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 nearest neighbor relationships between the Fo subunits of bovine mitochondrial H+-ATPase were studied by using copper-o-phenanthroline, an SH-oxidizing cross-linking reagent. The cross-linked samples of purified H+-ATPase, F1-ATPase or Fo were analyzed by sodium dodecyl sulfate/polyacrylamide gel electrophoresis (SDS-PAGE) and the disulfide cross-linked polypeptides were identified by enzyme-linked immunosorbent assay and immunoblot transfer using subunit specific antisera. SDS-PAGE of H+-ATPase showed several cross-links, although none involved subunits of Fo sector linked to those of F1. Both H+-ATPase and Fo showed formation of a 45-kDa product. Upon reduction, the 45-kDa component gave rise to a 21-kDa band, identified as oligomycin-sensitivity-conferring protein (OSCP), and a 24-kDa band. These two proteins thus appear to be near neighbors with their cysteine residues in close proximity with each other. Under the conditions of cross-linking, there was a concentration-dependent decrease in the Pi-ATP exchange activity of the intact H+-ATPase as well as of H+-ATPase reconstituted with copper-o-phenanthroline-treated Fo and untreated F1. The site of inhibition appeared to residue in the Fo sector. Loss of Pi-ATP exchange occurred at the same time as formation of the 45-kDa product. Our present data showing copper-o-phenanthroline-induced interactions of the 24-kDa protein with the OSCP and simultaneous inactivation of Pi-ATP exchange activity of the complex strengthen earlier suggestions [Hadikusumo, R.G., Hertzog, P.J. & Marzuki, S. (1984) Biochim. Biophys. Acta 765,258-267] that the 24-kDa protein may be a bona fide subunit of Fo.
...
PMID:Cross-linking of bovine mitochondrial H+-ATPase by copper--o-phenanthroline. Interaction of the oligomycin-sensitivity-conferring protein with a 24-kDa protein. 286 96

Sequencing of an open reading frame associated with cytoplasmic male sterility (CMS) in Petunia has revealed a gene fusion (the Pcf gene) containing the 5'-flanking and amino-terminal transmembrane segment of the ATP synthase proteolipid gene (atp9), parts of the cytochrome oxidase subunit II (coxII) coding region, and the carboxyl terminus and 3'-flanking region of an unidentified reading frame (urfS). The coxII region has several small deletions and tandem repeats that remove all of the segments coding for the residues involved in copper binding, but may possibly maintain the cytochrome c binding site. Normal atp9 and coxII genes and their transcripts are also present in the sterile cytoplasm. S1 nuclease protection studies identify fused gene transcripts only in CMS lines, with an increase in transcript amount in anthers relative to leaves.
...
PMID:A fused mitochondrial gene associated with cytoplasmic male sterility is developmentally regulated. 288 95

In order to examine the influence of protein structure on the post-translational import of a protein into mitochondria, the carboxyl-terminal 129 residues of F1-ATPase beta-subunit precursor (511aa) have been replaced with 61 residues of yeast copper metallothionein. Import of the F1 beta-copper metallothionein (beta CuMT) hybrid into mitochondria was as efficient as that of the F1 beta precursor in the absence of copper. Addition of copper to mitochondrial import reactions, which had no significant effect on import of the F1 beta-subunit precursor, blocked import of the beta CuMT protein. This copper-dependent transport block for the beta CuMT precursor occurred after the precursor was bound to mitochondria. Expression of the beta CuMT protein in vivo revealed that beta CuMT would bind copper and allow growth of a copper-sensitive yeast host on an otherwise inhibitory level of the cation as long as it was localized in the cytoplasm. These data indicate that the binding of copper by beta CuMT renders it refractile for partial unfolding which is necessary for its translocation into mitochondria. These observations provide an alternative scheme for the selection of mutants defective in mitochondrial import.
...
PMID:The role of protein structure in the mitochondrial import pathway. Unfolding of mitochondrially bound precursors is required for membrane translocation. 368 Feb 14

Membrane energization by ATP has been measured in vesicles containing purified bovine heart mitochondrial H+-ATPase (ATP synthase) with the voltage-sensitive dye oxonol VI. The dithiol chelator, Cd2+, and the thiol oxidant, copper o-phenanthroline, produced discharge of the membrane potential when added at the steady state and inhibited its establishment when added prior to energization by ATP. These effects, which were reversed by dithiothreitol, were not accompanied by an increase in the nonspecific H+ permeability of the membrane. Passive H+ conduction in proteoliposomes containing F0 (hydrophobic segment of ATP synthase) was assayed by the quenching of 9-aminoacridine fluorescence after establishing a K+ diffusion potential. This conductance was blocked by Cd2+, an inhibitor of coupling factor B (FB). Labeling of F0 with 115Cd2+ at the concentrations that inhibited the F0 conductance followed by gel electrophoresis yielded a single radioactive band with a molecular weight corresponding to FB, the presence of which in the F0 preparation was confirmed by immunoblot staining. The data offer strong evidence that FB is an essential component of the H+ channel of F0, because H+ conduction through the channel is inhibited by chemical modification of FB.
...
PMID:Evidence for the involvement of coupling factor B in the H+ channel of the mitochondrial H+-ATPase. 614 19

This study determined if reported decreases in the delta subunit of ATP synthase and nuclear-encoded cytochrome c oxidase subunits in hearts of copper-deficient rats were secondary to the heart disease pathology or due to lack of the trace element. Male weanling Long-Evans rats were randomly divided into six groups: rats fed a copper-adequate or copper-deficient diet (with free access) with or without 5% dimethyl sulfoxide (DMSO) in the drinking water and rats pair-fed the copper-adequate or copper-deficient diet without DMSO treatment. After 4 wk, rats in the groups fed the copper-deficient diet had lower liver superoxide dismutase and heart cytochrome c oxidase activities compared with groups fed the copper-adequate diet. Administration of DMSO, an antioxidant, and energy restriction (pair-feeding) partially blocked cardiac hypertrophy in rats fed the copper-deficient diet. Greater mitochondrial volume density and mitochondrial:myofibrillar ratio and disrupted myofibrils and basal laminae were observed in the hearts from rats fed the copper-deficient diet and not treated with DMSO compared with hearts from groups fed the copper-adequate diet. The DMSO-treated rats fed the copper-deficient diet had hearts with intact structure but enlarged mitochondria compared with other groups fed the copper-deficient diet. The delta subunit of ATP synthase and the nuclear-encoded cytochrome c oxidase subunits IV and V were depressed in rats fed a copper-deficient diet regardless of antioxidant treatment and pair-feeding. These data suggest that the effects of copper deficiency upon ATP synthase and cytochrome c oxidase proteins are not due to the cardiac pathology.
...
PMID:Low levels of ATP synthase and cytochrome c oxidase subunit peptide from hearts of copper-deficient rats are not altered by the administration of dimethyl sulfoxide. 820 36

Dietary copper restriction in rats results in cardiomyopathy. In rats fed copper-restricted diets from weaning for 5 to 8 weeks, a concentric hypertrophy is apparent, whereas postweaning copper restriction does produce cardiomyopathy without apparent hypertrophy. Both sets of circumstances appear to affect the integrity of the basal laminae of cardiac myocytes and capillaries. In rats fed copper-restricted diets from weaning, decreases in cytochrome c oxidase are related not only to copper's role as a coenzyme, but also to a marked decrease in the nuclear encoded subunits of the enzyme complex. Decreased levels of the delta-subunit of ATP synthase have been observed. However, such aberrations in mitochondrial enzymes, as well as morphologic alterations, apparently do not affect cardiac levels of ATP. This review suggests mechanisms of cardiac adaptation and initiation factors leading to cardiac hypertrophy. We present a hypothetical working model explaining the events leading to cardiac failure in the copper-deficient rat heart based on the present body of knowledge, and compare the pathology with other models of cardiomyopathies.
...
PMID:A unified perspective on copper deficiency and cardiomyopathy. 837 91

The soluble portion of the Escherichia coli F1F0 ATP synthase (ECF1) and E. coli F1F0 ATP synthase (ECF1F0) have been isolated from a novel mutant gammaY205C. ECF1 isolated from this mutant had an ATPase activity 3.5-fold higher than that of wild-type enzyme and could be activated further by maleimide modification of the introduced cysteine. This effect was not seen in ECF1F0. The mutation partly disrupts the F1 to F0 interaction, as indicated by a reduced efficiency of proton pumping. ECF1 containing the mutation gammaY205C was bound to the membrane-bound portion of the E. coli F1F0 ATP synthase (ECF0) isolated from mutants cA39C, cQ42C, cP43C, and cD44C to reconstitute hybrid enzymes. Cu2+ treatment or reaction with 5,5'-dithio-bis(2-nitro-benzoic acid) induced disulfide bond formation between the Cys at gamma position 205 and a Cys residue at positions 42, 43, or 44 in the c subunit but not at position 39. Using Cu2+ treatment, this covalent cross-linking was obtained in yields as high as 95% in the hybrid ECF1 gammaY205C/cQ42C and in ECF1F0 isolated from the double mutant of the same composition. The covalent linkage of the gamma to a c subunit had little effect on ATPase activity. However, ATP hydrolysis-linked proton translocation was lost, by modification of both gamma Cys-205 and c Cys-42 by bulky reagents such as 5,5'-dithio-bis (2-nitro-benzoic acid) or benzophenone-4-maleimide. In both ECF1 and ECF1F0 containing a Cys at gamma 205 and a Cys in the epsilon subunit (at position 38 or 43), cross-linking of the gamma to the epsilon subunit was induced in high yield by Cu2+. No cross-linking was observed in hybrid enzymes in which the Cys was at position 10, 65, or 108 of the epsilon subunit. Cross-linking of gamma to epsilon had only a minimal effect on ATP hydrolysis. The reactivity of the Cys at gamma 205 showed a nucleotide dependence of reactivity to maleimides in both ECF1 and ECF1F0, which was lost in ECF1 when the epsilon subunit was removed. Our results show that there is close interaction of the gamma and epsilon subunits for the full-length of the stalk region in ECF1F0. We argue that this interaction controls the coupling between nucleotide binding sites and the proton channel in ECF1F0.
...
PMID:The stalk region of the Escherichia coli ATP synthase. Tyrosine 205 of the gamma subunit is in the interface between the F1 and F0 parts and can interact with both the epsilon and c oligomer. 891 Apr 57

A triple mutant of Escherichia coli F1F0-ATP synthase, alphaQ2C/alphaS411C/epsilonS108C, has been generated for studying movements of the gamma and epsilon subunits during functioning of the enzyme. It includes mutations that allow disulfide bond formation between the Cys at alpha411 and both Cys-87 of gamma and Cys-108 of epsilon, two covalent cross-links that block enzyme function (Aggeler, R., and Capaldi, R. A. (1996) J. Biol. Chem. 271, 13888-13891). A cross-link is also generated between the Cys at alpha2 and Cys-140 of the delta subunit, which has no effect on functioning (Ogilvie, I., Aggeler, R., and Capaldi, R. A. (1997) J. Biol. Chem. 272, 16652-16656). CuCl2 treatment of the mutant alphaQ2C/alphaS411C/epsilonS108C generated five major cross-linked products. These are alpha-gamma-delta, alpha-gamma, alpha-delta-epsilon, alpha-delta, and alpha-epsilon. The ratio of alpha-gamma-delta to the alpha-gamma product was close to 1:2, i.e. in one-third of the ECF1F0 molecules the gamma subunit was attached to the alpha subunit at which the delta subunit is bound. Also, 20% of the epsilon subunit was present as a alpha-delta-epsilon product. With regard to the delta subunit, 30% was in the alpha-gamma-delta, 20% in the alpha-delta-epsilon, and 50% in the alpha-delta products when the cross-linking was done after incubation in ATP + MgCl2. The amounts of these three products were 40, 22, and 38%, respectively, in experiments where Cu2+ was added after preincubation in ATP + Mg2+ + azide. The delta subunit is fixed to, and therefore identifies, one specific alpha subunit (alphadelta). A distribution of the gamma and epsilon subunits, which is essentially random with respect to the alpha subunits, can only be explained by rotation of gamma-epsilon relative to the alpha3beta3 domain in ECF1F0.
...
PMID:Rotation of a gamma-epsilon subunit domain in the Escherichia coli F1F0-ATP synthase complex. The gamma-epsilon subunits are essentially randomly distributed relative to the alpha3beta3delta domain in the intact complex. 923 70

The cuproenzymes lysyl oxidase, cytochrome-c oxidase, and superoxide dismutase are key factors in understanding the cardiac hypertrophy and cardiomyopathy associated with dietary copper restriction. The role of copper in cardiac lipid and energy metabolism as a consequence of changes in some of these enzyme activities in comparison with what is known about normal cardiac substrate utilization is discussed here. While the decrease in the nuclear encoded subunits of cytochrome-c oxidase in hearts from copper-deficient rats is known, new evidence suggests that other factors, such as ATP synthase metabolism may be exerting an influence upon this observation. While this review focuses on newer knowledge about energy and fatty acid metabolism in copper deficiency, the extracellular matrix is considered as well. This complex interplay of extracellular and cellular events in copper restriction is outlined as a model for further studies of this unique model of concentric hypertrophy.
...
PMID:Newer findings on a unified perspective of copper restriction and cardiomyopathy. 927 Jul 15

Protein import into mitochondria involves several components of the mitochondrial outer and inner membranes as well as molecular chaperones located inside mitochondria. Here, we have investigated the effect of sulfhydryl group reagents on import of the in vitro transcribed/translated precursor of the F1 beta subunit of the ATP synthase (pF1 beta) into Solanum tuberosum mitochondria. We have used a reducing agent, dithiothreitol (DTT), a membrane-permeant alkylating agent, N-ethylmaleimide (NEM), a non-permeant alkylating agent, 3-(N-maleimidopropionyl)biocytin (MPB), an SH-group specific agent and cross-linker 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB) as well as an oxidizing cross-linker, copper sulfate. DTT stimulated the mitochondrial protein import, whereas NEM, MPB, DTNB and Cu2+ were inhibitory. Inhibition by Cu2+ could be reversed by addition of DTT. The efficiency of inhibition was higher in energized mitochondrial than in non-energized. We have dissected the effect of the SH-group reagents on binding, unfolding and transport of the precursor into mitochondria. Our results demonstrated that the inhibitory effect of NEM, DTNB and Cu2+ on the efficiency of import was not due to the interaction of the SH-group reagents with import receptors. Modification of pF1 beta with NEM prior to the import resulted in stimulation of import, whereas DTNB and Cu2+ were inhibitory. NEM, MPB, DTNB and Cu2+ inhibited import of the NEM-modified pF1 beta into intact mitochondria. Import of pF1 beta through a receptor-independent bypass-route as well as import into mitoplasts were sensitive to DTT, NEM, MPB, DTNB and Cu2+ in a similar manner as import into mitochondria. As MPB does not cross the inner membrane, these results indicated that redox and conformational status of SH groups located on the outer surface of the inner mitochondrial membrane were essential for protein import.
...
PMID:Mitochondrial protein import: modification of sulfhydryl groups of the inner mitochondrial membrane import machinery in Solanum tuberosum inhibits protein import. 942 1


1 2 3 4 5 Next >>

---