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 study is presented on the role of F0 and F1 subunits in oligomycin-sensitive H+ conduction and energy transfer reactions of bovine heart mitochondrial F0F1 H(+)-ATP synthase. Mild treatment with azodicarboxylic acid bis(dimethylamide) (diamide) enhanced oligomycin-sensitive H+ conduction in submitochondrial particles containing F1 attached to F0. This effect was associated with stimulation of the ATPase activity, with no effect on its inhibition by oligomycin, and depression of the 32Pi-ATP exchange. The stimulatory effect of diamide on H+ conduction decreased in particles from which F1 subunits were partially removed by urea. The stimulatory effect exerted by diamide in the submitochondrial particles with F1 attached to F0 was directly correlated with a decrease of the original electrophoretic bands of a subunit of F0 (F0I-PVP protein) and the gamma subunit of F1, with corresponding formation of their cross-linking product. In F0 liposomes, devoid of gamma subunit, diamide failed to stimulate H+ conduction and to cause disappearance of F0I-PVP protein, unless purified gamma subunit was added back. The addition to F0 liposomes of gamma subunit, but not that of alpha and beta subunits, caused per se inhibition of H+ conduction. It is concluded that F0I-PVP and gamma subunits are directly involved in the gate of the F0F1 H(+)-ATP synthase. Data are also presented indicating contribution to the gate of oligomycin-sensitivity conferral protein and of another protein subunit of F0, F6.
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PMID:Role of F0 and F1 subunits in the gating and coupling function of mitochondrial H(+)-ATP synthase. The effect of dithiol reagents. 138 61

The gamma subunit of the F1 moiety of the bovine mitochondrial H(+)-ATP synthase is shown to function as a component of the gate. Addition of purified gamma subunit to F0-liposomes inhibits transmembrane proton conduction. This inhibition can be removed by the bifunctional thiol reagent diamide. Immunoblot analysis shows that the diamide effect is likely due to disulphide bridging of the gamma subunit with the PVP protein of the F0 sector.
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PMID:The gamma subunit of F1 and the PVP protein of F0 (F0I) are components of the gate of the mitochondrial F0F1 H(+)-ATP synthase. 217 10

The membrane F0 sector of mitochondrial ATP synthase complex was rapidly isolated by direct extraction with CHAPS from F1-depleted submitochondrial particles. The preparation thus obtained is stable and can be reconstituted in artificial phospholipid membranes to result in oligomycin-sensitive proton conduction, or recombined with purified F1 to give the oligomycin-sensitive F0F1-ATPase complex. The F0 preparation and constituent polypeptides were characterized by SDS-polyacrylamide gel electrophoresis and immunoblot analysis. The functional role of F0 polypeptides was examined by means of trypsin digestion and reconstitution studies. It is shown that, in addition to the 8 kDa DCCD-binding protein, the nuclear encoded protein [(1987) J. Mol. Biol. 197, 89-100], characterized as an intrinsic component of F0 (F0I, PVP protein [(1988) FEBS Lett. 237,9-14]) [corrected] is involved in H+ translocation and the sensitivity of this process to the F0 inhibitors, DCCD and oligomycin.
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PMID:Mitochondrial F0F1 H+-ATP synthase. Characterization of F0 components involved in H+ translocation. 254 59

The time course of changes in mitochondrial energy metabolism during liver regeneration, following partial hepatectomy, is analyzed. For 24 h after surgical operation, a lag phase in the time course of the growth of liver is observed. In this period mitochondria showed a decrease of: (1) the respiratory control index; (2) the rate of oxidative phosphorylation; (3) the amount of immunodetected beta-F1 and F01-PVP subunits of F0F1-ATP synthase. No decrease, but instead a small increase in the content of mRNA for beta-F1 was observed in this phase. After this lag phase the growth of liver started, the content of mRNA for beta F1, as well as the level of immunodetected mitochondrial beta-F1 and F01-PVP subunits, increased and oxidative phosphorylation recovered. Analysis of the relative beta F1 protein/mRNA ratio indicates a decrease of beta F1 translational efficiency which remained low up to 72 h after partial hepatectomy and reached the same ratio of control at 96 h. It is concluded that the regenerating capability of rat liver is correlated with the efficiency of oxidative phosphorylation.
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PMID:Correlation between rat liver regeneration and mitochondrial energy metabolism. 754 40

To characterize the role of supernumerary subunits of the mammalian F0F1 ATP synthase, cross-reconstitution of mitochondrial and bacterial F0F1 complexes has been carried out. Escherichia coli F1 (EcF1) can be reconstituted with F1-stripped everted membranes of E. coli (UPEc) and of bovine heart mitochondria (USMP). Bovine heart mitochondrial F1 (BHF1) can also be reconstituted with both membranes. Both EcF1 and BHF1, when reconstituted with UPEc, exhibited oligomycin-insensitive ATP-hydrolase activity. Subunits of the mammalian F0, in particular F0I-PVP protein, F6 and oligomycin-sensitivity-conferring protein (OSCP) conferred oligomycin sensitivity to the catalytic activity of EcF1 or BHF1 reconstituted with UPEc. Reaction of N,N'-dicyclohexylcarbodiimide and development of inhibition of passive H+ conduction was, in UPEc, considerably slower and exhibited a lower apparent affinity than in USMP. The ATP hydrolase activity of UPEc+EcF1 or UPEc+BHF1 was, also, less sensitive to inhibition by N,N'-dicyclohexylcarbodiimide than USMP+EcF1 or USMP+BHF1. Addition of mitochondrial F0I-PVP to UPEc enhanced the sensitivity of H+ conduction to oligomycin. F0I-PVP and OSCP added to UPEc, promoted inhibition by N,N'-dicyclohexylcarbodiimide of passive H+ conduction and increased its binding affinity to subunit c of E. coli F0. The presence of F0I-PVP and OSCP also promoted inhibition by N,N'-dicyclohexylcarbodiimide of the ATP-hydrolase activity of EcF1 or BHF1 reconstituted with UPEc.
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PMID:Cross-reconstitution studies with polypeptides of Escherichia coli and bovine heart mitochondrial F0F1 ATP synthase. 802 87

The DCCD-sensitive proton permeability of chromatophores, from a green strain of Rhodobacter Capsulatus is potentiometrically detected following the proton release induced by a transmembrane diffusion potential imposed by a valinomycin-mediated potassium influx with a procedure already used for bovine heart submitochondrial particles (ESMP) and vesicles from Escherichia coli (Zanotti et al. (1994) Eur. J. Biochem. 222, 733-741). In the photosynthetic system, addition of increasing amounts of DCCD inhibits, with a similar titre, both proton permeability and MgATP-dependent ATPase activity as detected in the dark. The titre for 50% inhibition coincides with that obtained measuring proton permeability and ATP hydrolysis in ESMP. Upon removal of F1, the passive proton permeability is much less sensitive to DCCD in chromatophores than in USMP, suggesting that in chromatophores the F1-Fo interaction shapes the DCCD-sensitive proton conducting pathway. Addition of the purified mitochondrial FoI-PVP and oligomycin sensitivity-conferring (OSCP) proteins to the F1 stripped chromatophores restored the sensitivity of proton permeability to DCCD detected in untreated chromatophores. Analysis of the binding of 14C[DCCD] on F1 stripped chromatophores shows that the increase of DCCD sensitivity of proton permeability, caused by addition of mitochondrial Fo proteins, is related to an increase of the binding of the inhibitor to subunit c of Fo sector of ATP synthase complex.
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PMID:DCCD-sensitive proton permeability of bacterial photosynthetic membranes. Cross-reconstitution studies with purified bovine heart Fo subunits. 876 93

In liver mitochondria isolated from hypothyroid rats, the rate of ATP synthesis is lower than in mitochondria from normal rats. Oligomycin-sensitive ATP hydrolase activity and passive proton permeability were significantly lower in submitochondrial particles from hypothyroid rats compared to those isolated from normal rats. In mitochondria from hypothyroid rats, the changes in catalytic activities of F0F1-ATP synthase are accompanied by a decrease in the amount of immunodetected beta-F1, F0 1-PVP, and OSCP subunits of the complex. Northern blot hybridization shows a decrease in the relative cytosolic content of mRNA for beta-F1 subunit in liver of hypothyroid rats. Administration of 3,5,3'-triodo-L-thyronine to the hypothyroid rats tends to remedy the functional and structural defects of F0F1-ATP synthase observed in the hypothyroid rats. The results obtained indicate that hypothyroidism leads to a decreased expression of F0F1-ATP synthase complex in liver mitochondria and this contributes to the decrease of the efficiency of oxidative phosphorylation.
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PMID:Hypothyroidism leads to a decreased expression of mitochondrial F0F1-ATP synthase in rat liver. 973 93

Diamide treatment of the F0F1-ATP synthase in "inside out" submitochondrial particles (ESMP) in the absence of a respiratory Delta mu H+ as well as of isolated Fo reconstituted with F1 or F1-gamma subunit results in direct disulfide cross-linking between cysteine 197 in the carboxy-terminal region of the F0I-PVP(b) subunit and cysteine 91 at the carboxyl end of a small alpha-helix of subunit F1-gamma, both located in the stalk. The F0I-PVP(b) and F1-gamma cross-linking cause dramatic enhancement of oligomycin-sensitive decay of Delta mu H+. In ESMP and MgATP particles the cross-linking is accompanied by decoupling of respiratory ATP synthesis. These effects are consistent with the view that F0I-PVP(b) and F1-gamma are components of the stator and rotor of the proposed rotary motor, respectively. The fact that the carboxy-terminal region of F0I-PVP(b) and the short alpha-helix of F1-gamma can form a direct disulfide bridge shows that these two protein domains are, at least in the resting state of the enzyme, in direct contact. In isolated F0, diamide also induces cross-linking of OSCP with another subunit of F0, but this has no significant effect on proton conduction. When ESMP are treated with diamide in the presence of Delta mu H+ generated by respiration, neither cross-linking between F0I-PVP(b) and F1-gamma subunits nor the associated effects on proton conduction and ATP synthesis is observed. Cross-linking is restored in respiring ESMP by Delta mu H+ collapsing agents as well as by DCCD or oligomycin. These observations indicate that the torque generated by Delta mu H+ decay through Fo induces a relative motion and/or a separation of the F0I-PVP(b) subunit and F1-gamma which places the single cysteine residues, present in each of the two subunits, at a distance at which they cannot be engaged in disulfide bridging.
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PMID:Topological and functional relationship of subunits F1-gamma and F0I-PVP(b) in the mitochondrial H+-ATP synthase. 986 Aug 67

A study is presented on the effect of diamide-induced disulfide cross-linking of F(1)-gamma and F(0)I-PVP(b) subunits on proton translocation in the mitochondrial ATP synthase. The results show that, upon cross-linking of these subunits, whilst proton translocation from the A side to the B F(1) side is markedly accelerated with decoupling of oxidative phosphorylation, proton translocation in the reverse direction, driven by either ATP hydrolysis or a diffusion potential, is unaffected. These observations reveal further peculiarities of the mechanism of energy transfer in the ATP synthase of coupling membranes.
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PMID:Disulfide cross-linking of subunits F(1)-gamma and F(0)I-PVP(b) results in asymmetric effects on proton translocation in the mitochondrial ATP synthase. 1060 27

We have studied the functional effect of limited proteolysis by trypsin of the constituent subunits in the native and reconstituted F1F0 complex and isolated F1 of the bovine heart mitochondrial ATP synthase (EC 3.6.1.34). Chemical cross-linking of oligomycin-sensitivity conferring protein (OSCP) with other subunits of the ATP synthase and the consequent functional effects were also investigated. The results obtained show that the alpha subunit N-terminus is essential for the correct, functional connection of F1 to F0. The alpha-subunit N-terminus contacts OSCP which, in turn, contacts the F0I-PVP(b) and the F0-d subunits. The N-terminus of subunit alpha, OSCP, a segment of subunit d and the C-terminal and central region of F0I-PVP(b) subunits are peripherally located with respect to subunits gamma and delta which are completely shielded in the F1F0 complex against trypsin digestion. This qualifies the N-terminus of subunit alpha, OSCP, subunit d and F0I-PVP(b) as components of the lateral element of the stalk. These subunits, rather than being confined at one side of the complex which would leave most of the central part of the gamma subunit uncovered, surround the gamma and the delta subunits located in the central stalk.
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PMID:F1 and F0 connections in the bovine mitochondrial ATP synthase: the role of the of alpha subunit N-terminus, oligomycin-sensitivity conferring protein (OCSP) and subunit d. 1088 Sep 68


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