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ATP synthase

ATP synthase is an enzyme that catalyzes the formation of the energy storage molecule adenosine triphosphate (ATP) using adenosine diphosphate (ADP) and inorganic phosphate (Pi). ATP synthase is a molecular machine. The overall reaction catalyzed by ATP synthase is:

  • ADP + Pi + 2H+out ⇌ ATP + H2O + 2H+in
ATP Synthase
Molecular model of ATP synthase determined by X-ray crystallography. Stator is not shown here.
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EC no.7.1.2.2
CAS no.9000-83-3
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ATP synthase lies across a cellular membrane and forms an aperture that protons can cross from areas of high concentration to areas of low concentration, imparting energy for the synthesis of ATP. This electrochemical gradient is generated by the electron transport chain and allows cells to store energy in ATP for later use. In prokaryotic cells ATP synthase lies across the plasma membrane, while in eukaryotic cells it lies across the inner mitochondrial membrane. Organisms capable of photosynthesis also have ATP synthase across the thylakoid membrane, which in plants is located in the chloroplast and in cyanobacteria is located in the cytoplasm.

Eukaryotic ATP synthases are F-ATPases, running "in reverse" for an ATPase. This article deals mainly with this type. An F-ATPase consists of two main subunits, FO and F1, which has a rotational motor mechanism allowing for ATP production.[1][2]

Nomenclature edit

The F1 fraction derives its name from the term "Fraction 1" and FO (written as a subscript letter "o", not "zero") derives its name from being the binding fraction for oligomycin, a type of naturally derived antibiotic that is able to inhibit the FO unit of ATP synthase.[3][4] These functional regions consist of different protein subunits — refer to tables. This enzyme is used in synthesis of ATP through aerobic respiration.

Structure and function edit

 
Bovine mitochondrial ATP synthase. The FO, F1, axle, and stator regions are color coded magenta, green, orange, and cyan respectively i.e. FO, F1, axle, stator.[5][6]
 
Simplified model of FOF1-ATPase alias ATP synthase of E. coli. Subunits of the enzyme are labeled accordingly.
 
Rotation engine of ATP synthase.

Located within the thylakoid membrane and the inner mitochondrial membrane, ATP synthase consists of two regions FO and F1. FO causes rotation of F1 and is made of c-ring and subunits a, two b, F6. F1 is made of α, β, γ, and δ subunits. F1 has a water-soluble part that can hydrolyze ATP. FO on the other hand has mainly hydrophobic regions. FO F1 creates a pathway for protons movement across the membrane.[7]

F1 region edit

The F1 portion of ATP synthase is hydrophilic and responsible for hydrolyzing ATP. The F1 unit protrudes into the mitochondrial matrix space. Subunits α and β make a hexamer with 6 binding sites. Three of them are catalytically inactive and they bind ADP.

Three other subunits catalyze the ATP synthesis. The other F1 subunits γ, δ, and ε are a part of a rotational motor mechanism (rotor/axle). The γ subunit allows β to go through conformational changes (i.e., closed, half open, and open states) that allow for ATP to be bound and released once synthesized. The F1 particle is large and can be seen in the transmission electron microscope by negative staining.[8] These are particles of 9 nm diameter that pepper the inner mitochondrial membrane.

F1 – Subunits[9]
Subunit Human Gene Note
alpha ATP5A1, ATPAF2
beta ATP5B, ATPAF1
gamma ATP5C1
delta ATP5D Mitochondrial "delta" is bacterial/chloroplastic epsilon.
epsilon ATP5E Unique to mitochondria.
OSCP ATP5O Called "delta" in bacterial and chloroplastic versions.

FO region edit

 
FO subunit F6 from the peripheral stalk region of ATP synthase.[10]

FO is a water insoluble protein with eight subunits and a transmembrane ring. The ring has a tetrameric shape with a helix-loop-helix protein that goes through conformational changes when protonated and deprotonated, pushing neighboring subunits to rotate, causing the spinning of FO which then also affects conformation of F1, resulting in switching of states of alpha and beta subunits. The FO region of ATP synthase is a proton pore that is embedded in the mitochondrial membrane. It consists of three main subunits, a, b, and c. Six c subunits make up the rotor ring, and subunit b makes up a stalk connecting to F1 OSCP that prevents the αβ hexamer from rotating. Subunit a connects b to the c ring.[11] Humans have six additional subunits, d, e, f, g, F6, and 8 (or A6L). This part of the enzyme is located in the mitochondrial inner membrane and couples proton translocation to the rotation that causes ATP synthesis in the F1 region.

In eukaryotes, mitochondrial FO forms membrane-bending dimers. These dimers self-arrange into long rows at the end of the cristae, possibly the first step of cristae formation.[12] An atomic model for the dimeric yeast FO region was determined by cryo-EM at an overall resolution of 3.6 Å.[13]

FO-Main subunits
Subunit Human Gene
a MT-ATP6
b ATP5F1
c ATP5G1, ATP5G2, ATP5G3

Binding model edit

 
Mechanism of ATP synthase. ADP and Pi (pink) shown being combined into ATP (red), while the rotating γ (gamma) subunit in black causes conformational change.
 
Depiction of ATP synthase using the chemiosmotic proton gradient to power ATP synthesis through oxidative phosphorylation.

In the 1960s through the 1970s, Paul Boyer, a UCLA Professor, developed the binding change, or flip-flop, mechanism theory, which postulated that ATP synthesis is dependent on a conformational change in ATP synthase generated by rotation of the gamma subunit. The research group of John E. Walker, then at the MRC Laboratory of Molecular Biology in Cambridge, crystallized the F1 catalytic-domain of ATP synthase. The structure, at the time the largest asymmetric protein structure known, indicated that Boyer's rotary-catalysis model was, in essence, correct. For elucidating this, Boyer and Walker shared half of the 1997 Nobel Prize in Chemistry.

The crystal structure of the F1 showed alternating alpha and beta subunits (3 of each), arranged like segments of an orange around a rotating asymmetrical gamma subunit. According to the current model of ATP synthesis (known as the alternating catalytic model), the transmembrane potential created by (H+) proton cations supplied by the electron transport chain, drives the (H+) proton cations from the intermembrane space through the membrane via the FO region of ATP synthase. A portion of the FO (the ring of c-subunits) rotates as the protons pass through the membrane. The c-ring is tightly attached to the asymmetric central stalk (consisting primarily of the gamma subunit), causing it to rotate within the alpha3beta3 of F1 causing the 3 catalytic nucleotide binding sites to go through a series of conformational changes that lead to ATP synthesis. The major F1 subunits are prevented from rotating in sympathy with the central stalk rotor by a peripheral stalk that joins the alpha3beta3 to the non-rotating portion of FO. The structure of the intact ATP synthase is currently known at low-resolution from electron cryo-microscopy (cryo-EM) studies of the complex. The cryo-EM model of ATP synthase suggests that the peripheral stalk is a flexible structure that wraps around the complex as it joins F1 to FO. Under the right conditions, the enzyme reaction can also be carried out in reverse, with ATP hydrolysis driving proton pumping across the membrane.

The binding change mechanism involves the active site of a β subunit's cycling between three states.[14] In the "loose" state, ADP and phosphate enter the active site; in the adjacent diagram, this is shown in pink. The enzyme then undergoes a change in shape and forces these molecules together, with the active site in the resulting "tight" state (shown in red) binding the newly produced ATP molecule with very high affinity. Finally, the active site cycles back to the open state (orange), releasing ATP and binding more ADP and phosphate, ready for the next cycle of ATP production.[15]

Physiological role edit

Like other enzymes, the activity of F1FO ATP synthase is reversible. Large-enough quantities of ATP cause it to create a transmembrane proton gradient, this is used by fermenting bacteria that do not have an electron transport chain, but rather hydrolyze ATP to make a proton gradient, which they use to drive flagella and the transport of nutrients into the cell.

In respiring bacteria under physiological conditions, ATP synthase, in general, runs in the opposite direction, creating ATP while using the proton motive force created by the electron transport chain as a source of energy. The overall process of creating energy in this fashion is termed oxidative phosphorylation. The same process takes place in the mitochondria, where ATP synthase is located in the inner mitochondrial membrane and the F1-part projects into the mitochondrial matrix. By pumping proton cations into the matrix, the ATP-synthase converts ADP into ATP.

Evolution edit

The evolution of ATP synthase is thought to have been modular whereby two functionally independent subunits became associated and gained new functionality.[16][17] This association appears to have occurred early in evolutionary history, because essentially the same structure and activity of ATP synthase enzymes are present in all kingdoms of life.[16] The F-ATP synthase displays high functional and mechanistic similarity to the V-ATPase.[18] However, whereas the F-ATP synthase generates ATP by utilising a proton gradient, the V-ATPase generates a proton gradient at the expense of ATP, generating pH values of as low as 1.[19]

The F1 region also shows significant similarity to hexameric DNA helicases (especially the Rho factor), and the entire enzyme region shows some similarity to H+
-powered T3SS or flagellar motor complexes.[18][20][21] The α3β3 hexamer of the F1 region shows significant structural similarity to hexameric DNA helicases; both form a ring with 3-fold rotational symmetry with a central pore. Both have roles dependent on the relative rotation of a macromolecule within the pore; the DNA helicases use the helical shape of DNA to drive their motion along the DNA molecule and to detect supercoiling, whereas the α3β3 hexamer uses the conformational changes through the rotation of the γ subunit to drive an enzymatic reaction.[22]

The H+
motor of the FO particle shows great functional similarity to the H+
motors that drive flagella.[18] Both feature a ring of many small alpha-helical proteins that rotate relative to nearby stationary proteins, using a H+
potential gradient as an energy source. This link is tenuous, however, as the overall structure of flagellar motors is far more complex than that of the FO particle and the ring with about 30 rotating proteins is far larger than the 10, 11, or 14 helical proteins in the FO complex. More recent structural data do however show that the ring and the stalk are structurally similar to the F1 particle.[21]

Conformation changes of ATP synthase during synthesis

The modular evolution theory for the origin of ATP synthase suggests that two subunits with independent function, a DNA helicase with ATPase activity and a H+
motor, were able to bind, and the rotation of the motor drove the ATPase activity of the helicase in reverse.[16][22] This complex then evolved greater efficiency and eventually developed into today's intricate ATP synthases. Alternatively, the DNA helicase/H+
motor complex may have had H+
pump activity with the ATPase activity of the helicase driving the H+
motor in reverse.[16] This may have evolved to carry out the reverse reaction and act as an ATP synthase.[17][23][24]

Inhibitors edit

A variety of natural and synthetic inhibitors of ATP synthase have been discovered.[25] These have been used to probe the structure and mechanism of ATP synthase. Some may be of therapeutic use. There are several classes of ATP synthase inhibitors, including peptide inhibitors, polyphenolic phytochemicals, polyketides, organotin compounds, polyenic α-pyrone derivatives, cationic inhibitors, substrate analogs, amino acid modifiers, and other miscellaneous chemicals.[25] Some of the most commonly used ATP synthase inhibitors are oligomycin and DCCD.

In different organisms edit

Bacteria edit

E. coli ATP synthase is the simplest known form of ATP synthase, with 8 different subunit types.[11]

Bacterial F-ATPases can occasionally operate in reverse, turning them into an ATPase.[26] Some bacteria have no F-ATPase, using an A/V-type ATPase bidirectionally.[9]

Yeast edit

Yeast ATP synthase is one of the best-studied eukaryotic ATP synthases; and five F1, eight FO subunits, and seven associated proteins have been identified.[7] Most of these proteins have homologues in other eukaryotes.[27][28][29][30]

Plant edit

In plants, ATP synthase is also present in chloroplasts (CF1FO-ATP synthase). The enzyme is integrated into thylakoid membrane; the CF1-part sticks into stroma, where dark reactions of photosynthesis (also called the light-independent reactions or the Calvin cycle) and ATP synthesis take place. The overall structure and the catalytic mechanism of the chloroplast ATP synthase are almost the same as those of the bacterial enzyme. However, in chloroplasts, the proton motive force is generated not by respiratory electron transport chain but by primary photosynthetic proteins. The synthase has a 40-aa insert in the gamma-subunit to inhibit wasteful activity when dark.[31]

Mammal edit

The ATP synthase isolated from bovine (Bos taurus) heart mitochondria is, in terms of biochemistry and structure, the best-characterized ATP synthase. Beef heart is used as a source for the enzyme because of the high concentration of mitochondria in cardiac muscle. Their genes have close homology to human ATP synthases.[32][33][34]

Human genes that encode components of ATP synthases:

Other eukaryotes edit

Eukaryotes belonging to some divergent lineages have very special organizations of the ATP synthase. A euglenozoa ATP synthase forms a dimer with a boomerang-shaped F1 head like other mitochondrial ATP synthases, but the FO subcomplex has many unique subunits. It uses cardiolipin. The inhibitory IF1 also binds differently, in a way shared with trypanosomatida.[35]

Archaea edit

Archaea do not generally have an F-ATPase. Instead, they synthesize ATP using the A-ATPase/synthase, a rotary machine structurally similar to the V-ATPase but mainly functioning as an ATP synthase.[26] Like the bacteria F-ATPase, it is believed to also function as an ATPase.[9]

LUCA and earlier edit

F-ATPase gene linkage and gene order are widely conserved across ancient prokaryote lineages, implying that this system already existed at a date before the last universal common ancestor, the LUCA.[36]

See also edit

References edit

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  2. ^ Junge W, Nelson N (June 2015). "ATP synthase". Annual Review of Biochemistry. 84: 631–657. doi:10.1146/annurev-biochem-060614-034124. PMID 25839341.
  3. ^ Kagawa Y, Racker E (May 1966). "Partial resolution of the enzymes catalyzing oxidative phosphorylation. 8. Properties of a factor conferring oligomycin sensitivity on mitochondrial adenosine triphosphatase". The Journal of Biological Chemistry. 241 (10): 2461–2466. doi:10.1016/S0021-9258(18)96640-8. PMID 4223640.
  4. ^ Mccarty RE (November 1992). "A PLANT BIOCHEMIST'S VIEW OF H+-ATPases AND ATP SYNTHASES". The Journal of Experimental Biology. 172 (Pt 1): 431–441. doi:10.1242/jeb.172.1.431. PMID 9874753.
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  18. ^ a b c "ATP Synthase". InterPro Database.
  19. ^ Beyenbach KW, Wieczorek H (February 2006). "The V-type H+ ATPase: molecular structure and function, physiological roles and regulation". The Journal of Experimental Biology. 209 (Pt 4): 577–589. doi:10.1242/jeb.02014. PMID 16449553.
  20. ^ Skordalakes E, Berger JM (July 2003). "Structure of the Rho transcription terminator: mechanism of mRNA recognition and helicase loading". Cell. 114 (1): 135–146. doi:10.1016/S0092-8674(03)00512-9. PMID 12859904. S2CID 5765103.
  21. ^ a b Imada K, Minamino T, Uchida Y, Kinoshita M, Namba K (March 2016). "Insight into the flagella type III export revealed by the complex structure of the type III ATPase and its regulator". Proceedings of the National Academy of Sciences of the United States of America. 113 (13): 3633–3638. Bibcode:2016PNAS..113.3633I. doi:10.1073/pnas.1524025113. PMC 4822572. PMID 26984495.
  22. ^ a b Martinez LO, Jacquet S, Esteve JP, Rolland C, Cabezón E, Champagne E, et al. (January 2003). "Ectopic beta-chain of ATP synthase is an apolipoprotein A-I receptor in hepatic HDL endocytosis". Nature. 421 (6918): 75–79. Bibcode:2003Natur.421...75M. doi:10.1038/nature01250. PMID 12511957. S2CID 4333137.
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  25. ^ a b Hong S, Pedersen PL (December 2008). "ATP synthase and the actions of inhibitors utilized to study its roles in human health, disease, and other scientific areas". Microbiology and Molecular Biology Reviews. 72 (4): 590–641, Table of Contents. doi:10.1128/MMBR.00016-08. PMC 2593570. PMID 19052322.
  26. ^ a b Kühlbrandt W, Davies KM (January 2016). "Rotary ATPases: A New Twist to an Ancient Machine". Trends in Biochemical Sciences. 41 (1): 106–116. doi:10.1016/j.tibs.2015.10.006. PMID 26671611.
  27. ^ Devenish RJ, Prescott M, Roucou X, Nagley P (May 2000). "Insights into ATP synthase assembly and function through the molecular genetic manipulation of subunits of the yeast mitochondrial enzyme complex". Biochimica et Biophysica Acta (BBA) - Bioenergetics. 1458 (2–3): 428–442. doi:10.1016/S0005-2728(00)00092-X. PMID 10838056.
  28. ^ Kabaleeswaran V, Puri N, Walker JE, Leslie AG, Mueller DM (November 2006). "Novel features of the rotary catalytic mechanism revealed in the structure of yeast F1 ATPase". The EMBO Journal. 25 (22): 5433–5442. doi:10.1038/sj.emboj.7601410. PMC 1636620. PMID 17082766.
  29. ^ Stock D, Leslie AG, Walker JE (November 1999). "Molecular architecture of the rotary motor in ATP synthase". Science. 286 (5445): 1700–1705. doi:10.1126/science.286.5445.1700. PMID 10576729.
  30. ^ Liu S, Charlesworth TJ, Bason JV, Montgomery MG, Harbour ME, Fearnley IM, Walker JE (May 2015). "The purification and characterization of ATP synthase complexes from the mitochondria of four fungal species". The Biochemical Journal. 468 (1): 167–175. doi:10.1042/BJ20150197. PMC 4422255. PMID 25759169.
  31. ^ Hahn A, Vonck J, Mills DJ, Meier T, Kühlbrandt W (May 2018). "Structure, mechanism, and regulation of the chloroplast ATP synthase". Science. 360 (6389): eaat4318. doi:10.1126/science.aat4318. PMC 7116070. PMID 29748256.
  32. ^ Abrahams JP, Leslie AG, Lutter R, Walker JE (August 1994). "Structure at 2.8 A resolution of F1-ATPase from bovine heart mitochondria". Nature. 370 (6491): 621–628. Bibcode:1994Natur.370..621A. doi:10.1038/370621a0. PMID 8065448. S2CID 4275221.
  33. ^ Gibbons C, Montgomery MG, Leslie AG, Walker JE (November 2000). "The structure of the central stalk in bovine F(1)-ATPase at 2.4 A resolution". Nature Structural Biology. 7 (11): 1055–1061. doi:10.1038/80981. PMID 11062563. S2CID 23229994.
  34. ^ Menz RI, Walker JE, Leslie AG (August 2001). "Structure of bovine mitochondrial F(1)-ATPase with nucleotide bound to all three catalytic sites: implications for the mechanism of rotary catalysis". Cell. 106 (3): 331–341. doi:10.1016/s0092-8674(01)00452-4. PMID 11509182. S2CID 1266814.
  35. ^ Mühleip A, McComas SE, Amunts A (November 2019). "Structure of a mitochondrial ATP synthase with bound native cardiolipin". eLife. 8: e51179. doi:10.7554/eLife.51179. PMC 6930080. PMID 31738165.
    • "Different from the rest". eLife. December 24, 2019.
  36. ^ Matzke NJ, Lin A, Stone M, Baker MA (July 2021). "Flagellar export apparatus and ATP synthetase: Homology evidenced by synteny predating the Last Universal Common Ancestor". BioEssays. 43 (7): e2100004. doi:10.1002/bies.202100004. PMID 33998015. S2CID 234747849.

Further reading edit

  • Nick Lane: The Vital Question: Energy, Evolution, and the Origins of Complex Life, Ww Norton, 2015-07-20, ISBN 978-0393088816 (Link points to Figure 10 showing model of ATP synthase)

External links edit

  • Boris A. Feniouk: "ATP synthase — a splendid molecular machine"
  • Well illustrated ATP synthase lecture by Antony Crofts of the University of Illinois at Urbana–Champaign.
  • Proton and Sodium translocating F-type, V-type and A-type ATPases in OPM database
  • The Nobel Prize in Chemistry 1997 to Paul D. Boyer and John E. Walker for the enzymatic mechanism of synthesis of ATP; and to Jens C. Skou, for discovery of an ion-transporting enzyme, Na+
    , K+
    -ATPase.
  • – ATP synthesis animation
  • David Goodsell: "ATP Synthase- Molecule of the Month" 2015-09-05 at the Wayback Machine

synthase, enzyme, that, catalyzes, formation, energy, storage, molecule, adenosine, triphosphate, using, adenosine, diphosphate, inorganic, phosphate, molecular, machine, overall, reaction, catalyzed, inatp, synthasemolecular, model, determined, crystallograph. ATP synthase is an enzyme that catalyzes the formation of the energy storage molecule adenosine triphosphate ATP using adenosine diphosphate ADP and inorganic phosphate Pi ATP synthase is a molecular machine The overall reaction catalyzed by ATP synthase is ADP Pi 2H out ATP H2O 2H inATP SynthaseMolecular model of ATP synthase determined by X ray crystallography Stator is not shown here IdentifiersEC no 7 1 2 2CAS no 9000 83 3DatabasesIntEnzIntEnz viewBRENDABRENDA entryExPASyNiceZyme viewKEGGKEGG entryMetaCycmetabolic pathwayPRIAMprofilePDB structuresRCSB PDB PDBe PDBsumGene OntologyAmiGO QuickGOSearchPMCarticlesPubMedarticlesNCBIproteins ATP synthase lies across a cellular membrane and forms an aperture that protons can cross from areas of high concentration to areas of low concentration imparting energy for the synthesis of ATP This electrochemical gradient is generated by the electron transport chain and allows cells to store energy in ATP for later use In prokaryotic cells ATP synthase lies across the plasma membrane while in eukaryotic cells it lies across the inner mitochondrial membrane Organisms capable of photosynthesis also have ATP synthase across the thylakoid membrane which in plants is located in the chloroplast and in cyanobacteria is located in the cytoplasm Eukaryotic ATP synthases are F ATPases running in reverse for an ATPase This article deals mainly with this type An F ATPase consists of two main subunits FO and F1 which has a rotational motor mechanism allowing for ATP production 1 2 Contents 1 Nomenclature 2 Structure and function 2 1 F1 region 2 2 FO region 3 Binding model 4 Physiological role 5 Evolution 6 Inhibitors 7 In different organisms 7 1 Bacteria 7 2 Yeast 7 3 Plant 7 4 Mammal 7 5 Other eukaryotes 7 6 Archaea 7 7 LUCA and earlier 8 See also 9 References 10 Further reading 11 External linksNomenclature editThe F1 fraction derives its name from the term Fraction 1 and FO written as a subscript letter o not zero derives its name from being the binding fraction for oligomycin a type of naturally derived antibiotic that is able to inhibit the FO unit of ATP synthase 3 4 These functional regions consist of different protein subunits refer to tables This enzyme is used in synthesis of ATP through aerobic respiration Structure and function edit nbsp Bovine mitochondrial ATP synthase The FO F1 axle and stator regions are color coded magenta green orange and cyan respectively i e FO F1 axle stator 5 6 nbsp Simplified model of FOF1 ATPase alias ATP synthase of E coli Subunits of the enzyme are labeled accordingly nbsp Rotation engine of ATP synthase Located within the thylakoid membrane and the inner mitochondrial membrane ATP synthase consists of two regions FO and F1 FO causes rotation of F1 and is made of c ring and subunits a two b F6 F1 is made of a b g and d subunits F1 has a water soluble part that can hydrolyze ATP FO on the other hand has mainly hydrophobic regions FO F1 creates a pathway for protons movement across the membrane 7 F1 region edit The F1 portion of ATP synthase is hydrophilic and responsible for hydrolyzing ATP The F1 unit protrudes into the mitochondrial matrix space Subunits a and b make a hexamer with 6 binding sites Three of them are catalytically inactive and they bind ADP Three other subunits catalyze the ATP synthesis The other F1 subunits g d and e are a part of a rotational motor mechanism rotor axle The g subunit allows b to go through conformational changes i e closed half open and open states that allow for ATP to be bound and released once synthesized The F1 particle is large and can be seen in the transmission electron microscope by negative staining 8 These are particles of 9 nm diameter that pepper the inner mitochondrial membrane F1 Subunits 9 Subunit Human Gene Notealpha ATP5A1 ATPAF2beta ATP5B ATPAF1gamma ATP5C1delta ATP5D Mitochondrial delta is bacterial chloroplastic epsilon epsilon ATP5E Unique to mitochondria OSCP ATP5O Called delta in bacterial and chloroplastic versions FO region edit nbsp FO subunit F6 from the peripheral stalk region of ATP synthase 10 FO is a water insoluble protein with eight subunits and a transmembrane ring The ring has a tetrameric shape with a helix loop helix protein that goes through conformational changes when protonated and deprotonated pushing neighboring subunits to rotate causing the spinning of FO which then also affects conformation of F1 resulting in switching of states of alpha and beta subunits The FO region of ATP synthase is a proton pore that is embedded in the mitochondrial membrane It consists of three main subunits a b and c Six c subunits make up the rotor ring and subunit b makes up a stalk connecting to F1 OSCP that prevents the ab hexamer from rotating Subunit a connects b to the c ring 11 Humans have six additional subunits d e f g F6 and 8 or A6L This part of the enzyme is located in the mitochondrial inner membrane and couples proton translocation to the rotation that causes ATP synthesis in the F1 region In eukaryotes mitochondrial FO forms membrane bending dimers These dimers self arrange into long rows at the end of the cristae possibly the first step of cristae formation 12 An atomic model for the dimeric yeast FO region was determined by cryo EM at an overall resolution of 3 6 A 13 FO Main subunits Subunit Human Genea MT ATP6b ATP5F1c ATP5G1 ATP5G2 ATP5G3Binding model edit nbsp Mechanism of ATP synthase ADP and Pi pink shown being combined into ATP red while the rotating g gamma subunit in black causes conformational change nbsp Depiction of ATP synthase using the chemiosmotic proton gradient to power ATP synthesis through oxidative phosphorylation In the 1960s through the 1970s Paul Boyer a UCLA Professor developed the binding change or flip flop mechanism theory which postulated that ATP synthesis is dependent on a conformational change in ATP synthase generated by rotation of the gamma subunit The research group of John E Walker then at the MRC Laboratory of Molecular Biology in Cambridge crystallized the F1 catalytic domain of ATP synthase The structure at the time the largest asymmetric protein structure known indicated that Boyer s rotary catalysis model was in essence correct For elucidating this Boyer and Walker shared half of the 1997 Nobel Prize in Chemistry The crystal structure of the F1 showed alternating alpha and beta subunits 3 of each arranged like segments of an orange around a rotating asymmetrical gamma subunit According to the current model of ATP synthesis known as the alternating catalytic model the transmembrane potential created by H proton cations supplied by the electron transport chain drives the H proton cations from the intermembrane space through the membrane via the FO region of ATP synthase A portion of the FO the ring of c subunits rotates as the protons pass through the membrane The c ring is tightly attached to the asymmetric central stalk consisting primarily of the gamma subunit causing it to rotate within the alpha3beta3 of F1 causing the 3 catalytic nucleotide binding sites to go through a series of conformational changes that lead to ATP synthesis The major F1 subunits are prevented from rotating in sympathy with the central stalk rotor by a peripheral stalk that joins the alpha3beta3 to the non rotating portion of FO The structure of the intact ATP synthase is currently known at low resolution from electron cryo microscopy cryo EM studies of the complex The cryo EM model of ATP synthase suggests that the peripheral stalk is a flexible structure that wraps around the complex as it joins F1 to FO Under the right conditions the enzyme reaction can also be carried out in reverse with ATP hydrolysis driving proton pumping across the membrane The binding change mechanism involves the active site of a b subunit s cycling between three states 14 In the loose state ADP and phosphate enter the active site in the adjacent diagram this is shown in pink The enzyme then undergoes a change in shape and forces these molecules together with the active site in the resulting tight state shown in red binding the newly produced ATP molecule with very high affinity Finally the active site cycles back to the open state orange releasing ATP and binding more ADP and phosphate ready for the next cycle of ATP production 15 Physiological role editLike other enzymes the activity of F1FO ATP synthase is reversible Large enough quantities of ATP cause it to create a transmembrane proton gradient this is used by fermenting bacteria that do not have an electron transport chain but rather hydrolyze ATP to make a proton gradient which they use to drive flagella and the transport of nutrients into the cell In respiring bacteria under physiological conditions ATP synthase in general runs in the opposite direction creating ATP while using the proton motive force created by the electron transport chain as a source of energy The overall process of creating energy in this fashion is termed oxidative phosphorylation The same process takes place in the mitochondria where ATP synthase is located in the inner mitochondrial membrane and the F1 part projects into the mitochondrial matrix By pumping proton cations into the matrix the ATP synthase converts ADP into ATP Evolution editThe evolution of ATP synthase is thought to have been modular whereby two functionally independent subunits became associated and gained new functionality 16 17 This association appears to have occurred early in evolutionary history because essentially the same structure and activity of ATP synthase enzymes are present in all kingdoms of life 16 The F ATP synthase displays high functional and mechanistic similarity to the V ATPase 18 However whereas the F ATP synthase generates ATP by utilising a proton gradient the V ATPase generates a proton gradient at the expense of ATP generating pH values of as low as 1 19 The F1 region also shows significant similarity to hexameric DNA helicases especially the Rho factor and the entire enzyme region shows some similarity to H powered T3SS or flagellar motor complexes 18 20 21 The a3b3 hexamer of the F1 region shows significant structural similarity to hexameric DNA helicases both form a ring with 3 fold rotational symmetry with a central pore Both have roles dependent on the relative rotation of a macromolecule within the pore the DNA helicases use the helical shape of DNA to drive their motion along the DNA molecule and to detect supercoiling whereas the a3b3 hexamer uses the conformational changes through the rotation of the g subunit to drive an enzymatic reaction 22 The H motor of the FO particle shows great functional similarity to the H motors that drive flagella 18 Both feature a ring of many small alpha helical proteins that rotate relative to nearby stationary proteins using a H potential gradient as an energy source This link is tenuous however as the overall structure of flagellar motors is far more complex than that of the FO particle and the ring with about 30 rotating proteins is far larger than the 10 11 or 14 helical proteins in the FO complex More recent structural data do however show that the ring and the stalk are structurally similar to the F1 particle 21 source source source Conformation changes of ATP synthase during synthesisThe modular evolution theory for the origin of ATP synthase suggests that two subunits with independent function a DNA helicase with ATPase activity and a H motor were able to bind and the rotation of the motor drove the ATPase activity of the helicase in reverse 16 22 This complex then evolved greater efficiency and eventually developed into today s intricate ATP synthases Alternatively the DNA helicase H motor complex may have had H pump activity with the ATPase activity of the helicase driving the H motor in reverse 16 This may have evolved to carry out the reverse reaction and act as an ATP synthase 17 23 24 Inhibitors editA variety of natural and synthetic inhibitors of ATP synthase have been discovered 25 These have been used to probe the structure and mechanism of ATP synthase Some may be of therapeutic use There are several classes of ATP synthase inhibitors including peptide inhibitors polyphenolic phytochemicals polyketides organotin compounds polyenic a pyrone derivatives cationic inhibitors substrate analogs amino acid modifiers and other miscellaneous chemicals 25 Some of the most commonly used ATP synthase inhibitors are oligomycin and DCCD In different organisms editBacteria edit E coli ATP synthase is the simplest known form of ATP synthase with 8 different subunit types 11 Bacterial F ATPases can occasionally operate in reverse turning them into an ATPase 26 Some bacteria have no F ATPase using an A V type ATPase bidirectionally 9 Yeast edit Yeast ATP synthase is one of the best studied eukaryotic ATP synthases and five F1 eight FO subunits and seven associated proteins have been identified 7 Most of these proteins have homologues in other eukaryotes 27 28 29 30 Plant edit In plants ATP synthase is also present in chloroplasts CF1FO ATP synthase The enzyme is integrated into thylakoid membrane the CF1 part sticks into stroma where dark reactions of photosynthesis also called the light independent reactions or the Calvin cycle and ATP synthesis take place The overall structure and the catalytic mechanism of the chloroplast ATP synthase are almost the same as those of the bacterial enzyme However in chloroplasts the proton motive force is generated not by respiratory electron transport chain but by primary photosynthetic proteins The synthase has a 40 aa insert in the gamma subunit to inhibit wasteful activity when dark 31 Mammal edit The ATP synthase isolated from bovine Bos taurus heart mitochondria is in terms of biochemistry and structure the best characterized ATP synthase Beef heart is used as a source for the enzyme because of the high concentration of mitochondria in cardiac muscle Their genes have close homology to human ATP synthases 32 33 34 Human genes that encode components of ATP synthases ATP5A1 ATP5B ATP5C1 ATP5D ATP5E ATP5F1 ATP5G1 ATP5G2 ATP5G3 ATP5H ATP5I ATP5J ATP5J2 ATP5L ATP5O MT ATP6 MT ATP8Other eukaryotes edit Eukaryotes belonging to some divergent lineages have very special organizations of the ATP synthase A euglenozoa ATP synthase forms a dimer with a boomerang shaped F1 head like other mitochondrial ATP synthases but the FO subcomplex has many unique subunits It uses cardiolipin The inhibitory IF1 also binds differently in a way shared with trypanosomatida 35 Archaea edit Archaea do not generally have an F ATPase Instead they synthesize ATP using the A ATPase synthase a rotary machine structurally similar to the V ATPase but mainly functioning as an ATP synthase 26 Like the bacteria F ATPase it is believed to also function as an ATPase 9 LUCA and earlier edit F ATPase gene linkage and gene order are widely conserved across ancient prokaryote lineages implying that this system already existed at a date before the last universal common ancestor the LUCA 36 See also editATP10 protein required for the assembly of the FO sector of the mitochondrial ATPase complex Chloroplast Electron transfer chain Flavoprotein Mitochondrion Oxidative phosphorylation P ATPase Proton pump Rotating locomotion in living systems Transmembrane ATPase V ATPaseReferences edit Okuno D Iino R Noji H June 2011 Rotation and structure of FoF1 ATP synthase Journal of Biochemistry 149 6 655 664 doi 10 1093 jb mvr049 PMID 21524994 Junge W Nelson N June 2015 ATP synthase Annual Review of Biochemistry 84 631 657 doi 10 1146 annurev biochem 060614 034124 PMID 25839341 Kagawa Y Racker E May 1966 Partial resolution of the enzymes catalyzing oxidative phosphorylation 8 Properties of a factor conferring oligomycin sensitivity on mitochondrial adenosine triphosphatase The Journal of Biological Chemistry 241 10 2461 2466 doi 10 1016 S0021 9258 18 96640 8 PMID 4223640 Mccarty RE November 1992 A PLANT BIOCHEMIST S VIEW OF H ATPases AND ATP SYNTHASES The Journal of Experimental Biology 172 Pt 1 431 441 doi 10 1242 jeb 172 1 431 PMID 9874753 PDB 5ARA Zhou A Rohou A Schep DG Bason JV Montgomery MG Walker JE et al October 2015 Structure and conformational states of the bovine mitochondrial ATP synthase by cryo EM eLife 4 e10180 doi 10 7554 eLife 10180 PMC 4718723 PMID 26439008 Goodsell D December 2005 ATP Synthase Molecule of the Month doi 10 2210 rcsb pdb mom 2005 12 a b Velours J Paumard P Soubannier V Spannagel C Vaillier J Arselin G Graves PV May 2000 Organisation of the yeast ATP synthase F 0 a study based on cysteine mutants thiol modification and cross linking reagents Biochimica et Biophysica Acta BBA Bioenergetics 1458 2 3 443 456 doi 10 1016 S0005 2728 00 00093 1 PMID 10838057 Fernandez Moran H Oda T Blair PV Green DE July 1964 A macromolecular repeating unit of mitochondrial structure and function Correlated electron microscopic and biochemical studies of isolated mitochondria and submitochondrial particles of beef heart muscle The Journal of Cell Biology 22 1 63 100 doi 10 1083 jcb 22 1 63 PMC 2106494 PMID 14195622 a b c Stewart AG Laming EM Sobti M Stock D April 2014 Rotary ATPases dynamic molecular machines Current Opinion in Structural Biology 25 40 48 doi 10 1016 j sbi 2013 11 013 PMID 24878343 PDB 1VZS Carbajo RJ Silvester JA Runswick MJ Walker JE Neuhaus D September 2004 Solution structure of subunit F 6 from the peripheral stalk region of ATP synthase from bovine heart mitochondria Journal of Molecular Biology 342 2 593 603 doi 10 1016 j jmb 2004 07 013 PMID 15327958 a b Ahmad Z Okafor F Laughlin TF 2011 Role of Charged Residues in the Catalytic Sites of Escherichia coli ATP Synthase Journal of Amino Acids 2011 785741 doi 10 4061 2011 785741 PMC 3268026 PMID 22312470 Blum TB Hahn A Meier T Davies KM Kuhlbrandt W March 2019 Dimers of mitochondrial ATP synthase induce membrane curvature and self assemble into rows Proceedings of the National Academy of Sciences of the United States of America 116 10 4250 4255 Bibcode 2019PNAS 116 4250B doi 10 1073 pnas 1816556116 PMC 6410833 PMID 30760595 Guo H Bueler SA Rubinstein JL November 2017 Atomic model for the dimeric FO region of mitochondrial ATP synthase Science 358 6365 936 940 Bibcode 2017Sci 358 936G doi 10 1126 science aao4815 PMC 6402782 PMID 29074581 Gresser MJ Myers JA Boyer PD October 1982 Catalytic site cooperativity of beef heart mitochondrial F1 adenosine triphosphatase Correlations of initial velocity bound intermediate and oxygen exchange measurements with an alternating three site model The Journal of Biological Chemistry 257 20 12030 12038 doi 10 1016 S0021 9258 18 33672 X PMID 6214554 Nakamoto RK Baylis Scanlon JA Al Shawi MK August 2008 The rotary mechanism of the ATP synthase Archives of Biochemistry and Biophysics 476 1 43 50 doi 10 1016 j abb 2008 05 004 PMC 2581510 PMID 18515057 a b c d Doering C Ermentrout B Oster G December 1995 Rotary DNA motors Biophysical Journal 69 6 2256 2267 Bibcode 1995BpJ 69 2256D doi 10 1016 S0006 3495 95 80096 2 PMC 1236464 PMID 8599633 a b Crofts A Lecture 10 ATP synthase Life Sciences at the University of Illinois at Urbana Champaign a b c ATP Synthase InterPro Database Beyenbach KW Wieczorek H February 2006 The V type H ATPase molecular structure and function physiological roles and regulation The Journal of Experimental Biology 209 Pt 4 577 589 doi 10 1242 jeb 02014 PMID 16449553 Skordalakes E Berger JM July 2003 Structure of the Rho transcription terminator mechanism of mRNA recognition and helicase loading Cell 114 1 135 146 doi 10 1016 S0092 8674 03 00512 9 PMID 12859904 S2CID 5765103 a b Imada K Minamino T Uchida Y Kinoshita M Namba K March 2016 Insight into the flagella type III export revealed by the complex structure of the type III ATPase and its regulator Proceedings of the National Academy of Sciences of the United States of America 113 13 3633 3638 Bibcode 2016PNAS 113 3633I doi 10 1073 pnas 1524025113 PMC 4822572 PMID 26984495 a b Martinez LO Jacquet S Esteve JP Rolland C Cabezon E Champagne E et al January 2003 Ectopic beta chain of ATP synthase is an apolipoprotein A I receptor in hepatic HDL endocytosis Nature 421 6918 75 79 Bibcode 2003Natur 421 75M doi 10 1038 nature01250 PMID 12511957 S2CID 4333137 Cross RL Taiz L January 1990 Gene duplication as a means for altering H ATP ratios during the evolution of FOF1 ATPases and synthases FEBS Letters 259 2 227 229 doi 10 1016 0014 5793 90 80014 a PMID 2136729 S2CID 32559858 Cross RL Muller V October 2004 The evolution of A F and V type ATP synthases and ATPases reversals in function and changes in the H ATP coupling ratio FEBS Letters 576 1 2 1 4 doi 10 1016 j febslet 2004 08 065 PMID 15473999 S2CID 25800744 a b Hong S Pedersen PL December 2008 ATP synthase and the actions of inhibitors utilized to study its roles in human health disease and other scientific areas Microbiology and Molecular Biology Reviews 72 4 590 641 Table of Contents doi 10 1128 MMBR 00016 08 PMC 2593570 PMID 19052322 a b Kuhlbrandt W Davies KM January 2016 Rotary ATPases A New Twist to an Ancient Machine Trends in Biochemical Sciences 41 1 106 116 doi 10 1016 j tibs 2015 10 006 PMID 26671611 Devenish RJ Prescott M Roucou X Nagley P May 2000 Insights into ATP synthase assembly and function through the molecular genetic manipulation of subunits of the yeast mitochondrial enzyme complex Biochimica et Biophysica Acta BBA Bioenergetics 1458 2 3 428 442 doi 10 1016 S0005 2728 00 00092 X PMID 10838056 Kabaleeswaran V Puri N Walker JE Leslie AG Mueller DM November 2006 Novel features of the rotary catalytic mechanism revealed in the structure of yeast F1 ATPase The EMBO Journal 25 22 5433 5442 doi 10 1038 sj emboj 7601410 PMC 1636620 PMID 17082766 Stock D Leslie AG Walker JE November 1999 Molecular architecture of the rotary motor in ATP synthase Science 286 5445 1700 1705 doi 10 1126 science 286 5445 1700 PMID 10576729 Liu S Charlesworth TJ Bason JV Montgomery MG Harbour ME Fearnley IM Walker JE May 2015 The purification and characterization of ATP synthase complexes from the mitochondria of four fungal species The Biochemical Journal 468 1 167 175 doi 10 1042 BJ20150197 PMC 4422255 PMID 25759169 Hahn A Vonck J Mills DJ Meier T Kuhlbrandt W May 2018 Structure mechanism and regulation of the chloroplast ATP synthase Science 360 6389 eaat4318 doi 10 1126 science aat4318 PMC 7116070 PMID 29748256 Abrahams JP Leslie AG Lutter R Walker JE August 1994 Structure at 2 8 A resolution of F1 ATPase from bovine heart mitochondria Nature 370 6491 621 628 Bibcode 1994Natur 370 621A doi 10 1038 370621a0 PMID 8065448 S2CID 4275221 Gibbons C Montgomery MG Leslie AG Walker JE November 2000 The structure of the central stalk in bovine F 1 ATPase at 2 4 A resolution Nature Structural Biology 7 11 1055 1061 doi 10 1038 80981 PMID 11062563 S2CID 23229994 Menz RI Walker JE Leslie AG August 2001 Structure of bovine mitochondrial F 1 ATPase with nucleotide bound to all three catalytic sites implications for the mechanism of rotary catalysis Cell 106 3 331 341 doi 10 1016 s0092 8674 01 00452 4 PMID 11509182 S2CID 1266814 Muhleip A McComas SE Amunts A November 2019 Structure of a mitochondrial ATP synthase with bound native cardiolipin eLife 8 e51179 doi 10 7554 eLife 51179 PMC 6930080 PMID 31738165 Different from the rest eLife December 24 2019 Matzke NJ Lin A Stone M Baker MA July 2021 Flagellar export apparatus and ATP synthetase Homology evidenced by synteny predating the Last Universal Common Ancestor BioEssays 43 7 e2100004 doi 10 1002 bies 202100004 PMID 33998015 S2CID 234747849 Further reading editNick Lane The Vital Question Energy Evolution and the Origins of Complex Life Ww Norton 2015 07 20 ISBN 978 0393088816 Link points to Figure 10 showing model of ATP synthase External links editBoris A Feniouk ATP synthase a splendid molecular machine Well illustrated ATP synthase lecture by Antony Crofts of the University of Illinois at Urbana Champaign Proton and Sodium translocating F type V type and A type ATPases in OPM database The Nobel Prize in Chemistry 1997 to Paul D Boyer and John E Walker for the enzymatic mechanism of synthesis of ATP and to Jens C Skou for discovery of an ion transporting enzyme Na K ATPase Harvard Multimedia Production Site Videos ATP synthesis animation David Goodsell ATP Synthase Molecule of the Month Archived 2015 09 05 at the Wayback Machine Portal nbsp Biology Retrieved from https en wikipedia org w index php title ATP synthase amp oldid 1206854468, wikipedia, wiki, book, books, library,

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