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1.
Specific mgi mutations in the α, β or γ subunits of the mitochondrial F1-ATPase have previously been found to suppress ρ0 lethality in the petite-negative yeast Kluyveromyces lactis. To determine whether the suppressive activity of the altered F1 is dependent on the F0 sector of ATP synthase, we isolated and disrupted the genes KlATP4, 5 and 7, the three nuclear genes encoding subunits b, OSCP and d. Strains disrupted for any one, or all three of these genes are
respiration deficient and have reduced viability. However a strain devoid of the three nuclear genes is still unable to lose
mitochondrial DNA, whereas a mgi mutant with the three genes inactivated remains petite-positive. In the latter case, ρ0 mutants can be isolated, upon treatment with ethidium bromide, that lack six major F0 subunits, namely the nucleus-encoded subunits b, OSCP and d, and the mitochondrially encoded Atp6, 8 and 9p. Production of
ρ0 mutants indicates that an F1-complex carrying a mgi mutation can assemble in the absence of F0 subunits and that suppression of ρ0 lethality is an intrinsic property of the altered F1 particle.
Received: 7 April 1998 / Accepted: 10 June 1998 相似文献
2.
A homodimer of b subunits constitutes the peripheral stalk linking the F1 and F0 sectors of the Escherichia coli ATP synthase. Each b subunit has a single-membrane domain. The constraints on the membrane domain have been studied by systematic mutagenesis. Replacement of a segment proximal to the cytoplasmic side of the membrane had minimal impact on F1F0 ATP synthase. However, multiple substitutions on the periplasmic side resulted in defects in assembly of the enzyme complex. These mutants had insufficient oxidative phosphorylation to support growth, and biochemical studies showed little F1F0 ATPase and no detectable ATP-driven proton pumping activity. Expression of the b
N2A,T6A,Q10A
subunit was also oxidative phosphorylation deficient, but the b
N2A,T6A,Q10A
protein was incorporated into an F1F0 complex. Single amino acid substitutions had minimal reductions in F1F0 ATP synthase function. The evidence suggests that the b subunit membrane domain has several sites of interaction contributing to assembly of F0, and that these interactions are strongest on the periplasmic side of the bilayer. 相似文献
3.
In Escherichia coli, the F1FO ATP synthase b subunits house a conserved arginine in the tether domain at position 36 where the subunit emerges from the membrane. Previous
experiments showed that substitution of isoleucine or glutamate result in a loss of enzyme activity. Double mutants have been
constructed in an attempt to achieve an intragenic suppressor of the b
arg36→ile and the b
arg36→glu mutations. The b
arg36→ile mutation could not be suppressed. In contrast, the phenotypic defect resulting from the b
arg36→glu mutation was largely suppressed in the b
arg36→glu,glu39→arg double mutant. E. coli expressing the b
arg36→glu,glu39→arg subunit grew well on succinate-based medium. F1FO ATP synthase complexes were more efficiently assembled and ATP driven proton pumping activity was improved. The evidence
suggests that efficient coupling in F1FO ATP synthase is dependent upon a basic amino acid located at the base of the peripheral stalk. 相似文献
4.
Bisetto E Picotti P Giorgio V Alverdi V Mavelli I Lippe G 《Journal of bioenergetics and biomembranes》2008,40(4):257-267
The role of the integral inner membrane subunit e in self-association of F0F1ATP synthase from bovine heart mitochondria was analyzed by in situ limited proteolysis, blue native PAGE/iterative SDS-PAGE, and LC-MS/MS. Selective degradation of subunit e, without disrupting
membrane integrity or ATPase capacity, altered the oligomeric distribution of F0F1ATP synthase, by eliminating oligomers and reducing dimers in favor of monomers. The stoichiometry of subunit e was determined
by a quantitative MS-based proteomics approach, using synthetic isotope-labelled reference peptides IAQL*EEVK, VYGVGSL*ALYEK,
and ELAEAQEDTIL*K to quantify the b, γ and e subunits, respectively. Accuracy of the method was demonstrated by confirming
the 1:1 stoichiometry of subunits γ and b. Altogether, the results indicate that the integrity of a unique copy of subunit
e is essential for self-association of mammalian F0F1ATP synthase.
Elena Bisetto and Paola Picotti contributed equally to this work. 相似文献
5.
Bhatt D Cole SP Grabar TB Claggett SB Cain BD 《Journal of bioenergetics and biomembranes》2005,37(2):67-74
The peripheral stalk of F1F0 ATP synthase is composed of a parallel homodimer of b subunits that extends across the cytoplasmic membrane in F0 to the top of the F1 sector. The stalk serves as the stator necessary for holding F1 against movement of the rotor. A series of insertions and deletions have been engineered into the hydrophilic domain that interacts with F1. Only the hydrophobic segment from {val-121} to {ala-132} and the extreme carboxyl terminus proved to be highly sensitive to mutation. Deletions in either site apparently abolished enzyme function as a result of defects is assembly of the F1F0 complex. Other mutations manipulating the length of the sequence between these two areas had only limited effects on enzyme function. Expression of a b subunit with insertions with as few as two amino acids into the hydrophobic segment also resulted in loss of F1F0 ATP synthase. However, a fully defective b subunit with seven additional amino acids could be stabilized in a heterodimeric peripheral stalk within a functional F1F0 complex by a normal b subunit. 相似文献
6.
ATPases with unusual membrane-embedded rotor subunits were found in both F1F0 and A1A0 ATP synthases. The rotor subunit c of A1A0 ATPases is, in most cases, similar to subunit c from F0. Surprisingly, multiplied c subunits with four, six, or even 26 transmembrane spans have been found in some archaea and these multiplication events were
sometimes accompanied by loss of the ion-translocating group. Nevertheless, these enzymes are still active as ATP synthases.
A duplicated c subunit with only one ion-translocating group was found along with “normal” F0 c subunits in the Na+ F1F0 ATP synthase of the bacterium Acetobacterium woodii. These extraordinary features and exceptional structural and functional variability in the rotor of ATP synthases may have
arisen as an adaptation to different cellular needs and the extreme physicochemical conditions in the early history of life. 相似文献
7.
High-level expression of soluble subunit b of F1F0 ATP synthase in Escherichia coli cell-free system
Jiazhang Lian Yi Ma Jin Cai Ming Wu Jufang Wang Xiaoning Wang Zhinan Xu 《Applied microbiology and biotechnology》2009,85(2):303-311
The overexpression of subunit b of F1F0 adenosine triphosphate (ATP) synthase from Escherichia coli is so toxic that it even prevents the transformation of plasmids encoding this protein into E. coli BL21 (DE3). In the present work, E. coli cell-free system was chosen as an alternative to express this highly toxic membrane protein. This protein was either produced
as precipitates followed by detergent resolubilization or expressed as a soluble form with detergent addition. Among several
types of tested detergents, Brij 58 could effectively solubilize approximately 85% of the target membrane protein within a
wide range of concentration (48 to 178 times critical micelle concentration [CMC]) with little effect on the expression level.
With the presence of Brij 58 at the final concentration of 96 times CMC in the E. coli cell-free system, 789 μg/mL of soluble subunit b was achieved after 4 h biosynthesis, which is the highest level for the expression of membrane proteins in a batch-mode cell-free
expression system. The present work provides a rapid and efficient procedure of expressing one membrane protein with high
cytotoxicity in the cell-free system and will be helpful to further exploration of reconstituting F1F0 ATP synthase into liposome or polymer vesicle to design a nanoelectromechanical system device. 相似文献
8.
Tarek M. Zaida Tassilo Hornung Oleg A. Volkov Andrea D. Hoffman Susan J. Pandey John G. Wise Pia D. Vogel 《Journal of bioenergetics and biomembranes》2008,40(6):551-559
Conformational changes within the subunit b-dimer of the E. coli ATP synthase occur upon binding to the F1 sector. ESR spectra of spin-labeled b at room temperature indicated a pivotal point in the b-structure at residue 62. Spectra of frozen b ± F1 and calculated interspin distances suggested that where contact between b
2 and F1 occurs (above about residue 80), the structure of the dimer changes minimally. Between b-residues 33 and 64 inter-subunit distances in the F1-bound b-dimer were found to be too large to accommodate tightly coiled coil packing and therefore suggest a dissociation and disengagement
of the dimer upon F1-binding. Mechanistic implications of this “bubble” formation in the tether domain of ATP synthase b
2
are discussed.
This work was supported by grant from the National Science Foundation (MCB 0415713) to PDV 相似文献
9.
Richter ML Samra HS He F Giessel AJ Kuczera KK 《Journal of bioenergetics and biomembranes》2005,37(6):467-473
The chloroplast F0F1-ATP synthase-ATPase is a tiny rotary motor responsible for coupling ATP synthesis and hydrolysis to the light-driven electrochemical
proton gradient. Reversible oxidation/reduction of a dithiol, located within a special regulatory domain of the γ subunit
of the chloroplast F1 enzyme, switches the enzyme between an inactive and an active state. This regulatory mechanism is unique to the ATP synthases
of higher plants and its physiological significance lies in preventing nonproductive depletion of essential ATP pools in the
dark. The three-dimensional structure of the chloroplast F1 gamma subunit has not yet been solved. To examine the mechanism of dithiol regulation, a model of the chloroplast gamma subunit
was obtained through segmental homology modeling based on the known structures of the mitochondrial and bacterial γ subunits,
together with de novo construction of the unknown regulatory domain. The model has provided considerable insight into how the dithiol might modulate
catalytic function. This has, in turn, suggested a mechanism by which rotation of subunits in F0, the transmembrane proton channel portion of the enzyme, can be coupled, via the ε subunit, to rotation of the γ subunit
of F1 to achieve the 120° (or 90°+30°) stepping action that is characteristic of F1 γ subunit rotation. 相似文献
10.
Malyan AN 《Photosynthesis research》2006,88(1):9-18
A modified ‘cold chase’ technique was used to study tight [14C]ADP and [14C]ATP binding to noncatalytic sites of chloroplast ATP synthase (CF0F1). The binding was very low in the dark and sharply increased with light intensity. Dissociation of labeled nucleotides incorporated into noncatalytic sites of CF0F1 or CF1 reconstituted with EDTA-treated thylakoid membranes was also found to be light-dependent. Time dependence of nucleotide dissociation is described by the first order equation with a k
d of about 5 min−1. The exposure of thylakoid membranes to 0.7–24.8 μM nucleotides leads to filling of up to two noncatalytic sites of CF0F1. The sites differ in their specificity: one preferentially binds ADP, whereas the other – ATP. A much higher ATP/ADP ratio of nucleotides bound at noncatalytic sites of isolated CF1 dramatically decreases upon its reconstitution with EDTA-treated thylakoid membranes. It is suggested that the decrease is caused by conformational changes in one of the α subunits induced by its interaction with the δ subunit and/or subunit I–II when CF1 becomes bound to a thylakoid membrane. 相似文献
11.
F1FO ATP Synthase Is Expressed at the Surface of Embryonic Rat Heart‐Derived H9c2 Cells and Is Affected by Cardiac‐Like Differentiation
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Marina Comelli Rossana Domenis Alessia Buso Irene Mavelli 《Journal of cellular biochemistry》2016,117(2):470-482
Taking advantage from the peculiar features of the embryonic rat heart‐derived myoblast cell line H9c2, the present study is the first to provide evidence for the expression of F1FO ATP synthase and of ATPase Inhibitory Factor 1 (IF1) on the surface of cells of cardiac origin, together documenting that they were affected through cardiac‐like differentiation. Subunits of both the catalytic F1 sector of the complex (ATP synthase‐β) and of the peripheral stalk, responsible for the correct F1‐FO assembly/coupling, (OSCP, b, F6) were detected by immunofluorescence, together with IF1. The expression of ATP synthase‐β, ATP synthase‐b and F6 were similar for parental and differentiated H9c2, while the levels of OSCP increased noticeably in differentiated cells, where the results of in situ Proximity Ligation Assay were consistent with OSCP interaction within ecto‐F1FO complexes. An opposite trend was shown by IF1 whose ectopic expression appeared greater in the parental H9c2. Here, evidence for the IF1 interaction with ecto‐F1FO complexes was provided. Functional analyses corroborate both sets of data. i) An F1FO ATP synthase contribution to the exATP production by differentiated cells suggests an augmented expression of holo‐F1FO ATP synthase on plasma membrane, in line with the increase of OSCP expression and interaction considered as a requirement for favoring the F1‐FO coupling. ii) The absence of exATP generation by the enzyme, and the finding that exATP hydrolysis was largely oligomycin‐insensitive, are in line in parental cells with the deficit of OSCP and suggest the occurrence of sub‐assemblies together evoking more regulation by IF1. J. Cell. Biochem. 9999: 1–13, 2015. © 2015 Wiley Periodicals, Inc. J. Cell. Biochem. 117: 470–482, 2016. © 2015 Wiley Periodicals, Inc. 相似文献
12.
ATP synthases are motor complexes comprised of F0 and F1 parts that couple the proton gradient across the membrane to the synthesis of ATP by rotary catalysis. Although a great deal of information has been accumulated regarding the structure and function of ATP synthases, their motor functions are not fully understood. For this reason, we performed the alignments and analyses of the protein sequences comprising the core of the ATP synthase motor complex, and examined carefully the locations of the conserved residues in the subunit structures of ATP synthases. A summary of the findings from this bioinformatic study is as follows. First, we found that four conserved regions in the sequence of subunit are clustered into three patches in its structure. The interactions of these conserved patches with the and subunits are likely to be critical for energy coupling and catalytic activity of the ATP synthase. Second, we located a four-residue cluster at the N-terminal domain of mitochondrial OSCP or bacterial (or chloroplast) subunit which may be critical for the binding of these subunits to F1. Third, from the localizations of conserved residues in the subunits comprising the rotors of ATP synthases, we suggest that the conserved interaction site at the interface of subunit c and (mitochondria) or (bacteria and chloroplasts) may be important for connecting the rotor of F1 to the rotor of F0. Finally, we found the sequence of mitochondrial subunit b to be highly conserved, significantly longer than bacterial subunit b, and to contain a shorter dimerization domain than that of the bacterial protein. It is suggested that the different properties of mitochondrial subunit b may be necessary for interaction with other proteins, e.g., the supernumerary subunits. 相似文献
13.
Brian D. Cain 《Journal of bioenergetics and biomembranes》2000,32(4):365-371
The a and b subunits constitute the stator elements in the F0 sector of F1F0-ATP synthase.Both subunits have been difficult to study by physical means, so most of the information onstructure and function relationships in the a and b subunits has been obtained using mutagenesisin combination with biochemical methods. These approaches were used to demonstrate thatthe a subunit in association with the ring of c subunits houses the proton channel throughF1F0-ATP synthase. The map of the amino acids contributing to the proton channel is probablycomplete. The two b subunits dimerize, forming an extended flexible unit in the peripheralstalk linking the F1 and F0 sectors. The unique characteristics of specific amino acid substitutionsaffecting the a and b subunits suggested differential effects on rotation during F1F0-ATPaseactivity. 相似文献
14.
Although Saccharomyces cerevisiae can form petite mutants with deletions in mitochondrial DNA (mtDNA) (ρ−) and can survive complete loss of the organellar genome (ρo), the genetic factor(s) that permit(s) survival of ρ− and ρo mutants remain(s) unknown. In this report we show that a function associated with the F1-ATPase, which is distinct from its role in energy transduction, is required for the petite-positive phenotype of S. cerevisiae. Inactivation of either the α or β subunit, but not the γ, δ, or ɛ subunit of F1, renders cells petite-negative. The F1 complex, or a subcomplex composed of the α and β subunits only, is essential for survival of ρo cells and those impaired in electron transport. The activity of F1 that suppresses ρo lethality is independent of the membrane Fo complex, but is associated with an intrinsic ATPase activity. A further demonstration of the ability of F1 subunits to suppress ρo lethality has been achieved by simultaneous expression of S. cerevisiae F1α and γ subunit genes in Kluyveromyces lactis– which allows this petite-negative yeast to survive the loss of its mtDNA. Consequently, ATP1 and ATP2, in addition to the previously identified AAC2, YME1 and PEL1/PGS1 genes, are required for establishment of ρ− or ρo mutations in S. cerevisiae.
Received: 20 March 1999 / Accepted: 18 July 1999 相似文献
15.
Agarwal B 《Journal of bioenergetics and biomembranes》2011,43(3):299-310
ATP, the ‘universal biological energy currency’, is synthesized by utilizing energy either from oxidation of fuels or from
light, via the process of oxidative and photo-phosphorylation respectively. The process is mediated by the enzyme F1F0-ATP synthase, using the free energy of ion gradients in the final energy catalyzing step, i.e., the synthesis of ATP from
ADP and inorganic phosphate (Pi). The details of the molecular mechanism of ATP synthesis are among the most important fundamental issues in biology and
hence need to be properly understood. In this work, a role for anions in making ATP has been found. New experimental data
has been reported on the inhibition of ATP synthesis at nanomolar concentrations by the potent, specific anion channel blockers
4,4′-diisothiocyanostilbene-2, 2′-disulphonic acid (DIDS) and tributyltin chloride (TBTCl). Based on these inhibition studies,
attention has been drawn to anion translocation (in addition to proton translocation) as a requirement for ATP synthesis.
The type of inhibition has been quantified and an overall kinetic scheme for mixed inhibition that explains the data has been
evolved. The experimental data and the type of inhibition found have been interpreted in the light of the torsional mechanism
of energy transduction and ATP synthesis (Nath J Bioenerg Biomembr 42:293–300, 2010a; J Bioenerg Biomembr 42:301–309, 2010b). This detailed and unified mechanism resolves long-standing problems and inconsistencies in the first theories (Slater Nature
172:975–978, 1953; Williams J Theor Biol 1:1–17, 1961; Mitchell Nature 191:144–148, 1961; Mitchell Biol Rev 41:445–502, 1966), makes several novel predictions that are experimentally verifiable (Nath Biophys J 90:8–21, 2006a; Process Biochem 41:2218–2235, 2006b), and provides us with a new and fruitful paradigm in bioenergetics. The interpretation presented here provides intelligent
answers to the unexplained existing results in the literature. It is shown that mechanistic interpretation of the experimental
data requires substantial addition to available conceptual foundations such that present concepts, theories, and mechanisms
must be revised. 相似文献
16.
The F1-ATP synthase complex constitutes the catalytic component of F1F0-ATP synthase, the primary ATP synthetic enzyme in the cell. Previous studies indicate that the glacier ice worm, Mesenchytraeus solifugus, maintains unusually high ATP levels that continue to rise as temperatures decline, suggesting that molecular changes within
ice worm F1-ATP synthase subunits may contribute to this energetic anomaly. In this report, we compared ice worm F1-ATP synthase subunits (α, β, γ) with homologues across metazoan phyla (arthropod, chordate, nematode) and among a group of clitellate annelids (Enchytraeus albidus, Enchytraeus buchholzi, Lumbriculus variegatus, Theromyzon tessulatum). Amino acid alignments indicated that ice worm F1-ATP α and F1-ATP β subunits share strong sequence homology with their mesophilic counterparts, respectively, but that ATP γ has diverged more rapidly. Moreover, F1-ATP α and F1-ATP β displayed amino acid compositional changes consistent with trends observed in other cold adapted proteins, while F1-ATP γ diverged in unexpected directions (e.g., gains in size, charged residues). Several ice worm-specific amino acid substitutions
map to positions near the F1-ATP β catalytic site while others occur near subunit contact sites. 相似文献
17.
Mnatsakanyan N Bagramyan K Vassilian A Nakamoto RK Trchounian A 《Bioscience reports》2002,22(3-4):421-430
The single cysteine in the b subunit of the membranous F0 sector and the 19 cysteines in extramembranous F1 sector of the Escherichia coli ATP synthase were replaced by alanine. When cells were grown under anaerobic conditions on glucose, the k
cat for ATP hydrolysis of membrane vesicles containing the bCys21Ala mutant enzyme, but not enzymes with other cysteine replacements, was lower, while ATP-driven H+ pumping was unchanged. However, the ATP-dependent increase in the number of accessible thiol groups in membrane vesicles was negated. Furthermore, K+ uptake and molecular hydrogen production by whole cells and protoplasts was greatly decreased. These results indicate a role for the F0 subunit bCys21 in the functionality of F0F1 and coupling to other membranous activities under fermentative conditions. 相似文献
18.
Caroline E. Dewar Silke Oeljeklaus Christoph Wenger Bettina Warscheid Andr Schneider 《The Journal of biological chemistry》2022,298(4)
The mitochondrial F1Fo ATP synthase of the parasite Trypanosoma brucei has been previously studied in detail. This unusual enzyme switches direction in functionality during the life cycle of the parasite, acting as an ATP synthase in the insect stages, and as an ATPase to generate mitochondrial membrane potential in the mammalian bloodstream stages. Whereas the trypanosome F1 moiety is relatively highly conserved in structure and composition, the Fo subcomplex and the peripheral stalk have been shown to be more variable. Interestingly, a core subunit of the latter, the normally conserved subunit b, has been resistant to identification by sequence alignment or biochemical methods. Here, we identified a 17 kDa mitochondrial protein of the inner membrane, Tb927.8.3070, that is essential for normal growth, efficient oxidative phosphorylation, and membrane potential maintenance. Pull-down experiments and native PAGE analysis indicated that the protein is both associated with the F1Fo ATP synthase and integral to its assembly. In addition, its knockdown reduced the levels of Fo subunits, but not those of F1, and disturbed the cell cycle. Finally, analysis of structural homology using the HHpred algorithm showed that this protein has structural similarities to Fo subunit b of other species, indicating that this subunit may be a highly diverged form of the elusive subunit b. 相似文献
19.
Jörg-Christian Greie Gabriele Deckers-Hebestreit Karlheinz Altendorf 《Journal of bioenergetics and biomembranes》2000,32(4):357-364
Membrane-bound ATP synthases (F1F0) catalyze the synthesis of ATP via a rotary catalyticmechanism utilizing the energy of an electrochemical ion gradient. The transmembrane potentialis supposed to propel rotation of a subunit c ring of F0 together with subunits and of F1,hereby forming the rotor part of the enzyme, whereas the remainder of the F1F0 complexfunctions as a stator for compensation of the torque generated during rotation. This reviewfocuses on our recent work on the stator part of the F0 complex, e.g., subunits a and b. Usingepitope insertion and antibody binding, subunit a was shown to comprise six transmembranehelixes with both the N- and C-terminus oriented toward the cytoplasm. By use of circulardichroism (CD) spectroscopy, the secondary structure of subunit b incorporated intoproteoliposomes was determined to be 80% -helical together with 14% turn conformation, providingflexibility to the second stalk. Reconstituted subunit b together with isolated ac subcomplexwas shown to be active in proton translocation and functional F1 binding revealing the nativeconformation of the polypeptide chain. Chemical crosslinking in everted membrane vesiclesled to the formation of subunit b homodimers around residues bQ37 to bL65, whereas bA32Ccould be crosslinked to subunit a, indicating a close proximity of subunits a and b near themembrane. Further evidence for the proposed direct interaction between subunits a and b wasobtained by purification of a stable ab
2 subcomplex via affinity chromatography using Histags fused to subunit a or b. This ab
2 subcomplex was shown to be active in proton translocationand F1 binding, when coreconstituted with subunit c. Consequences of crosslink formationand subunit interaction within the F1F0 complex are discussed. 相似文献
20.
N,N-Dicyclohexylcarbodiimide (DCCD) is a classical inhibitor of the F0F1-ATP synthase (F0F1), which covalently binds to the highly conserved carboxylic acid of the proteolipid subunit (c subunit) in F0. Although it is well known that DCCD modification of the c subunit blocks proton translocation in F0 and the coupled ATP hydrolysis activity of F1, how DCCD inhibits the rotary dynamics of F0F1 remains elusive. Here, we carried out single-molecule rotation assays to characterize the DCCD inhibition of Escherichia coli F0F1. Upon the injection of DCCD, rotations irreversibly terminated with first order reaction kinetics, suggesting that the incorporation of a single DCCD moiety is sufficient to block the rotary catalysis of the F0F1. Individual molecules terminated at different angles relative to the three catalytic angles of F1, suggesting that DCCD randomly reacts with one of the 10 c subunits. DCCD-inhibited F0F1 sometimes showed transient activation; molecules abruptly rotated and stopped after one revolution at the original termination angle, suggesting that hindrance by the DCCD moiety is released due to thermal fluctuation. To explore the mechanical activation of DCCD-inhibited molecules, we perturbed inhibited molecules using magnetic tweezers. The probability of transient activation increased upon a forward forcible rotation. Interestingly, during the termination F0F1, showed multiple positional shifts, which implies that F1 stochastically changes the angular position of its rotor upon a catalytic reaction. This effect could be caused by balancing the angular positions of the F1 and the F0 rotors, which are connected via elastic elements. 相似文献