scholarly journals A critical appraisal of evidence for localized energy coupling. Kinetic studies on liposomes containing bacteriorhodopsin and ATP synthase

1985 ◽  
Vol 230 (2) ◽  
pp. 543-549 ◽  
Author(s):  
R L Van der Bend ◽  
J Petersen ◽  
J A Berden ◽  
K Van Dam ◽  
H V Westerhoff
Keyword(s):  
Electron Transfer ◽  
Atp Synthase ◽  
Critical Appraisal ◽  
Atp Synthesis ◽  
Kinetic Studies ◽  
Energy Coupling ◽  
Proton Pumps ◽  
Specific Interactions ◽  
Mitochondrial Atp Synthase ◽  
Different Levels

In intact systems (chloroplasts, mitochondria and bacteria) many experiments have been reported which are indicative of localized coupling between ATP synthase and electron transfer complexes. We have carried out similar experiments with a system in which we may assume that specific interactions between the proton pumps are absent: reconstituted vesicles containing bacteriorhodopsin and yeast mitochondrial ATP synthase. The only experiment that gives results which differ from those previously published for intact systems concerns the effect of uncouplers on the rate of ATP synthesis at different levels of inhibition of the ATP synthase. We propose that this type of experiment may discriminate between localized and delocalized coupling.

Molecular Features of Energy Coupling in the F0F1 ATP Synthase

Physiology ◽  
1999 ◽  
Vol 14 (1) ◽  
pp. 40-46
Author(s):  
Robert K. Nakamoto
Keyword(s):  
Atp Synthase ◽  
Catalytic Domain ◽  
Atp Synthesis ◽  
Energy Coupling ◽  
F0f1 Atp Synthase ◽  
Molecular Features ◽  
Rotary Mechanism ◽  
Transport Domain

H+ translocation is coupled to ATP synthesis in the F0F1 ATP synthase via a rotary mechanism. Catalytic turnover, site-site cooperativity, and H+ transport obligatorily involve rotation of a set of subunits. The transport domain in the membranous F0 and the catalytic domain in the F1 are mechanisms designed for generating torque.

scholarly journals Reversible Thiol Oxidation Inhibits the Mitochondrial ATP Synthase in Xenopus laevis Oocytes

Antioxidants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 215 ◽  
Author(s):  
James Cobley ◽  
Anna Noble ◽  
Rachel Bessell ◽  
Matthew Guille ◽  
Holger Husi
Keyword(s):  
Xenopus Laevis ◽  
Atp Synthase ◽  
Xenopus Laevis Oocytes ◽  
Proton Pumps ◽  
Thiol Oxidation ◽  
Protein Thiol ◽  
Complex Iv ◽  
Subunit C ◽  
Catalyst Free ◽  
Mitochondrial Atp Synthase

Oocytes are postulated to repress the proton pumps (e.g., complex IV) and ATP synthase to safeguard mitochondrial DNA homoplasmy by curtailing superoxide production. Whether the ATP synthase is inhibited is, however, unknown. Here we show that: oligomycin sensitive ATP synthase activity is significantly greater (~170 vs. 20 nmol/min−1/mg−1) in testes compared to oocytes in Xenopus laevis (X. laevis). Since ATP synthase activity is redox regulated, we explored a regulatory role for reversible thiol oxidation. If a protein thiol inhibits the ATP synthase, then constituent subunits must be reversibly oxidised. Catalyst-free trans-cyclooctene 6-methyltetrazine (TCO-Tz) immunocapture coupled to redox affinity blotting reveals several subunits in F1 (e.g., ATP-α-F1) and Fo (e.g., subunit c) are reversibly oxidised. Catalyst-free TCO-Tz Click PEGylation reveals significant (~60%) reversible ATP-α-F1 oxidation at two evolutionary conserved cysteine residues (C244 and C294) in oocytes. TCO-Tz Click PEGylation reveals ~20% of the total thiols in the ATP synthase are substantially oxidised. Chemically reversing thiol oxidation significantly increased oligomycin sensitive ATP synthase activity from ~12 to 100 nmol/min−1/mg−1 in oocytes. We conclude that reversible thiol oxidation inhibits the mitochondrial ATP synthase in X. laevis oocytes.

scholarly journals Feedback limitation of photosynthesis at high CO2 acts by modulating the activity of the chloroplast ATP synthase

2009 ◽  
Vol 36 (11) ◽  
pp. 893 ◽  
Author(s):  
Olavi Kiirats ◽  
Jeffrey A. Cruz ◽  
Gerald E. Edwards ◽  
David M. Kramer
Keyword(s):  
Electron Transfer ◽  
Atp Synthase ◽  
Atp Synthesis ◽  
Nicotiana Sylvestris ◽  
O2 Evolution ◽  
High Co2 ◽  
Chloroplast Atp Synthase ◽  
Low Co2 ◽  
Photosynthetic Electron Transfer

It was previously shown that photosynthetic electron transfer is controlled under low CO2 via regulation of the chloroplast ATP synthase. In the current work, we studied the regulation of photosynthesis under feedback limiting conditions, where photosynthesis is limited by the capacity to utilise triose-phosphate for synthesis of end products (starch or sucrose), in a starch-deficient mutant of Nicotiana sylvestris Speg. & Comes. At high CO2, we observed feedback control that was progressively reversed by increasing O2 levels from 2 to 40%. The activity of the ATP synthase, probed in vivo by the dark-interval relaxation kinetics of the electrochromic shift, was proportional to the O2-induced increases in O2 evolution from PSII (JO2), as well as the sum of Rubisco oxygenation (vo) and carboxylation (vc) rates. The altered ATP synthase activity led to changes in the light-driven proton motive force, resulting in regulation of the rate of plastoquinol oxidation at the cytochrome b6f complex, quantitatively accounting for the observed control of photosynthetic electron transfer. The ATP content of the cell decreases under feedback limitation, suggesting that the ATP synthesis was downregulated to a larger extent than ATP consumption. This likely resulted in slowing of ribulose bisphosphate regeneration and JO2). Overall, our results indicate that, just as at low CO2, feedback limitations control the light reactions of photosynthesis via regulation of the ATP synthase, and can be reconciled with regulation via stromal Pi, or an unknown allosteric affector.

Phosphate exchange and ATP synthesis by DMSO-pretreated purified bovine mitochondrial ATP synthase

2001 ◽  
Vol 353 (2) ◽  
pp. 215-222
Author(s):  
Seelochan BEHARRY ◽  
Philip D. BRAGG
Keyword(s):  
Exchange Reaction ◽  
Atp Synthase ◽  
Atp Synthesis ◽  
Catalytic Site ◽  
Phosphate Removal ◽  
Subsequent Removal ◽  
F1fo Atp Synthase ◽  
Mitochondrial Atp Synthase ◽  
Phosphate Exchange

Purified soluble bovine mitochondrial F1Fo-ATP synthase contained 2mol of ATP, 2mol of ADP and 6mol of Pi/mol. Incubation of this enzyme with 1mM [32P]Pi caused the exchange of 2mol of Pi/mol of F1Fo-ATP synthase. The labelled phosphates were not displaced by ATP. Transfer of F1Fo-ATP synthase to a buffer containing 30% (v/v) DMSO and 1mM [32P]Pi resulted in the loss of bound nucleotides with the retention of 1mol of ATP/mol of F1Fo-ATP synthase. Six molecules of [32P]Pi were incorporated by exchange with the existing bound phosphate. Removal of the DMSO by passage of the enzyme through a centrifuged column of Sephadex G-50 resulted in the exchange of one molecule of bound [32P]Pi into the bound ATP. Azide did not prevent this [32P]Pi ↔ ATP exchange reaction. The bound labelled ATP could be displaced from the enzyme by exogenous ATP. Addition of ADP to the DMSO-pretreated F1Fo-ATP synthase in the original DMSO-free buffer resulted in the formation of an additional molecule of bound ATP. It was concluded that following pretreatment with and subsequent removal of DMSO the F1Fo-ATP synthase contained one molecule of ATP at a catalytic site which was competent to carry out a phosphateŐATP exchange reaction using enzyme-bound inorganic radiolabelled phosphate. In the presence of ADP an additional molecule of labelled ATP was formed from enzyme-bound Pi at a second catalytic site. The bound phosphateŐATP exchange reaction is not readily accommodated by current mechanisms for the ATP synthase.

scholarly journals Rotary substates of mitochondrial ATP synthase reveal the basis of flexible F1-Fo coupling

2019 ◽  
Author(s):  
Bonnie J. Murphy ◽  
Niklas Klusch ◽  
Julian D. Langer ◽  
Deryck J. Mills ◽  
Özkan Yildiz ◽  
...  
Keyword(s):  
Atp Synthase ◽  
Metal Ion ◽  
De Novo ◽  
Atp Synthesis ◽  
Joint Movement ◽  
Access Channel ◽  
Subunit Interface ◽  
Ring Rotation ◽  
Mitochondrial Atp Synthase ◽  
Ordered Water

F1Fo-ATP synthases play a central role in cellular metabolism, making the energy of the proton-motive force across a membrane available for a large number of energy-consuming processes. We determined the single-particle cryo-EM structure of active dimeric ATP synthase from mitochondria of Polytomella sp. at 2.7- 2.8 Å resolution. Separation of 13 well-defined rotary substates by 3D classification provides a detailed picture of the molecular motions that accompany c-ring rotation and result in ATP synthesis. Crucially, the F1 head rotates along with the central stalk and c-ring rotor for the first ~30° of each 120° primary rotary step. The joint movement facilitates flexible coupling of the stoichiometrically mismatched F1 and Fo subcomplexes. Flexibility is mediated primarily by the interdomain hinge of the conserved OSCP subunit, a well-established target of physiologically important inhibitors. Our maps provide atomic detail of the c-ring/a-subunit interface in the membrane, where protonation and deprotonation of c-ring cGlu111 drives rotary catalysis. An essential histidine residue in the lumenal proton access channel binds a strong non-peptide density assigned to a metal ion that may facilitate c-ring protonation, as its coordination geometry changes with c-ring rotation. We resolve ordered water molecules in the proton access and release channels and at the gating aArg239 that is critical in all rotary ATPases. We identify the previously unknown ASA10 subunit and present complete de novo atomic models of subunits ASA1-10, which make up the two interlinked peripheral stalks that stabilize the Polytomella ATP synthase dimer.

scholarly journals Rotary substates of mitochondrial ATP synthase reveal the basis of flexible F1-Focoupling

Science ◽  
2019 ◽  
Vol 364 (6446) ◽  
pp. eaaw9128 ◽  
Author(s):  
Bonnie J. Murphy ◽  
Niklas Klusch ◽  
Julian Langer ◽  
Deryck J. Mills ◽  
Özkan Yildiz ◽  
...  
Keyword(s):  
Atp Synthase ◽  
Metal Ion ◽  
Three Dimensional ◽  
Atp Synthesis ◽  
Access Channel ◽  
Dimensional Classification ◽  
Ring Rotation ◽  
Mitochondrial Atp Synthase ◽  
Central Stalk ◽  
Energy Consuming

F1Fo–adenosine triphosphate (ATP) synthases make the energy of the proton-motive force available for energy-consuming processes in the cell. We determined the single-particle cryo–electron microscopy structure of active dimeric ATP synthase from mitochondria ofPolytomellasp. at a resolution of 2.7 to 2.8 angstroms. Separation of 13 well-defined rotary substates by three-dimensional classification provides a detailed picture of the molecular motions that accompanyc-ring rotation and result in ATP synthesis. Crucially, the F1head rotates along with the central stalk andc-ring rotor for the first ~30° of each 120° primary rotary step to facilitate flexible coupling of the stoichiometrically mismatched F1and Fosubcomplexes. Flexibility is mediated primarily by the interdomain hinge of the conserved OSCP subunit. A conserved metal ion in the proton access channel may synchronizec-ring protonation with rotation.

scholarly journals Structure and conformational states of the bovine mitochondrial ATP synthase by cryo-EM

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Anna Zhou ◽  
Alexis Rohou ◽  
Daniel G Schep ◽  
John V Bason ◽  
Martin G Montgomery ◽  
...  
Keyword(s):  
Atp Synthase ◽  
Catalytic Mechanism ◽  
Proton Translocation ◽  
Atp Synthesis ◽  
Bioinformatic Analysis ◽  
Mitochondrial Atp Synthase ◽  
A Subunit ◽  
Classification Of Images ◽  
Atp Synthases

Adenosine triphosphate (ATP), the chemical energy currency of biology, is synthesized in eukaryotic cells primarily by the mitochondrial ATP synthase. ATP synthases operate by a rotary catalytic mechanism where proton translocation through the membrane-inserted FO region is coupled to ATP synthesis in the catalytic F1 region via rotation of a central rotor subcomplex. We report here single particle electron cryomicroscopy (cryo-EM) analysis of the bovine mitochondrial ATP synthase. Combining cryo-EM data with bioinformatic analysis allowed us to determine the fold of the a subunit, suggesting a proton translocation path through the FO region that involves both the a and b subunits. 3D classification of images revealed seven distinct states of the enzyme that show different modes of bending and twisting in the intact ATP synthase. Rotational fluctuations of the c8-ring within the FO region support a Brownian ratchet mechanism for proton-translocation-driven rotation in ATP synthases.

scholarly journals IF1, a natural inhibitor of mitochondrial ATP synthase, is not essential for the normal growth and breeding of mice

2013 ◽  
Vol 33 (5) ◽  
Author(s):  
Junji Nakamura ◽  
Makoto Fujikawa ◽  
Masasuke Yoshida
Keyword(s):  
Atp Synthase ◽  
Mouse Strain ◽  
Reactive Oxygen Species Generation ◽  
Atp Synthesis ◽  
Normal Growth ◽  
Test Results ◽  
Mitochondrial Atp Synthase ◽  
Evolutionarily Conserved ◽  
Natural Inhibitor ◽  
Synthesis Activity

IF1 is an endogenous inhibitor protein of mitochondrial ATP synthase. It is evolutionarily conserved throughout all eukaryotes and it has been proposed to play crucial roles in prevention of the wasteful reverse reaction of ATP synthase, in the metabolic shift from oxidative phosphorylation to glycolysis, in the suppression of ROS (reactive oxygen species) generation, in mitochondria morphology and in haem biosynthesis in mitochondria, which leads to anaemia. Here, we report the phenotype of a mouse strain in which IF1 gene was destroyed. Unexpectedly, individuals of this IF1-KO (knockout) mouse strain grew and bred without defect. The general behaviours, blood test results and responses to starvation of the IF1-KO mice were apparently normal. There were no abnormalities in the tissue anatomy or the autophagy. Mitochondria of the IF1-KO mice were normal in morphology, in the content of ATP synthase molecules and in ATP synthesis activity. Thus, IF1 is not an essential protein for mice despite its ubiquitous presence in eukaryotes.

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