Activation of ATPase of spinach coupling factor 1. Release of tightly bound ADP from the soluble enzyme

Sherman, Paula A.; Wimmer, Mary J.

doi:10.1111/j.1432-1033.1984.tb08015.x

Cited by 13 publications

(3 citation statements)

References 40 publications

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“…Several studies also confirmed that both activation and ADP release can be caused by membrane energization (i.e. by pmf-driven rotation of subunit ␥) (27)(28)(29)(30)(31)(32)(33)36). The results shown in Figs.…”

Section: Discussionsupporting

confidence: 57%

“…Single molecule experiments revealed that ADP inhibition results in long pauses in enzyme turnover (23) and that the rotation of subunit ␥, caused by either external forces or thermal fluctuations, relieves ADP inhibition (26). It was also demonstrated that the tightly bound inhibitory ADP can be expelled by pmf (19,(27)(28)(29)(30). This phenomenon underlies the so-called "activation by pmf," that is, the increase in ATPase activity of the enzyme after membrane energization (31)(32)(33)(34)(35)(36).…”

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confidence: 99%

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Regulatory Interplay between Proton Motive Force, ADP, Phosphate, and Subunit ϵ in Bacterial ATP Synthase

Feniouk¹,

Suzuki

Yoshida

2007

Journal of Biological Chemistry

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ATP synthase couples transmembrane proton transport, driven by the proton motive force (pmf), to the synthesis of ATP from ADP and inorganic phosphate (P i ). In certain bacteria, the reaction is reversed and the enzyme generates pmf, working as a proton-pumping ATPase. The ATPase activity of bacterial enzymes is prone to inhibition by both ADP and the C-terminal domain of subunit ⑀. We studied the effects of ADP, P i , pmf, and the C-terminal domain of subunit ⑀ on the ATPase activity of thermophilic Bacillus PS3 and Escherichia coli ATP synthases. We found that pmf relieved ADP inhibition during steady-state ATP hydrolysis, but only in the presence of P i . The C-terminal domain of subunit ⑀ in the Bacillus PS3 enzyme enhanced ADP inhibition by counteracting the effects of pmf. It appears that these features allow the enzyme to promptly respond to changes in the ATP:ADP ratio and in pmf levels in order to avoid potentially wasteful ATP hydrolysis in vivo.ATP synthase (F O F 1 ) is a ubiquitous enzyme present in the plasma membrane of bacteria, the thylakoid membrane of chloroplasts, and the inner mitochondrial membrane. The enzyme catalyzes ATP synthesis coupled to transmembrane proton translocation 2 driven by the proton motive force (pmf).3 At low pmf the activity is reversed and the enzyme functions as a proton-pumping ATPase. ATP synthase consists of two distinct regions: the hydrophobic F O , which is embedded in the membrane, and the hydrophilic F 1 that protrudes ϳ100 Å from the membrane bilayer. F 1 contains three catalytic and three non-catalytic nucleotide-binding sites and is responsible for both ATP synthesis and hydrolysis reactions. F O performs transmembrane proton transport. The simplest subunit composition is found in bacteria (e.g. Escherichia coli or thermophilic Bacillus PS3; see Refs. 1 and 2 for reviews), where F 1 is a complex of five types of subunits at a stoichiometry of ␣ 3 ␤ 3 ␥ 1 ␦ 1 ⑀ 1 , and F O is a complex of three types of subunits at a stoichiometry of a 1 b 2 c 10 .It is now widely accepted that the enzyme operates according to the "binding change mechanism" (see Ref. 3 and the references therein). Briefly, proton translocation is coupled to the rotation of the c-ring oligomer (4) together with the ␥⑀ complex relative to the rest of the enzyme (see Refs. 5-7 and references therein for details). Rotation of the ␥ subunit inside the ␣ 3 ␤ 3 hexamer causes sequential conformational changes to the catalytic sites. These sequential conformational changes result in substrate binding, the chemical step, and product release (8 -10). This "rotary binding change mechanism" is usually considered reversible, and numerous demonstrations of ATPdriven proton pumping support this assumption. However, several observations indicate that this is not the case. Many factors (e.g. products/substrates of catalysis, inhibitors, inorganic anions, etc.) affect ATP synthesis and the hydrolysis activities of the enzyme (see Ref. 11 for a detailed discussion). One of the most well known anisotropic reg...

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Section: Discussionsupporting

confidence: 57%

mentioning

confidence: 99%

Regulatory Interplay between Proton Motive Force, ADP, Phosphate, and Subunit ϵ in Bacterial ATP Synthase

Feniouk¹,

Suzuki

Yoshida

2007

Journal of Biological Chemistry

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“…This appears not to be the case here, since sulfite stimulates even when the Mg2+ concentration is below inhibitory levels. Alcohols are known to stimulate chloroplast coupling factors from spinach (35) and Chlamydomonas reinhardii (22). In spinach chloroplasts, alcohols seem to function by enhancing the release of tightly bound ADP.…”

Section: Downloaded Frommentioning

confidence: 99%

Purification and characterization of the F1-ATPase from Clostridium thermoaceticum

Ivey¹,

Ljungdahl²

1986

J Bacteriol

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The F1 portion of the H+-ATPase from Clostridium thermoaceticum was purified to homogeneity by solubilization at low ionic strength, ion-exchange chromatography, and gel filtration. The last indicated the Mr to be 370,000. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the pure enzyme revealed four bands with Mr corresponding to 60,000, 55,000, 37,000, and 17,000 in an apparent molar ratio of 3:3:1:1. The purified enzyme would bind to stripped membranes to reconstitute dicyclohexylcarbodiimide-sensitive ATPase activity. Phosphohydrolase activity, measured at 58°C, was optimal at pH 8.5. In the presence of a 1 mM excess of Mg+ over the concentration of ATP, the Km for ATP was 0.4 mM, and the Vmax was 6.7 Fmol min' mg-'. Unlike the membrane-bound F1F0 complex, the Fl-ATPase was relatively insensitive to the inhibitors dicyclohexylcarbodiimide and tributyltin chloride. Both the complex and the Fl-ATPase were inhibited by quercetin, azide, 7-chloro-4-nitro-benz-2-oxa-1,3-diazole, and free magnesium, and both were stimulated by primary alcohols and sulfite. In whole cells, the F1F0-ATPase catalyzed the synthesis of ATP in response to a pH gradient.

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Regulatory Mechanisms of Proton-Translocating FOF1-ATP Synthase

Feniouk

Yoshida

Results and Problems in Cell Differentiation

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H(+)-F(O)F(1)-ATP synthase catalyzes synthesis of ATP from ADP and inorganic phosphate using the energy of transmembrane electrochemical potential difference of proton (deltamu(H)(+). The enzyme can also generate this potential difference by working as an ATP-driven proton pump. Several regulatory mechanisms are known to suppress the ATPase activity of F(O)F(1): 1. Non-competitive inhibition by MgADP, a feature shared by F(O)F(1) from bacteria, chloroplasts and mitochondria 2. Inhibition by subunit epsilon in chloroplast and bacterial enzyme 3. Inhibition upon oxidation of two cysteines in subunit gamma in chloroplast F(O)F(1) 4. Inhibition by an additional regulatory protein (IF(1)) in mitochondrial enzyme In this review we summarize the information available on these regulatory mechanisms and discuss possible interplay between them.

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Activation of ATPase of spinach coupling factor 1. Release of tightly bound ADP from the soluble enzyme

Cited by 13 publications

References 40 publications

Regulatory Interplay between Proton Motive Force, ADP, Phosphate, and Subunit ϵ in Bacterial ATP Synthase

Regulatory Interplay between Proton Motive Force, ADP, Phosphate, and Subunit ϵ in Bacterial ATP Synthase

Purification and characterization of the F1-ATPase from Clostridium thermoaceticum

Regulatory Mechanisms of Proton-Translocating FOF1-ATP Synthase

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