scholarly journals The pathogenic m.8993 T > G mutation in mitochondrial ATP6 gene prevents proton release from the subunit c-ring rotor of ATP synthase

2021 ◽  
Author(s):  
Xin Su ◽  
Alain Dautant ◽  
Malgorzata Rak ◽  
François Godard ◽  
Nahia Ezkurdia ◽  
...  
Keyword(s):  
Atp Synthase ◽  
Electrostatic Interactions ◽  
Neuromuscular Diseases ◽  
Atp Synthesis ◽  
Biochemical Properties ◽  
Gene Encoding ◽  
Subunit C ◽  
Subunit A ◽  
C Subunit ◽  
Respiratory Growth

Abstract The human ATP synthase is an assembly of 29 subunits of 18 different types, of which only two (a and 8) are encoded in the mitochondrial genome. Subunit a, together with an oligomeric ring of c-subunit (c-ring), forms the proton pathway responsible for the transport of protons through the mitochondrial inner membrane, coupled to rotation of the c-ring and ATP synthesis. Neuromuscular diseases have been associated to a number of mutations in the gene encoding subunit a, ATP6. The most common, m.8993 T > G, leads to replacement of a strictly conserved leucine residue with arginine (aL156R). We previously showed that the equivalent mutation (aL173R) dramatically compromises respiratory growth of Saccharomyces cerevisiae and causes a 90% drop in the rate of mitochondrial ATP synthesis. Here we isolated revertants from the aL173R strain that show improved respiratory growth. Four first-site reversions at codon 173 (aL173M, aL173S, aL173K, and aL173W) and five second-site reversions at another codon (aR169M, aR169S, aA170P, aA170G, and aI216S) were identified. Based on the atomic structures of yeast ATP synthase and the biochemical properties of the revertant strains, we propose that the aL173R mutation is responsible for unfavorable electrostatic interactions that prevent the release of protons from the c-ring into a channel from which protons move from the c-ring to the mitochondrial matrix. The results provide further evidence that yeast aL173 (and thus human aL156) optimizes the exit of protons from ATP synthase, but is not essential despite its strict evolutionnary conservation.

scholarly journals Crystallographic structure of the turbine C-ring from spinach chloroplast F-ATP synthase

2014 ◽  
Vol 34 (2) ◽  
Author(s):  
Asha Manikkoth Balakrishna ◽  
Holger Seelert ◽  
Sven-Hendric Marx ◽  
Norbert A. Dencher ◽  
Gerhard Grüber
Keyword(s):  
Atp Synthase ◽  
Ring Width ◽  
Atp Synthesis ◽  
Crystallographic Structure ◽  
Unit Cell Parameters ◽  
Subunit C ◽  
Cell Parameters ◽  
Ring Diameter ◽  
C Subunit

In eukaryotic and prokaryotic cells, F-ATP synthases provide energy through the synthesis of ATP. The chloroplast F-ATP synthase (CF1FO-ATP synthase) of plants is integrated into the thylakoid membrane via its FO-domain subunits a, b, b’ and c. Subunit c with a stoichiometry of 14 and subunit a form the gate for H+-pumping, enabling the coupling of electrochemical energy with ATP synthesis in the F1 sector. Here we report the crystallization and structure determination of the c14-ring of subunit c of the CF1FO-ATP synthase from spinach chloroplasts. The crystals belonged to space group C2, with unit-cell parameters a=144.420, b=99.295, c=123.51 Å, and β=104.34° and diffracted to 4.5 Å resolution. Each c-ring contains 14 monomers in the asymmetric unit. The length of the c-ring is 60.32 Å, with an outer ring diameter 52.30 Å and an inner ring width of 40 Å.

scholarly journals pH-dependent 11° F1FO ATP synthase sub-steps reveal insight into the FO torque generating mechanism

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Seiga Yanagisawa ◽  
Wayne D Frasch
Keyword(s):  
Atp Synthase ◽  
Single Molecule ◽  
Atp Hydrolysis ◽  
Proton Translocation ◽  
Atp Synthesis ◽  
Proton Pumping ◽  
Subunit A ◽  
Pka Values ◽  
C Subunit ◽  
Ph Dependent

Most cellular ATP is made by rotary F1FO ATP synthases using proton translocation-generated clockwise torque on the FO c-ring rotor, while F1-ATP hydrolysis can force counterclockwise rotation and proton pumping. The FO torque-generating mechanism remains elusive even though the FO interface of stator subunit-a, which contains the transmembrane proton half-channels, and the c-ring is known from recent F1FO structures. Here, single-molecule F1FO rotation studies determined that the pKa values of the half-channels differ, show that mutations of residues in these channels change the pKa values of both half-channels, and reveal the ability of FO to undergo single c-subunit rotational stepping. These experiments provide evidence to support the hypothesis that proton translocation through FO operates via a Grotthuss mechanism involving a column of single water molecules in each half-channel linked by proton translocation-dependent c-ring rotation. We also observed pH-dependent 11° ATP synthase-direction sub-steps of the E. coli c10-ring of F1FO against the torque of F1-ATPase-dependent rotation that result from H+ transfer events from FO subunit-a groups with a low pKa to one c-subunit in the c-ring, and from an adjacent c-subunit to stator groups with a high pKa. These results support a mechanism in which alternating proton translocation-dependent 11° and 25° synthase-direction rotational sub-steps of the c10-ring occur to sustain F1FO ATP synthesis.

scholarly journals ATP synthesis without R210 of subunit a in the Escherichia coli ATP synthase

2008 ◽  
Vol 1777 (1) ◽  
pp. 32-38 ◽  
Author(s):  
Robert R. Ishmukhametov ◽  
J. Blake Pond ◽  
Asma Al-Huqail ◽  
Mikhail A. Galkin ◽  
Steven B. Vik
Keyword(s):  
Escherichia Coli ◽  
Atp Synthase ◽  
Atp Synthesis ◽  
Subunit A

scholarly journals Molecular Basis of the Pathogenic Mechanism Induced by the m.9191T>C Mutation in Mitochondrial ATP6 Gene

2020 ◽  
Vol 21 (14) ◽  
pp. 5083 ◽  
Author(s):  
Xin Su ◽  
Alain Dautant ◽  
François Godard ◽  
Marine Bouhier ◽  
Teresa Zoladek ◽  
...  
Keyword(s):  
Atp Synthase ◽  
Atp Synthesis ◽  
Pathogenic Mutation ◽  
Loss Of Function ◽  
Subunit A ◽  
Mtdna Mutations ◽  
Leucine Residue ◽  
Atp6 Gene ◽  
Functional Consequences ◽  
Α Helix

Probing the pathogenicity and functional consequences of mitochondrial DNA (mtDNA) mutations from patient’s cells and tissues is difficult due to genetic heteroplasmy (co-existence of wild type and mutated mtDNA in cells), occurrence of numerous mtDNA polymorphisms, and absence of methods for genetically transforming human mitochondria. Owing to its good fermenting capacity that enables survival to loss-of-function mtDNA mutations, its amenability to mitochondrial genome manipulation, and lack of heteroplasmy, Saccharomyces cerevisiae is an excellent model for studying and resolving the molecular bases of human diseases linked to mtDNA in a controlled genetic background. Using this model, we previously showed that a pathogenic mutation in mitochondrial ATP6 gene (m.9191T>C), that converts a highly conserved leucine residue into proline in human ATP synthase subunit a (aL222P), severely compromises the assembly of yeast ATP synthase and reduces by 90% the rate of mitochondrial ATP synthesis. Herein, we report the isolation of intragenic suppressors of this mutation. In light of recently described high resolution structures of ATP synthase, the results indicate that the m.9191T>C mutation disrupts a four α-helix bundle in subunit a and that the leucine residue it targets indirectly optimizes proton conduction through the membrane domain of ATP synthase.

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.

scholarly journals Sequences of members of the human gene family for the c subunit of mitochondrial ATP synthase

1993 ◽  
Vol 293 (1) ◽  
pp. 51-64 ◽  
Author(s):  
M R Dyer ◽  
J E Walker
Keyword(s):  
Human Genome ◽  
Atp Synthase ◽  
Dna Sequences ◽  
Human Gene ◽  
Membrane Component ◽  
Subunit C ◽  
Coding Sequences ◽  
Mitochondrial Atp Synthase ◽  
C Subunit ◽  
Potential Promoter

Subunit c is an intrinsic membrane component of ATP synthase, and in mammals it is encoded by two expressed nuclear genes, P1 and P2. Both genes encode the same mature c subunit, but the mitochondrial import pre-sequences in the precursors of subunit c are different. The DNA sequences of the human P1 and P2 genes are described. They occupy about 3.0 and 10.9 kb respectively of the human genome, and both genes are split into five exons. The human genome also contains about 14 related spliced pseudogenes, and the sequence of one such pseudogene related to P2 is described. Sequences flanking the 5′ ends of the human P1 and P2 coding sequences each contain a CpG-rich island. Potential promoter elements (TATA and CCAAT boxes) are present in the 5′ sequences of the P1 gene, but not that of P2, although there is no direct experimental evidence to show the involvement of these sequences in transcription of the genes.

scholarly journals TBAJ-876 Retains Bedaquiline’s Activity against Subunits c and ε of Mycobacterium tuberculosis F-ATP Synthase

2019 ◽  
Vol 63 (10) ◽  
Author(s):  
Jickky Palmae Sarathy ◽  
Priya Ragunathan ◽  
Joon Shin ◽  
Christopher B. Cooper ◽  
Anna M. Upton ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Binding Site ◽  
Atp Synthase ◽  
Atp Synthesis ◽  
Antitubercular Activity ◽  
Drug Binding ◽  
Missense Mutations ◽  
Content Type ◽  
Qt Interval Prolongation ◽  
C Subunit

ABSTRACT The antituberculosis drug bedaquiline (BDQ) inhibits Mycobacterium tuberculosis F-ATP synthase by interfering with two subunits. Drug binding to the c subunit stalls the rotation of the c ring, while binding to the ε subunit blocks coupling of c ring rotation to ATP synthesis at the catalytic α3:β3 headpiece. BDQ is used for the treatment of drug-resistant tuberculosis. However, the drug is highly lipophilic, displays a long terminal half-life, and has a cardiotoxicity liability by causing QT interval prolongation. Recent medicinal chemistry campaigns have resulted in the discovery of 3,5-dialkoxypyridine analogues of BDQ that are less lipophilic, have higher clearance, and display lower cardiotoxic potential. TBAJ-876, which is a new developmental compound of this series, shows attractive antitubercular activity and efficacy in a murine tuberculosis model. Here, we asked whether TBAJ-876 and selected analogues of the compound retain BDQ’s mechanism of action. Biochemical assays showed that TBAJ-876 is a potent inhibitor of mycobacterial F-ATP synthase. Selection of spontaneous TBAJ-876-resistant mutants identified missense mutations at BDQ’s binding site on the c subunit, suggesting that TBAJ-876 retains BDQ’s targeting of the c ring. Susceptibility testing against a strain overexpressing the ε subunit and a strain harboring an engineered mutation in BDQ’s ε subunit binding site suggest that TBAJ-876 retains BDQ’s activity on the ε subunit. Nuclear magnetic resonance (NMR) titration studies confirmed that TBAJ-876 binds to the ε subunit at BDQ’s binding site. We show that TBAJ-876 retains BDQ’s antimycobacterial mode of action. The developmental compound inhibits the mycobacterial F-ATP synthase via a dual-subunit mechanism of interfering with the functions of both the enzyme’s c and ε subunits.

scholarly journals Rotating with the brakes on and other unresolved features of the vacuolar ATPase

2016 ◽  
Vol 44 (3) ◽  
pp. 851-855 ◽  
Author(s):  
Shaun Rawson ◽  
Michael A. Harrison ◽  
Stephen P. Muench
Keyword(s):  
Secondary Structure ◽  
Atp Synthase ◽  
Atp Synthesis ◽  
Vacuolar Atpase ◽  
Proton Gradient ◽  
Subunit A ◽  
Secondary Transport

The rotary ATPase family comprises the ATP synthase (F-ATPase), vacuolar ATPase (V-ATPase) and archaeal ATPase (A-ATPase). These either predominantly utilize a proton gradient for ATP synthesis or use ATP to produce a proton gradient, driving secondary transport and acidifying organelles. With advances in EM has come a significant increase in our understanding of the rotary ATPase family. Following the sub nm resolution reconstructions of both the F- and V-ATPases, the secondary structure organization of the elusive subunit a has now been resolved, revealing a novel helical arrangement. Despite these significant developments in our understanding of the rotary ATPases, there are still a number of unresolved questions about the mechanism, regulation and overall architecture, which this mini-review aims to highlight and discuss.

Structure and function of the F(o) complex of the ATP synthase from Escherichia coli

2000 ◽  
Vol 203 (1) ◽  
pp. 19-28
Author(s):  
K. Altendorf ◽  
W. Stalz ◽  
J. Greie ◽  
G. Deckers-Hebestreit
Keyword(s):  
Escherichia Coli ◽  
Monoclonal Antibodies ◽  
Atp Synthase ◽  
Proton Translocation ◽  
Water Soluble ◽  
Proton Channel ◽  
Enzyme Linked Immunosorbent Assay ◽  
Subunit C ◽  
Subunit A ◽  
Subunit B

The membrane-bound ATP synthase (F(1)F(o)) from mitochondria, chloroplasts and bacteria plays a crucial role in energy-transducing reactions. In the case of Escherichia coli, the reversible, proton-translocating ATPase complex consists of two different entities, F(1) and F(o). The water-soluble F(1) part carries the catalytic sites for ATP synthesis and hydrolysis. It is associated with the membrane-embedded F(o) complex, which functions as a proton channel and consists of subunits a, b and c present in a stoichiometry of 1:2:12.Subunit b was isolated by preparative gel electrophoresis, acetone-precipitated and renatured in a cholate-containing buffer. Reconstituted subunit b together with purified ac subcomplex is active in proton translocation and F(1) binding, thereby demonstrating that subunit b had recovered its native conformation. Circular dichroism spectroscopy of subunit b reconstituted into liposomes revealed a rather high degree of alpha -helical conformation of 80%. After addition of a His(6)-tag to the N terminus of subunit a, a stable ab(2) subcomplex was purified instead of a single subunit a, arguing in favour of a direct interaction between these subunits. After addition of subunit c and reconstitution into phospholipid vesicles, an F(o) complex was obtained exhibiting rates of proton translocation and F(1) binding comparable with those of wild-type F(o).The epitopes of monoclonal antibodies against subunit c are located in the hydrophilic loop region (cL31-Q42) as mapped by enzyme-linked immunosorbent assay using overlapping synthetic heptapeptides. Binding studies revealed that all monoclonal antibodies (mAbs) bind to everted membrane vesicles irrespective of the presence or absence of F(1). Although the hydrophilic region of subunit c, and especially the highly conserved residues cA40, cR41, cQ42 and cP43, are known to interact with subunits gamma and epsilon of the F(1) part, the mAb molecules have no effect on the function of F(o), either in proton translocation or in F(1) binding. However, the F(1) part and the mAb molecule(s) are bound simultaneously to the F(o) complex, suggesting that not all c subunits are involved in the interaction with F(1).

scholarly journals Persistence of the mitochondrial permeability transition in the absence of subunit c of human ATP synthase

2017 ◽  
Vol 114 (13) ◽  
pp. 3409-3414 ◽  
Author(s):  
Jiuya He ◽  
Holly C. Ford ◽  
Joe Carroll ◽  
Shujing Ding ◽  
Ian M. Fearnley ◽  
...  
Keyword(s):  
Atp Synthase ◽  
Mitochondrial Permeability Transition ◽  
Proton Translocation ◽  
Atp Synthesis ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Mitochondrial Targeting ◽  
Inner Membrane ◽  
C Subunit ◽  
Mitochondrial Targeting Sequences

The permeability transition in human mitochondria refers to the opening of a nonspecific channel, known as the permeability transition pore (PTP), in the inner membrane. Opening can be triggered by calcium ions, leading to swelling of the organelle, disruption of the inner membrane, and ATP synthesis, followed by cell death. Recent proposals suggest that the pore is associated with the ATP synthase complex and specifically with the ring of c-subunits that constitute the membrane domain of the enzyme’s rotor. The c-subunit is produced from three nuclear genes, ATP5G1, ATP5G2, and ATP5G3, encoding identical copies of the mature protein with different mitochondrial-targeting sequences that are removed during their import into the organelle. To investigate the involvement of the c-subunit in the PTP, we generated a clonal cell, HAP1-A12, from near-haploid human cells, in which ATP5G1, ATP5G2, and ATP5G3 were disrupted. The HAP1-A12 cells are incapable of producing the c-subunit, but they preserve the characteristic properties of the PTP. Therefore, the c-subunit does not provide the PTP. The mitochondria in HAP1-A12 cells assemble a vestigial ATP synthase, with intact F1-catalytic and peripheral stalk domains and the supernumerary subunits e, f, and g, but lacking membrane subunits ATP6 and ATP8. The same vestigial complex plus associated c-subunits was characterized from human 143B ρ0 cells, which cannot make the subunits ATP6 and ATP8, but retain the PTP. Therefore, none of the membrane subunits of the ATP synthase that are involved directly in transmembrane proton translocation is involved in forming the PTP.

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