scholarly journals An Algal Nucleus-encoded Subunit of Mitochondrial ATP Synthase Rescues a Defect in the Analogous Human Mitochondrial-encoded Subunit

2002 ◽  
Vol 13 (11) ◽  
pp. 3836-3844 ◽  
Author(s):  
Joseline Ojaimi ◽  
Junmin Pan ◽  
Sumana Santra ◽  
William J. Snell ◽  
Eric A. Schon
Keyword(s):  
Atp Synthase ◽  
Nuclear Gene ◽  
Mitochondrial Diseases ◽  
Atp Synthesis ◽  
Single Copy ◽  
Human Cells ◽  
Mitochondrial Targeting ◽  
Mitochondrial Atp Synthase ◽  
Targeting Signal ◽  
Atpase 6

Unlike most organisms, the mitochondrial DNA (mtDNA) ofChlamydomonas reinhardtii, a green alga, does not encode subunit 6 of F0F1-ATP synthase. We hypothesized that C. reinhardtii ATPase 6 is nucleus encoded and identified cDNAs and a single-copy nuclear gene specifying this subunit (CrATP6, with eight exons, four of which encode a mitochondrial targeting signal). Although the algal and humanATP6 genes are in different subcellular compartments and the encoded polypeptides are highly diverged, their secondary structures are remarkably similar. When CrATP6 was expressed in human cells, a significant amount of the precursor polypeptide was targeted to mitochondria, the mitochondrial targeting signal was cleaved within the organelle, and the mature polypeptide was assembled into human ATP synthase. In spite of the evolutionary distance between algae and mammals, C. reinhardtii ATPase 6 functioned in human cells, because deficiencies in both cell viability and ATP synthesis in transmitochondrial cell lines harboring a pathogenic mutation in the human mtDNA-encoded ATP6 gene were overcome by expression of CrATP6. The ability to express a nucleus-encoded version of a mammalian mtDNA-encoded protein may provide a way to import other highly hydrophobic proteins into mitochondria and could serve as the basis for a gene therapy approach to treat human mitochondrial diseases.

Rat mitochondrial ATP synthase ATP5G3: cloning and upregulation in pancreas after chronic ethanol feeding

2001 ◽  
Vol 6 (2) ◽  
pp. 91-98 ◽  
Author(s):  
HA-SHENG LI ◽  
JI-YING ZHANG ◽  
BRYAN S. THOMPSON ◽  
XIAO-YING DENG ◽  
MICHAEL E. FORD ◽  
...  
Keyword(s):  
Atp Synthase ◽  
Cellular Response ◽  
Molecular Mechanisms ◽  
Metabolic Stress ◽  
Nuclear Gene ◽  
Chronic Ethanol ◽  
Ethanol Ingestion ◽  
Pancreatic Acinar Cells ◽  
Mitochondrial Atp Synthase ◽  
Ethanol Feeding

Individuals with chronic excessive alcohol ingestion are put at the risk of acute and chronic pancreatitis. Underlying molecular mechanisms are unknown. Differential gene expression in the pancreas was profiled using mRNA differential display by comparison between control and ethanol-consuming rats. Male Wistar rats were fed with diets containing 6.7% (vol/vol) ethanol for 4 wk. A cDNA tag that was overexpressed in the pancreas of rats fed ethanol was isolated. A 723-bp cDNA was cloned from a rat pancreatic cDNA library, which encodes a novel rat mitochondrial ATP synthase subunit 9, isoform 3 (ATP5G3), which is homologous to a human ATP5G3 gene. Real-time PCR demonstrated that all three nuclear gene isoforms (ATP5G1, ATP5G2, and ATP5G3) were consistently upregulated in the pancreas of alcohol-consuming rats, parallel with mitochondrial injury. The cellular response to mitochondrial damage and metabolic stress may reflect an adaptive process for mitochondrial repair in pancreatic acinar cells during chronic ethanol ingestion.

scholarly journals Altered properties of mitochondrial ATP-synthase in patients with a T → G mutation in the ATPase 6 (subunit a) gene at position 8993 of mtDNA

1995 ◽  
Vol 1271 (2-3) ◽  
pp. 349-357 ◽  
Author(s):  
Josef Houštek ◽  
Petr Klement ◽  
Jana Hermanska ◽  
Hana Houšťková ◽  
Hana Hansíková ◽  
...  
Keyword(s):  
Atp Synthase ◽  
Subunit A ◽  
Mitochondrial Atp Synthase ◽  
Atpase 6

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.

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 Characterization of the expressed genes for subunit c of mitochondrial ATP synthase in sheep with ceroid lipofuscinosis

1993 ◽  
Vol 293 (1) ◽  
pp. 65-73 ◽  
Author(s):  
S M Medd ◽  
J E Walker ◽  
R D Jolly
Keyword(s):  
Atp Synthase ◽  
Mitochondrial Targeting ◽  
Mitochondrial Import ◽  
Fragment Analysis ◽  
Subunit C ◽  
Ceroid Lipofuscinosis ◽  
Mitochondrial Atp Synthase ◽  
C Subunit ◽  
Healthy Control

The human and bovine genomes each contain two expressed nuclear genes, called P1 and P2, for subunit c, a hydrophobic subunit of the membrane sector, Fo, of mitochondrial ATP synthase. Both P1 and P2 encode the same mature protein, but the associated mitochondrial import sequences are different. In sheep with the neurodegenerative disease ceroid lipofuscinosis, and also in humans with Batten's disease, unmodified subunit c accumulates in lysosome-derived organelles in a variety of tissues. However, the sequences of cDNAs for P1 and P2 from sheep with ceroid lipofuscinosis were identical to those in healthy control animals. Therefore, since there was no mutation in either of the mitochondrial import sequences of subunit c in the diseased animals, ceroid lipofuscinosis does not arise from changes in an import sequence causing mis-targeting of the c subunit to lysosomes. The levels of expression of P1 and P2 genes were approximately the same in diseased and healthy animals, and so the protein is unlikely to accumulate because of excessive transcription of either gene. Transcription of a spliced pseudogene related to P2 was detected in both a control animal and a sheep with ceroid lipofuscinosis. The transcripts encode amino acids 1-31 of the P2 mitochondrial targeting sequence. In the diseased animal, an arginine replaced a glutamine in the control sequence. However, restriction fragment analysis of genomic DNA from a further 12 sheep established that the sequence differences were not linked to ceroid lipofuscinosis.

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