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Zhuang H, Qin M, Liu B, Li R, Li Z. Combination of transcriptomics, metabolomics and physiological traits reveals the effects of polystyrene microplastics on photosynthesis, carbon and nitrogen metabolism in cucumber (Cucumis sativus L.). PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2023; 205:108201. [PMID: 37995577 DOI: 10.1016/j.plaphy.2023.108201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 10/20/2023] [Accepted: 11/13/2023] [Indexed: 11/25/2023]
Abstract
Although microplastic pollution has been widely studied, the mechanism by which they influence plant photosynthesis and carbon and nitrogen metabolism remains unclear. We aimed to explore the effects of polystyrene microplastics (PS) on photosynthesis and carbon and nitrogen metabolism in cucumber using 5 μm and 0.1 μm PS particles. The PS treatments significantly reduced the stability of cucumber mesophyll cells and photosynthetic parameters and increased the soluble sugar content in cucumber leaves. The 5 μm PS affected the photosynthetic pathway by changing the expression of enzyme genes required for the synthesis of NADPH and ATP, which decreased the photosynthetic capacity in cucumber leaves. However, 0.1 μm PS altered the genes expression of phosphoenolpyruvate carboxykinase (PEPCK) and phosphoenolpyruvate carboxylase (PEPC), which affected the intercellular CO2 concentration and attenuated the negative effects on photosynthetic efficiency. Additionally, PS reduced the expression levels of nitrate/nitrite transporter (NRT) and nitrate reductase (NR), reducing the nitrogen use efficiency in cucumber leaves and mesophyll cells damage through increased accumulation of reduced glutathione (GSH), γ-glutamylcysteine (γ-GC), and citrulline. This study provides a new scientific basis for exploring the effects of microplastics on plant photosynthesis and carbon and nitrogen metabolism.
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Affiliation(s)
- Haoran Zhuang
- College of Horticulture and Landscape, Henan Institute of Science and Technology, Xinxiang, Henan, 453003, China
| | - Mengru Qin
- College of Horticulture and Landscape, Henan Institute of Science and Technology, Xinxiang, Henan, 453003, China
| | - Bo Liu
- College of Horticulture and Landscape, Henan Institute of Science and Technology, Xinxiang, Henan, 453003, China
| | - Ruijing Li
- College of Horticulture and Landscape, Henan Institute of Science and Technology, Xinxiang, Henan, 453003, China
| | - Zhenxia Li
- College of Horticulture and Landscape, Henan Institute of Science and Technology, Xinxiang, Henan, 453003, China; Henan Province Engineering Research Center of Horticultural Plant Resource Utilization and Germplasm Enhancement, Xinxiang, Henan, 453003, China.
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2
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Nesterov SV, Yaguzhinsky LS. Directed proton transfer from F o to F 1 extends the multifaceted proton functions in ATP synthase. Biophys Rev 2023; 15:859-873. [PMID: 37975013 PMCID: PMC10643803 DOI: 10.1007/s12551-023-01132-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 08/30/2023] [Indexed: 11/19/2023] Open
Abstract
The role of protons in ATP synthase is typically considered to be energy storage in the form of an electrochemical potential, as well as an operating element proving rotation. However, this review emphasizes that protons also act as activators of conformational changes in F1 and as direct participants in phosphorylation reaction. The protons transferred through Fo do not immediately leave to the bulk aqueous phase, but instead provide for the formation of a pH gradient between acidifying Fo and alkalizing F1. It facilitates a directed inter-subunit proton transfer to F1, where they are used in the ATP synthesis reaction. This ensures that the enzyme activity is not limited by a lack of protons in the alkaline mitochondrial matrix or chloroplast stroma. Up to one hundred protons bind to the carboxyl groups of the F1 subunit, altering the electrical interactions between the amino acids of the enzyme. This removes the inhibition of ATP synthase caused by the electrostatic attraction of charged amino acids of the stator and rotor and also makes the enzyme more prone to conformational changes. Protonation occurs during ATP synthesis initiation and during phosphorylation, while deprotonation blocks the rotation inhibiting both synthesis and hydrolysis. Thus, protons participate in the functioning of all main components of ATP synthase molecular machine making it effectively a proton-driven electric machine. The review highlights the key role of protons as a coupling factor in ATP synthase with multifaceted functions, including charge and energy transport, torque generation, facilitation of conformational changes, and participation in the ATP synthesis reaction.
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Affiliation(s)
- Semen V. Nesterov
- Kurchatov Complex of NBICS-Technologies, National Research Center Kurchatov Institute, 123182 Moscow, Russia
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, 141701 Dolgoprudny, Russia
| | - Lev S. Yaguzhinsky
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, 141701 Dolgoprudny, Russia
- Belozersky Research Institute for Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia
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3
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Mackieh R, Al-Bakkar N, Kfoury M, Roufayel R, Sabatier JM, Fajloun Z. Inhibitors of ATP Synthase as New Antibacterial Candidates. Antibiotics (Basel) 2023; 12:antibiotics12040650. [PMID: 37107012 PMCID: PMC10135114 DOI: 10.3390/antibiotics12040650] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 03/20/2023] [Accepted: 03/22/2023] [Indexed: 03/29/2023] Open
Abstract
ATP, the power of all cellular functions, is constantly used and produced by cells. The enzyme called ATP synthase is the energy factory in all cells, which produces ATP by adding inorganic phosphate (Pi) to ADP. It is found in the inner, thylakoid and plasma membranes of mitochondria, chloroplasts and bacteria, respectively. Bacterial ATP synthases have been the subject of multiple studies for decades, since they can be genetically manipulated. With the emergence of antibiotic resistance, many combinations of antibiotics with other compounds that enhance the effect of these antibiotics have been proposed as approaches to limit the spread of antibiotic-resistant bacteria. ATP synthase inhibitors, such as resveratrol, venturicidin A, bedaquiline, tomatidine, piceatannol, oligomycin A and N,N-dicyclohexylcarbodiimide were the starting point of these combinations. However, each of these inhibitors target ATP synthase differently, and their co-administration with antibiotics increases the susceptibility of pathogenic bacteria. After a brief description of the structure and function of ATP synthase, we aim in this review to highlight therapeutic applications of the major bacterial ATP synthase inhibitors, including animal’s venoms, and to emphasize their importance in decreasing the activity of this enzyme and subsequently eradicating resistant bacteria as ATP synthase is their source of energy.
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4
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F1·Fo ATP Synthase/ATPase: Contemporary View on Unidirectional Catalysis. Int J Mol Sci 2023; 24:ijms24065417. [PMID: 36982498 PMCID: PMC10049701 DOI: 10.3390/ijms24065417] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 03/05/2023] [Accepted: 03/10/2023] [Indexed: 03/14/2023] Open
Abstract
F1·Fo-ATP synthases/ATPases (F1·Fo) are molecular machines that couple either ATP synthesis from ADP and phosphate or ATP hydrolysis to the consumption or production of a transmembrane electrochemical gradient of protons. Currently, in view of the spread of drug-resistant disease-causing strains, there is an increasing interest in F1·Fo as new targets for antimicrobial drugs, in particular, anti-tuberculosis drugs, and inhibitors of these membrane proteins are being considered in this capacity. However, the specific drug search is hampered by the complex mechanism of regulation of F1·Fo in bacteria, in particular, in mycobacteria: the enzyme efficiently synthesizes ATP, but is not capable of ATP hydrolysis. In this review, we consider the current state of the problem of “unidirectional” F1·Fo catalysis found in a wide range of bacterial F1·Fo and enzymes from other organisms, the understanding of which will be useful for developing a strategy for the search for new drugs that selectively disrupt the energy production of bacterial cells.
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5
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Heitkamp T, Börsch M. Fast ATP-Dependent Subunit Rotation in Reconstituted F oF 1-ATP Synthase Trapped in Solution. J Phys Chem B 2021; 125:7638-7650. [PMID: 34254808 DOI: 10.1021/acs.jpcb.1c02739] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
FoF1-ATP synthases are ubiquitous membrane-bound, rotary motor enzymes that can catalyze ATP synthesis and hydrolysis. Their enzyme kinetics are controlled by internal subunit rotation, by substrate and product concentrations, and by mechanical inhibitory mechanisms but also by the electrochemical potential of protons across the membrane. Single-molecule Förster resonance energy transfer (smFRET) has been used to detect subunit rotation within FoF1-ATP synthases embedded in freely diffusing liposomes. We now report that kinetic monitoring of functional rotation can be prolonged from milliseconds to seconds by utilizing an anti-Brownian electrokinetic trap (ABEL trap). These extended observation times allowed us to observe fluctuating rates of functional rotation for individual FoF1-liposomes in solution. Broad distributions of ATP-dependent catalytic rates were revealed. The buildup of an electrochemical potential of protons was confirmed to limit the maximum rate of ATP hydrolysis. In the presence of ionophores or uncouplers, the fastest subunit rotation speeds measured in single reconstituted FoF1-ATP synthases were 180 full rounds per second. This was much faster than measured by biochemical ensemble averaging, but not as fast as the maximum rotational speed reported previously for isolated single F1 complexes uncoupled from the membrane-embedded Fo complex. Further application of ABEL trap measurements should help resolve the mechanistic causes of such fluctuating rates of subunit rotation.
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Affiliation(s)
- Thomas Heitkamp
- Single-Molecule Microscopy Group, Jena University Hospital, Nonnenplan 2-4, 07743 Jena, Germany
| | - Michael Börsch
- Single-Molecule Microscopy Group, Jena University Hospital, Nonnenplan 2-4, 07743 Jena, Germany
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6
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Feng M, Gilson MK. Mechanistic analysis of light-driven overcrowded alkene-based molecular motors by multiscale molecular simulations. Phys Chem Chem Phys 2021; 23:8525-8540. [PMID: 33876015 PMCID: PMC8102045 DOI: 10.1039/d0cp06685k] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
We analyze light-driven overcrowded alkene-based molecular motors, an intriguing class of small molecules that have the potential to generate MHz-scale rotation rates. The full rotation process is simulated at multiple scales by combining quantum surface-hopping molecular dynamics (MD) simulations for the photoisomerization step with classical MD simulations for the thermal helix inversion step. A Markov state analysis resolves conformational substates, their interconversion kinetics, and their roles in the motor's rotation process. Furthermore, motor performance metrics, including rotation rate and maximal power output, are computed to validate computations against experimental measurements and to inform future designs. Lastly, we find that to correctly model these motors, the force field must be optimized by fitting selected parameters to reference quantum mechanical energy surfaces. Overall, our simulations yield encouraging agreement with experimental observables such as rotation rates, and provide mechanistic insights that may help future designs.
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Affiliation(s)
- Mudong Feng
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, 92093, USA.
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7
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Jarman OD, Biner O, Hirst J. Regulation of ATP hydrolysis by the ε subunit, ζ subunit and Mg-ADP in the ATP synthase of Paracoccus denitrificans. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1862:148355. [PMID: 33321110 PMCID: PMC8039183 DOI: 10.1016/j.bbabio.2020.148355] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 11/27/2020] [Accepted: 12/08/2020] [Indexed: 12/17/2022]
Abstract
F1FO-ATP synthase is a crucial metabolic enzyme that uses the proton motive force from respiration to regenerate ATP. For maximum thermodynamic efficiency ATP synthesis should be fully reversible, but the enzyme from Paracoccus denitrificans catalyzes ATP hydrolysis at far lower rates than it catalyzes ATP synthesis, an effect often attributed to its unique ζ subunit. Recently, we showed that deleting ζ increases hydrolysis only marginally, indicating that other common inhibitory mechanisms such as inhibition by the C-terminal domain of the ε subunit (ε-CTD) or Mg-ADP may be more important. Here, we created mutants lacking the ε-CTD, and double mutants lacking both the ε-CTD and ζ subunit. No substantial activation of ATP hydrolysis was observed in any of these strains. Instead, hydrolysis in even the double mutant strains could only be activated by oxyanions, the detergent lauryldimethylamine oxide, or a proton motive force, which are all considered to release Mg-ADP inhibition. Our results establish that P. denitrificans ATP synthase is regulated by a combination of the ε and ζ subunits and Mg-ADP inhibition.
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Affiliation(s)
- Owen D Jarman
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Olivier Biner
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Judy Hirst
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK.
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8
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Milgrom YM, Duncan TM. F-ATP-ase of Escherichia coli membranes: The ubiquitous MgADP-inhibited state and the inhibited state induced by the ε-subunit's C-terminal domain are mutually exclusive. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148189. [PMID: 32194063 DOI: 10.1016/j.bbabio.2020.148189] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 03/10/2020] [Accepted: 03/13/2020] [Indexed: 12/21/2022]
Abstract
ATP synthases are important energy-coupling, rotary motor enzymes in all kingdoms of life. In all F-type ATP synthases, the central rotor of the catalytic F1 complex is composed of the γ subunit and the N-terminal domain (NTD) of the ε subunit. In the enzymes of diverse bacteria, the C-terminal domain of ε (εCTD) can undergo a dramatic conformational change to trap the enzyme in a transiently inactive state. This inhibitory mechanism is absent in the mitochondrial enzyme, so the εCTD could provide a means to selectively target ATP synthases of pathogenic bacteria for antibiotic development. For Escherichia coli and other bacterial model systems, it has been difficult to dissect the relationship between ε inhibition and a MgADP-inhibited state that is ubiquitous for FOF1 from bacteria and eukaryotes. A prior study with the isolated catalytic complex from E. coli, EcF1, showed that these two modes of inhibition are mutually exclusive, but it has long been known that interactions of F1 with the membrane-embedded FO complex modulate inhibition by the εCTD. Here, we study membranes containing EcFOF1 with wild-type ε, ε lacking the full εCTD, or ε with a small deletion at the C-terminus. By using compounds with distinct activating effects on F-ATP-ase activity, we confirm that εCTD inhibition and ubiquitous MgADP inhibition are mutually exclusive for membrane-bound E. coli F-ATP-ase. We determine that most of the enzyme complexes in wild-type membranes are in the ε-inhibited state (>50%) or in the MgADP-inhibited state (30%).
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Affiliation(s)
- Yakov M Milgrom
- Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University, 750 E Adams St, Syracuse, NY 13210, USA.
| | - Thomas M Duncan
- Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University, 750 E Adams St, Syracuse, NY 13210, USA.
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9
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Abstract
Many enzymes appear to diffuse faster in the presence of substrate and to drift either up or down a concentration gradient of their substrate. Observations of these phenomena, termed enhanced enzyme diffusion (EED) and enzyme chemotaxis, respectively, lead to a novel view of enzymes as active matter. Enzyme chemotaxis and EED may be important in biology and could have practical applications in biotechnology and nanotechnology. They are also of considerable biophysical interest; indeed, their physical mechanisms are still quite uncertain. This review provides an analytic summary of experimental studies of these phenomena and of the mechanisms that have been proposed to explain them and offers a perspective on future directions for the field.
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Affiliation(s)
- Mudong Feng
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA;
| | - Michael K Gilson
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA; .,Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093, USA
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10
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Feng M, Gilson MK. A Thermodynamic Limit on the Role of Self-Propulsion in Enhanced Enzyme Diffusion. Biophys J 2019; 116:1898-1906. [PMID: 31053258 PMCID: PMC6531786 DOI: 10.1016/j.bpj.2019.04.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 03/06/2019] [Accepted: 04/02/2019] [Indexed: 01/01/2023] Open
Abstract
A number of enzymes reportedly exhibit enhanced diffusion in the presence of their substrates, with a Michaelis-Menten-like concentration dependence. Although no definite explanation of this phenomenon has emerged, a physical picture of enzyme self-propulsion using energy from the catalyzed reaction has been widely considered. Here, we present a kinematic and thermodynamic analysis of enzyme self-propulsion that is independent of any specific propulsion mechanism. Using this theory, along with biophysical data compiled for all enzymes so far shown to undergo enhanced diffusion, we show that the propulsion speed required to generate experimental levels of enhanced diffusion exceeds the speeds of well-known active biomolecules, such as myosin, by several orders of magnitude. Furthermore, the minimal power dissipation required to account for enzyme enhanced diffusion by self-propulsion markedly exceeds the chemical power available from enzyme-catalyzed reactions. Alternative explanations for the observation of enhanced enzyme diffusion therefore merit stronger consideration.
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Affiliation(s)
- Mudong Feng
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California
| | - Michael K Gilson
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California; Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California.
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11
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Inabe K, Kondo K, Yoshida K, Wakabayashi KI, Hisabori T. The N-terminal region of the ϵ subunit from cyanobacterial ATP synthase alone can inhibit ATPase activity. J Biol Chem 2019; 294:10094-10103. [PMID: 31068416 DOI: 10.1074/jbc.ra118.007131] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 05/07/2019] [Indexed: 11/06/2022] Open
Abstract
ATP hydrolysis activity catalyzed by chloroplast and proteobacterial ATP synthase is inhibited by their ϵ subunits. To clarify the function of the ϵ subunit from phototrophs, here we analyzed the ϵ subunit-mediated inhibition (ϵ-inhibition) of cyanobacterial F1-ATPase, a subcomplex of ATP synthase obtained from the thermophilic cyanobacterium Thermosynechococcus elongatus BP-1. We generated three C-terminal α-helix null ϵ-mutants; one lacked the C-terminal α-helices, and in the other two, the C-terminal conformation could be locked by a disulfide bond formed between two α-helices or an α-helix and a β-sandwich structure. All of these ϵ-mutants maintained ATPase-inhibiting competency. We then used single-molecule observation techniques to analyze the rotary motion of F1-ATPase in the presence of these ϵ-mutants. The stop angular position of the γ subunit in the presence of the ϵ-mutant was identical to that in the presence of the WT ϵ. Using magnetic tweezers, we examined recovery from the inhibited rotation and observed restoration of rotation by 80° forcing of the γ subunit in the case of the ADP-inhibited form, but not when the rotation was inhibited by the ϵ-mutants or by the WT ϵ subunit. These results imply that the C-terminal α-helix domain of the ϵ subunit of cyanobacterial enzyme does not directly inhibit ATP hydrolysis and that its N-terminal domain alone can inhibit the hydrolysis activity. Notably, this property differed from that of the proteobacterial ϵ, which could not tightly inhibit rotation. We conclude that phototrophs and heterotrophs differ in the ϵ subunit-mediated regulation of ATP synthase.
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Affiliation(s)
- Kosuke Inabe
- From the Laboratory for Chemistry and Life Science, Tokyo Institute of Technology, Nagatsuta-cho 4259-R1-8, Midori-ku, Yokohama 226-8503, Japan and.,the School of Life Science and Technology, Tokyo Institute of Technology, Nagatsuta-cho 4259, Midori-ku, Yokohama 226-8501, Japan
| | - Kumiko Kondo
- From the Laboratory for Chemistry and Life Science, Tokyo Institute of Technology, Nagatsuta-cho 4259-R1-8, Midori-ku, Yokohama 226-8503, Japan and
| | - Keisuke Yoshida
- From the Laboratory for Chemistry and Life Science, Tokyo Institute of Technology, Nagatsuta-cho 4259-R1-8, Midori-ku, Yokohama 226-8503, Japan and
| | - Ken-Ichi Wakabayashi
- From the Laboratory for Chemistry and Life Science, Tokyo Institute of Technology, Nagatsuta-cho 4259-R1-8, Midori-ku, Yokohama 226-8503, Japan and.,the School of Life Science and Technology, Tokyo Institute of Technology, Nagatsuta-cho 4259, Midori-ku, Yokohama 226-8501, Japan
| | - Toru Hisabori
- From the Laboratory for Chemistry and Life Science, Tokyo Institute of Technology, Nagatsuta-cho 4259-R1-8, Midori-ku, Yokohama 226-8503, Japan and .,the School of Life Science and Technology, Tokyo Institute of Technology, Nagatsuta-cho 4259, Midori-ku, Yokohama 226-8501, Japan
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12
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Akanuma G, Tagana T, Sawada M, Suzuki S, Shimada T, Tanaka K, Kawamura F, Kato-Yamada Y. C-terminal regulatory domain of the ε subunit of F o F 1 ATP synthase enhances the ATP-dependent H + pumping that is involved in the maintenance of cellular membrane potential in Bacillus subtilis. Microbiologyopen 2019; 8:e00815. [PMID: 30809948 PMCID: PMC6692558 DOI: 10.1002/mbo3.815] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 01/16/2019] [Accepted: 01/18/2019] [Indexed: 01/23/2023] Open
Abstract
The ε subunit of FoF1‐ATPase/synthase (FoF1) plays a crucial role in regulating FoF1 activity. To understand the physiological significance of the ε subunit‐mediated regulation of FoF1 in Bacillus subtilis, we constructed and characterized a mutant harboring a deletion in the C‐terminal regulatory domain of the ε subunit (ε∆C). Analyses using inverted membrane vesicles revealed that the ε∆C mutation decreased ATPase activity and the ATP‐dependent H+‐pumping activity of FoF1. To enhance the effects of ε∆C mutation, this mutation was introduced into a ∆rrn8 strain harboring only two of the 10 rrn (rRNA) operons (∆rrn8 ε∆C mutant strain). Interestingly, growth of the ∆rrn8 ε∆C mutant stalled at late‐exponential phase. During the stalled growth phase, the membrane potential of the ∆rrn8 ε∆C mutant cells was significantly reduced, which led to a decrease in the cellular level of 70S ribosomes. The growth stalling was suppressed by adding glucose into the culture medium. Our findings suggest that the C‐terminal region of the ε subunit is important for alleviating the temporal reduction in the membrane potential, by enhancing the ATP‐dependent H+‐pumping activity of FoF1.
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Affiliation(s)
- Genki Akanuma
- Department of Life Science, College of Science, Rikkyo University, Toshima-ku, Tokyo, Japan.,Research Center for Life Science, College of Science, Rikkyo University, Toshima-ku, Tokyo, Japan
| | - Tomoaki Tagana
- Department of Life Science, College of Science, Rikkyo University, Toshima-ku, Tokyo, Japan
| | - Maho Sawada
- Department of Life Science, College of Science, Rikkyo University, Toshima-ku, Tokyo, Japan
| | - Shota Suzuki
- Department of Life Science, College of Science, Rikkyo University, Toshima-ku, Tokyo, Japan
| | - Tomohiro Shimada
- Laboratory for Chemistry and Life Science, Institute of Innovative Science, Tokyo Institute of Technology, Yokohama, Midori-ku, Japan
| | - Kan Tanaka
- Laboratory for Chemistry and Life Science, Institute of Innovative Science, Tokyo Institute of Technology, Yokohama, Midori-ku, Japan
| | - Fujio Kawamura
- Department of Life Science, College of Science, Rikkyo University, Toshima-ku, Tokyo, Japan
| | - Yasuyuki Kato-Yamada
- Department of Life Science, College of Science, Rikkyo University, Toshima-ku, Tokyo, Japan.,Research Center for Life Science, College of Science, Rikkyo University, Toshima-ku, Tokyo, Japan
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13
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Mendoza-Hoffmann F, Zarco-Zavala M, Ortega R, García-Trejo JJ. Control of rotation of the F1FO-ATP synthase nanomotor by an inhibitory α-helix from unfolded ε or intrinsically disordered ζ and IF1 proteins. J Bioenerg Biomembr 2018; 50:403-424. [DOI: 10.1007/s10863-018-9773-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 09/13/2018] [Indexed: 12/14/2022]
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14
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Abstract
Emerging microtechnologies are aimed at developing a microsystem with densely packed array structure, i.e., an array with a femtoliter reaction chamber, for highly sensitive and quantitative biological assays. Here, we describe a novel femtoliter chamber array system (arrayed lipid bilayer chambers, ALBiC) that contains approximately a million femtoliter chambers, each sealed with a phospholipid bilayer membrane with extremely high efficiency (>90%). This novel platform enables detection of membrane transporter activity at the single-molecule level and thus expands the applicability of femtoliter chamber arrays to highly sensitive assays of transporters.
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15
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Sielaff H, Duncan TM, Börsch M. The regulatory subunit ε in Escherichia coli F OF 1-ATP synthase. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:775-788. [PMID: 29932911 DOI: 10.1016/j.bbabio.2018.06.013] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 06/13/2018] [Accepted: 06/14/2018] [Indexed: 11/16/2022]
Abstract
F-type ATP synthases are extraordinary multisubunit proteins that operate as nanomotors. The Escherichia coli (E. coli) enzyme uses the proton motive force (pmf) across the bacterial plasma membrane to drive rotation of the central rotor subunits within a stator subunit complex. Through this mechanical rotation, the rotor coordinates three nucleotide binding sites that sequentially catalyze the synthesis of ATP. Moreover, the enzyme can hydrolyze ATP to turn the rotor in the opposite direction and generate pmf. The direction of net catalysis, i.e. synthesis or hydrolysis of ATP, depends on the cell's bioenergetic conditions. Different control mechanisms have been found for ATP synthases in mitochondria, chloroplasts and bacteria. This review discusses the auto-inhibitory behavior of subunit ε found in FOF1-ATP synthases of many bacteria. We focus on E. coli FOF1-ATP synthase, with insights into the regulatory mechanism of subunit ε arising from structural and biochemical studies complemented by single-molecule microscopy experiments.
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Affiliation(s)
- Hendrik Sielaff
- Single-Molecule Microscopy Group, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Thomas M Duncan
- Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Michael Börsch
- Single-Molecule Microscopy Group, Jena University Hospital, Friedrich Schiller University, Jena, Germany.
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16
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Krah A, Zarco-Zavala M, McMillan DGG. Insights into the regulatory function of the ɛ subunit from bacterial F-type ATP synthases: a comparison of structural, biochemical and biophysical data. Open Biol 2018; 8:170275. [PMID: 29769322 PMCID: PMC5990651 DOI: 10.1098/rsob.170275] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Accepted: 04/24/2018] [Indexed: 01/07/2023] Open
Abstract
ATP synthases catalyse the formation of ATP, the most common chemical energy storage unit found in living cells. These enzymes are driven by an electrochemical ion gradient, which allows the catalytic evolution of ATP by a binding change mechanism. Most ATP synthases are capable of catalysing ATP hydrolysis to varying degrees, and to prevent wasteful ATP hydrolysis, bacteria and mitochondria have regulatory mechanisms such as ADP inhibition. Additionally, ɛ subunit inhibition has also been described in three bacterial systems, Escherichia coli, Bacillus PS3 and Caldalkalibacillus thermarum TA2.A1. Previous studies suggest that the ɛ subunit is capable of undergoing an ATP-dependent conformational change from the ATP hydrolytic inhibitory 'extended' conformation to the ATP-induced non-inhibitory 'hairpin' conformation. A recently published crystal structure of the F1 domain of the C. thermarum TA2.A1 F1Fo ATP synthase revealed a mutant ɛ subunit lacking the ability to bind ATP in a hairpin conformation. This is a surprising observation considering it is an organism that performs no ATP hydrolysis in vivo, and appears to challenge the current dogma on the regulatory role of the ɛ subunit. This has prompted a re-examination of present knowledge of the ɛ subunits role in different organisms. Here, we compare published biochemical, biophysical and structural data involving ɛ subunit-mediated ATP hydrolysis regulation in a variety of organisms, concluding that the ɛ subunit from the bacterial F-type ATP synthases is indeed capable of regulating ATP hydrolysis activity in a wide variety of bacteria, making it a potentially valuable drug target, but its exact role is still under debate.
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Affiliation(s)
- Alexander Krah
- School of Computational Sciences, Korea Institute for Advanced Study, 85 Hoegiro Dongdaemun-gu, Seoul 02455, Republic of Korea
| | - Mariel Zarco-Zavala
- Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan
| | - Duncan G G McMillan
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, Delft 2629 HZ, The Netherlands
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17
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Zhang F, Hu H, Wang L, Zhou Q, Huang X. Effects of rare earth and acid rain pollution on plant chloroplast ATP synthase and element contents at different growth stages. CHEMOSPHERE 2018; 194:441-449. [PMID: 29227892 DOI: 10.1016/j.chemosphere.2017.12.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 11/30/2017] [Accepted: 12/01/2017] [Indexed: 06/07/2023]
Abstract
UNLABELLED Combined rare earth and acid rain pollution has become a new environmental problem, seriously affecting plant survival. The effects of these two kinds of pollutants on plant photosynthesis have been reported, but the micro mechanisms are not very clear. In this research, we studied the effects of lanthanum [La(III), 0.08, 1.20 and 2.40 mM] and acid rain (pH value = 2.5, 3.5 and 4.5) on the ATPase activity and gene transcription level and the functional element contents in rice leaf chloroplasts. The results showed that the combined 0.08 mM La(III) and pH 4.5 acid rain increased the ATPase activity and gene transcription level as well as contents of some functional elements. But other combined treatments of acid rain and La(III) reduced the ATPase activity and gene transcription level as well as functional element contents. The change magnitude of the above indexes at rice booting stage was greater than that in seedling stage or grain filling stage. These results reveal that effects of La(III) and acid rain on ATPase activity and functional element contents in rice leaf chloroplasts are related to the combination of La(III) dose and acid rain intensity and the plant growth stage. In addition, the changes in the ATPase activity were related to ATPase gene transcription level. This study would provide a reference for understanding the microcosmic mechanism of rare earth and acid rain pollution on plant photosynthesis and contribute to evaluate the possible environmental risks associated with combined La(III) and acid rain pollution. ONE SENTENCE SUMMARY The effects of La(III) and acid rain on activity and gene transcription level of rice chloroplast ATPase and contents of functional elements were different at different growth stages.
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Affiliation(s)
- Fan Zhang
- State Key Laboratory of Food Science and Technology, Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China
| | - Huiqing Hu
- State Key Laboratory of Food Science and Technology, Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China
| | - Lihong Wang
- State Key Laboratory of Food Science and Technology, Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China
| | - Qing Zhou
- State Key Laboratory of Food Science and Technology, Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China; Jiangsu Cooperative Innovation Center of Water Treatment Technology and Materials, Suzhou University of Science and Technology, Suzhou 215009, China.
| | - Xiaohua Huang
- Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, Jiangsu Key Laboratory of Biomedical Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210046, China.
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18
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Mendoza-Hoffmann F, Pérez-Oseguera Á, Cevallos MÁ, Zarco-Zavala M, Ortega R, Peña-Segura C, Espinoza-Simón E, Uribe-Carvajal S, García-Trejo JJ. The Biological Role of the ζ Subunit as Unidirectional Inhibitor of the F 1F O-ATPase of Paracoccus denitrificans. Cell Rep 2018; 22:1067-1078. [PMID: 29386127 DOI: 10.1016/j.celrep.2017.12.106] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 09/09/2017] [Accepted: 12/28/2017] [Indexed: 11/16/2022] Open
Abstract
The biological roles of the three natural F1FO-ATPase inhibitors, ε, ζ, and IF1, on cell physiology remain controversial. The ζ subunit is a useful model for deletion studies since it mimics mitochondrial IF1, but in the F1FO-ATPase of Paracoccus denitrificans (PdF1FO), it is a monogenic and supernumerary subunit. Here, we constructed a P. denitrificans 1222 derivative (PdΔζ) with a deleted ζ gene to determine its role in cell growth and bioenergetics. The results show that the lack of ζ in vivo strongly restricts respiratory P. denitrificans growth, and this is restored by complementation in trans with an exogenous ζ gene. Removal of ζ increased the coupled PdF1FO-ATPase activity without affecting the PdF1FO-ATP synthase turnover, and the latter was not affected at all by ζ reconstitution in vitro. Therefore, ζ works as a unidirectional pawl-ratchet inhibitor of the PdF1FO-ATPase nanomotor favoring the ATP synthase turnover to improve respiratory cell growth and bioenergetics.
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Affiliation(s)
- Francisco Mendoza-Hoffmann
- Departamento de Biología, Facultad de Química, Ciudad Universitaria, Universidad Nacional Autónoma de México (U.N.A.M.), Delegación Coyoacán, Ciudad de México (CDMX) 04510, México
| | - Ángeles Pérez-Oseguera
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, U.N.A.M., Cuernavaca, Morelos, México
| | - Miguel Ángel Cevallos
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, U.N.A.M., Cuernavaca, Morelos, México
| | | | - Raquel Ortega
- Departamento de Biología, Facultad de Química, Ciudad Universitaria, Universidad Nacional Autónoma de México (U.N.A.M.), Delegación Coyoacán, Ciudad de México (CDMX) 04510, México
| | | | | | | | - José J García-Trejo
- Departamento de Biología, Facultad de Química, Ciudad Universitaria, Universidad Nacional Autónoma de México (U.N.A.M.), Delegación Coyoacán, Ciudad de México (CDMX) 04510, México.
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19
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Heiske M, Letellier T, Klipp E. Comprehensive mathematical model of oxidative phosphorylation valid for physiological and pathological conditions. FEBS J 2017. [PMID: 28646582 DOI: 10.1111/febs.14151] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
We developed a mathematical model of oxidative phosphorylation (OXPHOS) that allows for a precise description of mitochondrial function with respect to the respiratory flux and the ATP production. The model reproduced flux-force relationships under various experimental conditions (state 3 and 4, uncoupling, and shortage of respiratory substrate) as well as time courses, exhibiting correct P/O ratios. The model was able to reproduce experimental threshold curves for perturbations of the respiratory chain complexes, the F1 F0 -ATP synthase, the ADP/ATP carrier, the phosphate/OH carrier, and the proton leak. Thus, the model is well suited to study complex interactions within the OXPHOS system, especially with respect to physiological adaptations or pathological modifications, influencing substrate and product affinities or maximal catalytic rates. Moreover, it could be a useful tool to study the role of OXPHOS and its capacity to compensate or enhance physiopathologies of the mitochondrial and cellular energy metabolism.
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Affiliation(s)
- Margit Heiske
- Laboratoire d'Anthropologie Moléculaire et Imaginérie de Synthèse, Médecine Evolutive, UMR 5288 CNRS, Faculté de Médecine, Université de Toulouse, France.,Theoretische Biophysik, Institut für Biologie, Humboldt-Universität zu Berlin, Germany
| | - Thierry Letellier
- Laboratoire d'Anthropologie Moléculaire et Imaginérie de Synthèse, Médecine Evolutive, UMR 5288 CNRS, Faculté de Médecine, Université de Toulouse, France
| | - Edda Klipp
- Theoretische Biophysik, Institut für Biologie, Humboldt-Universität zu Berlin, Germany
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20
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Krah A, Kato-Yamada Y, Takada S. The structural basis of a high affinity ATP binding ε subunit from a bacterial ATP synthase. PLoS One 2017; 12:e0177907. [PMID: 28542497 PMCID: PMC5436830 DOI: 10.1371/journal.pone.0177907] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 05/04/2017] [Indexed: 01/09/2023] Open
Abstract
The ε subunit from bacterial ATP synthases functions as an ATP sensor, preventing ATPase activity when the ATP concentration in bacterial cells crosses a certain threshold. The R103A/R115A double mutant of the ε subunit from thermophilic Bacillus PS3 has been shown to bind ATP two orders of magnitude stronger than the wild type protein. We use molecular dynamics simulations and free energy calculations to derive the structural basis of the high affinity ATP binding to the R103A/R115A double mutant. Our results suggest that the double mutant is stabilized by an enhanced hydrogen-bond network and fewer repulsive contacts in the ligand binding site. The inferred structural basis of the high affinity mutant may help to design novel nucleotide sensors based on the ε subunit from bacterial ATP synthases.
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Affiliation(s)
- Alexander Krah
- Department of Biophysics, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto, Japan
- School of Computational Sciences, Korea Institute for Advanced Study, Dongdaemun-gu, Seoul, Republic of Korea
- * E-mail:
| | - Yasuyuki Kato-Yamada
- Department of Life Science, College of Science, Rikkyo University, Nishi-Ikebukuro, Toshima-ku, Tokyo, Japan
| | - Shoji Takada
- Department of Biophysics, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto, Japan
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21
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AKUTSU H. Dynamic mechanisms driving conformational conversions of the β and ε subunits involved in rotational catalysis of F 1-ATPase. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2017; 93:630-647. [PMID: 29021512 PMCID: PMC5743862 DOI: 10.2183/pjab.93.040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 06/16/2017] [Indexed: 05/26/2023]
Abstract
F-type ATPase is a ubiquitous molecular motor. Investigations on thermophilic F1-ATPase and its subunits, β and ε, by NMR were reviewed. Using specific isotope labeling, pKa of the putative catalytic carboxylate in β was estimated. Segmental isotope-labeling enabled us to monitor most residues of β, revealing that the conformational conversion from open to closed form of β on nucleotide binding found in ATPase was an intrinsic property of β and could work as a driving force of the rotational catalysis. A stepwise conformational change was driven by switching of the hydrogen bond networks involving Walker A and B motifs. Segmentally labeled ATPase provided a well resolved NMR spectra, revealing while the open form of β was identical for β monomer and ATPase, its closed form could be different. ATP-binding was also a critical factor in the conformational conversion of ε, an ATP hydrolysis inhibitor. Its structural elucidation was described.
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Affiliation(s)
- Hideo AKUTSU
- Institute for Protein Research, Osaka University, Osaka, Japan
- Graduate School of Medical Life Science, Yokohama City University, Yokohama, Japan
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22
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Ju SY, Kim JH, Lee PC. Long-term adaptive evolution of Leuconostoc mesenteroides for enhancement of lactic acid tolerance and production. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:240. [PMID: 27843489 PMCID: PMC5103595 DOI: 10.1186/s13068-016-0662-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 11/04/2016] [Indexed: 05/24/2023]
Abstract
BACKGROUND Lactic acid has been approved by the United States Food and Drug Administration as Generally Regarded As Safe (GRAS) and is commonly used in the cosmetics, pharmaceutical, and food industries. Applications of lactic acid have also emerged in the plastics industry. Lactic acid bacteria (LAB), such as Leuconostoc and Lactobacillus, are widely used as lactic acid producers for food-related and biotechnological applications. Nonetheless, industrial mass production of lactic acid in LAB is a challenge mainly because of growth inhibition caused by the end product, lactic acid. Thus, it is important to improve acid tolerance of LAB to achieve balanced cell growth and a high titer of lactic acid. Recently, adaptive evolution has been employed as one of the strategies to improve the fitness and to induce adaptive changes in bacteria under specific growth conditions, such as acid stress. RESULTS Wild-type Leuconostoc mesenteroides was challenged long term with exogenously supplied lactic acid, whose concentration was increased stepwise (for enhancement of lactic acid tolerance) during 1 year. In the course of the adaptive evolution at 70 g/L lactic acid, three mutants (LMS50, LMS60, and LMS70) showing high specific growth rates and lactic acid production were isolated and characterized. Mutant LMS70, isolated at 70 g/L lactic acid, increased d-lactic acid production up to 76.8 g/L, which was twice that in the wild type (37.8 g/L). Proteomic, genomic, and physiological analyses revealed that several possible factors affected acid tolerance, among which a mutation of ATPase ε subunit (involved in the regulation of intracellular pH) and upregulation of intracellular ammonia, as a buffering system, were confirmed to contribute to the observed enhancement of tolerance and production of d-lactic acid. CONCLUSIONS During adaptive evolution under lethal stress conditions, the fitness of L. mesenteroides gradually increased to accumulate beneficial mutations according to the stress level. The enhancement of acid tolerance in the mutants contributed to increased production of d-lactic acid. The observed genetic and physiological changes may systemically help remove protons and retain viability at high lactic acid concentrations.
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Affiliation(s)
- Si Yeon Ju
- Department of Molecular Science and Technology, Ajou University, Woncheon-dong, Yeongtong-gu, Suwon, 443-749 South Korea
- Department of Applied Chemistry and Biological Engineering, Ajou University, Woncheon-dong, Yeongtong-gu, Suwon, 443-749 South Korea
| | - Jin Ho Kim
- Department of Molecular Science and Technology, Ajou University, Woncheon-dong, Yeongtong-gu, Suwon, 443-749 South Korea
- Department of Applied Chemistry and Biological Engineering, Ajou University, Woncheon-dong, Yeongtong-gu, Suwon, 443-749 South Korea
| | - Pyung Cheon Lee
- Department of Molecular Science and Technology, Ajou University, Woncheon-dong, Yeongtong-gu, Suwon, 443-749 South Korea
- Department of Applied Chemistry and Biological Engineering, Ajou University, Woncheon-dong, Yeongtong-gu, Suwon, 443-749 South Korea
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23
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D'Alessandro M, Turina P, Melandri BA, Dunn SD. Modulation of coupling in the Escherichia coli ATP synthase by ADP and P i: Role of the ε subunit C-terminal domain. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1858:34-44. [PMID: 27751906 DOI: 10.1016/j.bbabio.2016.10.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Revised: 08/06/2016] [Accepted: 10/13/2016] [Indexed: 01/28/2023]
Abstract
The ε-subunit of ATP-synthase is an endogenous inhibitor of the hydrolysis activity of the complex and its α-helical C-terminal domain (εCTD) undergoes drastic changes among at least two different conformations. Even though this domain is not essential for ATP synthesis activity, there is evidence for its involvement in the coupling mechanism of the pump. Recently, it was proposed that coupling of the ATP synthase can vary as a function of ADP and Pi concentration. In the present work, we have explored the possible role of the εCTD in this ADP- and Pi-dependent coupling, by examining an εCTD-lacking mutant of Escherichia coli. We show that the loss of Pi-dependent coupling can be observed also in the εCTD-less mutant, but the effects of Pi on both proton pumping and ATP hydrolysis were much weaker in the mutant than in the wild-type. We also show that the εCTD strongly influences the binding of ADP to a very tight binding site (half-maximal effect≈1nM); binding at this site induces higher coupling in EFOF1 and increases responses to Pi. It is proposed that one physiological role of the εCTD is to regulate the kinetics and affinity of ADP/Pi binding, promoting ADP/Pi-dependent coupling.
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Affiliation(s)
- M D'Alessandro
- Department of Biology, Laboratory of Biochemistry and Biophysics, University of Bologna, Via Irnerio 42, 40126 Bologna, Italy
| | - P Turina
- Department of Biology, Laboratory of Biochemistry and Biophysics, University of Bologna, Via Irnerio 42, 40126 Bologna, Italy.
| | - B A Melandri
- Department of Biology, Laboratory of Biochemistry and Biophysics, University of Bologna, Via Irnerio 42, 40126 Bologna, Italy
| | - S D Dunn
- Department of Biochemistry, University of Western Ontario, London, Ontario N6A 5C1, Canada
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24
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Biophysical comparison of ATP synthesis mechanisms shows a kinetic advantage for the rotary process. Proc Natl Acad Sci U S A 2016; 113:11220-11225. [PMID: 27647911 DOI: 10.1073/pnas.1608533113] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The ATP synthase (F-ATPase) is a highly complex rotary machine that synthesizes ATP, powered by a proton electrochemical gradient. Why did evolution select such an elaborate mechanism over arguably simpler alternating-access processes that can be reversed to perform ATP synthesis? We studied a systematic enumeration of alternative mechanisms, using numerical and theoretical means. When the alternative models are optimized subject to fundamental thermodynamic constraints, they fail to match the kinetic ability of the rotary mechanism over a wide range of conditions, particularly under low-energy conditions. We used a physically interpretable, closed-form solution for the steady-state rate for an arbitrary chemical cycle, which clarifies kinetic effects of complex free-energy landscapes. Our analysis also yields insights into the debated "kinetic equivalence" of ATP synthesis driven by transmembrane pH and potential difference. Overall, our study suggests that the complexity of the F-ATPase may have resulted from positive selection for its kinetic advantage.
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25
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Hu H, Wang L, Li Y, Sun J, Zhou Q, Huang X. Insight into mechanism of lanthanum (III) induced damage to plant photosynthesis. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2016; 127:43-50. [PMID: 26802561 DOI: 10.1016/j.ecoenv.2016.01.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Revised: 12/31/2015] [Accepted: 01/11/2016] [Indexed: 06/05/2023]
Abstract
A great deal of literature is available regarding the environmental and ecological effects of rare earth element pollution on plants. These studies have shown that excess lanthanum (La) (III) in the environment can inhibit plant growth and even cause plant death. Moreover, inhibition of plant photosynthesis is known to be one of the physiological bases of these damages. However, the mechanism responsible for these effects is still unclear. In this study, the mechanism of La(III)-induced damage to plant photosynthesis was clarified from the viewpoint of the chloroplast ultrastructure, the contents of chloroplast mineral elements and chlorophyll, the transcription of chloroplast ATPase subunits and chloroplast Mg(2+)-ATPase activity, in which rice was selected as a study object. Following treatment with low level of La(III), the chloroplast ultrastructure of rice was not changed, and the contents of chloroplast mineral elements (Mg, P, K, Ca, Mn, Fe, Ni, Cu, and Zn) increased, but the chlorophyll content did not change significantly. Moreover, the transcription of chloroplast ATPase subunits, chloroplast Mg(2+)-ATPase activity, the net photosynthetic rate and growth indices increased. Following treatment with high levels of La(III), the chloroplast ultrastructure was damaged, chloroplast mineral elements (except Cu and Zn) and chlorophyll contents decreased, and the transcription of chloroplast ATPase subunits, chloroplast Mg(2+)-ATPase activity, the net photosynthetic rate and growth indices decreased. Based on these results, a possible mechanism of La(III)-induced damage to plant photosynthesis was proposed to provide a reference for scientific evaluation of the potential ecological risk of rare earth elements in the environment.
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Affiliation(s)
- Huiqing Hu
- State Key Laboratory of Food Science and Technology, Jiangsu Coorperative Innovation Center of Water Treatment Technology and Materials, College of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China; School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China
| | - Lihong Wang
- State Key Laboratory of Food Science and Technology, Jiangsu Coorperative Innovation Center of Water Treatment Technology and Materials, College of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China; School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China
| | - Yueli Li
- State Key Laboratory of Food Science and Technology, Jiangsu Coorperative Innovation Center of Water Treatment Technology and Materials, College of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China; School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China
| | - Jingwen Sun
- State Key Laboratory of Food Science and Technology, Jiangsu Coorperative Innovation Center of Water Treatment Technology and Materials, College of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China; School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China
| | - Qing Zhou
- State Key Laboratory of Food Science and Technology, Jiangsu Coorperative Innovation Center of Water Treatment Technology and Materials, College of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China; School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China.
| | - Xiaohua Huang
- Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, Jiangsu Key Laboratory of Biomedical Materials, College of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210046, China; School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China.
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26
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Vázquez-Acevedo M, Vega-deLuna F, Sánchez-Vásquez L, Colina-Tenorio L, Remacle C, Cardol P, Miranda-Astudillo H, González-Halphen D. Dissecting the peripheral stalk of the mitochondrial ATP synthase of chlorophycean algae. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1183-1190. [PMID: 26873638 DOI: 10.1016/j.bbabio.2016.02.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 01/25/2016] [Accepted: 02/05/2016] [Indexed: 12/13/2022]
Abstract
The algae Chlamydomonas reinhardtii and Polytomella sp., a green and a colorless member of the chlorophycean lineage respectively, exhibit a highly-stable dimeric mitochondrial F1Fo-ATP synthase (complex V), with a molecular mass of 1600 kDa. Polytomella, lacking both chloroplasts and a cell wall, has greatly facilitated the purification of the algal ATP-synthase. Each monomer of the enzyme has 17 polypeptides, eight of which are the conserved, main functional components, and nine polypeptides (Asa1 to Asa9) unique to chlorophycean algae. These atypical subunits form the two robust peripheral stalks observed in the highly-stable dimer of the algal ATP synthase in several electron-microscopy studies. The topological disposition of the components of the enzyme has been addressed with cross-linking experiments in the isolated complex; generation of subcomplexes by limited dissociation of complex V; detection of subunit-subunit interactions using recombinant subunits; in vitro reconstitution of subcomplexes; silencing of the expression of Asa subunits; and modeling of the overall structural features of the complex by EM image reconstruction. Here, we report that the amphipathic polymer Amphipol A8-35 partially dissociates the enzyme, giving rise to two discrete dimeric subcomplexes, whose compositions were characterized. An updated model for the topological disposition of the 17 polypeptides that constitute the algal enzyme is suggested. This article is part of a Special Issue entitled 'EBEC 2016: 19th European Bioenergetics Conference, Riva del Garda, Italy, July 2-6, 2016', edited by Prof. Paolo Bernardi.
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Affiliation(s)
- Miriam Vázquez-Acevedo
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México D.F., Mexico
| | - Félix Vega-deLuna
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México D.F., Mexico
| | - Lorenzo Sánchez-Vásquez
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México D.F., Mexico
| | - Lilia Colina-Tenorio
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México D.F., Mexico
| | - Claire Remacle
- Genetics and Physiology of Microalgae, Department of Life Sciences, University of Liège, B-4000 Liège, Belgium
| | - Pierre Cardol
- Genetics and Physiology of Microalgae, Department of Life Sciences, University of Liège, B-4000 Liège, Belgium
| | - Héctor Miranda-Astudillo
- Genetics and Physiology of Microalgae, Department of Life Sciences, University of Liège, B-4000 Liège, Belgium
| | - Diego González-Halphen
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México D.F., Mexico.
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27
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Nakanishi-Matsui M, Sekiya M, Futai M. ATP synthase from Escherichia coli : Mechanism of rotational catalysis, and inhibition with the ε subunit and phytopolyphenols. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:129-140. [DOI: 10.1016/j.bbabio.2015.11.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 10/19/2015] [Accepted: 11/13/2015] [Indexed: 10/22/2022]
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28
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Kato-Yamada Y. High affinity nucleotide-binding mutant of the ε subunit of thermophilic F1-ATPase. Biochem Biophys Res Commun 2015; 469:1129-32. [PMID: 26746006 DOI: 10.1016/j.bbrc.2015.12.121] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 12/28/2015] [Indexed: 10/22/2022]
Abstract
Specific ATP binding to the ε subunit of thermophilic F1-ATPase has been utilized for the biosensors of ATP in vivo. I report here that the ε subunit containing R103A/R115A mutations can bind ATP with a dissociation constant at 52 nM, which is two orders of magnitude higher affinity than the wild type. The mutant retained specificity for ATP; ADP and GTP bound to the mutant with dissociation constants 16 and 53 μM, respectively. Thus, the mutant would be a good platform for various types of nucleotide biosensor with appropriate modifications.
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Affiliation(s)
- Yasuyuki Kato-Yamada
- Department of Life Science, College of Science, Rikkyo University, Japan; Research Center for Life Science, College of Science, Rikkyo University, Japan.
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Linking structural features from mitochondrial and bacterial F-type ATP synthases to their distinct mechanisms of ATPase inhibition. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2015; 119:94-102. [DOI: 10.1016/j.pbiomolbio.2015.06.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 06/25/2015] [Accepted: 06/26/2015] [Indexed: 01/11/2023]
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30
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On the Mg2+ binding site of the ε subunit from bacterial F-type ATP synthases. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:1101-12. [DOI: 10.1016/j.bbabio.2015.05.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Revised: 05/20/2015] [Accepted: 05/22/2015] [Indexed: 11/19/2022]
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31
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Shah NB, Duncan TM. Aerobic Growth of Escherichia coli Is Reduced, and ATP Synthesis Is Selectively Inhibited when Five C-terminal Residues Are Deleted from the ϵ Subunit of ATP Synthase. J Biol Chem 2015; 290:21032-21041. [PMID: 26160173 PMCID: PMC4543661 DOI: 10.1074/jbc.m115.665059] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 06/19/2015] [Indexed: 11/06/2022] Open
Abstract
F-type ATP synthases are rotary nanomotor enzymes involved in cellular energy metabolism in eukaryotes and eubacteria. The ATP synthase from Gram-positive and -negative model bacteria can be autoinhibited by the C-terminal domain of its ϵ subunit (ϵCTD), but the importance of ϵ inhibition in vivo is unclear. Functional rotation is thought to be blocked by insertion of the latter half of the ϵCTD into the central cavity of the catalytic complex (F1). In the inhibited state of the Escherichia coli enzyme, the final segment of ϵCTD is deeply buried but has few specific interactions with other subunits. This region of the ϵCTD is variable or absent in other bacteria that exhibit strong ϵ-inhibition in vitro. Here, genetically deleting the last five residues of the ϵCTD (ϵΔ5) caused a greater defect in respiratory growth than did the complete absence of the ϵCTD. Isolated membranes with ϵΔ5 generated proton-motive force by respiration as effectively as with wild-type ϵ but showed a nearly 3-fold decrease in ATP synthesis rate. In contrast, the ϵΔ5 truncation did not change the intrinsic rate of ATP hydrolysis with membranes. Further, the ϵΔ5 subunit retained high affinity for isolated F1 but reduced the maximal inhibition of F1-ATPase by ϵ from >90% to ∼20%. The results suggest that the ϵCTD has distinct regulatory interactions with F1 when rotary catalysis operates in opposite directions for the hydrolysis or synthesis of ATP.
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Affiliation(s)
- Naman B Shah
- Department of Biochemistry and Molecular Biology, State University of New York, Upstate Medical University, Syracuse, New York 13210
| | - Thomas M Duncan
- Department of Biochemistry and Molecular Biology, State University of New York, Upstate Medical University, Syracuse, New York 13210.
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Kasumov EA, Kasumov RE, Kasumova IV. A mechano-chemiosmotic model for the coupling of electron and proton transfer to ATP synthesis in energy-transforming membranes: a personal perspective. PHOTOSYNTHESIS RESEARCH 2015; 123:1-22. [PMID: 25266924 PMCID: PMC4272416 DOI: 10.1007/s11120-014-0043-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 09/18/2014] [Indexed: 05/03/2023]
Abstract
ATP is synthesized using ATP synthase by utilizing energy either from the oxidation of organic compounds, or from light, via redox reactions (oxidative- or photo phosphorylation), in energy-transforming membranes of mitochondria, chloroplasts, and bacteria. ATP synthase undergoes several changes during its functioning. The generally accepted model for ATP synthesis is the well-known rotatory model (see e.g., Junge et al., Nature 459:364-370, 2009; Junge and Müller, Science 333:704-705, 2011). Here, we present an alternative modified model for the coupling of electron and proton transfer to ATP synthesis, which was initially developed by Albert Lester Lehninger (1917-1986). Details of the molecular mechanism of ATP synthesis are described here that involves cyclic low-amplitude shrinkage and swelling of mitochondria. A comparison of the well-known current model and the mechano-chemiosmotic model is also presented. Based on structural, and other data, we suggest that ATP synthase is a Ca(2+)/H(+)-K(+) Cl(-)-pump-pore-enzyme complex, in which γ-subunit rotates 360° in steps of 30°, and 90° due to the binding of phosphate ions to positively charged amino acid residues in the N-terminal γ-subunit, while in the electric field. The coiled coil b 2-subunits are suggested to act as ropes that are shortened by binding of phosphate ions to positively charged lysines or arginines; this process is suggested to pull the α 3 β 3-hexamer to the membrane during the energization process. ATP is then synthesized during the reverse rotation of the γ-subunit by destabilizing the phosphated N-terminal γ-subunit and b 2-subunits under the influence of Ca(2+) ions, which are pumped over from storage-intermembrane space into the matrix, during swelling of intermembrane space. In the process of ATP synthesis, energy is first, predominantly, used in the delivery of phosphate ions and protons to the α 3 β 3-hexamer against the energy barrier with the help of C-terminal alpha-helix of γ-subunit that acts as a lift; then, in the formation of phosphoryl group; and lastly, in the release of ATP molecules from the active center of the enzyme and the loading of ADP. We are aware that our model is not an accepted model for ATP synthesis, but it is presented here for further examination and test.
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Affiliation(s)
- Eldar A Kasumov
- Research and Production Centre «KORVET», Moscow Region, Domodedovo, Russia,
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33
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Ueno H, Minagawa Y, Hara M, Rahman S, Yamato I, Muneyuki E, Noji H, Murata T, Iino R. Torque generation of Enterococcus hirae V-ATPase. J Biol Chem 2014; 289:31212-23. [PMID: 25258315 DOI: 10.1074/jbc.m114.598177] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
V-ATPase (V(o)V1) converts the chemical free energy of ATP into an ion-motive force across the cell membrane via mechanical rotation. This energy conversion requires proper interactions between the rotor and stator in V(o)V1 for tight coupling among chemical reaction, torque generation, and ion transport. We developed an Escherichia coli expression system for Enterococcus hirae V(o)V1 (EhV(o)V1) and established a single-molecule rotation assay to measure the torque generated. Recombinant and native EhV(o)V1 exhibited almost identical dependence of ATP hydrolysis activity on sodium ion and ATP concentrations, indicating their functional equivalence. In a single-molecule rotation assay with a low load probe at high ATP concentration, EhV(o)V1 only showed the "clear" state without apparent backward steps, whereas EhV1 showed two states, "clear" and "unclear." Furthermore, EhV(o)V1 showed slower rotation than EhV1 without the three distinct pauses separated by 120° that were observed in EhV1. When using a large probe, EhV(o)V1 showed faster rotation than EhV1, and the torque of EhV(o)V1 estimated from the continuous rotation was nearly double that of EhV1. On the other hand, stepping torque of EhV1 in the clear state was comparable with that of EhV(o)V1. These results indicate that rotor-stator interactions of the V(o) moiety and/or sodium ion transport limit the rotation driven by the V1 moiety, and the rotor-stator interactions in EhV(o)V1 are stabilized by two peripheral stalks to generate a larger torque than that of isolated EhV1. However, the torque value was substantially lower than that of other rotary ATPases, implying the low energy conversion efficiency of EhV(o)V1.
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Affiliation(s)
- Hiroshi Ueno
- From the Department of Physics, Faculty of Science and Engineering, Chuo University, Tokyo 112-8551, Japan
| | - Yoshihiro Minagawa
- the Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan
| | - Mayu Hara
- the Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan
| | - Suhaila Rahman
- the Department of Biological Science and Technology, Tokyo University of Science, Tokyo 125-8585, Japan
| | - Ichiro Yamato
- the Department of Biological Science and Technology, Tokyo University of Science, Tokyo 125-8585, Japan
| | - Eiro Muneyuki
- From the Department of Physics, Faculty of Science and Engineering, Chuo University, Tokyo 112-8551, Japan
| | - Hiroyuki Noji
- the Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan
| | - Takeshi Murata
- the Department of Chemistry, Graduate School of Science, Chiba University, Chiba 263-8522, Japan, JST, PRESTO, Chiba 263-8522, Japan,
| | - Ryota Iino
- the Okazaki Institute for Integrative Bioscience, Institute for Molecular Science, National Institutes of Natural Sciences, Aichi 444-8787, Japan, and the Department of Functional Molecular Science, School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), Kanagawa 240-0193, Japan
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Malyan AN. Noncatalytic nucleotide binding sites: properties and mechanism of involvement in ATP synthase activity regulation. BIOCHEMISTRY (MOSCOW) 2014; 78:1512-23. [PMID: 24490737 DOI: 10.1134/s0006297913130099] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
ATP synthases (FoF1-ATPases) of chloroplasts, mitochondria, and bacteria catalyze ATP synthesis or hydrolysis coupled with the transmembrane transfer of protons or sodium ions. Their activity is regulated through their reversible inactivation resulting from a decreased transmembrane potential difference. The inactivation is believed to conserve ATP previously synthesized under conditions of sufficient energy supply against unproductive hydrolysis. This review is focused on the mechanism of nucleotide-dependent regulation of the ATP synthase activity where the so-called noncatalytic nucleotide binding sites are involved. Properties of these sites varying upon free enzyme transition to its membrane-bound form, their dependence on membrane energization, and putative mechanisms of noncatalytic site-mediated regulation of the ATP synthase activity are discussed.
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Affiliation(s)
- A N Malyan
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
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35
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Nakanishi-Matsui M, Sekiya M, Yano S, Futai M. Inhibition of F1-ATPase rotational catalysis by the carboxyl-terminal domain of the ϵ subunit. J Biol Chem 2014; 289:30822-30831. [PMID: 25228697 DOI: 10.1074/jbc.m114.578872] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Escherichia coli ATP synthase (F0F1) couples catalysis and proton transport through subunit rotation. The ϵ subunit, an endogenous inhibitor, lowers F1-ATPase activity by decreasing the rotation speed and extending the duration of the inhibited state (Sekiya, M., Hosokawa, H., Nakanishi-Matsui, M., Al-Shawi, M. K., Nakamoto, R. K., and Futai, M. (2010) Single molecule behavior of inhibited and active states of Escherichia coli ATP synthase F1 rotation. J. Biol. Chem. 285, 42058-42067). In this study, we constructed a series of ϵ subunits truncated successively from the carboxyl-terminal domain (helix 1/loop 2/helix 2) and examined their effects on rotational catalysis (ATPase activity, average rotation rate, and duration of inhibited state). As expected, the ϵ subunit lacking helix 2 caused about ½-fold reduced inhibition, and that without loop 2/helix 2 or helix 1/loop 2/helix 2 showed a further reduced effect. Substitution of ϵSer(108) in loop 2 and ϵTyr(114) in helix 2, which possibly interact with the β and γ subunits, respectively, decreased the inhibitory effect. These results suggest that the carboxyl-terminal domain of the ϵ subunit plays a pivotal role in the inhibition of F1 rotation through interaction with other subunits.
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Affiliation(s)
- Mayumi Nakanishi-Matsui
- Department of Biochemistry, Faculty of Pharmaceutical Sciences, Iwate Medical University, Nishitokuta 2-1-1, Yahaba, Iwate 028-3694, Japan.
| | - Mizuki Sekiya
- Department of Biochemistry, Faculty of Pharmaceutical Sciences, Iwate Medical University, Nishitokuta 2-1-1, Yahaba, Iwate 028-3694, Japan
| | - Shio Yano
- Department of Biochemistry, Faculty of Pharmaceutical Sciences, Iwate Medical University, Nishitokuta 2-1-1, Yahaba, Iwate 028-3694, Japan
| | - Masamitsu Futai
- Department of Biochemistry, Faculty of Pharmaceutical Sciences, Iwate Medical University, Nishitokuta 2-1-1, Yahaba, Iwate 028-3694, Japan
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36
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Arrayed lipid bilayer chambers allow single-molecule analysis of membrane transporter activity. Nat Commun 2014; 5:4519. [PMID: 25058452 PMCID: PMC4124872 DOI: 10.1038/ncomms5519] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 06/25/2014] [Indexed: 11/09/2022] Open
Abstract
Nano- to micron-size reaction chamber arrays (femtolitre chamber arrays) have facilitated the development of sensitive and quantitative biological assays, such as single-molecule enzymatic assays, digital PCR and digital ELISA. However, the versatility of femtolitre chamber arrays is limited to reactions that occur in aqueous solutions. Here we report an arrayed lipid bilayer chamber system (ALBiC) that contains sub-million femtolitre chambers, each sealed with a stable 4-μm-diameter lipid bilayer membrane. When reconstituted with a limiting amount of the membrane transporter proteins α-hemolysin or F0F1-ATP synthase, the chambers within the ALBiC exhibit stochastic and quantized transporting activities. This demonstrates that the single-molecule analysis of passive and active membrane transport is achievable with the ALBiC system. This new platform broadens the versatility of femtolitre chamber arrays and paves the way for novel applications aimed at furthering our mechanistic understanding of membrane proteins' function.
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37
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Schuhmacher T, Löffler M, Hurler T, Takors R. Phosphate limited fed-batch processes: impact on carbon usage and energy metabolism in Escherichia coli. J Biotechnol 2014; 190:96-104. [PMID: 24833421 DOI: 10.1016/j.jbiotec.2014.04.025] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 04/22/2014] [Accepted: 04/28/2014] [Indexed: 10/25/2022]
Abstract
Phosphate starvation is often applied as a tool to limit cell growth in microbial production processes without hampering carbon and/or nitrogen supply alternatively. This contribution focuses on the interplay of process induced phosphate starvation and microbial performance studying an l-tryptophan overproducing Escherichia coli strain as a model for highly ATP demanding processes in comparison with an E. coli wildtype strain. To enable a time-resolved analysis, constant phosphate feeding strategies were applied to elongate the transition from phosphate saturated to phosphate limited cell growth. With increasing phosphate limitation, a reduced cellular efficiency of ATP formation via respiratory chain activity and the ATP synthase complex was found for both strains. Process balancing, transcriptome analysis and flux balance analysis are pointing toward a multi-stage decoupling scenario, which in essence deteriorates the stoichiometric ratio of ATP formation to proton translocation, thereby affecting ATP availability from respiration and carbon usage. Starting off with a potential influence on ATP-synthase efficiency (stage 1), decoupling is further increased by modified respiratory activity (stage 2) and byproduct overflow (stage 3) finally resulting in a metabolic breakdown entering complete phosphate depletion (stage 4). The decoupling is initiated by phosphate limitation; further effects are mainly mediated on metabolic level through ATP availability and energy charge, additionally affected by ATP demanding product synthesis.
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Affiliation(s)
- Tom Schuhmacher
- Institute of Biochemical Engineering, University of Stuttgart, Allmandring 31, D-70569 Stuttgart, Germany.
| | - Michael Löffler
- Institute of Biochemical Engineering, University of Stuttgart, Allmandring 31, D-70569 Stuttgart, Germany.
| | - Thilo Hurler
- Institute of Biochemical Engineering, University of Stuttgart, Allmandring 31, D-70569 Stuttgart, Germany.
| | - Ralf Takors
- Institute of Biochemical Engineering, University of Stuttgart, Allmandring 31, D-70569 Stuttgart, Germany.
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38
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Bockenhauer SD, Duncan TM, Moerner WE, Börsch M. The regulatory switch of F 1-ATPase studied by single-molecule FRET in the ABEL Trap. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2014; 8950:89500H. [PMID: 25309100 DOI: 10.1117/12.2042688] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
F1-ATPase is the soluble portion of the membrane-embedded enzyme FoF1-ATP synthase that catalyzes the production of adenosine triphosphate in eukaryotic and eubacterial cells. In reverse, the F1 part can also hydrolyze ATP quickly at three catalytic binding sites. Therefore, catalysis of 'non-productive' ATP hydrolysis by F1 (or FoF1) must be minimized in the cell. In bacteria, the ε subunit is thought to control and block ATP hydrolysis by mechanically inserting its C-terminus into the rotary motor region of F1. We investigate this proposed mechanism by labeling F1 specifically with two fluorophores to monitor the C-terminus of the ε subunit by Förster resonance energy transfer. Single F1 molecules are trapped in solution by an Anti-Brownian electrokinetic trap which keeps the FRET-labeled F1 in place for extended observation times of several hundreds of milliseconds, limited by photobleaching. FRET changes in single F1 and FRET histograms for different biochemical conditions are compared to evaluate the proposed regulatory mechanism.
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Affiliation(s)
- Samuel D Bockenhauer
- Department of Chemistry, Stanford University, Stanford, CA, USA ; Department of Physics, Stanford University, Stanford, CA, USA
| | - Thomas M Duncan
- Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - W E Moerner
- Department of Chemistry, Stanford University, Stanford, CA, USA
| | - Michael Börsch
- Single-Molecule Microscopy Group, Jena University Hospital, Friedrich Schiller University, Jena, Germany
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39
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Towards a computational model of a methane producing archaeum. ARCHAEA-AN INTERNATIONAL MICROBIOLOGICAL JOURNAL 2014; 2014:898453. [PMID: 24729742 PMCID: PMC3960522 DOI: 10.1155/2014/898453] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 12/18/2013] [Indexed: 11/17/2022]
Abstract
Progress towards a complete model of the methanogenic archaeum Methanosarcina acetivorans is reported. We characterized size distribution of the cells using differential interference contrast microscopy, finding them to be ellipsoidal with mean length and width of 2.9 μm and 2.3 μm, respectively, when grown on methanol and 30% smaller when grown on acetate. We used the single molecule pull down (SiMPull) technique to measure average copy number of the Mcr complex and ribosomes. A kinetic model for the methanogenesis pathways based on biochemical studies and recent metabolic reconstructions for several related methanogens is presented. In this model, 26 reactions in the methanogenesis pathways are coupled to a cell mass production reaction that updates enzyme concentrations. RNA expression data (RNA-seq) measured for cell cultures grown on acetate and methanol is used to estimate relative protein production per mole of ATP consumed. The model captures the experimentally observed methane production rates for cells growing on methanol and is most sensitive to the number of methyl-coenzyme-M reductase (Mcr) and methyl-tetrahydromethanopterin:coenzyme-M methyltransferase (Mtr) proteins. A draft transcriptional regulation network based on known interactions is proposed which we intend to integrate with the kinetic model to allow dynamic regulation.
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40
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Duncan TM, Düser MG, Heitkamp T, McMillan DGG, Börsch M. Regulatory conformational changes of the ε subunit in single FRET-labeled F oF 1-ATP synthase. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2014; 8948:89481J. [PMID: 25076824 DOI: 10.1117/12.2040463] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Subunit ε is an intrinsic regulator of the bacterial FoF1-ATP synthase, the ubiquitous membrane-embedded enzyme that utilizes a proton motive force in most organisms to synthesize adenosine triphosphate (ATP). The C-terminal domain of ε can extend into the central cavity formed by the α and β subunits, as revealed by the recent X-ray structure of the F1 portion of the Escherichia coli enzyme. This insertion blocks the rotation of the central γ subunit and, thereby, prevents wasteful ATP hydrolysis. Here we aim to develop an experimental system that can reveal conditions under which ε inhibits the holoenzyme FoF1-ATP synthase in vitro. Labeling the C-terminal domain of ε and the γ subunit specifically with two different fluorophores for single-molecule Förster resonance energy transfer (smFRET) allowed monitoring of the conformation of ε in the reconstituted enzyme in real time. New mutants were made for future three-color smFRET experiments to unravel the details of regulatory conformational changes in ε.
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Affiliation(s)
- Thomas M Duncan
- Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Monika G Düser
- 3 Institute of Physics, Stuttgart University, Stuttgart, Germany
| | - Thomas Heitkamp
- Single-Molecule Microscopy Group, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Duncan G G McMillan
- Single-Molecule Microscopy Group, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Michael Börsch
- Single-Molecule Microscopy Group, Jena University Hospital, Friedrich Schiller University, Jena, Germany
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41
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Zarco-Zavala M, Morales-Ríos E, Mendoza-Hernández G, Ramírez-Silva L, Pérez-Hernández G, García-Trejo JJ. The ζ subunit of the F1FO-ATP synthase of α-proteobacteria controls rotation of the nanomotor with a different structure. FASEB J 2014; 28:2146-57. [PMID: 24522203 DOI: 10.1096/fj.13-241430] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The ζ subunit is a novel natural inhibitor of the α-proteobacterial F1FO-ATPase described originally in Paracoccus denitrificans. To characterize the mechanism by which this subunit inhibits the F1FO nanomotor, the ζ subunit of Paracoccus denitrificans (Pd-ζ) was analyzed by the combination of kinetic, biochemical, bioinformatic, proteomic, and structural approaches. The ζ subunit causes full inhibition of the sulfite-activated PdF1-ATPase with an apparent IC50 of 270 nM by a mechanism independent of the ε subunit. The inhibitory region of the ζ subunit resides in the first 14 N-terminal residues of the protein, which protrude from the 4-α-helix bundle structure of the isolated ζ subunit, as resolved by NMR. Cross-linking experiments show that the ζ subunit interacts with rotor (γ) and stator (α, β) subunits of the F1-ATPase, indicating that the ζ subunit hinders rotation of the central stalk. In addition, a putatively regulatory nucleotide-binding site was found in the ζ subunit by isothermal titration calorimetry. Together, the data show that the ζ subunit controls the rotation of F1FO-ATPase by a mechanism reminiscent of, but different from, those described for mitochondrial IF1 and bacterial ε subunits where the 4-α-helix bundle of ζ seems to work as an anchoring domain that orients the N-terminal inhibitory domain to hinder rotation of the central stalk.
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Affiliation(s)
- Mariel Zarco-Zavala
- 1Universidad Nacional Autónoma de México (UNAM), Facultad de Química, Departamento de Biología, Circuito Escolar, s/n, Laboratorio 206, Edificio F, Ciudad Universitaria, Coyoacán, CP 04510, México, DF.
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42
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Assessment of the requirements for magnesium transporters in Bacillus subtilis. J Bacteriol 2014; 196:1206-14. [PMID: 24415722 DOI: 10.1128/jb.01238-13] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Magnesium is the most abundant divalent metal in cells and is required for many structural and enzymatic functions. For bacteria, at least three families of proteins function as magnesium transporters. In recent years, it has been shown that a subset of these transport proteins is regulated by magnesium-responsive genetic control elements. In this study, we investigated the cellular requirements for magnesium homeostasis in the model microorganism Bacillus subtilis. Putative magnesium transporter genes were mutationally disrupted, singly and in combination, in order to assess their general importance. Mutation of only one of these genes resulted in strong dependency on supplemental extracellular magnesium. Notably, this transporter gene, mgtE, is known to be under magnesium-responsive genetic regulatory control. This suggests that the identification of magnesium-responsive genetic mechanisms may generally denote primary transport proteins for bacteria. To investigate whether B. subtilis encodes yet additional classes of transport mechanisms, suppressor strains that permitted the growth of a transporter-defective mutant were identified. Several of these strains were sequenced to determine the genetic basis of the suppressor phenotypes. None of these mutations occurred in transport protein homologues; instead, they affected housekeeping functions, such as signal recognition particle components and ATP synthase machinery. From these aggregate data, we speculate that the mgtE protein provides the primary route of magnesium import in B. subtilis and that the other putative transport proteins are likely to be utilized for more-specialized growth conditions.
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43
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Biased Brownian stepping rotation of FoF1-ATP synthase driven by proton motive force. Nat Commun 2013; 4:1631. [PMID: 23535652 DOI: 10.1038/ncomms2631] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Accepted: 02/21/2013] [Indexed: 11/08/2022] Open
Abstract
FoF1-ATP synthase (FoF1) produces most of the ATP in cells, uniquely, by converting the proton motive force (pmf) into ATP production via mechanical rotation of the inner rotor complex. Technical difficulties have hampered direct investigation of pmf-driven rotation, which are crucial to elucidating the chemomechanical coupling mechanism of FoF1. Here we develop a novel supported membrane system for direct observation of the rotation of FoF1 driven by pmf that was formed by photolysis of caged protons. Upon photolysis, FoF1 initiated rotation in the opposite direction to that of the ATP-driven rotation. The step size of pmf-driven rotation was 120°, suggesting that the kinetic bottleneck is a catalytic event on F1 with threefold symmetry. The reaction equilibrium was slightly biased to ATP synthesis like under physiological conditions, and FoF1 showed highly stochastic behaviour, frequently making a 120° backward step. This new experimental system would be applicable to single-molecule study of other membrane proteins.
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44
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Toei M, Noji H. Single-molecule analysis of F0F1-ATP synthase inhibited by N,N-dicyclohexylcarbodiimide. J Biol Chem 2013; 288:25717-25726. [PMID: 23893417 DOI: 10.1074/jbc.m113.482455] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
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.
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Affiliation(s)
- Masashi Toei
- From the Department of Applied Chemistry, School of Engineering, University of Tokyo, Tokyo 113-8656, Japan
| | - Hiroyuki Noji
- From the Department of Applied Chemistry, School of Engineering, University of Tokyo, Tokyo 113-8656, Japan.
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45
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Watanabe R. Rotary catalysis of FoF1-ATP synthase. Biophysics (Nagoya-shi) 2013; 9:51-6. [PMID: 27493540 PMCID: PMC4629669 DOI: 10.2142/biophysics.9.51] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 04/22/2013] [Indexed: 12/01/2022] Open
Abstract
The synthesis of ATP, the key reaction of biological energy metabolism, is accomplished by the rotary motor protein; FoF1-ATP synthase (FoF1). In vivo, FoF1, located on the cell membrane, carries out ATP synthesis by using the proton motive force. This heterologous energy conversion is supposed to be mediated by the mechanical rotation of FoF1; however, it still remained unclear. Recently, we developed the novel experimental setup to reproduce the proton motive force in vitro and succeeded in directly observing the proton-driven rotation of FoF1. In this review, we describe the interesting working principles determined so far for FoF1 and then introduce results from our recent study.
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Affiliation(s)
- Rikiya Watanabe
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan
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46
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Mashkovtseva E, Boronovsky S, Nartsissov Y. Combined mathematical methods in the description of the F(o)F(1)-ATP synthase catalytic cycle. Math Biosci 2013; 243:117-25. [PMID: 23499574 DOI: 10.1016/j.mbs.2013.02.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 02/15/2013] [Accepted: 02/21/2013] [Indexed: 11/26/2022]
Abstract
The FoF1-ATP synthase is one of the key enzymes in supplying energy production in almost all living systems. In this paper, we provide a theoretical description of its catalytic cycle using combined mathematical methods. These methods include Langevin dynamics for the rotation of the central protein core and the Monte-Carlo method to model nucleotide and proton binding. This model is the first in which ATP synthesis and hydrolysis can occur depending on the nucleotide concentration and system conditions. The main advantage of the presented model is the possibility of obtaining results for both single-molecular protein-machines and large ensembles of proteins. The calculated rates are close to the experimentally measured rates for a single enzyme. The model has been formalised as a computer simulation that allows researchers to evaluate ATP production in different types of living cells.
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Shah NB, Hutcheon ML, Haarer BK, Duncan TM. F1-ATPase of Escherichia coli: the ε- inhibited state forms after ATP hydrolysis, is distinct from the ADP-inhibited state, and responds dynamically to catalytic site ligands. J Biol Chem 2013; 288:9383-95. [PMID: 23400782 DOI: 10.1074/jbc.m113.451583] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
F1-ATPase is the catalytic complex of rotary nanomotor ATP synthases. Bacterial ATP synthases can be autoinhibited by the C-terminal domain of subunit ε, which partially inserts into the enzyme's central rotor cavity to block functional subunit rotation. Using a kinetic, optical assay of F1·ε binding and dissociation, we show that formation of the extended, inhibitory conformation of ε (εX) initiates after ATP hydrolysis at the catalytic dwell step. Prehydrolysis conditions prevent formation of the εX state, and post-hydrolysis conditions stabilize it. We also show that ε inhibition and ADP inhibition are distinct, competing processes that can follow the catalytic dwell. We show that the N-terminal domain of ε is responsible for initial binding to F1 and provides most of the binding energy. Without the C-terminal domain, partial inhibition by the ε N-terminal domain is due to enhanced ADP inhibition. The rapid effects of catalytic site ligands on conformational changes of F1-bound ε suggest dynamic conformational and rotational mobility in F1 that is paused near the catalytic dwell position.
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Affiliation(s)
- Naman B Shah
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY 13210, USA
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48
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Börsch M. Microscopy of single F(o) F(1) -ATP synthases--the unraveling of motors, gears, and controls. IUBMB Life 2013; 65:227-37. [PMID: 23378185 DOI: 10.1002/iub.1149] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Accepted: 01/12/2013] [Indexed: 11/09/2022]
Abstract
Optical microscopy of single F(1) -ATPase and F(o) F(1) -ATP synthases started 15 years ago. Direct demonstration of ATP-driven subunit rotation by videomicroscopy became the new exciting tool to analyze the conformational changes of this enzyme during catalysis. Stimulated by these experiments, technical improvements for higher time resolution, better angular resolution, and reduced viscous drag were developed rapidly. Optics and single-molecule enzymology were entangled to benefit both biochemists and microscopists. Today, several single-molecule microscopy methods are established including controls for the precise nanomanipulation of individual enzymes in vitro. Förster resonance energy transfer, which has been used for simultaneous monitoring of conformational changes of different parts of this rotary motor, is one of them and may become the tool for the analysis of single F(o) F(1) -ATP synthases in membranes of living cells. Here, breakthrough experiments are critically reviewed and challenges are discussed for the future microscopy of single ATP synthesizing enzymes at work.
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Affiliation(s)
- Michael Börsch
- Single-Molecule Microscopy Group, Jena University Hospital, Friedrich Schiller University, Jena, Germany.
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Biuković G, Basak S, Manimekalai MSS, Rishikesan S, Roessle M, Dick T, Rao SPS, Hunke C, Grüber G. Variations of subunit {varepsilon} of the Mycobacterium tuberculosis F1Fo ATP synthase and a novel model for mechanism of action of the tuberculosis drug TMC207. Antimicrob Agents Chemother 2013; 57:168-76. [PMID: 23089752 PMCID: PMC3535943 DOI: 10.1128/aac.01039-12] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2012] [Accepted: 10/11/2012] [Indexed: 11/20/2022] Open
Abstract
The subunit ε of bacterial F(1)F(O) ATP synthases plays an important regulatory role in coupling and catalysis via conformational transitions of its C-terminal domain. Here we present the first low-resolution solution structure of ε of Mycobacterium tuberculosis (Mtε) F(1)F(O) ATP synthase and the nuclear magnetic resonance (NMR) structure of its C-terminal segment (Mtε(103-120)). Mtε is significantly shorter (61.6 Å) than forms of the subunit in other bacteria, reflecting a shorter C-terminal sequence, proposed to be important in coupling processes via the catalytic β subunit. The C-terminal segment displays an α-helical structure and a highly positive surface charge due to the presence of arginine residues. Using NMR spectroscopy, fluorescence spectroscopy, and mutagenesis, we demonstrate that the new tuberculosis (TB) drug candidate TMC207, proposed to bind to the proton translocating c-ring, also binds to Mtε. A model for the interaction of TMC207 with both ε and the c-ring is presented, suggesting that TMC207 forms a wedge between the two rotating subunits by interacting with the residues W15 and F50 of ε and the c-ring, respectively. T19 and R37 of ε provide the necessary polar interactions with the drug molecule. This new model of the mechanism of TMC207 provides the basis for the design of new drugs targeting the F(1)F(O) ATP synthase in M. tuberculosis.
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Affiliation(s)
- Goran Biuković
- School of Biological Sciences, Nanyang Technological University, Singapore, Republic of Singapore
| | - Sandip Basak
- School of Biological Sciences, Nanyang Technological University, Singapore, Republic of Singapore
| | | | | | - Manfred Roessle
- European Molecular Biology Laboratory, Hamburg Outstation, EMBL c/o DESY, Hamburg, Germany
| | - Thomas Dick
- National University of Singapore, Yong Loo Lin School of Medicine, Department of Microbiology, Singapore, Republic of Singapore
| | - Srinivasa P. S. Rao
- Novartis Institute for Tropical Diseases Pte. Ltd., Singapore, Republic of Singapore
| | - Cornelia Hunke
- School of Biological Sciences, Nanyang Technological University, Singapore, Republic of Singapore
| | - Gerhard Grüber
- School of Biological Sciences, Nanyang Technological University, Singapore, Republic of Singapore
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50
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Soga N, Kinosita K, Yoshida M, Suzuki T. Kinetic equivalence of transmembrane pH and electrical potential differences in ATP synthesis. J Biol Chem 2012; 287:9633-9. [PMID: 22253434 PMCID: PMC3308813 DOI: 10.1074/jbc.m111.335356] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Revised: 01/12/2012] [Indexed: 11/06/2022] Open
Abstract
ATP synthase is the key player of Mitchell's chemiosmotic theory, converting the energy of transmembrane proton flow into the high energy bond between ADP and phosphate. The proton motive force that drives this reaction consists of two components, the pH difference (ΔpH) across the membrane and transmembrane electrical potential (Δψ). The two are considered thermodynamically equivalent, but kinetic equivalence in the actual ATP synthesis is not warranted, and previous experimental results vary. Here, we show that with the thermophilic Bacillus PS3 ATP synthase that lacks an inhibitory domain of the ε subunit, ΔpH imposed by acid-base transition and Δψ produced by valinomycin-mediated K(+) diffusion potential contribute equally to the rate of ATP synthesis within the experimental range examined (ΔpH -0.3 to 2.2, Δψ -30 to 140 mV, pH around the catalytic domain 8.0). Either ΔpH or Δψ alone can drive synthesis, even when the other slightly opposes. Δψ was estimated from the Nernst equation, which appeared valid down to 1 mm K(+) inside the proteoliposomes, due to careful removal of K(+) from the lipid.
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Affiliation(s)
- Naoki Soga
- From the Department of Physics, Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan
| | - Kazuhiko Kinosita
- From the Department of Physics, Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan
| | - Masasuke Yoshida
- the International Cooperative Research Project (ICORP) ATP Synthesis Regulation Project, Japan Science and Technology Agency, 2-3-6 Aomi, Koto-ku, Tokyo 135-0064, Japan, and
- the Department of Molecular Bioscience, Kyoto Sangyo University, Kamigamo-Motoyama, Kyoto 603-8555, Japan
| | - Toshiharu Suzuki
- the International Cooperative Research Project (ICORP) ATP Synthesis Regulation Project, Japan Science and Technology Agency, 2-3-6 Aomi, Koto-ku, Tokyo 135-0064, Japan, and
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