alpha, beta, gamma, delta, and epsilon and F(o) subunits a, b, and c. The subunits were identified by N-terminal protein sequencing and mass spectroscopy. A notable feature of the ATP synthase from strain TA2.A1 was its specific blockage in ATP hydrolysis activity. ATPase activity was unmasked by using the detergent lauryldimethylamine oxide (LDAO), which activated ATP hydrolysis >15-fold. This activation was the same for either the F(1)F(o) holoenzyme or the isolated F(1) moiety, and therefore latent ATP hydrolysis activity is an intrinsic property of F(1). After reconstitution into proteoliposomes, the enzyme catalyzed ATP synthesis driven by an artificially induced transmembrane electrical potential (Deltapsi). A transmembrane proton gradient or sodium ion gradient in the absence of Deltapsi was not sufficient to drive ATP synthesis. ATP synthesis was eliminated by the electrogenic protonophore carbonyl cyanide m-chlorophenylhydrazone, while the electroneutral Na(+)/H(+) antiporter monensin had no effect. Neither ATP synthesis nor ATP hydrolysis was stimulated by Na(+) ions, suggesting that protons are the coupling ions of the ATP synthase from strain TA2.A1, as documented previously for mesophilic alkaliphilic Bacillus species. The ATP synthase was specifically modified at its c subunits by N,N'-dicyclohexylcarbodiimide, and this modification inhibited ATP synthesis.
...
PMID:Purification and biochemical characterization of the F1Fo-ATP synthase from thermoalkaliphilic Bacillus sp. strain TA2.A1. 1286 53

The atp operon encoding F1Fo ATP synthase in the fermentative obligate anaerobic bacterium Clostridium pasteurianum was sequenced. It consisted of nine genes arranged in the order atpI(i), atpB(a), atpE(c), atpF(b), atpH(delta), atpA(alpha), atpG(gamma), atpD(beta), and atpC(epsilon), which was identical to that found in many bacteria. Reverse transcription-PCR confirmed the presence of the transcripts of all nine genes. The amount of ATPase activity in the membranes of C. pasteurianum was low compared to what has been found in many other bacteria. The F1Fo complexes solubilized from membranes of C. pasteurianum and Escherichia coli had similar masses, suggesting similar compositions for the F1Fo complexes from the two bacteria. Western blotting experiments with antibodies raised against the purified subunits of F1Fo detected the presence of eight subunits, alpha, beta, gamma, delta, epsilon, a, b, and c, in the F1Fo complex from C. pasteurianum. The F1Fo complex from C. pasteurianum was activated by thiocyanate, cyanate, or sulfhydryl compounds; inhibited by sulfite, bisulfite, or bicarbonate; and had tolerance to inhibition by dicyclohexylcarbodiimide. The target of thiol activation of the F1Fo complex from C. pasteurianum was F1. Thiocyanate and sulfite were noncompetitive with respect to substrate Mg ATP but competitive with respect to each other. The F1 and Fo parts of the F1Fo complexes from C. pasteurianum and E. coli bound to each other, but the hybrid F1Fo complexes were not functionally active.
...
PMID:Clostridium pasteurianum F1Fo ATP synthase: operon, composition, and some properties. 1294 5

Mitochondrial ATP synthase (F1Fo-ATPase) catalyzes the terminal step of oxidative phosphorylation. In this paper, we demonstrate the functional expression of the hexahistidine-tagged beta-subunit of yeast ATP synthase and the purification of the F1-ATPase from yeast cells. A gene encoding the beta-subunit from Saccharomyces cerevisiae was modified to encode a protein of which the original N-terminus import signal sequence was replaced by a sequence containing the import signal sequence of a mitochondrial ATPase inhibitor, its processing site, and six consecutive histidines. Expression of the modified gene generated a functional F1Fo complex in host yeast cells lacking a functional copy of the endogenous ATP2 gene, as judged by growth of rescued cells on lactate medium. F1 was extracted from the yeast mitochondria by chloroform treatment and purified by immobilized metal affinity chromatography and gel filtration chromatography. The specific activity of the purified F1 was comparable to that of the wild-type enzyme, and the F1 contained all of the 5 known subunits (alpha, beta, gamma, delta, and epsilon). Moreover, the activity of the F1 was completely inhibited by the specific ATPase inhibitor protein, IF1. These results indicate that F1 containing the tagged beta-subunit is fully assembled and active. The application of this novel procedure simplifies the number of steps required for the isolation of F1 used for studying the molecular mechanism of catalysis and regulation of the enzyme.
...
PMID:Functional expression of hexahistidine-tagged beta-subunit of yeast F1-ATPase and isolation of the enzyme by immobilized metal affinity chromatography. 1529 86

The chloroplast ATP synthase coupling factor CF1 complex contains five nonidentical subunits, alpha, beta, gamma, delta, and epsilon, with a stoichiometry of 3:3:1:1:1. The beta subunit contains the catalytic site for ATP synthesis during photooxidative phosphorylation in the chloroplast. In this study, we have identified two isoforms of the CF1-beta subunit at 56 and 54 kDa in the chloroplast of Brassica rapa, through isolation/purification, proteolytic digestion and internal peptide sequencing. Examining their accumulation pattern demonstrates that both isoforms coexist during chloroplast biogenesis and in mature thylakoid membranes, but the 54 kDa isoform is more apparently upregulated by light or under light stress. LiDS-PAGE shows that the 56 kDa is a major isoform of the CF1-beta subunit under normal light conditions, and its amount was not influenced during high light or other light stress treatments. The 54 kDa isoform is a minor band at normal conditions; however, it significantly increased under excess light stresses, such as high or low light with drought and/or high temperature. Particularly, a ninefold increase was observed after 8-10 h of high light treatment with drought and high temperature. The results suggest that light stress induction of the 54 kDa CF1-beta isoform may present a positive response during chloroplast photoacclimation.
...
PMID:Identification and differential accumulation of two isoforms of the CF1-beta subunit under high light stress in Brassica rapa. 1569 82

The F(1) component of mitochondrial ATP synthase is an oligomeric assembly of five different subunits, alpha, beta, gamma, delta, and epsilon. In terms of mass, the bulk of the structure ( approximately 90%) is provided by the alpha and beta subunits, which form an (alphabeta)(3) hexamer with adenine nucleotide binding sites at the alpha/beta interfaces. We report here ultrastructural and immunocytochemical analyses of yeast mutants that are unable to form the alpha(3)beta(3) oligomer, either because the alpha or the beta subunit is missing or because the cells are deficient for proteins that mediate F assembly (e.g. Atp11p, Atp12p, or Fmc1p). The F(1) alpha(1) and beta subunits of such mutant strains are detected within large electron-dense particles in the mitochondrial matrix. The composition of the aggregated species is principally full-length F(1) alpha and/or beta subunit protein that has been processed to remove the amino-terminal targeting peptide. To our knowledge this is the first demonstration of mitochondrial inclusion bodies that are formed largely of one particular protein species. We also show that yeast mutants lacking the alpha(3)beta(3) oligomer are devoid of mitochondrial cristae and are severely deficient for respiratory complexes III and IV. These observations are in accord with other studies in the literature that have pointed to a central role for the ATP synthase in biogenesis of the mitochondrial inner membrane.
...
PMID:Failure to assemble the alpha 3 beta 3 subcomplex of the ATP synthase leads to accumulation of the alpha and beta subunits within inclusion bodies and the loss of mitochondrial cristae in Saccharomyces cerevisiae. 1571 75

ATPase was purified 51-fold from a chemoautotrophic, obligately acidophilic iron-oxidizing bacterium, Acidithiobacillus ferrooxidans NASF-1. The purified ATPase showed the typical subunit pattern of the F1-ATPase on a polyacrylamide gel containing sodium dodecyl sulfate, with 5 subunits of apparent molecular masses of 55, 50, 33, 20, and 18 kDa. The enzyme hydrolyzed ATP, GTP, and ITP, but neither UTP nor ADP. The K(m) value for ATP was 1.8 mM. ATPase activity was optimum at pH 8.5 at 45 degrees C, and was activated by sulfite. Azide strongly inhibited the enzyme activity, whereas the enzyme was relatively resistant to vanadate, nitrate, and N,N'-dicyclohexylcarbodiimide. The genes encoding the subunits for the F1F(O)-ATPase from A. ferrooxidans NASF-1 were cloned as three overlapping fragments by PCR cloning and sequenced. The molecular masses of the alpha, beta, gamma, delta, and epsilon subunits of the F1 portion were deduced from the amino acid sequences to be 55.5, 50.5, 33.1, 19.2, and 15.1 kDa, respectively.
...
PMID:Purification and biochemical characterization of the F1-ATPase from Acidithiobacillus ferrooxidans NASF-1 and analysis of the atp operon. 1624 38

The properties of the soluble moiety (F(1)) of the mitochondrial H(+)-ATPase from oat roots were examined and compared to those of the native mitochondrial membrane-bound enzyme. The chloroform soluble preparation was purified by Sephadex G-200 and DEAE-cellulose chromatography. The purified F(1) preparation contained major polypeptides corresponding to alpha, beta, gamma, delta, and epsilon of apparent molecular mass 58, 55, 35, 22, and 14 kilodaltons, respectively. The purified F(1)-ATPase, like the native enzyme, was inhibited by azide (I(50) = 10 micromolar), nitrate (I(50) = 7-10 millimolar), 4,4'-diisothiocyano-2,2'-stilbene disulfonic acid (I(50) = 1-3 micromolar), and 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole (I(50) = 3 micromolar). F(1)-ATPase activity was stimulated by bicarbonate but not by chloride. In both the native and the F(1)-form of the ATPase, ATP was hydrolyzed in preference to GTP. The results indicate that these properties of the native membrane-bound mitochondrial ATPase have been conserved in the purified F(1). In contrast to the membrane-bound enzyme, the F(1)-ATPase was not inhibited by oligomycin or by N,N'-dicyclohexylcarbodiimide. The mitochondrial F(1)-ATPase from oat roots is analogous to other known F(1)F(0)-ATPases.
...
PMID:Purification and Characterization of the Soluble F(1)-ATPase of Oat Root Mitochondria. 1666 52


<< Previous 1 2 3 4 5 6 Next >>

---