1
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Broch F, El Hajji L, Pietrancosta N, Gautier A. Engineering of Tunable Allosteric-like Fluorogenic Protein Sensors. ACS Sens 2023; 8:3933-3942. [PMID: 37830919 DOI: 10.1021/acssensors.3c01536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2023]
Abstract
Optical protein sensors that enable detection of relevant biomolecules of interest play central roles in biological research. Coupling fluorescent reporters with protein sensing units has enabled the development of a wide range of biosensors that recognize analytes with high selectivity. In these sensors, analyte recognition induces a conformational change in the protein sensing unit that can modulate the optical signal of the fluorescent reporter. Here, we explore various designs for the creation of tunable allosteric-like fluorogenic protein sensors through incorporation of sensing protein units within the chemogenetic fluorescence-activating and absorption-shifting tag (FAST) that selectively binds and stabilizes the fluorescent state of 4-hydroxybenzylidene rhodanine (HBR) analogs. Conformational coupling allowed us to design analyte-responsive optical protein sensors through allosteric-like modulation of fluorogen binding.
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Affiliation(s)
- Fanny Broch
- Sorbonne Université, École Normale Supérieure, Université PSL, CNRS, Laboratoire des Biomolécules, LBM, 75005 Paris, France
| | - Lina El Hajji
- Sorbonne Université, École Normale Supérieure, Université PSL, CNRS, Laboratoire des Biomolécules, LBM, 75005 Paris, France
| | - Nicolas Pietrancosta
- Sorbonne Université, École Normale Supérieure, Université PSL, CNRS, Laboratoire des Biomolécules, LBM, 75005 Paris, France
- Neuroscience Paris Seine-Institut de Biologie Paris Seine (NPS-IBPS) INSERM, CNRS, Sorbonne Université, 75005 Paris, France
| | - Arnaud Gautier
- Sorbonne Université, École Normale Supérieure, Université PSL, CNRS, Laboratoire des Biomolécules, LBM, 75005 Paris, France
- Institut Universitaire de France, 75231 Paris, France
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2
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Changes within the central stalk of E. coli F 1F o ATP synthase observed after addition of ATP. Commun Biol 2023; 6:26. [PMID: 36631659 PMCID: PMC9834311 DOI: 10.1038/s42003-023-04414-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 01/03/2023] [Indexed: 01/13/2023] Open
Abstract
F1Fo ATP synthase functions as a biological generator and makes a major contribution to cellular energy production. Proton flow generates rotation in the Fo motor that is transferred to the F1 motor to catalyze ATP production, with flexible F1/Fo coupling required for efficient catalysis. F1Fo ATP synthase can also operate in reverse, hydrolyzing ATP and pumping protons, and in bacteria this function can be regulated by an inhibitory ε subunit. Here we present cryo-EM data showing E. coli F1Fo ATP synthase in different rotational and inhibited sub-states, observed following incubation with 10 mM MgATP. Our structures demonstrate how structural transitions within the inhibitory ε subunit induce torsional movement in the central stalk, thereby enabling its rotation within the Fο motor. This highlights the importance of the central rotor for flexible coupling of the F1 and Fo motors and provides further insight into the regulatory mechanism mediated by subunit ε.
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3
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Krah A, Vogelaar T, de Jong SI, Claridge JK, Bond PJ, McMillan DGG. ATP binding by an F 1F o ATP synthase ε subunit is pH dependent, suggesting a diversity of ε subunit functional regulation in bacteria. Front Mol Biosci 2023; 10:1059673. [PMID: 36923639 PMCID: PMC10010621 DOI: 10.3389/fmolb.2023.1059673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 01/03/2023] [Indexed: 03/03/2023] Open
Abstract
It is a conjecture that the ε subunit regulates ATP hydrolytic function of the F1Fo ATP synthase in bacteria. This has been proposed by the ε subunit taking an extended conformation, with a terminal helix probing into the central architecture of the hexameric catalytic domain, preventing ATP hydrolysis. The ε subunit takes a contracted conformation when bound to ATP, thus would not interfere with catalysis. A recent crystallographic study has disputed this; the Caldalkalibacillus thermarum TA2.A1 F1Fo ATP synthase cannot natively hydrolyse ATP, yet studies have demonstrated that the loss of the ε subunit terminal helix results in an ATP synthase capable of ATP hydrolysis, supporting ε subunit function. Analysis of sequence and crystallographic data of the C. thermarum F1Fo ATP synthase revealed two unique histidine residues. Molecular dynamics simulations suggested that the protonation state of these residues may influence ATP binding site stability. Yet these residues lie outside the ATP/Mg2+ binding site of the ε subunit. We then probed the effect of pH on the ATP binding affinity of the ε subunit from the C. thermarum F1Fo ATP synthase at various physiologically relevant pH values. We show that binding affinity changes 5.9 fold between pH 7.0, where binding is weakest, to pH 8.5 where it is strongest. Since the C. thermarum cytoplasm is pH 8.0 when it grows optimally, this correlates to the ε subunit being down due to ATP/Mg2+ affinity, and not being involved in blocking ATP hydrolysis. Here, we have experimentally correlated that the pH of the bacterial cytoplasm is of critical importance for ε subunit ATP affinity regulated by second-shell residues thus the function of the ε subunit changes with growth conditions.
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Affiliation(s)
- Alexander Krah
- Korea Institute for Advanced Study, School of Computational Sciences, Seoul, South Korea.,Bioinformatics Institute, Agency for Science, Technology and Research (ASTAR), Singapore, Singapore
| | - Timothy Vogelaar
- Department of Biotechnology, Delft University of Technology, Delft, Netherlands
| | - Sam I de Jong
- Department of Biotechnology, Delft University of Technology, Delft, Netherlands
| | - Jolyon K Claridge
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Peter J Bond
- Bioinformatics Institute, Agency for Science, Technology and Research (ASTAR), Singapore, Singapore.,Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Duncan G G McMillan
- Department of Biotechnology, Delft University of Technology, Delft, Netherlands.,School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
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4
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Nakano A, Kishikawa JI, Nakanishi A, Mitsuoka K, Yokoyama K. Structural basis of unisite catalysis of bacterial F 0F 1-ATPase. PNAS NEXUS 2022; 1:pgac116. [PMID: 36741449 PMCID: PMC9896953 DOI: 10.1093/pnasnexus/pgac116] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 07/07/2022] [Indexed: 06/17/2023]
Abstract
Adenosine triphosphate (ATP) synthases (F0F1-ATPases) are crucial for all aerobic organisms. F1, a water-soluble domain, can catalyze both the synthesis and hydrolysis of ATP with the rotation of the central γε rotor inside a cylinder made of α 3 β 3 in three different conformations (referred to as β E, β TP, and β DP). In this study, we determined multiple cryo-electron microscopy structures of bacterial F0F1 exposed to different reaction conditions. The structures of nucleotide-depleted F0F1 indicate that the ε subunit directly forces β TP to adopt a closed form independent of the nucleotide binding to β TP. The structure of F0F1 under conditions that permit only a single catalytic β subunit per enzyme to bind ATP is referred to as unisite catalysis and reveals that ATP hydrolysis unexpectedly occurs on β TP instead of β DP, where ATP hydrolysis proceeds in the steady-state catalysis of F0F1. This indicates that the unisite catalysis of bacterial F0F1 significantly differs from the kinetics of steady-state turnover with continuous rotation of the shaft.
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Affiliation(s)
- Atsuki Nakano
- Department of Molecular Biosciences, Kyoto Sangyo University, Kamigamo-Motoyama, Kita-ku, Kyoto 603-8555, Japan
| | - Jun-ichi Kishikawa
- Department of Molecular Biosciences, Kyoto Sangyo University, Kamigamo-Motoyama, Kita-ku, Kyoto 603-8555, Japan
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Atsuko Nakanishi
- Department of Molecular Biosciences, Kyoto Sangyo University, Kamigamo-Motoyama, Kita-ku, Kyoto 603-8555, Japan
- Research Center for Ultra-High Voltage Electron Microscopy, Osaka University, 7-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
| | - Kaoru Mitsuoka
- Research Center for Ultra-High Voltage Electron Microscopy, Osaka University, 7-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
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5
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A second shell residue modulates a conserved ATP-binding site with radically different affinities for ATP. Biochim Biophys Acta Gen Subj 2020; 1865:129766. [PMID: 33069831 DOI: 10.1016/j.bbagen.2020.129766] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 09/16/2020] [Accepted: 10/14/2020] [Indexed: 11/20/2022]
Abstract
BACKGROUND Prediction of ligand binding and design of new function in enzymes is a time-consuming and expensive process. Crystallography gives the impression that proteins adopt a fixed shape, yet enzymes are functionally dynamic. Molecular dynamics offers the possibility of probing protein movement while predicting ligand binding. Accordingly, we choose the bacterial F1Fo ATP synthase ε subunit to unravel why ATP affinity by ε subunits from Bacillus subtilis and Bacillus PS3 differs ~500-fold, despite sharing identical sequences at the ATP-binding site. METHODS We first used the Bacillus PS3 ε subunit structure to model the B. subtilis ε subunit structure and used this to explore the utility of molecular dynamics (MD) simulations to predict the influence of residues outside the ATP binding site. To verify the MD predictions, point mutants were made and ATP binding studies were employed. RESULTS MD simulations predicted that E102 in the B. subtilis ε subunit, outside of the ATP binding site, influences ATP binding affinity. Engineering E102 to alanine or arginine revealed a ~10 or ~54 fold increase in ATP binding, respectively, confirming the MD prediction that E102 drastically influences ATP binding affinity. CONCLUSIONS These findings reveal how MD can predict how changes in the "second shell" residues around substrate binding sites influence affinity in simple protein structures. Our results reveal why seemingly identical ε subunits in different ATP synthases have radically different ATP binding affinities. GENERAL SIGNIFICANCE This study may lead to greater utility of molecular dynamics as a tool for protein design and exploration of protein design and function.
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6
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Krah A, Huber RG, McMillan DGG, Bond PJ. The Molecular Basis for Purine Binding Selectivity in the Bacterial ATP Synthase ϵ Subunit. Chembiochem 2020; 21:3249-3254. [PMID: 32608105 DOI: 10.1002/cbic.202000291] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 06/30/2020] [Indexed: 12/21/2022]
Abstract
The ϵ subunit of ATP synthases has been proposed to regulate ATP hydrolysis in bacteria. Prevailing evidence supports the notion that when the ATP concentration falls below a certain threshold, the ϵ subunit changes its conformation from a non-inhibitory down-state to an extended up-state that then inhibits enzymatic ATP hydrolysis by binding to the catalytic domain. It has been demonstrated that the ϵ subunit from Bacillus PS3 is selective for ATP over other nucleotides, including GTP. In this study, the purine triphosphate selectivity is rationalized by using results from MD simulations and free energy calculations for the R103A/R115A mutant of the ϵ subunit from Bacillus PS3, which binds ATP more strongly than the wild-type protein. Our results are in good agreement with experimental data, and the elucidated molecular basis for selectivity could help to guide the design of novel GTP sensors.
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Affiliation(s)
- Alexander Krah
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), 30 Biopolis Str. #07-01 Matrix, Singapore, 138671, Singapore.,Korea Institute for Advanced Study, School of Computational Sciences, 85 Hoegiro, Dongdaemun-gu, Seoul, 02455, Republic of Korea
| | - Roland G Huber
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), 30 Biopolis Str. #07-01 Matrix, Singapore, 138671, Singapore
| | - Duncan G G McMillan
- Delft University of Technology, Department of Biotechnology, Van der Maasweg 9, Delft, 2629HZ, The Netherlands
| | - Peter J Bond
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), 30 Biopolis Str. #07-01 Matrix, Singapore, 138671, Singapore.,National University of Singapore, Department of Biological Sciences, 14 Science Drive 4, Singapore, 117543, Singapore
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7
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Kitajima N, Takikawa K, Sekiya H, Satoh K, Asanuma D, Sakamoto H, Takahashi S, Hanaoka K, Urano Y, Namiki S, Iino M, Hirose K. Real-time in vivo imaging of extracellular ATP in the brain with a hybrid-type fluorescent sensor. eLife 2020; 9:e57544. [PMID: 32648544 PMCID: PMC7398694 DOI: 10.7554/elife.57544] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 07/09/2020] [Indexed: 02/06/2023] Open
Abstract
Adenosine 5' triphosphate (ATP) is a ubiquitous extracellular signaling messenger. Here, we describe a method for in-vivo imaging of extracellular ATP with high spatiotemporal resolution. We prepared a comprehensive set of cysteine-substitution mutants of ATP-binding protein, Bacillus FoF1-ATP synthase ε subunit, labeled with small-molecule fluorophores at the introduced cysteine residue. Screening revealed that the Cy3-labeled glutamine-105 mutant (Q105C-Cy3; designated ATPOS) shows a large fluorescence change in the presence of ATP, with submicromolar affinity, pH-independence, and high selectivity for ATP over ATP metabolites and other nucleotides. To enable in-vivo validation, we introduced BoNT/C-Hc for binding to neuronal plasma membrane and Alexa Fluor 488 for ratiometric measurement. The resulting ATPOS complex binds to neurons in cerebral cortex of living mice, and clearly visualized a concentrically propagating wave of extracellular ATP release in response to electrical stimulation. ATPOS should be useful to probe the extracellular ATP dynamics of diverse biological processes in vivo.
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Grants
- 17H04029 Ministry of Education, Culture, Sports, Science, and Technology
- 17K08584 Ministry of Education, Culture, Sports, Science, and Technology
- JPMJPR17P1 Japan Science and Technology Agency
- 19K22247 Ministry of Education, Culture, Sports, Science, and Technology
- 25221304 Ministry of Education, Culture, Sports, Science, and Technology
- 18K14915 Ministry of Education, Culture, Sports, Science, and Technology
- 17H04764 Ministry of Education, Culture, Sports, Science, and Technology
- 18H04726 Ministry of Education, Culture, Sports, Science, and Technology
- 19K16251 Ministry of Education, Culture, Sports, Science, and Technology
- 18H04609 Ministry of Education, Culture, Sports, Science, and Technology
- 19H05414 Ministry of Education, Culture, Sports, Science, and Technology
- Takeda Science Foundation
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Affiliation(s)
- Nami Kitajima
- Department of Pharmacology, Graduate School of Medicine, The University of TokyoTokyoJapan
| | - Kenji Takikawa
- Department of Pharmacology, Graduate School of Medicine, The University of TokyoTokyoJapan
| | - Hiroshi Sekiya
- Department of Physiology, Graduate School of Medicine, The University of TokyoTokyoJapan
| | - Kaname Satoh
- Department of Pharmacology, Graduate School of Medicine, The University of TokyoTokyoJapan
| | - Daisuke Asanuma
- Department of Pharmacology, Graduate School of Medicine, The University of TokyoTokyoJapan
| | - Hirokazu Sakamoto
- Department of Pharmacology, Graduate School of Medicine, The University of TokyoTokyoJapan
| | - Shodai Takahashi
- Graduate School of Pharmaceutical Sciences, The University of TokyoTokyoJapan
| | - Kenjiro Hanaoka
- Graduate School of Pharmaceutical Sciences, The University of TokyoTokyoJapan
| | - Yasuteru Urano
- Graduate School of Pharmaceutical Sciences, The University of TokyoTokyoJapan
- Graduate School of Medicine, The University of TokyoTokyoJapan
| | - Shigeyuki Namiki
- Department of Pharmacology, Graduate School of Medicine, The University of TokyoTokyoJapan
| | - Masamitsu Iino
- Department of Cellular and Molecular Pharmacology, Nihon University School of MedicineTokyoJapan
| | - Kenzo Hirose
- Department of Pharmacology, Graduate School of Medicine, The University of TokyoTokyoJapan
- International Research Center for Neurointelligence, The University of Tokyo Institutes for Advanced Study, The University of TokyoTokyoJapan
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8
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Krah A, Huber RG, Bond PJ. How Ligand Binding Affects the Dynamical Transition Temperature in Proteins. Chemphyschem 2020; 21:916-926. [DOI: 10.1002/cphc.201901221] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 03/03/2020] [Indexed: 11/11/2022]
Affiliation(s)
- Alexander Krah
- School of Computational SciencesKorea Institute for Advanced Study 85 Hoegiro, Dongdaemun-gu Seoul 02455 Republic of Korea
- Bioinformatics InstituteAgency for Science Technology and Research (A*STAR) 30 Biopolis Str., #07-01 Matrix 138671 Singapore
| | - Roland G. Huber
- Bioinformatics InstituteAgency for Science Technology and Research (A*STAR) 30 Biopolis Str., #07-01 Matrix 138671 Singapore
| | - Peter J. Bond
- Bioinformatics InstituteAgency for Science Technology and Research (A*STAR) 30 Biopolis Str., #07-01 Matrix 138671 Singapore
- National University of SingaporeDepartment of Biological Sciences 14 Science Drive 4 Singapore 117543
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9
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ATP-binding affinity of the ε subunit of thermophilic F 1-ATPase under label-free conditions. Biochem Biophys Rep 2020; 21:100725. [PMID: 31938734 PMCID: PMC6953521 DOI: 10.1016/j.bbrep.2020.100725] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 11/29/2019] [Accepted: 01/03/2020] [Indexed: 12/31/2022] Open
Abstract
The ε subunits of several bacterial F1-ATPases bind ATP. ATP binding to the ε subunit has been shown to be involved in the regulation of F1-ATPase from thermophilic Bacillus sp. PS3 (TF1). We previously reported that the dissociation constant for ATP of wild-type ε subunit of TF1 at 25 °C is 4.3 μM by measuring changes in the fluorescence of the dye attached to the ε subunit (Kato, S. et al. (2007) J. Biol. Chem.282, 37618). However, we have recently noticed that this varies with the dye used. In this report, to determine the affinity for ATP under label-free conditions, we have measured the competitive displacement of 2′(3′)-O-N′-methylaniloyl-aminoadenosine-5′-triphosphate (Mant-ATP), a fluorescent analog of ATP, by ATP. The dissociation constant for ATP of wild-type ε subunit of TF1 at 25 °C was determined to be 0.29 μM, which is one order of magnitude higher affinity than previously reported values. The ε subunit of F1-ATPase from Bacillus PS3 specifically binds ATP. Fluorescent labeling of ε subunit for the measurement may affect binding affinity. ATP binding affinity under label-free conditions was determined. Affinity of ε subunit for ATP is revised.
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10
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Petri J, Nakatani Y, Montgomery MG, Ferguson SA, Aragão D, Leslie AGW, Heikal A, Walker JE, Cook GM. Structure of F 1-ATPase from the obligate anaerobe Fusobacterium nucleatum. Open Biol 2019; 9:190066. [PMID: 31238823 PMCID: PMC6597759 DOI: 10.1098/rsob.190066] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The crystal structure of the F1-catalytic domain of the adenosine triphosphate (ATP) synthase has been determined from the pathogenic anaerobic bacterium Fusobacterium nucleatum. The enzyme can hydrolyse ATP but is partially inhibited. The structure is similar to those of the F1-ATPases from Caldalkalibacillus thermarum, which is more strongly inhibited in ATP hydrolysis, and in Mycobacterium smegmatis, which has a very low ATP hydrolytic activity. The βE-subunits in all three enzymes are in the conventional ‘open’ state, and in the case of C. thermarum and M. smegmatis, they are occupied by an ADP and phosphate (or sulfate), but in F. nucleatum, the occupancy by ADP appears to be partial. It is likely that the hydrolytic activity of the F. nucleatum enzyme is regulated by the concentration of ADP, as in mitochondria.
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Affiliation(s)
- Jessica Petri
- 1 Department of Microbiology and Immunology, Otago School of Medical Sciences, University of Otago , Dunedin 9054 , New Zealand
| | - Yoshio Nakatani
- 1 Department of Microbiology and Immunology, Otago School of Medical Sciences, University of Otago , Dunedin 9054 , New Zealand.,2 Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland , Private Bag 92019, Auckland 1042 , New Zealand
| | - Martin G Montgomery
- 3 Medical Research Council Mitochondrial Biology Unit , Cambridge Biomedical Campus, Cambridge CB2 0XY , UK
| | - Scott A Ferguson
- 1 Department of Microbiology and Immunology, Otago School of Medical Sciences, University of Otago , Dunedin 9054 , New Zealand
| | - David Aragão
- 4 Australian Synchrotron , 800 Blackburn Road, Clayton, Victoria 3168 , Australia
| | - Andrew G W Leslie
- 5 Medical Research Council Laboratory of Molecular Biology , Cambridge Biomedical Campus, Cambridge CB2 0QH , UK
| | - Adam Heikal
- 1 Department of Microbiology and Immunology, Otago School of Medical Sciences, University of Otago , Dunedin 9054 , New Zealand.,2 Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland , Private Bag 92019, Auckland 1042 , New Zealand
| | - John E Walker
- 3 Medical Research Council Mitochondrial Biology Unit , Cambridge Biomedical Campus, Cambridge CB2 0XY , UK
| | - Gregory M Cook
- 1 Department of Microbiology and Immunology, Otago School of Medical Sciences, University of Otago , Dunedin 9054 , New Zealand.,2 Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland , Private Bag 92019, Auckland 1042 , New Zealand
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11
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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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12
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The structure of the catalytic domain of the ATP synthase from Mycobacterium smegmatis is a target for developing antitubercular drugs. Proc Natl Acad Sci U S A 2019; 116:4206-4211. [PMID: 30683723 DOI: 10.1073/pnas.1817615116] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The crystal structure of the F1-catalytic domain of the adenosine triphosphate (ATP) synthase has been determined from Mycobacterium smegmatis which hydrolyzes ATP very poorly. The structure of the α3β3-component of the catalytic domain is similar to those in active F1-ATPases in Escherichia coli and Geobacillus stearothermophilus However, its ε-subunit differs from those in these two active bacterial F1-ATPases as an ATP molecule is not bound to the two α-helices forming its C-terminal domain, probably because they are shorter than those in active enzymes and they lack an amino acid that contributes to the ATP binding site in active enzymes. In E. coli and G. stearothermophilus, the α-helices adopt an "up" state where the α-helices enter the α3β3-domain and prevent the rotor from turning. The mycobacterial F1-ATPase is most similar to the F1-ATPase from Caldalkalibacillus thermarum, which also hydrolyzes ATP poorly. The βE-subunits in both enzymes are in the usual "open" conformation but appear to be occupied uniquely by the combination of an adenosine 5'-diphosphate molecule with no magnesium ion plus phosphate. This occupation is consistent with the finding that their rotors have been arrested at the same point in their rotary catalytic cycles. These bound hydrolytic products are probably the basis of the inhibition of ATP hydrolysis. It can be envisaged that specific as yet unidentified small molecules might bind to the F1 domain in Mycobacterium tuberculosis, prevent ATP synthesis, and inhibit the growth of the pathogen.
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13
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Lapashina AS, Feniouk BA. ADP-Inhibition of H+-F OF 1-ATP Synthase. BIOCHEMISTRY (MOSCOW) 2018; 83:1141-1160. [PMID: 30472953 DOI: 10.1134/s0006297918100012] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
H+-FOF1-ATP synthase (F-ATPase, F-type ATPase, FOF1 complex) catalyzes ATP synthesis from ADP and inorganic phosphate in eubacteria, mitochondria, chloroplasts, and some archaea. ATP synthesis is powered by the transmembrane proton transport driven by the proton motive force (PMF) generated by the respiratory or photosynthetic electron transport chains. When the PMF is decreased or absent, ATP synthase catalyzes the reverse reaction, working as an ATP-dependent proton pump. The ATPase activity of the enzyme is regulated by several mechanisms, of which the most conserved is the non-competitive inhibition by the MgADP complex (ADP-inhibition). When ADP binds to the catalytic site without phosphate, the enzyme may undergo conformational changes that lock bound ADP, resulting in enzyme inactivation. PMF can induce release of inhibitory ADP and reactivate ATP synthase; the threshold PMF value required for enzyme reactivation might exceed the PMF for ATP synthesis. Moreover, membrane energization increases the catalytic site affinity to phosphate, thereby reducing the probability of ADP binding without phosphate and preventing enzyme transition to the ADP-inhibited state. Besides phosphate, oxyanions (e.g., sulfite and bicarbonate), alcohols, lauryldimethylamine oxide, and a number of other detergents can weaken ADP-inhibition and increase ATPase activity of the enzyme. In this paper, we review the data on ADP-inhibition of ATP synthases from different organisms and discuss the in vivo role of this phenomenon and its relationship with other regulatory mechanisms, such as ATPase activity inhibition by subunit ε and nucleotide binding in the noncatalytic sites of the enzyme. It should be noted that in Escherichia coli enzyme, ADP-inhibition is relatively weak and rather enhanced than prevented by phosphate.
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Affiliation(s)
- A S Lapashina
- Lomonosov Moscow State University, Faculty of Bioengineering and Bioinformatics, Moscow, 119991, Russia.,Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - B A Feniouk
- Lomonosov Moscow State University, Faculty of Bioengineering and Bioinformatics, Moscow, 119991, Russia. .,Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
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14
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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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15
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Structure of the γ-ε complex of cyanobacterial F 1-ATPase reveals a suppression mechanism of the γ subunit on ATP hydrolysis in phototrophs. Biochem J 2018; 475:2925-2939. [PMID: 30054433 DOI: 10.1042/bcj20180481] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 07/23/2018] [Accepted: 07/25/2018] [Indexed: 11/17/2022]
Abstract
F1-ATPase forms the membrane-associated segment of F0F1-ATP synthase - the fundamental enzyme complex in cellular bioenergetics for ATP hydrolysis and synthesis. Here, we report a crystal structure of the central F1 subcomplex, consisting of the rotary shaft γ subunit and the inhibitory ε subunit, from the photosynthetic cyanobacterium Thermosynechococcus elongatus BP-1, at 1.98 Å resolution. In contrast with their homologous bacterial and mitochondrial counterparts, the γ subunits of photosynthetic organisms harbour a unique insertion of 35-40 amino acids. Our structural data reveal that this region forms a β-hairpin structure along the central stalk. We identified numerous critical hydrogen bonds and electrostatic interactions between residues in the hairpin and the rest of the γ subunit. To elaborate the critical function of this β-hairpin in inhibiting ATP hydrolysis, the corresponding domain was deleted in the cyanobacterial F1 subcomplex. Biochemical analyses of the corresponding α3β3γ complex confirm that the clinch of the hairpin structure plays a critical role and accounts for a significant interaction in the α3β3 complex to induce ADP inhibition during ATP hydrolysis. In addition, we found that truncating the β-hairpin insertion structure resulted in a marked impairment of the interaction with the ε subunit, which binds to the opposite side of the γ subunit from the β-hairpin structure. Combined with structural analyses, our work provides experimental evidence supporting the molecular principle of how the insertion region of the γ subunit suppresses F1 rotation during ATP hydrolysis.
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16
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Krah A, Bond PJ. Single mutations in the ε subunit from thermophilic Bacillus PS3 generate a high binding affinity site for ATP. PeerJ 2018; 6:e5505. [PMID: 30202650 PMCID: PMC6129141 DOI: 10.7717/peerj.5505] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 08/02/2018] [Indexed: 01/23/2023] Open
Abstract
The ε subunit from ATP synthases acts as an ATP sensor in the bacterial cell to prevent ATP hydrolysis and thus the waste of ATP under conditions of low ATP concentration. However, the ATP binding affinities from various bacterial organisms differ markedly, over several orders of magnitude. For example, the ATP synthases from thermophilic Bacillus PS3 and Escherichia coli exhibit affinities of 4 µM and 22 mM, respectively. The recently reported R103A/R115A double mutant of Bacillus PS3 ATP synthase demonstrated an increased binding affinity by two orders of magnitude with respect to the wild type. Here, we used atomic-resolution molecular dynamics simulations to determine the role of the R103A and R115A single mutations. These lead us to predict that both single mutations also cause an increased ATP binding affinity. Evolutionary analysis reveals R103 and R115 substitutions in the ε subunit from other bacillic organisms, leading us to predict they likely have a higher ATP binding affinity than previously expected.
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Affiliation(s)
- Alexander Krah
- School of Computational Sciences, Korea Institute for Advanced Study, Seoul, Republic of Korea.,Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Peter J Bond
- Bioinformatics Institute, Agency for Science, Technology and Research (ASTAR), Singapore, Singapore.,Department of Biological Sciences, National University of Singapore, Singapore, Singapore
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17
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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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18
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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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19
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Regulation of the thermoalkaliphilic F1-ATPase from Caldalkalibacillus thermarum. Proc Natl Acad Sci U S A 2016; 113:10860-5. [PMID: 27621435 DOI: 10.1073/pnas.1612035113] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The crystal structure has been determined of the F1-catalytic domain of the F-ATPase from Caldalkalibacillus thermarum, which hydrolyzes adenosine triphosphate (ATP) poorly. It is very similar to those of active mitochondrial and bacterial F1-ATPases. In the F-ATPase from Geobacillus stearothermophilus, conformational changes in the ε-subunit are influenced by intracellular ATP concentration and membrane potential. When ATP is plentiful, the ε-subunit assumes a "down" state, with an ATP molecule bound to its two C-terminal α-helices; when ATP is scarce, the α-helices are proposed to inhibit ATP hydrolysis by assuming an "up" state, where the α-helices, devoid of ATP, enter the α3β3-catalytic region. However, in the Escherichia coli enzyme, there is no evidence that such ATP binding to the ε-subunit is mechanistically important for modulating the enzyme's hydrolytic activity. In the structure of the F1-ATPase from C. thermarum, ATP and a magnesium ion are bound to the α-helices in the down state. In a form with a mutated ε-subunit unable to bind ATP, the enzyme remains inactive and the ε-subunit is down. Therefore, neither the γ-subunit nor the regulatory ATP bound to the ε-subunit is involved in the inhibitory mechanism of this particular enzyme. The structure of the α3β3-catalytic domain is likewise closely similar to those of active F1-ATPases. However, although the βE-catalytic site is in the usual "open" conformation, it is occupied by the unique combination of an ADP molecule with no magnesium ion and a phosphate ion. These bound hydrolytic products are likely to be the basis of inhibition of ATP hydrolysis.
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20
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On the ATP binding site of the ε subunit from bacterial F-type ATP synthases. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:332-40. [PMID: 26780667 DOI: 10.1016/j.bbabio.2016.01.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 12/11/2015] [Accepted: 01/14/2016] [Indexed: 11/20/2022]
Abstract
F-type ATP synthases are reversible machinery that not only synthesize adenosine triphosphate (ATP) using an electrochemical gradient across the membrane, but also can hydrolyze ATP to pump ions under certain conditions. To prevent wasteful ATP hydrolysis, subunit ε in bacterial ATP synthases changes its conformation from the non-inhibitory down- to the inhibitory up-state at a low cellular ATP concentration. Recently, a crystal structure of the ε subunit in complex with ATP was solved in a non-biologically relevant dimeric form. Here, to derive the functional ATP binding site motif, we carried out molecular dynamics simulations and free energy calculations. Our results suggest that the ATP binding site markedly differs from the experimental resolved one; we observe a reorientation of several residues, which bind to ATP in the crystal structure. In addition we find that an Mg(2+) ion is coordinated by ATP, replacing interactions of the second chain in the crystal structure. Thus we demonstrate more generally the influence of crystallization effects on ligand binding sites and their respective binding modes. Furthermore, we propose a role for two highly conserved residues to control the ATP binding/unbinding event, which have not been considered before. Additionally our results provide the basis for the rational development of new biosensors based on subunit ε, as shown previously for novel sensors measuring the ATP concentration in cells.
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21
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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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22
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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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23
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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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24
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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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25
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Lu P, Lill H, Bald D. ATP synthase in mycobacteria: special features and implications for a function as drug target. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:1208-18. [PMID: 24513197 DOI: 10.1016/j.bbabio.2014.01.022] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2013] [Revised: 01/28/2014] [Accepted: 01/29/2014] [Indexed: 10/25/2022]
Abstract
ATP synthase is a ubiquitous enzyme that is largely conserved across the kingdoms of life. This conservation is in accordance with its central role in chemiosmotic energy conversion, a pathway utilized by far by most living cells. On the other hand, in particular pathogenic bacteria whilst employing ATP synthase have to deal with energetically unfavorable conditions such as low oxygen tensions in the human host, e.g. Mycobacterium tuberculosis can survive in human macrophages for an extended time. It is well conceivable that such ATP synthases may carry idiosyncratic features that contribute to efficient ATP production. In this review genetic and biochemical data on mycobacterial ATP synthase are discussed in terms of rotary catalysis, stator composition, and regulation of activity. ATP synthase in mycobacteria is of particular interest as this enzyme has been validated as a target for promising new antibacterial drugs. A deeper understanding of the working of mycobacterial ATP synthase and its atypical features can provide insight in adaptations of bacterial energy metabolism. Moreover, pinpointing and understanding critical differences as compared with human ATP synthase may provide input for the design and development of selective ATP synthase inhibitors as antibacterials. This article is part of a Special Issue entitled: 18th European Bioenergetic Conference.
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Affiliation(s)
- Ping Lu
- Department of Molecular Cell Biology, AIMMS, Faculty of Earth- and Life Sciences, VU University Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Holger Lill
- Department of Molecular Cell Biology, AIMMS, Faculty of Earth- and Life Sciences, VU University Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Dirk Bald
- Department of Molecular Cell Biology, AIMMS, Faculty of Earth- and Life Sciences, VU University Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands.
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26
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Hisabori T, Sunamura EI, Kim Y, Konno H. The chloroplast ATP synthase features the characteristic redox regulation machinery. Antioxid Redox Signal 2013; 19:1846-54. [PMID: 23145525 PMCID: PMC3837435 DOI: 10.1089/ars.2012.5044] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
SIGNIFICANCE Regulation of the activity of the chloroplast ATP synthase is largely accomplished by the chloroplast thioredoxin system, the main redox regulation system in chloroplasts, which is directly coupled to the photosynthetic reaction. We review the current understanding of the redox regulation system of the chloroplast ATP synthase. RECENT ADVANCES The thioredoxin-targeted portion of the ATP synthase consists of two cysteines located on the central axis subunit γ. The redox state of these two cysteines is under the influence of chloroplast thioredoxin, which directly controls rotation during catalysis by inducing a conformational change in this subunit. The molecular mechanism of redox regulation of the chloroplast ATP synthase has recently been determined. CRITICAL ISSUES Regulation of the activity of the chloroplast ATP synthase is critical in driving efficiency into the ATP synthesis reaction in chloroplasts. FUTURE DIRECTIONS The molecular architecture of the chloroplast ATP synthase, which confers redox regulatory properties requires further investigation, in light of the molecular structure of the enzyme complex as well as the physiological significance of the regulation system.
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Affiliation(s)
- Toru Hisabori
- 1 Chemical Resources Laboratory, Tokyo Institute of Technology , Yokohama, Japan
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27
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ε subunit of Bacillus subtilis F1-ATPase relieves MgADP inhibition. PLoS One 2013; 8:e73888. [PMID: 23967352 PMCID: PMC3742539 DOI: 10.1371/journal.pone.0073888] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 07/23/2013] [Indexed: 11/19/2022] Open
Abstract
MgADP inhibition, which is considered as a part of the regulatory system of ATP synthase, is a well-known process common to all F1-ATPases, a soluble component of ATP synthase. The entrapment of inhibitory MgADP at catalytic sites terminates catalysis. Regulation by the ε subunit is a common mechanism among F1-ATPases from bacteria and plants. The relationship between these two forms of regulatory mechanisms is obscure because it is difficult to distinguish which is active at a particular moment. Here, using F1-ATPase from Bacillus subtilis (BF1), which is strongly affected by MgADP inhibition, we can distinguish MgADP inhibition from regulation by the ε subunit. The ε subunit did not inhibit but activated BF1. We conclude that the ε subunit relieves BF1 from MgADP inhibition.
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28
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29
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ATP binding to the ϵ subunit of thermophilic ATP synthase is crucial for efficient coupling of ATPase and H+ pump activities. Biochem J 2011; 437:135-40. [PMID: 21510843 DOI: 10.1042/bj20110443] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
ATP binding to the ϵ subunit of F1-ATPase, a soluble subcomplex of TFoF1 (FoF1-ATPase synthase from the thermophilic Bacillus strain PS3), affects the regulation of F1-ATPase activity by stabilizing the compact, ATPase-active, form of the ϵ subunit [Kato, S., Yoshida, M. and Kato-Yamada, Y. (2007) J. Biol. Chem. 282, 37618-37623]. In the present study, we report how ATP binding to the ϵ subunit affects ATPase and H+ pumping activities in the holoenzyme TFoF1. Wild-type TFoF1 showed significant H+ pumping activity when ATP was used as the substrate. However, GTP, which bound poorly to the ϵ subunit, did not support efficient H+ pumping. Addition of small amounts of ATP to the GTP substrate restored coupling between GTPase and H+ pumping activities. Similar uncoupling was observed when TFoF1 contained an ATP-binding-deficient ϵ subunit, even with ATP as a substrate. Further analysis suggested that the compact conformation of the ϵ subunit induced by ATP binding was required to couple ATPase and H+ pumping activities in TFoF1 unless the ϵ subunit was in its extended-state conformation. The present study reveals a novel role of the ϵ subunit as an ATP-sensitive regulator of the coupling of ATPase and H+ pumping activities of TFoF1.
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30
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Abstract
AbstractThe rotary ATPase family of membrane protein complexes may have only three members, but each one plays a fundamental role in biological energy conversion. The F1Fo-ATPase (F-ATPase) couples ATP synthesis to the electrochemical membrane potential in bacteria, mitochondria and chloroplasts, while the vacuolar H+-ATPase (V-ATPase) operates as an ATP-driven proton pump in eukaryotic membranes. In different species of archaea and bacteria, the A1Ao-ATPase (A-ATPase) can function as either an ATP synthase or an ion pump. All three of these multi-subunit complexes are rotary molecular motors, sharing a fundamentally similar mechanism in which rotational movement drives the energy conversion process. By analogy to macroscopic systems, individual subunits can be assigned to rotor, axle or stator functions. Recently, three-dimensional reconstructions from electron microscopy and single particle image processing have led to a significant step forward in understanding of the overall architecture of all three forms of these complexes and have allowed the organisation of subunits within the rotor and stator parts of the motors to be more clearly mapped out. This review describes the emerging consensus regarding the organisation of the rotor and stator components of V-, A- and F-ATPases, examining core similarities that point to a common evolutionary origin, and highlighting key differences. In particular, it discusses how newly revealed variation in the complexity of the inter-domain connections may impact on the mechanics and regulation of these molecular machines.
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31
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Haruyama T, Hirono-Hara Y, Kato-Yamada Y. Inhibition of thermophilic F 1-ATPase by the ε subunit takes different path from the ADP-Mg inhibition. Biophysics (Nagoya-shi) 2010; 6:59-65. [PMID: 27857586 PMCID: PMC5036666 DOI: 10.2142/biophysics.6.59] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2010] [Accepted: 11/28/2010] [Indexed: 12/01/2022] Open
Abstract
The F1-ATPase, the soluble part of FoF1-ATP synthase, is a rotary molecular motor consisting of α3β3γδε. The γ and ε subunits rotate relative to the α3β3δ sub-complex on ATP hydrolysis by the β subunit. The ε subunit is known as an endogenous inhibitor of the ATPase activity of the F1-ATPase and is believed to function as a regulator of the ATP synthase. This inhibition by the ε subunit (ε inhibition) of F1-ATPase from thermophilic Bacillus PS3 was analyzed by single molecule measurements. By using a mutant ε subunit deficient in ATP binding, reversible transitions between active and inactive states were observed. Analysis of pause and rotation durations showed that the ε inhibition takes a different path from the ADP-Mg inhibition. Furthermore, the addition of the mutant ε subunit to the α3β3γ sub-complex was found to facilitate recovery of the ATPase activity from the ADP-Mg inhibition. Thus, it was concluded that these two inhibitions are essentially exclusive of each other.
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Affiliation(s)
- Takamitsu Haruyama
- Department of Life Science, Rikkyo University, 3-34-1, Nishi-Ikebukuro, Toshima-ku, Tokyo 171-8501, Japan; Frontier Project "Adaptation and Evolution of Extremophile", College of Science, Rikkyo University, 3-34-1, Nishi-Ikebukuro, Toshima-ku, Tokyo 171-8501, Japan
| | - Yoko Hirono-Hara
- Institute of Industrial Science, the University of Tokyo, 4-6-1, Komaba, Meguro-ku, Tokyo 153-8505, Japan
| | - Yasuyuki Kato-Yamada
- Department of Life Science, Rikkyo University, 3-34-1, Nishi-Ikebukuro, Toshima-ku, Tokyo 171-8501, Japan; Frontier Project "Adaptation and Evolution of Extremophile", College of Science, Rikkyo University, 3-34-1, Nishi-Ikebukuro, Toshima-ku, Tokyo 171-8501, Japan
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32
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Schmidt F, Stadlbauer S, König B. Zinc-cyclen coordination to UTP, TTP or pyrophosphate induces pyrene excimer emission. Dalton Trans 2010; 39:7250-61. [PMID: 20520892 DOI: 10.1039/c0dt00001a] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Pyrene labelled Zn(2+)-cyclen 1 and bis-Zn(2+)-bis-cyclen 2 complexes were synthesized. The reversible coordination at physiological pH of Zn(2+)-cyclens to phosphate anions and to imide moieties, as present in thymine and uracil nucleotides, is well known. In the presence of analytes bearing a phosphate and an imide or two phosphate groups the formation of a ternary complex consisting of two pyrene-labelled metal complexes and the analyte molecule, is observed. The close proximity of the pyrene labels in the complex induces pyrene excimer emission, which is observable by the unarmed eye. By this, the presence of UMP, UDP, UTP and TTP in buffered aqueous solution is signalled, while other nucleotides are not able to induce excimer emission. In the same way, Zn(2+)-cyclen-pyrene acts as luminescent chemosensor for PP(i) and fructose-1,6-bisphosphate in aqueous buffer.
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Affiliation(s)
- Florian Schmidt
- Institute for Organic Chemistry, University of Regensburg, Universitätsstrasse 31, 93053, Regensburg, Germany
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33
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Saita EI, Iino R, Suzuki T, Feniouk BA, Kinosita K, Yoshida M. Activation and stiffness of the inhibited states of F1-ATPase probed by single-molecule manipulation. J Biol Chem 2010; 285:11411-7. [PMID: 20154086 DOI: 10.1074/jbc.m109.099143] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
F(1)-ATPase (F(1)), a soluble portion of F(o)F(1)-ATP synthase (F(o)F(1)), is an ATP-driven motor in which gammaepsilon subunits rotate in the alpha(3)beta(3) cylinder. Activity of F(1) and F(o)F(1) from Bacillus PS3 is attenuated by the epsilon subunit in an inhibitory extended form. In this study we observed ATP-dependent transition of epsilon in single F(1) molecules from extended form to hairpin form by fluorescence resonance energy transfer. The results justify the previous bulk experiments and ensure that fraction of F(1) with hairpin epsilon directly determines the fraction of active F(1) at any ATP concentration. Next, mechanical activation and stiffness of epsilon-inhibited F(1) were examined by the forced rotation of magnetic beads attached to gamma. Compared with ADP inhibition, which is another manner of inhibition, rotation by a larger angle was required for the activation from epsilon inhibition when the beads were forced to rotate to ATP hydrolysis direction, and more torque was required to reach the same rotation angle when beads were forced to rotate to ATP synthesis direction. The results imply that if F(o)F(1) is resting in the epsilon-inhibited state, F(o) motor must transmit to gamma a torque larger than expected from thermodynamic equilibrium to initiate ATP synthesis.
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Affiliation(s)
- Ei-ichiro Saita
- ICORP ATP Synthesis Regulation Project, Japan Science and Technology Corporation, Aomi 2-3-6, Tokyo 135-0064, Japan
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Feniouk BA, Kato-Yamada Y, Yoshida M, Suzuki T. Conformational transitions of subunit epsilon in ATP synthase from thermophilic Bacillus PS3. Biophys J 2010; 98:434-42. [PMID: 20141757 PMCID: PMC2814204 DOI: 10.1016/j.bpj.2009.10.023] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Revised: 10/09/2009] [Accepted: 10/15/2009] [Indexed: 11/26/2022] Open
Abstract
Subunit epsilon of bacterial and chloroplast F(O)F(1)-ATP synthase is responsible for inhibition of ATPase activity. In Bacillus PS3 enzyme, subunit epsilon can adopt two conformations. In the "extended", inhibitory conformation, its two C-terminal alpha-helices are stretched along subunit gamma. In the "contracted", noninhibitory conformation, these helices form a hairpin. The transition of subunit epsilon from an extended to a contracted state was studied in ATP synthase incorporated in Bacillus PS3 membranes at 59 degrees C. Fluorescence energy resonance transfer between fluorophores introduced in the C-terminus of subunit epsilon and in the N-terminus of subunit gamma was used to follow the conformational transition in real time. It was found that ATP induced the conformational transition from the extended to the contracted state (half-maximum transition extent at 140 microM ATP). ADP could neither prevent nor reverse the ATP-induced conformational change, but it did slow it down. Acid residues in the DELSEED region of subunit beta were found to stabilize the extended conformation of epsilon. Binding of ATP directly to epsilon was not essential for the ATP-induced conformational change. The ATP concentration necessary for the half-maximal transition (140 microM) suggests that subunit epsilon probably adopts the extended state and strongly inhibits ATP hydrolysis only when the intracellular ATP level drops significantly below the normal value.
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Affiliation(s)
- Boris A. Feniouk
- ICORP ATP Synthesis Regulation Project, Japan Science and Technology Corporation, Tokyo, Japan
| | | | - Masasuke Yoshida
- ICORP ATP Synthesis Regulation Project, Japan Science and Technology Corporation, Tokyo, Japan
- Faculty of Engineering, Kyoto Sangyo University, Kyoto, Japan
| | - Toshiharu Suzuki
- ICORP ATP Synthesis Regulation Project, Japan Science and Technology Corporation, Tokyo, Japan
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Structural and functional analysis of the intrinsic inhibitor subunit epsilon of F1-ATPase from photosynthetic organisms. Biochem J 2009; 425:85-94. [PMID: 19785575 DOI: 10.1042/bj20091247] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The epsilon subunit, a small subunit located in the F1 domain of ATP synthase and comprising two distinct domains, an N-terminal beta-sandwich structure and a C-terminal alpha-helical region, serves as an intrinsic inhibitor of ATP hydrolysis activity. This inhibitory function is especially important in photosynthetic organisms as the enzyme cannot synthesize ATP in the dark, but may catalyse futile ATP hydrolysis reactions. To understand the structure-function relationship of this subunit in F1 from photosynthetic organisms, we solved the NMR structure of the epsilon subunit of ATP synthase obtained from the thermophilic cyanobacterium Thermosynechococcus elongatus BP-1, and examined the flexibility of the C-terminal domains using molecular dynamics simulations. In addition, we revealed the significance of the C-terminal alpha-helical region of the epsilon subunit in determining the binding affinity to the complex based on the assessment of the inhibition of ATPase activity by the cyanobacterial epsilon subunit and the chimaeric subunits composed of the N-terminal domain from the cyanobacterium and the C-terminal domain from spinach. The differences observed in the structural and biochemical properties of chloroplast and bacterial epsilon subunits explains the distinctive characteristics of the epsilon subunits in the ATPase complex of the photosynthetic organism.
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Modulation of nucleotide binding to the catalytic sites of thermophilic F(1)-ATPase by the epsilon subunit: implication for the role of the epsilon subunit in ATP synthesis. Biochem Biophys Res Commun 2009; 390:230-4. [PMID: 19785990 DOI: 10.1016/j.bbrc.2009.09.092] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Accepted: 09/23/2009] [Indexed: 11/22/2022]
Abstract
Effect of epsilon subunit on the nucleotide binding to the catalytic sites of F(1)-ATPase from the thermophilic Bacillus PS3 (TF(1)) has been tested by using alpha(3)beta(3)gamma and alpha(3)beta(3)gammaepsilon complexes of TF(1) containing betaTyr341 to Trp substitution. The nucleotide binding was assessed with fluorescence quenching of the introduced Trp. The presence of the epsilon subunit weakened ADP binding to each catalytic site, especially to the highest affinity site. This effect was also observed when GDP or IDP was used. The ratio of the affinity of the lowest to the highest nucleotide binding sites had changed two orders of magnitude by the epsilon subunit. The differences may relate to the energy required for the binding change in the ATP synthesis reaction and contribute to the efficient ATP synthesis.
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Visualization of ATP levels inside single living cells with fluorescence resonance energy transfer-based genetically encoded indicators. Proc Natl Acad Sci U S A 2009; 106:15651-6. [PMID: 19720993 DOI: 10.1073/pnas.0904764106] [Citation(s) in RCA: 752] [Impact Index Per Article: 50.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Adenosine 5'-triphosphate (ATP) is the major energy currency of cells and is involved in many cellular processes. However, there is no method for real-time monitoring of ATP levels inside individual living cells. To visualize ATP levels, we generated a series of fluorescence resonance energy transfer (FRET)-based indicators for ATP that were composed of the epsilon subunit of the bacterial F(o)F(1)-ATP synthase sandwiched by the cyan- and yellow-fluorescent proteins. The indicators, named ATeams, had apparent dissociation constants for ATP ranging from 7.4 muM to 3.3 mM. By targeting ATeams to different subcellular compartments, we unexpectedly found that ATP levels in the mitochondrial matrix of HeLa cells are significantly lower than those of cytoplasm and nucleus. We also succeeded in measuring changes in the ATP level inside single HeLa cells after treatment with inhibitors of glycolysis and/or oxidative phosphorylation, revealing that glycolysis is the major ATP-generating pathway of the cells grown in glucose-rich medium. This was also confirmed by an experiment using oligomycin A, an inhibitor of F(o)F(1)-ATP synthase. In addition, it was demonstrated that HeLa cells change ATP-generating pathway in response to changes of nutrition in the environment.
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Abstract
Purines appear to be the most primitive and widespread chemical messengers in the animal and plant kingdoms. The evidence for purinergic signalling in plants, invertebrates and lower vertebrates is reviewed. Much is based on pharmacological studies, but important recent studies have utilized the techniques of molecular biology and receptors have been cloned and characterized in primitive invertebrates, including the social amoeba Dictyostelium and the platyhelminth Schistosoma, as well as the green algae Ostreococcus, which resemble P2X receptors identified in mammals. This suggests that contrary to earlier speculations, P2X ion channel receptors appeared early in evolution, while G protein-coupled P1 and P2Y receptors were introduced either at the same time or perhaps even later. The absence of gene coding for P2X receptors in some animal groups [e.g. in some insects, roundworms (Caenorhabditis elegans) and the plant Arabidopsis] in contrast to the potent pharmacological actions of nucleotides in the same species, suggests that novel receptors are still to be discovered.
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Affiliation(s)
- G Burnstock
- Autonomic Neuroscience Centre, Royal Free and University College Medical School, London, UK.
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García-Trejo JJ, Morales-Ríos E. Regulation of the F1F0-ATP synthase rotary nanomotor in its monomeric-bacterial and dimeric-mitochondrial forms. J Biol Phys 2008; 34:197-212. [PMID: 19669503 DOI: 10.1007/s10867-008-9114-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2007] [Accepted: 09/08/2008] [Indexed: 12/21/2022] Open
Abstract
The F(1)F(0)-adenosine triphosphate (ATP) synthase rotational motor synthesizes most of the ATP required for living from adenosine diphosphate, Pi, and a proton electrochemical gradient across energy-transducing membranes of bacteria, chloroplasts, and mitochondria. However, as a reversible nanomotor, it also hydrolyzes ATP during de-energized conditions in all energy-transducing systems. Thus, different subunits and mechanisms have emerged in nature to control the intrinsic rotation of the enzyme to favor the ATP synthase activity over its opposite and commonly wasteful ATPase turnover. Recent advances in the structural analysis of the bacterial and mitochondrial ATP synthases are summarized to review the distribution and mechanism of the subunits that are part of the central rotor and regulate its gyration. In eubacteria, the epsilon subunit works as a ratchet to favor the rotation of the central stalk in the ATP synthase direction by extending and contracting two alpha-helixes of its C-terminal side and also by binding ATP with low affinity in thermophilic bacteria. On the other hand, in bovine heart mitochondria, the so-called inhibitor protein (IF(1)) interferes with the intrinsic rotational mechanism of the central gamma subunit and with the opening and closing of the catalytic beta-subunits to inhibit its ATPase activity. Besides its inhibitory role, the IF(1) protein also promotes the dimerization of the bovine and rat mitochondrial enzymes, albeit it is not essential for dimerization of the yeast F(1)F(0) mitochondrial complex. High-resolution electron microscopy of the dimeric enzyme in its bovine and yeast forms shows a conical shape that is compatible with the role of the ATP synthase dimer in the formation of tubular the cristae membrane of mitochondria after further oligomerization. Dimerization of the mitochondrial ATP synthase diminishes the rotational drag of the central rotor that would decrease the coupling efficiency between rotation of the central stalk and ATP synthesis taking place at the F(1) portion. In addition, F(1)F(0) dimerization and its further oligomerization also increase the stability of the enzyme to natural or experimentally induced destabilizing conditions.
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Affiliation(s)
- José J García-Trejo
- Facultad de Química, Departamento de Biología, Lab. F-117, Universidad Nacional Autónoma de México, México, D.F., 04510, México.
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