The rate of ATP‐synthesis as a function of ΔpH and Δψ catalyzed by the active, reduced H<sup>+</sup>‐ATPase from chloroplasts

Junesch, Ulrike; Gräber, Peter

doi:10.1016/0014-5793(91)81447-g

Cited by 78 publications

(38 citation statements)

References 14 publications

(9 reference statements)

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“…s -I . CF,F,-' with a higher energy supply by cyclic electron transport applying phenazinemethosulfate as electron acceptor (cyclic photophosphorylation; Engelbrecht et al, 1989) or by acidbase transition combined with a K'halinomycin diffusion potential (Junesch and Graber, 1991;compare Table 1). The rates are calculated on the bases that, in thylakoids, 0.37 mg CF, are presenvmg chlorophyll (Frasch et al.…”

Section: Discussionmentioning

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

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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...

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Section: Discussionmentioning

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

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“…Our analysis suggests that variant experimental conditions likely underlie conflicting evidence regarding kinetic equivalence of pmf components Δ pH and Δψ. Some in vitro studies have found that the effect of the two components of pmf are equivalent (39)(40)(41)(42), whereas others have concluded that they are not (43)(44)(45). There is no inherent reason to expect kinetic equivalence (53) because Δ pH and Δψ affect kinetics through different mechanisms: Δ pH through H + concentration, and Δψ most likely through binding affinity dictated by the thermodynamic cycle constraint, as described in SI Appendix.…”

Section: Kinetic Equivalence Of Pmf Components May Depend On Experimementioning

confidence: 99%

“…Additional analysis sheds light on contradictory reports on the "kinetic equivalence" of different components of the driving protonmotive force (pmf) (39)(40)(41)(42)(43)(44)(45)(46): should the synthesis rate be sensitive to whether the pmf is generated by a pH difference or transmembrane potential difference? We show that kinetic behavior is approximately equivalent under most physiological conditions, but that variant conditions can clearly exhibit nonequivalence.…”

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Biophysical comparison of ATP synthesis mechanisms shows a kinetic advantage for the rotary process

Anandakrishnan

Zhang

Donovan-Maiye

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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The ATP synthase (F-ATPase) is a highly complex rotary machine that synthesizes ATP, powered by a proton electrochemical gradient. Why did evolution select such an elaborate mechanism over arguably simpler alternating-access processes that can be reversed to perform ATP synthesis? We studied a systematic enumeration of alternative mechanisms, using numerical and theoretical means. When the alternative models are optimized subject to fundamental thermodynamic constraints, they fail to match the kinetic ability of the rotary mechanism over a wide range of conditions, particularly under low-energy conditions. We used a physically interpretable, closed-form solution for the steady-state rate for an arbitrary chemical cycle, which clarifies kinetic effects of complex free-energy landscapes. Our analysis also yields insights into the debated "kinetic equivalence" of ATP synthesis driven by transmembrane pH and potential difference. Overall, our study suggests that the complexity of the F-ATPase may have resulted from positive selection for its kinetic advantage.ATP synthase | kinetic mechanism | free-energy landscape | nonequilibrium steady state | evolution T he F-ATPase performs molecular-level free-energy (FE) transduction to phosphorylate ADP and yield ATP, the primary energy carrier that drives a vast range of cellular processes. It spurred Mitchell's chemiosmotic hypothesis (1) and Boyer's now-validated proposal for the binding-change mechanism (2) in which a proton electrochemical gradient is transduced to rotationbased mechanical energy and then back to chemical FE as ADP is phosphorylated. The F-ATPase's two-domain uniaxial rotary structure is conserved across all three domains of life (3-6), and details of its function have been the subject of a multitude of studies (e.g., refs. 7-30).Here, we address a relatively narrow question with potentially significant evolutionary implications: Why is ATP synthesized by a rotary mechanism instead of a potentially much simpler alternating-access mechanism (Fig. 1)? Using thermodynamic and kinetic constraints, we address the question of whether evolution tends to arrive at optimal molecular processes (31), building on established concepts of optimality-derived evolutionary convergence (32, 33). Presumably, performance advantages in the central task of ATP synthesis would be under significant evolutionary pressure. Previous modeling studies of the F-ATPase have addressed structural and mechanistic questions about the rotary mechanism (e.g., refs. 11-20), but not the metaissue of the mechanism itself compared with alternatives.To assess whether the rotary mechanism possesses any intrinsic performance advantage, we constructed a series of kinetic models abstracted from known mechanisms (Fig. 1). Beyond the rotarybased model, we considered a series of alternating-access analogs (Fig. 2), building on the demonstrated capacity for ATP-hydrolyzing transporters to be driven in reverse to synthesize ATP (34, 35). The discrete-state models do not include structural details, bu...

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“…The chloroplast CF 0 -CF 1 -ATP synthase (ATP synthase) 2 drives the reversible synthesis of ATP from ADP and P i using energy from the light-driven proton electrochemical gradient, or proton motive force (pmf) (1,2). This multisubunit complex is composed of two subcomplexes.…”

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confidence: 99%

Light- and Metabolism-related Regulation of the Chloroplast ATP Synthase Has Distinct Mechanisms and Functions

Kohzuma

Bosco

Meurer

et al. 2013

Journal of Biological Chemistry

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Background: Chloroplast ATP synthase activity is regulated by both light and metabolic factors, but the relationship between these regulatory modes is not established. Results: Mutating three highly conserved acidic amino acid residues in the ␥ subunit alters light-but not metabolism-induced regulation. Conclusion: Metabolism and light regulation operates via distinct mechanisms. Significance: The chloroplast ATP synthase is a key control point for the light and dark reactions of photosynthesis.

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The rate of ATP‐synthesis as a function of ΔpH and Δψ catalyzed by the active, reduced H⁺‐ATPase from chloroplasts

Cited by 78 publications

References 14 publications

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

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

Biophysical comparison of ATP synthesis mechanisms shows a kinetic advantage for the rotary process

Light- and Metabolism-related Regulation of the Chloroplast ATP Synthase Has Distinct Mechanisms and Functions

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The rate of ATP‐synthesis as a function of ΔpH and Δψ catalyzed by the active, reduced H+‐ATPase from chloroplasts

Cited by 78 publications

References 14 publications

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

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

Biophysical comparison of ATP synthesis mechanisms shows a kinetic advantage for the rotary process

Light- and Metabolism-related Regulation of the Chloroplast ATP Synthase Has Distinct Mechanisms and Functions

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The rate of ATP‐synthesis as a function of ΔpH and Δψ catalyzed by the active, reduced H⁺‐ATPase from chloroplasts

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

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