Characterization of the Interface between γ and ε Subunits of Escherichia coli F1-ATPase

Tang, Chunlin; Capaldi, Roderick A.

doi:10.1074/jbc.271.6.3018

Cited by 83 publications

(53 citation statements)

References 38 publications

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“…There is now experimental evidence to show that, during the catalytic cycle, the γ subunit rotates about its long axis with respect to each α\β dimer in the F " sector, in a socalled ' entropic motor ' [173,[214][215][216]. The γ subunit also interfaces with the ε subunit [217], and both of these subunits in turn contact both the β subunit in F " [218] and subunit c in the F o sector [143,219,220]. Both subunits certainly undergo conformational changes during the catalytic cycle [210,221,222].…”

Section: Coupling Of Atp Hydrolysis To Proton Pumpingmentioning

confidence: 99%

The vacuolar H+-ATPase: a universal proton pump of eukaryotes

Finbow

Harrison

1997

Biochemical Journal

239

179

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The vacuolar H + -ATPase (V-ATPase) is a universal component of eukaryotic organisms. It is present in the membranes of many organelles, where its proton-pumping action creates the low intravacuolar pH found, for example, in lysosomes. In addition, there are a number of differentiated cell types that have V-ATPases on their surface that contribute to the physiological functions of these cells. The V-ATPase is a multi-subunit enzyme composed of a membrane sector and a cytosolic catalytic sector. It is related to the familiar F o F " ATP synthase (F-ATPase), having the same basic architectural construction, and many of the subunits from

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Section: Coupling Of Atp Hydrolysis To Proton Pumpingmentioning

confidence: 99%

The vacuolar H+-ATPase: a universal proton pump of eukaryotes

Finbow

Harrison

1997

Biochemical Journal

239

179

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“…The N-terminal domain is positioned below this, attached to the first of the two ␣ helices of the C-terminal domain at its top (13) and to the c subunits of the F 0 part via the bottom of the ␤ sandwich in an interaction that involves residues Glu-31 (17,18) and possibly His-38 (19). Our recent cross-linking and protease protection studies have established that one face of the ␤-sheet sandwich of the ⑀ subunit interacts with the ␥ subunit (16). In one set of experiments, cross-linking was obtained from Cys-10 of ⑀ to a region of the ␥ subunit around residue 228.…”

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confidence: 99%

The Stalk Region of the Escherichia coli ATP Synthase

Watts

Tang

Capaldi

1996

Journal of Biological Chemistry

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The soluble portion of the Escherichia coli F 1 F 0 ATP synthase (ECF 1 ) and E. coli F 1 F 0 ATP synthase (ECF 1 F 0 ) have been isolated from a novel mutant ␥Y205C. ECF 1 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 ECF 1 F 0 . The mutation partly disrupts the F 1 to F 0 interaction, as indicated by a reduced efficiency of proton pumping. ECF 1 containing the mutation ␥Y205C was bound to the membrane-bound portion of the E. coli F 1 F 0 ATP synthase (ECF 0 ) isolated from mutants cA39C, cQ42C, cP43C, and cD44C to reconstitute hybrid enzymes. Cu Cross-linking of ␥ to ⑀ had only a minimal effect on ATP hydrolysis. The reactivity of the Cys at ␥ 205 showed a nucleotide dependence of reactivity to maleimides in both ECF 1 and ECF 1 F 0 , which was lost in ECF 1 when the ⑀ subunit was removed. Our results show that there is close interaction of the ␥ and ⑀ subunits for the fulllength of the stalk region in ECF 1 F 0 . We argue that this interaction controls the coupling between nucleotide binding sites and the proton channel in ECF 1 F 0 .F 1 F 0 type ATP synthases play a key role in oxidative phosphorylation and photophosphorylation. The F 1 , which can be detached from the F 0 and studied separately, is a complex of five different types of subunits called ␣, ␤, ␥, ␦, and ⑀ that are present in the molar ratio 3:3:1:1:1. The F 0 part in the Escherichia coli enzyme is composed of three different subunits: a, b, and c in the molar ratio 1:2:10 -12 (1-4). Electron microscopy first showed that the ␣ and ␤ subunits are arranged hexagonally and alternate around a central cavity in which the ␥ subunit is located (5-7). Biochemical studies place the ⑀ subunit (nomenclature for the E. coli enzyme) at the bottom of the ␣ 3 ␤ 3 ␥ core complex (4, 8) in the stalk region, which is a 40 -45-Å-long structure that links the F 1 to the F 0 part (9, 10).The recently published high resolution structure of a major part of the beef heart F 1 molecule confirms the above-described arrangement of the ␣, ␤, and ␥ subunits and adds important details (11). In particular, it shows the ␥ subunit arranged with a long C-terminal ␣-helix extending from the top of the ␣ and ␤ subunits into the stalk region. A shorter N-terminal ␣-helix is also present, running from the catalytic site region into the stalk region. These two ␣ helices form a coiled coil. A third short ␣-helix of the ␥ subunit (residues 83-99 in the E. coli sequence) is inclined at about 45°to the two larger helices at the bottom of the F 1 as it becomes the stalk. Approximately half of the ␥ subunit is unresolved in the structure, presumably because it is disordered in the crystal form.Recently, we observed cross-linking between a Cys introduced at position 44 of the polar loop of the c subunits and a site or sites on the ␥ subunit in the region between residues 202 and 230 (12). This result implies that the ␥ subunit exte...

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“…ATPase activity of CF 1 is enhanced by either reduction of the disulfide bond of ␥ subunit or removal of ⑀ subunit (28,29). Recently, Capaldi and co-worker (30) have extensively studied the interaction of ⑀ subunit with the ␣, ␤, and ␥ subunits in EF 1 by using cross-linking and chemical modification. Interestingly, ⑀ subunit changes the partner subunit of cross-linking dependent on the nucleotide in the solution.…”

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confidence: 99%

Thermophilic F1-ATPase Is Activated without Dissociation of an Endogenous Inhibitor, ε Subunit

Kato

Matsui²,

Tanaka

et al. 1997

Journal of Biological Chemistry

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of thermophilic F 1 -ATPase were prepared, and their catalytic properties were compared to know the role of ␦ and ⑀ subunits in catalysis. The presence of ␦ subunit in the complexes had slight inhibitory effect on the ATPase activity. The effect of ⑀ subunit was more profound. The (؊⑀) complexes, ␣ 3 ␤ 3 ␥ and ␣ 3 ␤ 3 ␥␦, initiated ATP hydrolysis without a lag. In contrast, the (؉⑀) complexes, ␣ 3 ␤ 3 ␥⑀ and ␣ 3 ␤ 3 ␥␦⑀, started hydrolysis of ATP (<700 M) with a lag phase that was gradually activated during catalytic turnover. As ATP concentration increased, the lag phase of the (؉⑀) complexes became shorter, and it was not observed above 1 mM ATP. Analysis of binding and hydrolysis of the ATP analog, 2 ,3 -O-(2,4,6-trinitrophenyl)-ATP, suggested that the (؉⑀) complexes bound substrate only slowly. Differing from Escherichia coli F 1 -ATPase, the activation of the (؉⑀) complexes from the lag phase was not due to dissociation of ⑀ subunit since the re-isolated activated complex retained ⑀ subunit. This indicates that there are two alternative forms of the (؉⑀) complex, inhibited form and activated form, and the inhibited one is converted to the activated one during catalytic turnover.

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Characterization of the Interface between γ and ε Subunits of Escherichia coli F1-ATPase

Cited by 83 publications

References 38 publications

The vacuolar H+-ATPase: a universal proton pump of eukaryotes

The vacuolar H+-ATPase: a universal proton pump of eukaryotes

The Stalk Region of the Escherichia coli ATP Synthase

Thermophilic F1-ATPase Is Activated without Dissociation of an Endogenous Inhibitor, ε Subunit

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