γε sub-complex of thermophilic ATP synthase has the ability to bind ATP

Iizuka, Satoshi; Kato, Shigeyuki; Yoshida, Masasuke; Kato-Yamada, Yasuyuki

doi:10.1016/j.bbrc.2006.09.001

Cited by 11 publications

(10 citation statements)

References 28 publications

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“…A peculiar feature of Bacillus PS3 F O F 1 is that ATP can bind directly to subunit 3 (44,45). The recently published structure of the 3-ATP complex confirms that ATP binds when subunit 3 is in the hairpin noninhibitory conformation (46).…”

Section: Introductionmentioning

confidence: 85%

Conformational Transitions of Subunit ɛ in ATP Synthase from Thermophilic Bacillus PS3

Feniouk¹,

Kato-Yamada

Yoshida

et al. 2010

Biophysical Journal

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Subunit epsilon of bacterial and chloroplast F(O)F(1)-ATP synthase is responsible for inhibition of ATPase activity. In Bacillus PS3 enzyme, subunit epsilon can adopt two conformations. In the "extended", inhibitory conformation, its two C-terminal alpha-helices are stretched along subunit gamma. In the "contracted", noninhibitory conformation, these helices form a hairpin. The transition of subunit epsilon from an extended to a contracted state was studied in ATP synthase incorporated in Bacillus PS3 membranes at 59 degrees C. Fluorescence energy resonance transfer between fluorophores introduced in the C-terminus of subunit epsilon and in the N-terminus of subunit gamma was used to follow the conformational transition in real time. It was found that ATP induced the conformational transition from the extended to the contracted state (half-maximum transition extent at 140 microM ATP). ADP could neither prevent nor reverse the ATP-induced conformational change, but it did slow it down. Acid residues in the DELSEED region of subunit beta were found to stabilize the extended conformation of epsilon. Binding of ATP directly to epsilon was not essential for the ATP-induced conformational change. The ATP concentration necessary for the half-maximal transition (140 microM) suggests that subunit epsilon probably adopts the extended state and strongly inhibits ATP hydrolysis only when the intracellular ATP level drops significantly below the normal value.

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Section: Introductionmentioning

confidence: 85%

Conformational Transitions of Subunit ɛ in ATP Synthase from Thermophilic Bacillus PS3

Feniouk¹,

Kato-Yamada

Yoshida

et al. 2010

Biophysical Journal

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“…Except for the E83A and E83A/Q107C mutants, the ⑀ subunits were prepared as described previously (16,30). It was noticed that the use of a large sized butyl-TOYOPEARL column resulted in a reduced amount of bound ATP in the ⑀ subunit preparation, reaching Ͻ0.05 mol/mol (23). The E83A mutant ⑀ subunit was prepared as follows.…”

Section: Methodsmentioning

confidence: 99%

“…ATP may stabilize the folded conformation of the ⑀ subunit (22). ATP binding was also observed with the ⑀ subunit in the ␥⑀ subcomplex, indicating that ATP binding to the ⑀ subunit can occur in ATP synthase, in which it may play a regulatory role (23).…”

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confidence: 98%

Role of the ϵ Subunit of Thermophilic F1-ATPase as a Sensor for ATP

Kato

Yoshida

Kato-Yamada

2007

Journal of Biological Chemistry

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The ⑀ subunit of F 1 -ATPase from the thermophilic Bacillus PS3 (TF 1 ) has been shown to bind ATP. The precise nature of the regulatory role of ATP binding to the ⑀ subunit remains to be determined. To address this question, 11 mutants of the ⑀ subunit were prepared, in which one of the basic or acidic residues was substituted with alanine. ATP binding to these mutants was tested by gel-filtration chromatography. Among them, four mutants that showed no ATP binding were selected and reconstituted with the ␣ 3 ␤ 3 ␥ complex of TF 1 . The ATPase activity of the resulting ␣ 3 ␤ 3 ␥⑀ complexes was measured, and the extent of inhibition by the mutant ⑀ subunits was compared in each case. With one exception, weaker binding of ATP correlated with greater inhibition of ATPase activity. These results clearly indicate that ATP binding to the ⑀ subunit plays a regulatory role and that ATP binding may stabilize the ATPase-active form of TF 1 by fixing the ⑀ subunit into the folded conformation.F 0 F 1 -ATPase/synthase (F 0 F 1 ) catalyzes ATP synthesis via coupling of the proton flow driven by the electrochemical gradient of protons or sodium. F 0 F 1 consists of two rotary molecular motors: a water-soluble, ATP-driven F 1 motor and a membrane-embedded, H ϩ -or Na ϩ -driven F 0 motor. These molecular motors are connected together to couple ATP synthesis/hydrolysis and ion flow (1-4). The F 1 -ATPase (␣ 3 ␤ 3 ␦␥⑀) hydrolyzes ATP into ADP and inorganic phosphate, and the hydrolysis of one ATP drives the discrete 120°rotation of the ␥⑀ subunits relative to the other subunits (5, 6).As the smallest subunit of F 1 -ATPase, the ⑀ subunit acts as an endogenous inhibitor of the ATPase activity in both the bacterial and chloroplast F 1 -ATPase, where it is believed to play a regulatory role in ATP synthase (7-10). A recent single molecule study revealed its importance in efficient coupling in rotation and ATP synthesis (11). The ⑀ subunit consists of two distinct domains, an N-terminal ␤ sandwich domain and a C-terminal ␣ helical domain. Structural and biochemical studies have shown that the ⑀ subunit adopts at least two different conformations in F 1 and F 0 F 1 (10,(12)(13)(14)(15)(16)(17)(18)(19). The conformation that results in the inhibition of ATPase exists in an extended state, in which the C-terminal helical domain of the ⑀ subunit unfolds to run parallel to the ␥ subunit. The conformation in which ATPase is active is known as the folded state and is characterized by C-terminal ␣ helices folded into a hairpin configuration. The conformational change of the ⑀ subunit is controlled by the concentration of both ATP and ADP as well as the membrane potential (16 -19).The isolated ⑀ subunit of F 1 from the thermophilic Bacillus strain PS3 (TF 1 ) 2 was recently found to bind ATP (20). Binding was so specific that GTP and ADP failed to form a complex with the ⑀ subunit, as assayed by gel filtration. These results led to the suggestion that the ⑀ subunit is both a regulator and sensor of cellular ATP concentration. ATP binding was ...

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“…When ε-CTD interacts in its extended form with the DELSEED motif of the β-subunit, ATP hydrolysis is inhibited [54]. The conformational changes of the ε-subunit are influenced by the ATP/ADP ratio: bacterial ε-subunits can bind ATP [55][56][57] and in the presence of ATP and an increased pmf, the extended conformation of the ε-subunit is converted into the down-state conformation. Conversely, addition of ADP reverses this transition [58].…”

Section: Regulation Of F 1 F 0 -Atp Synthase Activitymentioning

confidence: 99%