Studies on the mechanism of oxidative phosphorylation: effects of specific F0 modifiers on ligand-induced conformation changes of F1.

Matsuno‐Yagi, Akemi; Yagi, Takao; Hatefi, Youssef

doi:10.1073/pnas.82.22.7550

Cited by 47 publications

(13 citation statements)

References 36 publications

(34 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Early association between subunits a and c is essential for the control of proton flux through F 0 , therefore an unassembled F 1 F 0 -ATPase could be associated with either a block or a fully uncontrolled translocation of the protons within F 0 . Observations made in other laboratories [12,34] and the findings of the present study are also in agreement with this view, that the enzyme activities are fully oligomycin-sensitive, a property that is lost, for instance, when the enzyme structure is severely altered [35,36]. On the other hand indirect indications of the presence of assembled F 1 F 0 in mutated cells can also be inferred from our previous work [11], showing both unaffected F 1 F 0 -catalysed ATP hydrolysis and ATPdriven proton translocation in NARP mitochondria exposed to sonic oscillation.…”

Section: Discussionsupporting

confidence: 93%

Inefficient coupling between proton transport and ATP synthesis may be the pathogenic mechanism for NARP and Leigh syndrome resulting from the T8993G mutation in mtDNA

Sgarbi

Baracca

Lenaz

et al. 2006

Biochemical Journal

102

View full text Add to dashboard Cite

Mutations in the ATP6 gene of mtDNA (mitochondrial DNA) have been shown to cause several different neurological disorders. The product of this gene is ATPase 6, an essential component of the F1F0-ATPase. In the present study we show that the function of the F1F0-ATPase is impaired in lymphocytes from ten individuals harbouring the mtDNA T8993G point mutation associated with NARP (neuropathy, ataxia and retinitis pigmentosa) and Leigh syndrome. We show that the impaired function of both the ATP synthase and the proton transport activity of the enzyme correlates with the amount of the mtDNA that is mutated, ranging from 13-94%. The fluorescent dye RH-123 (Rhodamine-123) was used as a probe to determine whether or not passive proton flux (i.e. from the intermembrane space to the matrix) is affected by the mutation. Under state 3 respiratory conditions, a slight difference in RH-123 fluorescence quenching kinetics was observed between mutant and control mitochondria that suggests a marginally lower F0 proton flux capacity in cells from patients. Moreover, independent of the cellular mutant load the specific inhibitor oligomycin induced a marked enhancement of the RH-123 quenching rate, which is associated with a block in proton conductivity through F0 [Linnett and Beechey (1979) Inhibitors of the ATP synthethase system. Methods Enzymol. 55, 472-518]. Overall, the results rule out the previously proposed proton block as the basis of the pathogenicity of the mtDNA T8993G mutation. Since the ATP synthesis rate was decreased by 70% in NARP patients compared with controls, we suggest that the T8993G mutation affects the coupling between proton translocation through F0 and ATP synthesis on F1. We discuss our findings in view of the current knowledge regarding the rotary mechanism of catalysis of the enzyme.

show abstract

Section: Discussionsupporting

confidence: 93%

Inefficient coupling between proton transport and ATP synthesis may be the pathogenic mechanism for NARP and Leigh syndrome resulting from the T8993G mutation in mtDNA

Sgarbi

Baracca

Lenaz

et al. 2006

Biochemical Journal

102

View full text Add to dashboard Cite

show abstract

“…However, the lack of sensitivity of these fluxes to CSA does not support this notion. It also should be kept in mind that, although DCCD suppresses both these selective fluxes and the nonspecific permeability increase, this does not unequivocally indicate operation of PTP because, in contrast to CSA, this compound can modify other mitochondrial proteins such as the K ϩ /H ϩ exchanger (33) of the inner mitochondrial membrane and the F 0 channel of mitochondrial ATPase (34,35).…”

Section: Discussionmentioning

confidence: 99%

Positively Charged Ceramide Is a Potent Inducer of Mitochondrial Permeabilization

Novgorodov¹,

Szulc

Luberto

et al. 2005

Journal of Biological Chemistry

107

View full text Add to dashboard Cite

Ceramide-induced cell death is thought to be mediated by change in mitochondrial function, although the precise mechanism is unclear. Proposed models suggest that ceramide induces cell death through interaction with latent binding sites on the outer or inner mitochondrial membranes, followed by an increase in membrane permeability, as an intermediate step in ceramide signal propagation. To investigate these models, we developed a new generation of positively charged ceramides that readily accumulate in isolated and in situ mitochondria. Accumulated, positively charged ceramides increased inner membrane permeability and triggered release of mitochondrial cytochrome c. Furthermore, the positively charged ceramide-induced permeability increase was suppressed by cyclosporin A (60%) and 1,3-dicyclohexylcarbodiimide (90%). These observations suggest that the inner membrane permeability increase is due to activation of specific ion transporters, not the generalized loss of lipid bilayer barrier functions. The difference in sensitivity of ceramide-induced ion fluxes to inhibitors of mitochondrial transporters suggests activation of at least two transport systems: the permeability transition pore and the electrogenic H ؉ channel. Our results indicate the presence of specific ceramide targets in the mitochondrial matrix, the occupation of which triggers permeability alterations of the inner and outer mitochondrial membranes. These findings also suggest a novel therapeutic role for positively charged ceramides.

show abstract

“…A comparison with F,F, complexes from other sources revealed similar K,,, values under conditions of multisite catalysis, e.g. 30 pM for CF,F, (Stroop and Boyer, 1985;Labahn and Griiber, 1993), 6-10pM for MF,F, (Matsuno-Yagi et al, 1985 ;Matsuno-Yagi and Hatefi, 1986) and 11 pM for F,F, from Purucoccus denitrfificaris (Perez andFerguson, 1990: compare also Boyer, 1993). In this work the lowest ADP concentration used was 1 pM.…”

Section: Turnover Number Of Efmentioning

confidence: 99%

Turnover Number of Escherichia coli F₀F₁ ATP Synthase for ATP Synthesis in Membrane Vesicles

Etzold

Deckers-Hebestreit

Altendorf

1997

European Journal of Biochemistry

View full text Add to dashboard Cite

The rate of ATP synthesized by the ATP synthase (F,,F,-ATPase) is limited by the rate of energy production via the respiratory chain, when measured in everted membrane vesicles of an Eschericliia coli atp wild-type strain. After energization of the membranes with NADH, fractional inactivation of F,,F, by the covalent inhibitor N,N'-dicyclohexylcarbodiimide allowed the rate of ATP synthedmol remaining active ATP synthase complexes to increase ; the active ATP synthase complexes were calculated using ATP hydrolysis rates as the defining parameter. In addition, variation of the assay temperature revealed an increase of the ATP synthesis rate up to a temperature of 37"C, the optimal growth temperature of E. coli. In parallel, the amount of F,,F, complexes present in membrane vesicles was determined by immnnoquantitation to be 3.3 t 0.3 % of the membrane protein for cells grown in rich medium and 6.6 t 0.3 % for cells grown in minimal medium with glycerol as sole carbon and energy source. Based on these data, a turnover number for ATP synthesis of 270 5 40 s~' could be determined in the presence of 5 8 active F,F, complexes. Therefore, these studies demonstrate that the ATP synthase complex of E. coli has, with respect to maximum rates, the same capacity as the corresponding enzymes of eukaryotic organells.Keywords: F,,F, ATP synthase ; oxidative phosphorylation ; turnover number; dicyclohexylcarbodiimide : Escherichia coli.ATP synthases (F,F,-ATPases) are found in energy-transducing membranes of mitochondria, chloroplasts and bacteria, where they catalyze the synthesis of ATP from ADP and inorganic phosphate using an electrochemical gradient of protons built up by respiration or photosynthesis. In bacteria. the enzyme can also function in the reverse direction by coupling the hydrolysis of ATP to the translocation of protons. The multisubunit enzyme complex consists of the globular, water-soluble F, complex and the membrane-integrated F, complex linked by a stalk. The F, complex carries the catalytic sites for ATP synthesis and hydrolysis, whereas the F,, complex constitutes a path for protons across the membrane. Energy released by proton translocation through F,, is relayed to the catalytic sites in F, by conformational changes. In Escherichia coli, the F, complex is composed of the three different polypeptides a, b, and c in a stoichiometry of 1 : 2: 10 t 1, whereas the F, complex consists of five subunits with a stoichiometry of a&& (Fillingame, 1990, 1992: Capaldi et al., 1994Deckers-Hebestreit and Altendorf, 1996). Recently, the F, part of bovine heart mitochondria was crystallized and the structures of the subunits a, / l , and part of 7 , have been solved by X-ray diffraction at 0.28-nm resolution (Abrahams et al., 1994).F,F,-ATPases from different sources reveal great similarities in subunit composition, structure and function. Hence, one could Enzyme. ATP synthase (F,,F,) (EC 3.6.1.34).Bertani; SMP, submitochondrial particles.imply that also the catalytic mechanisms and the turnover numbers of the enzyme c...

show abstract

Studies on the mechanism of oxidative phosphorylation: effects of specific F0 modifiers on ligand-induced conformation changes of F1.

Cited by 47 publications

References 36 publications

Inefficient coupling between proton transport and ATP synthesis may be the pathogenic mechanism for NARP and Leigh syndrome resulting from the T8993G mutation in mtDNA

Inefficient coupling between proton transport and ATP synthesis may be the pathogenic mechanism for NARP and Leigh syndrome resulting from the T8993G mutation in mtDNA

Positively Charged Ceramide Is a Potent Inducer of Mitochondrial Permeabilization

Turnover Number of Escherichia coli F₀F₁ ATP Synthase for ATP Synthesis in Membrane Vesicles

Contact Info

Product

Resources

About

Studies on the mechanism of oxidative phosphorylation: effects of specific F0 modifiers on ligand-induced conformation changes of F1.

Cited by 47 publications

References 36 publications

Inefficient coupling between proton transport and ATP synthesis may be the pathogenic mechanism for NARP and Leigh syndrome resulting from the T8993G mutation in mtDNA

Inefficient coupling between proton transport and ATP synthesis may be the pathogenic mechanism for NARP and Leigh syndrome resulting from the T8993G mutation in mtDNA

Positively Charged Ceramide Is a Potent Inducer of Mitochondrial Permeabilization

Turnover Number of Escherichia coli F0F1 ATP Synthase for ATP Synthesis in Membrane Vesicles

Contact Info

Product

Resources

About

Turnover Number of Escherichia coli F₀F₁ ATP Synthase for ATP Synthesis in Membrane Vesicles