1
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Nesci S. What happens when the mitochondrial H +-translocating F 1F O-ATP(hydrol)ase becomes a molecular target of calcium? The pore opens. Biochimie 2022; 198:92-95. [PMID: 35367315 DOI: 10.1016/j.biochi.2022.03.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 03/19/2022] [Accepted: 03/28/2022] [Indexed: 12/29/2022]
Abstract
The F1FO-ATPase has Mg2+ cofactor as the natural divalent cation to support the bifunctional activity of ATP synthesis and hydrolysis. Different physio(patho)logical conditions permit the molecular interaction of Ca2+ with the enzyme and the modification of the biological role. Three distinct binding regions of Ca2+ have been localized on the enzyme complex: one in the F1 catalytic sites and the other two sites in the membrane-embedded domain FO. In all likelihood, Ca2+-activated enzyme most frequently works as an H+-translocating F1FO-ATP(hydrol)ase with a monofunctional activity that triggers the formation of mitochondrial permeability transition pore (mPTP) phenomenon. The protein(s) component of the mPTP is considered an arcane mystery. However, the F1FO-ATPase could reveal the molecular mechanism of pore opening when Ca2+ is bound to the enzyme. In this regard, the role of Ca2+-dependent function of the F1FO-ATPase in the formation of the mPTP is discussed.
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Affiliation(s)
- Salvatore Nesci
- Department of Veterinary Medical Sciences, University of Bologna, Via Tolara di Sopra, 50, 40064, Ozzano Emilia, Bologna, Italy.
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2
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Nesci S, Pagliarani A. Ca 2+ as cofactor of the mitochondrial H + -translocating F 1 F O -ATP(hydrol)ase. Proteins 2021; 89:477-482. [PMID: 33378096 DOI: 10.1002/prot.26040] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 12/03/2020] [Accepted: 12/27/2020] [Indexed: 01/05/2023]
Abstract
The mitochondrial F1 FO -ATPase in the presence of the natural cofactor Mg2+ acts as the enzyme of life by synthesizing ATP, but it can also hydrolyze ATP to pump H+ . Interestingly, Mg2+ can be replaced by Ca2+ , but only to sustain ATP hydrolysis and not ATP synthesis. When Ca2+ inserts in F1 , the torque generation built by the chemomechanical coupling between F1 and the rotating central stalk was reported as unable to drive the transmembrane H+ flux within FO . However, the failed H+ translocation is not consistent with the oligomycin-sensitivity of the Ca2+ -dependent F1 FO -ATP(hydrol)ase. New enzyme roles in mitochondrial energy transduction are suggested by recent advances. Accordingly, the structural F1 FO -ATPase distortion driven by ATP hydrolysis sustained by Ca2+ is consistent with the permeability transition pore signal propagation pathway. The Ca2+ -activated F1 FO -ATPase, by forming the pore, may contribute to dissipate the transmembrane H+ gradient created by the same enzyme complex.
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Affiliation(s)
- Salvatore Nesci
- Department of Veterinary Medical Sciences, University of Bologna, Ozzano Emilia, Bologna, Italy
| | - Alessandra Pagliarani
- Department of Veterinary Medical Sciences, University of Bologna, Ozzano Emilia, Bologna, Italy
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3
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Carraro M, Carrer A, Urbani A, Bernardi P. Molecular nature and regulation of the mitochondrial permeability transition pore(s), drug target(s) in cardioprotection. J Mol Cell Cardiol 2020; 144:76-86. [DOI: 10.1016/j.yjmcc.2020.05.014] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 04/28/2020] [Accepted: 05/20/2020] [Indexed: 12/12/2022]
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4
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The β-hairpin region of the cyanobacterial F 1-ATPase γ-subunit plays a regulatory role in the enzyme activity. Biochem J 2019; 476:1771-1780. [PMID: 31164401 DOI: 10.1042/bcj20190242] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 05/29/2019] [Accepted: 05/31/2019] [Indexed: 01/21/2023]
Abstract
The γ-subunit of cyanobacterial and chloroplast ATP synthase, the rotary shaft of F1-ATPase, equips a specific insertion region that is only observed in photosynthetic organisms. This region plays a physiologically pivotal role in enzyme regulation, such as in ADP inhibition and redox response. Recently solved crystal structures of the γ-subunit of F1-ATPase from photosynthetic organisms revealed that the insertion region forms a β-hairpin structure, which is positioned along the central stalk. The structure-function relationship of this specific region was studied by constraining the expected conformational change in this region caused by the formation of a disulfide bond between Cys residues introduced on the central stalk and this β-hairpin structure. This fixation of the β-hairpin region in the α3β3γ complex affects both ADP inhibition and the binding of the ε-subunit to the complex, indicating the critical role that the β-hairpin region plays as a regulator of the enzyme. This role must be important for the maintenance of the intracellular ATP levels in photosynthetic organisms.
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5
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Carraro M, Checchetto V, Szabó I, Bernardi P. F‐ATPsynthase and the permeability transition pore: fewer doubts, more certainties. FEBS Lett 2019; 593:1542-1553. [DOI: 10.1002/1873-3468.13485] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Revised: 06/09/2019] [Accepted: 06/10/2019] [Indexed: 12/27/2022]
Affiliation(s)
- Michela Carraro
- Department of Biomedical Sciences University of Padova Italy
| | | | - Ildikó Szabó
- Department of Biology University of Padova Italy
| | - Paolo Bernardi
- Department of Biomedical Sciences University of Padova Italy
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6
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Bernardi P. Why F-ATP Synthase Remains a Strong Candidate as the Mitochondrial Permeability Transition Pore. Front Physiol 2018; 9:1543. [PMID: 30443222 PMCID: PMC6221903 DOI: 10.3389/fphys.2018.01543] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 10/15/2018] [Indexed: 01/12/2023] Open
Affiliation(s)
- Paolo Bernardi
- Department of Biomedical Sciences, University of Padua, Padua, Italy
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7
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Giorgio V, Burchell V, Schiavone M, Bassot C, Minervini G, Petronilli V, Argenton F, Forte M, Tosatto S, Lippe G, Bernardi P. Ca 2+ binding to F-ATP synthase β subunit triggers the mitochondrial permeability transition. EMBO Rep 2017; 18:1065-1076. [PMID: 28507163 DOI: 10.15252/embr.201643354] [Citation(s) in RCA: 159] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 04/02/2017] [Accepted: 04/05/2017] [Indexed: 01/28/2023] Open
Abstract
F-ATP synthases convert the electrochemical energy of the H+ gradient into the chemical energy of ATP with remarkable efficiency. Mitochondrial F-ATP synthases can also undergo a Ca2+-dependent transformation to form channels with properties matching those of the permeability transition pore (PTP), a key player in cell death. The Ca2+ binding site and the mechanism(s) through which Ca2+ can transform the energy-conserving enzyme into a dissipative structure promoting cell death remain unknown. Through in vitro, in vivo and in silico studies we (i) pinpoint the "Ca2+-trigger site" of the PTP to the catalytic site of the F-ATP synthase β subunit and (ii) define a conformational change that propagates from the catalytic site through OSCP and the lateral stalk to the inner membrane. T163S mutants of the β subunit, which show a selective decrease in Ca2+-ATP hydrolysis, confer resistance to Ca2+-induced, PTP-dependent death in cells and developing zebrafish embryos. These findings are a major advance in the molecular definition of the transition of F-ATP synthase to a channel and of its role in cell death.
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Affiliation(s)
- Valentina Giorgio
- Department of Biomedical Sciences, University of Padova, Padova, Italy .,Consiglio Nazionale delle Ricerche Neuroscience Institute, Padova, Italy
| | - Victoria Burchell
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Marco Schiavone
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Claudio Bassot
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | | | - Valeria Petronilli
- Department of Biomedical Sciences, University of Padova, Padova, Italy.,Consiglio Nazionale delle Ricerche Neuroscience Institute, Padova, Italy
| | | | - Michael Forte
- Vollum Institute, Oregon Health and Sciences University, Portland, OR, USA
| | - Silvio Tosatto
- Department of Biomedical Sciences, University of Padova, Padova, Italy.,Consiglio Nazionale delle Ricerche Neuroscience Institute, Padova, Italy
| | - Giovanna Lippe
- Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, Udine, Italy
| | - Paolo Bernardi
- Department of Biomedical Sciences, University of Padova, Padova, Italy .,Consiglio Nazionale delle Ricerche Neuroscience Institute, Padova, Italy
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8
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Giorgio V, Guo L, Bassot C, Petronilli V, Bernardi P. Calcium and regulation of the mitochondrial permeability transition. Cell Calcium 2017; 70:56-63. [PMID: 28522037 DOI: 10.1016/j.ceca.2017.05.004] [Citation(s) in RCA: 122] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 05/05/2017] [Accepted: 05/05/2017] [Indexed: 12/11/2022]
Abstract
Recent years have seen renewed interest in the permeability transition pore, a high conductance channel responsible for permeabilization of the inner mitochondrial membrane, a process that leads to depolarization and Ca2+ release. Transient openings may be involved in physiological Ca2+ homeostasis while long-lasting openings may trigger and/or execute cell death. In this review we specifically focus (i) on the hypothesis that the PTP forms from the F-ATP synthase and (ii) on the mechanisms through which Ca2+ can reversibly switch this energy-conserving nanomachine into an energy-dissipating device.
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Affiliation(s)
- Valentina Giorgio
- Department of Biomedical Sciences and CNR Neuroscience Institute, University of Padova, Italy
| | - Lishu Guo
- Department of Biomedical Sciences and CNR Neuroscience Institute, University of Padova, Italy
| | - Claudio Bassot
- Department of Biomedical Sciences and CNR Neuroscience Institute, University of Padova, Italy
| | - Valeria Petronilli
- Department of Biomedical Sciences and CNR Neuroscience Institute, University of Padova, Italy
| | - Paolo Bernardi
- Department of Biomedical Sciences and CNR Neuroscience Institute, University of Padova, Italy.
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9
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Zulian A, Schiavone M, Giorgio V, Bernardi P. Forty years later: Mitochondria as therapeutic targets in muscle diseases. Pharmacol Res 2016; 113:563-573. [PMID: 27697642 DOI: 10.1016/j.phrs.2016.09.043] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 09/29/2016] [Indexed: 11/22/2022]
Abstract
The hypothesis that mitochondrial dysfunction can be a general mechanism for cell death in muscle diseases is 40 years old. The key elements of the proposed pathogenetic sequence (cytosolic Ca2+ overload followed by excess mitochondrial Ca2+ uptake, functional and then structural damage of mitochondria, energy shortage, worsened elevation of cytosolic Ca2+ levels, hypercontracture of muscle fibers, cell necrosis) have been confirmed in amazing detail by subsequent work in a variety of models. The explicit implication of the hypothesis was that it "may provide the basis for a more rational treatment for some conditions even before their primary causes are known" (Wrogemann and Pena, 1976, Lancet, 1, 672-674). This prediction is being fulfilled, and the potential of mitochondria as pharmacological targets in muscle diseases may soon become a reality, particularly through inhibition of the mitochondrial permeability transition pore and its regulator cyclophilin D.
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Affiliation(s)
- Alessandra Zulian
- CNR Neuroscience Institute and Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Marco Schiavone
- CNR Neuroscience Institute and Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Valentina Giorgio
- CNR Neuroscience Institute and Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Paolo Bernardi
- CNR Neuroscience Institute and Department of Biomedical Sciences, University of Padova, Padova, Italy.
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10
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Yang JH, Sarrou I, Martin-Garcia JM, Zhang S, Redding KE, Fromme P. Purification and biochemical characterization of the ATP synthase from Heliobacterium modesticaldum. Protein Expr Purif 2015; 114:1-8. [PMID: 25979464 DOI: 10.1016/j.pep.2015.05.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 04/28/2015] [Accepted: 05/06/2015] [Indexed: 11/26/2022]
Abstract
Heliobacterium modesticaldum is an anaerobic photosynthetic bacterium that grows optimally at pH 6-7 and 52°C and is the only phototrophic member of the Firmicutes phylum family (gram-positive bacteria with low GC content). The ATP synthase of H. modesticaldum was isolated and characterized at the biochemical and biophysical levels. The isolated holoenzyme exhibited the subunit patterns of F-type ATP synthases containing a 5-subunit hydrophilic F1 subcomplex and a 3-subunit hydrophobic F0 subcomplex. ATP hydrolysis by the isolated HF1F0 ATP synthase was successfully detected after pretreatment with different detergents by an in-gel ATPase activity assay, which showed that the highest activity was detected in the presence of mild detergents such as LDAO; moreover, high catalytic activity in the gel was already detected after the initial incubation period of 0.5h. In contrast, HF1F0 showed extremely low ATPase activity in harsher detergents such as TODC. The isolated fully functional enzyme will form the basis for future structural studies.
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Affiliation(s)
- Jay-How Yang
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287-1604, USA; Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University, Tempe, AZ 85287-1604, USA
| | - Iosifina Sarrou
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287-1604, USA; Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology-Hellas, Nikolaou Plastira 100, GR-70013 Heraklion, Crete, Greece
| | - Jose M Martin-Garcia
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287-1604, USA; Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University, Tempe, AZ 85287-1604, USA
| | - Shangji Zhang
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-1604, USA
| | - Kevin E Redding
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287-1604, USA
| | - Petra Fromme
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287-1604, USA; Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University, Tempe, AZ 85287-1604, USA.
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11
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Sunamura EI, Konno H, Imashimizu-Kobayashi M, Sugano Y, Hisabori T. Physiological impact of intrinsic ADP inhibition of cyanobacterial FoF1 conferred by the inherent sequence inserted into the gammasubunit. PLANT & CELL PHYSIOLOGY 2010; 51:855-65. [PMID: 20421199 DOI: 10.1093/pcp/pcq061] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The F(o)F(1)-ATPase, which synthesizes ATP with a rotary motion, is highly regulated in vivo in order to function efficiently, although there remains a limited understanding of the physiological significance of this regulation. Compared with its bacterial and mitochondrial counterparts, the gamma subunit of cyanobacterial F(1), which makes up the central shaft of the motor enzyme, contains an additional inserted region. Although deletion of this region results in the acceleration of the rate of ATP hydrolysis, the functional significance of the region has not yet been determined. By analysis of rotation, we successfully determined that this region confers the ability to shift frequently into an ADP inhibition state; this is a highly conserved regulatory mechanism which prevents ATP synthase from carrying out the reverse reaction. We believe that the physiological significance of this increased likelihood of shifting into the ADP inhibition state allows the intracellular ATP levels to be maintained, which is especially critical for photosynthetic organisms.
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Affiliation(s)
- Ei-Ichiro Sunamura
- Chemical Resources Laboratory, Tokyo Institute of Technology, Nagatsuta 4259-R1-8, Midori-Ku, Yokohama 226-8503, Japan
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12
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Samra HS, He F, Degner NR, Richter ML. The role of specific beta-gamma subunit interactions in oxyanion stimulation of the MgATP hydrolysis of a hybrid photosynthetic F1-ATPase. J Bioenerg Biomembr 2008; 40:69-76. [PMID: 18415008 DOI: 10.1007/s10863-008-9131-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2007] [Accepted: 01/09/2008] [Indexed: 11/25/2022]
Abstract
Pairs of cysteine residues were introduced into the twisted N- and C-terminal helices of the gamma subunit of the chloroplast F1-ATPase to test, via disulfide cross-linking, potential inter-helical movements involved in catalysis of ATP hydrolysis. The extent of disulfide cross-linking was determined by estimating the amount of free sulfhydryl available for labeling with fluoresceinyl maleimide before and after cross-linking. Significant disulfide formation (50-75%) was observed between cysteines introduced at positions 30 and 31 in the N-terminal helix and 276 and 278 in the C-terminal helix. Cross-linking had no apparent effect on catalysis, therefore eliminating the involvement of large-scale inter-helical movements within this region of the gamma subunit in cooperative ATP hydrolysis. However, the presence of the two cysteines together in the gammaV31C/A276C double mutant, irrespective of whether or not they were cross-linked together, lowered the MgATPase activity by more than 70% and completely eliminated the well-known activating effect of the oxyanion sulfite. The CaATPase activity was unaffected. Similar but less pronounced effects were seen with the gammaK30C/A276C double mutant. The results indicate that residues at or near positions 31 and 276 within the twisted helical pair of the gamma subunit are required to overcome Mg2+ inhibition of ATP hydrolysis. These residues are likely to be involved in forming a point of contact between the gamma and beta subunits that is responsible for this effect.
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Affiliation(s)
- Hardeep S Samra
- Department of Molecular Biosciences, The University of Kansas, 1200 Sunnyside Ave., Lawrence, KS 66045, USA
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13
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Konno H, Murakami-Fuse T, Fujii F, Koyama F, Ueoka-Nakanishi H, Pack CG, Kinjo M, Hisabori T. The regulator of the F1 motor: inhibition of rotation of cyanobacterial F1-ATPase by the epsilon subunit. EMBO J 2006; 25:4596-604. [PMID: 16977308 PMCID: PMC1589999 DOI: 10.1038/sj.emboj.7601348] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2006] [Accepted: 08/22/2006] [Indexed: 11/09/2022] Open
Abstract
The chloroplast-type F(1) ATPase is the key enzyme of energy conversion in chloroplasts, and is regulated by the endogenous inhibitor epsilon, tightly bound ADP, the membrane potential and the redox state of the gamma subunit. In order to understand the molecular mechanism of epsilon inhibition, we constructed an expression system for the alpha(3)beta(3)gamma subcomplex in thermophilic cyanobacteria allowing thorough investigation of epsilon inhibition. epsilon Inhibition was found to be ATP-independent, and different to that observed for bacterial F(1)-ATPase. The role of the additional region on the gamma subunit of chloroplast-type F(1)-ATPase in epsilon inhibition was also determined. By single molecule rotation analysis, we succeeded in assigning the pausing angular position of gamma in epsilon inhibition, which was found to be identical to that observed for ATP hydrolysis, product release and ADP inhibition, but distinctly different from the waiting position for ATP binding. These results suggest that the epsilon subunit of chloroplast-type ATP synthase plays an important regulator for the rotary motor enzyme, thus preventing wasteful ATP hydrolysis.
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Affiliation(s)
- Hiroki Konno
- Chemical Resources Laboratory, Tokyo Institute of Technology, Nagatsuta, Midori-ku, Yokohama, Japan
- ATP System Project, Exploratory Research for Advanced Technology (ERATO), Japan Science and Technology Corporation (JST), Nagatsuta-cho, Midori-ku, Yokohama, Japan
| | - Tomoe Murakami-Fuse
- Chemical Resources Laboratory, Tokyo Institute of Technology, Nagatsuta, Midori-ku, Yokohama, Japan
- ATP System Project, Exploratory Research for Advanced Technology (ERATO), Japan Science and Technology Corporation (JST), Nagatsuta-cho, Midori-ku, Yokohama, Japan
| | - Fumihiko Fujii
- Laboratory of Supramolecular Biophysics, Research Institute for Electronic Science, Hokkaido University, Kita-ku, Sapporo, Hokkaido, Japan
| | - Fumie Koyama
- Chemical Resources Laboratory, Tokyo Institute of Technology, Nagatsuta, Midori-ku, Yokohama, Japan
- ATP System Project, Exploratory Research for Advanced Technology (ERATO), Japan Science and Technology Corporation (JST), Nagatsuta-cho, Midori-ku, Yokohama, Japan
| | - Hanayo Ueoka-Nakanishi
- ATP System Project, Exploratory Research for Advanced Technology (ERATO), Japan Science and Technology Corporation (JST), Nagatsuta-cho, Midori-ku, Yokohama, Japan
| | - Chan-Gi Pack
- Laboratory of Supramolecular Biophysics, Research Institute for Electronic Science, Hokkaido University, Kita-ku, Sapporo, Hokkaido, Japan
| | - Masataka Kinjo
- Laboratory of Supramolecular Biophysics, Research Institute for Electronic Science, Hokkaido University, Kita-ku, Sapporo, Hokkaido, Japan
| | - Toru Hisabori
- Chemical Resources Laboratory, Tokyo Institute of Technology, Nagatsuta, Midori-ku, Yokohama, Japan
- ATP System Project, Exploratory Research for Advanced Technology (ERATO), Japan Science and Technology Corporation (JST), Nagatsuta-cho, Midori-ku, Yokohama, Japan
- Chemical Resources Laboratory, Tokyo Institute of Technology, Nagatsuta 4259-R1-8, Midori-Ku, Yokohama, Kanagawa 226-8503, Japan. Tel.: +81 45 924 5234; Fax: +81 45 924 5277; E-mail:
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14
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Ni ZL, Dong H, Wei JM. N-terminal deletion of the gamma subunit affects the stabilization and activity of chloroplast ATP synthase. FEBS J 2005; 272:1379-85. [PMID: 15752355 DOI: 10.1111/j.1742-4658.2005.04570.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Five truncation mutants of chloroplast ATP synthase gamma subunit from spinach (Spinacia oleracea) lacking 8, 12, 16, 20 or 60 N-terminal amino acids were generated by PCR by a mutagenesis method. The recombinant gamma genes were overexpressed in Escherichia coli and assembled with alphabeta subunits into a native complex. The wild-type (WT) alphabetagamma assembly i.e. alphabetagammaWT exhibited high (Mg2+)-dependent and (Ca2+)-dependent ATP hydrolytic activity. Deletions of eight residues of the gamma subunit N-terminus caused a decrease in rates of ATP hydrolysis to 30% of that of the alphabetaWT assembly. Furthermore, only approximately 6% of ATP hydrolytic activity was retained with the sequential deletions of gamma subunit up to 20 residues compared with the activity of the alphabetaWT assembly. The inhibitory effect of the epsilon subunit on ATP hydrolysis of these alphabetagamma assemblies varied to a large extent. These observations indicate that the N-terminus of the gamma subunit is very important, together with other regions of the gamma subunit, in stabilization of the enzyme complex or during cooperative catalysis. In addition, the in vitro binding assay showed that the gamma subunit N-terminus is not a crucial region in binding of the epsilon subunit.
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Affiliation(s)
- Zhang-Lin Ni
- Shanghai Institute of Plant Physiology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
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15
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Tucker WC, Schwarz A, Levine T, Du Z, Gromet-Elhanan Z, Richter ML, Haran G. Observation of calcium-dependent unidirectional rotational motion in recombinant photosynthetic F1-ATPase molecules. J Biol Chem 2004; 279:47415-8. [PMID: 15377671 DOI: 10.1074/jbc.c400269200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
ATP hydrolysis and synthesis by the F(0)F(1)-ATP synthase are coupled to proton translocation across the membrane in the presence of magnesium. Calcium is known, however, to disrupt this coupling in the photosynthetic enzyme in a unique way: it does not support ATP synthesis, and CaATP hydrolysis is decoupled from any proton translocation, but the membrane does not become leaky to protons. Understanding the molecular basis of these calcium-dependent effects can shed light on the as yet unclear mechanism of coupling between proton transport and rotational catalysis. We show here, using an actin filament gamma-rotation assay, that CaATP is capable of sustaining rotational motion in a highly active hybrid photosynthetic F(1)-ATPase consisting of alpha and beta subunits from Rhodospirillum rubrum and gamma subunit from spinach chloroplasts (alpha(R)(3)beta(R)(3)gamma(C)). The rotation was found to be similar to that induced by MgATP in Escherichia coli F(1)-ATPase molecules. Our results suggest a possible long range pathway that enables the bound CaATP to induce full rotational motion of gamma but might block transmission of this rotational motion into proton translocation by the F(0) part of the ATP synthase.
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Affiliation(s)
- Ward C Tucker
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas 66045, USA
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16
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Grüber G, Godovac-Zimmermann J, Link TA, Coskun U, Rizzo VF, Betz C, Bailer SM. Expression, purification, and characterization of subunit E, an essential subunit of the vacuolar ATPase. Biochem Biophys Res Commun 2002; 298:383-91. [PMID: 12413952 DOI: 10.1016/s0006-291x(02)02468-3] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A recombinant form of subunit E (Vma4p) from yeast vacuolar ATPases (V-ATPases) has been overexpressed in Escherichia coli, purified to homogeneity, and explored by mass spectrometry. Analysis of the secondary structure of Vma4p by circular dichroism spectroscopy indicated 32% alpha-helix and 23% beta-sheet content. Vma4p formed a hybrid-complex with the nucleotide-binding subunits alpha and beta of the closely related F(1) ATPase of the thermophilic bacterium PS3 (TF(1)). The alpha(3)beta(3)E-hybrid-complex had 56% of the ATPase activity of the native TF(1). By comparison, an alpha(3)beta(3)-formation without Vma4p showed about 24% of total TF(1) ATPase activity. This is the first demonstration of a hydrolytically active hybrid-complex consisting of F(1) and V(1) subunits. The arrangement of subunit E in V(1) has been probed using the recombinant Vma4p, the alpha(3)beta(3)E-hybrid-complex together with V(1) and an A(3)B(3)HEG-subcomplex of the V(1) ATPase from Manduca sexta, respectively, indicating that subunit E is shielded in V(1).
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Affiliation(s)
- Gerhard Grüber
- Fachrichtung 2.5-Biophysik, Universität des Saarlandes, D-66421 Homburg, Germany.
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Tucker WC, Du Z, Gromet-Elhanan Z, Richter ML. Formation and properties of hybrid photosynthetic F1-ATPases. Demonstration of different structural requirements for stimulation and inhibition by tentoxin. EUROPEAN JOURNAL OF BIOCHEMISTRY 2001; 268:2179-86. [PMID: 11277942 DOI: 10.1046/j.1432-1327.2001.02110.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A hybrid ATPase composed of cloned chloroplast ATP synthase beta and gamma subunits (betaC and gammaC) and the cloned alpha subunit from the Rhodospirillum rubrum ATP synthase (alphaR) was assembled using solubilized inclusion bodies and a simple single-step folding procedure. The catalytic properties of the assembled alpha3Rbeta3CgammaC were compared to those of the core alpha3Cbeta3CgammaC complex of the native chloroplast coupling factor 1 (CF1) and to another recently described hybrid enzyme containing R. rubrum alpha and beta subunits and the CF1 gamma subunit (alpha3Rbeta3RgammaC). All three enzymes were similarly stimulated by dithiothreitol and inhibited by copper chloride in response to reduction and oxidation, respectively, of the disulfide bond in the chloroplast gamma subunit. In addition, all three enzymes exhibited the same concentration dependence for inhibition by the CF1 epsilon subunit. Thus the CF1 gamma subunit conferred full redox regulation and normal epsilon binding to the two hybrid enzymes. Only the native CF1 alpha3Cbeta3CgammaC complex was inhibited by tentoxin, confirming the requirement for both CF1 alpha and beta subunits for tentoxin inhibition. However, the alpha3Rbeta3CgammaC complex, like the alpha3Cbeta3CgammaC complex, was stimulated by tentoxin at concentrations in excess of 10 microm. In addition, replacement of the aspartate at position 83 in betaC with leucine resulted in the loss of stimulation in the alpha3Rbeta3CgammaC hybrid. The results indicate that both inhibition and stimulation by tentoxin require a similar structural contribution from the beta subunit, but differ in their requirements for alpha subunit structure.
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Affiliation(s)
- W C Tucker
- Department of Molecular Biosciences, University of Kansas, Lawrence 66045, USA
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