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Nath S. Symmetry breaking and mismatch in the torsional mechanism of ATP synthesis by F OF 1-ATP synthase: mathematical number theory proof and its chemical and biological implications. Theory Biosci 2025; 144:81-93. [PMID: 39709580 DOI: 10.1007/s12064-024-00434-3] [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] [Received: 09/05/2024] [Accepted: 12/15/2024] [Indexed: 12/23/2024]
Abstract
Can mathematical proofs be employed for the solution of fundamental molecular-level problems in biology? Recently, I mathematically tackled complex mechanistic problems arising during the synthesis of the universal biological currency, adenosine triphosphate (ATP) by the FOF1-ATP synthase, nature's smallest rotary molecular motor, using graph-theoretical and combinatorial approaches for the membrane-bound FO and water-soluble F1 domains of this fascinating molecule (see Nath in Theory Biosci 141:249‒260, 2022 and Theory Biosci 143:217‒227, 2024). In the third part of this trilogy, I investigate another critical aspect of the molecular mechanism-that of coupling between the FO and F1 domains of the ATP synthase mediated by the central γ-subunit of ∼ 1 nanometer diameter. According to Nath's torsional mechanism of energy transduction and ATP synthesis the γ-subunit twists during ATP synthesis and the release of stored torsional energy in the central γ-stalk causes conformational changes in the catalytic sites that lead to ATP synthesis, with 1 ATP molecule synthesized per discrete 120° rotation. The twisted γ-subunit breaks the symmetry of the molecule, and its residual torsional strain is shown to readily accommodate any symmetry mismatch existing between FO and F1. A mathematical number theory proof is developed to quantify the extent of symmetry mismatch at any angular position during rotation and derive the conditions for the regaining of symmetry at the end of a 360° rotation. The many chemical and biological implications of the mechanism and the mathematical proof are discussed in detail. Finally, suggestions for further mathematical development of the subject based on ideas from symmetry and group theory have been made. In sum, the answer to the question posed at the beginning of the Abstract is a resounding YES. There exists new, relatively unexplored territory at the interface of mathematics and molecular biology, especially at the level of molecular mechanism. It is hoped that more mathematicians and scientists interested in interdisciplinary work are encouraged to include in their research program approaches of this type-a mathematical proofs-inspired molecular biology-that have the power to lead to new vistas. Such molecular-scale mechanistic problems in biology have proved extraordinarily difficult to solve definitively using conventional experimental, theoretical, and computational approaches.
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Affiliation(s)
- Sunil Nath
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India.
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Amthor JS. ATP yield of plant respiration: potential, actual and unknown. ANNALS OF BOTANY 2023; 132:133-162. [PMID: 37409716 PMCID: PMC10550282 DOI: 10.1093/aob/mcad075] [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: 03/31/2023] [Accepted: 07/04/2023] [Indexed: 07/07/2023]
Abstract
BACKGROUND AND AIMS The ATP yield of plant respiration (ATP/hexose unit respired) quantitatively links active heterotrophic processes with substrate consumption. Despite its importance, plant respiratory ATP yield is uncertain. The aim here was to integrate current knowledge of cellular mechanisms with inferences required to fill knowledge gaps to generate a contemporary estimate of respiratory ATP yield and identify important unknowns. METHOD A numerical balance sheet model combining respiratory carbon metabolism and electron transport pathways with uses of the resulting transmembrane electrochemical proton gradient was created and parameterized for healthy, non-photosynthesizing plant cells catabolizing sucrose or starch to produce cytosolic ATP. KEY RESULTS Mechanistically, the number of c subunits in the mitochondrial ATP synthase Fo sector c-ring, which is unquantified in plants, affects ATP yield. A value of 10 was (justifiably) used in the model, in which case respiration of sucrose potentially yields about 27.5 ATP/hexose (0.5 ATP/hexose more from starch). Actual ATP yield often will be smaller than its potential due to bypasses of energy-conserving reactions in the respiratory chain, even in unstressed plants. Notably, all else being optimal, if 25 % of respiratory O2 uptake is via the alternative oxidase - a typically observed fraction - ATP yield falls 15 % below its potential. CONCLUSIONS Plant respiratory ATP yield is smaller than often assumed (certainly less than older textbook values of 36-38 ATP/hexose) leading to underestimation of active-process substrate requirements. This hinders understanding of ecological/evolutionary trade-offs between competing active processes and assessments of crop growth gains possible through bioengineering of processes that consume ATP. Determining the plant mitochondrial ATP synthase c-ring size, the degree of any minimally required (useful) bypasses of energy-conserving reactions in the respiratory chain, and the magnitude of any 'leaks' in the inner mitochondrial membrane are key research needs.
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Affiliation(s)
- J S Amthor
- Center for Ecosystem Science and Society and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
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3
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Yokoyama R. EngineeRING the gear of ATP synthase: a way to address complexity and flexibility of photosynthesis. PLANT PHYSIOLOGY 2023; 192:691-693. [PMID: 36880386 DOI: 10.1093/plphys/kiad148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 02/21/2023] [Accepted: 02/22/2023] [Indexed: 06/01/2023]
Affiliation(s)
- Ryo Yokoyama
- Assistant Features Editor, Plant Physiology, American Society of Plant Biologists, USA
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, Potsdam-Golm, 14476, Germany
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Yamamoto H, Cheuk A, Shearman J, Nixon PJ, Meier T, Shikanai T. Impact of engineering the ATP synthase rotor ring on photosynthesis in tobacco chloroplasts. PLANT PHYSIOLOGY 2023; 192:1221-1233. [PMID: 36703219 PMCID: PMC10231360 DOI: 10.1093/plphys/kiad043] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 01/05/2023] [Accepted: 01/06/2023] [Indexed: 06/01/2023]
Abstract
The chloroplast ATP synthase produces the ATP needed for photosynthesis and plant growth. The trans-membrane flow of protons through the ATP synthase rotates an oligomeric assembly of c subunits, the c-ring. The ion-to-ATP ratio in rotary F1F0-ATP synthases is defined by the number of c-subunits in the rotor c-ring. Engineering the c-ring stoichiometry is, therefore, a possible route to manipulate ATP synthesis by the ATP synthase and hence photosynthetic efficiency in plants. Here, we describe the construction of a tobacco (Nicotiana tabacum) chloroplast atpH (chloroplastic ATP synthase subunit c gene) mutant in which the c-ring stoichiometry was increased from 14 to 15 c-subunits. Although the abundance of the ATP synthase was decreased to 25% of wild-type (WT) levels, the mutant lines grew as well as WT plants and photosynthetic electron transport remained unaffected. To synthesize the necessary ATP for growth, we found that the contribution of the membrane potential to the proton motive force was enhanced to ensure a higher proton flux via the c15-ring without unwanted low pH-induced feedback inhibition of electron transport. Our work opens avenues to manipulate plant ion-to-ATP ratios with potentially beneficial consequences for photosynthesis.
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Affiliation(s)
- Hiroshi Yamamoto
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Anthony Cheuk
- Department of Life Sciences, Sir Ernst Chain Building-Wolfson Laboratories, Imperial College London, S. Kensington Campus, London SW7 2AZ, UK
| | - Julia Shearman
- Department of Life Sciences, Sir Ernst Chain Building-Wolfson Laboratories, Imperial College London, S. Kensington Campus, London SW7 2AZ, UK
| | - Peter J Nixon
- Department of Life Sciences, Sir Ernst Chain Building-Wolfson Laboratories, Imperial College London, S. Kensington Campus, London SW7 2AZ, UK
| | - Thomas Meier
- Department of Life Sciences, Sir Ernst Chain Building-Wolfson Laboratories, Imperial College London, S. Kensington Campus, London SW7 2AZ, UK
| | - Toshiharu Shikanai
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
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5
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Ortega D, Beeby M. How Did the Archaellum Get Its Rotation? Front Microbiol 2022; 12:803720. [PMID: 35558523 PMCID: PMC9087265 DOI: 10.3389/fmicb.2021.803720] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 12/20/2021] [Indexed: 11/13/2022] Open
Abstract
How new functions evolve fascinates many evolutionary biologists. Particularly captivating is the evolution of rotation in molecular machines, as it evokes familiar machines that we have made ourselves. The archaellum, an archaeal analog of the bacterial flagellum, is one of the simplest rotary motors. It features a long helical propeller attached to a cell envelope-embedded rotary motor. Satisfyingly, the archaellum is one of many members of the large type IV filament superfamily, which includes pili, secretion systems, and adhesins, relationships that promise clues as to how the rotating archaellum evolved from a non-rotary ancestor. Nevertheless, determining exactly how the archaellum got its rotation remains frustratingly elusive. Here we review what is known about how the archaellum got its rotation, what clues exist, and what more is needed to address this question.
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Affiliation(s)
| | - Morgan Beeby
- Department of Life Sciences, Imperial College London, London, United Kingdom
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6
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Review on the applications of atomic force microscopy imaging in proteins. Micron 2022; 159:103293. [DOI: 10.1016/j.micron.2022.103293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 04/22/2022] [Accepted: 05/06/2022] [Indexed: 11/19/2022]
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Vu Huu K, Zangl R, Hoffmann J, Just A, Morgner N. Bacterial F-type ATP synthases follow a well-choreographed assembly pathway. Nat Commun 2022; 13:1218. [PMID: 35260553 PMCID: PMC8904574 DOI: 10.1038/s41467-022-28828-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 02/04/2022] [Indexed: 12/23/2022] Open
Abstract
F-type ATP synthases are multiprotein complexes composed of two separate coupled motors (F1 and FO) generating adenosine triphosphate (ATP) as the universal major energy source in a variety of relevant biological processes in mitochondria, bacteria and chloroplasts. While the structure of many ATPases is solved today, the precise assembly pathway of F1FO-ATP synthases is still largely unclear. Here, we probe the assembly of the F1 complex from Acetobacterium woodii. Using laser induced liquid bead ion desorption (LILBID) mass spectrometry, we study the self-assembly of purified F1 subunits in different environments under non-denaturing conditions. We report assembly requirements and identify important assembly intermediates in vitro and in cellula. Our data provide evidence that nucleotide binding is crucial for in vitro F1 assembly, whereas ATP hydrolysis appears to be less critical. We correlate our results with activity measurements and propose a model for the assembly pathway of a functional F1 complex. ATPases are the macromolecular machines for cellular energy production. Here the authors investigate factors that govern the assembly of the F1 complex from a bacterial F-type ATPase and relate differences in activity of complexes assembled in cells and in vitro to structural changes.
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Affiliation(s)
- Khanh Vu Huu
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt/Main, Max-von-Laue-Str. 9, 60438, Frankfurt/Main, Germany
| | - Rene Zangl
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt/Main, Max-von-Laue-Str. 9, 60438, Frankfurt/Main, Germany
| | - Jan Hoffmann
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt/Main, Max-von-Laue-Str. 9, 60438, Frankfurt/Main, Germany
| | - Alicia Just
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt/Main, Max-von-Laue-Str. 9, 60438, Frankfurt/Main, Germany
| | - Nina Morgner
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt/Main, Max-von-Laue-Str. 9, 60438, Frankfurt/Main, Germany.
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8
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Nirody JA, Budin I, Rangamani P. ATP synthase: Evolution, energetics, and membrane interactions. J Gen Physiol 2021; 152:152111. [PMID: 32966553 PMCID: PMC7594442 DOI: 10.1085/jgp.201912475] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 08/24/2020] [Indexed: 12/24/2022] Open
Abstract
The synthesis of ATP, life’s “universal energy currency,” is the most prevalent chemical reaction in biological systems and is responsible for fueling nearly all cellular processes, from nerve impulse propagation to DNA synthesis. ATP synthases, the family of enzymes that carry out this endless task, are nearly as ubiquitous as the energy-laden molecule they are responsible for making. The F-type ATP synthase (F-ATPase) is found in every domain of life and has facilitated the survival of organisms in a wide range of habitats, ranging from the deep-sea thermal vents to the human intestine. Accordingly, there has been a large amount of work dedicated toward understanding the structural and functional details of ATP synthases in a wide range of species. Less attention, however, has been paid toward integrating these advances in ATP synthase molecular biology within the context of its evolutionary history. In this review, we present an overview of several structural and functional features of the F-type ATPases that vary across taxa and are purported to be adaptive or otherwise evolutionarily significant: ion channel selectivity, rotor ring size and stoichiometry, ATPase dimeric structure and localization in the mitochondrial inner membrane, and interactions with membrane lipids. We emphasize the importance of studying these features within the context of the enzyme’s particular lipid environment. Just as the interactions between an organism and its physical environment shape its evolutionary trajectory, ATPases are impacted by the membranes within which they reside. We argue that a comprehensive understanding of the structure, function, and evolution of membrane proteins—including ATP synthase—requires such an integrative approach.
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Affiliation(s)
- Jasmine A Nirody
- Center for Studies in Physics and Biology, The Rockefeller University, New York, NY.,All Souls College, University of Oxford, Oxford, UK
| | - Itay Budin
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA
| | - Padmini Rangamani
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA
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9
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Kondo K, Izumi M, Inabe K, Yoshida K, Imashimizu M, Suzuki T, Hisabori T. The phototroph-specific β-hairpin structure of the γ subunit of F oF 1-ATP synthase is important for efficient ATP synthesis of cyanobacteria. J Biol Chem 2021; 297:101027. [PMID: 34339736 PMCID: PMC8390522 DOI: 10.1016/j.jbc.2021.101027] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 07/26/2021] [Accepted: 07/29/2021] [Indexed: 12/01/2022] Open
Abstract
The FoF1 synthase produces ATP from ADP and inorganic phosphate. The γ subunit of FoF1 ATP synthase in photosynthetic organisms, which is the rotor subunit of this enzyme, contains a characteristic β-hairpin structure. This structure is formed from an insertion sequence that has been conserved only in phototrophs. Using recombinant subcomplexes, we previously demonstrated that this region plays an essential role in the regulation of ATP hydrolysis activity, thereby functioning in controlling intracellular ATP levels in response to changes in the light environment. However, the role of this region in ATP synthesis has long remained an open question because its analysis requires the preparation of the whole FoF1 complex and a transmembrane proton-motive force. In this study, we successfully prepared proteoliposomes containing the entire FoF1 ATP synthase from a cyanobacterium, Synechocystis sp. PCC 6803, and measured ATP synthesis/hydrolysis and proton-translocating activities. The relatively simple genetic manipulation of Synechocystis enabled the biochemical investigation of the role of the β-hairpin structure of FoF1 ATP synthase and its activities. We further performed physiological analyses of Synechocystis mutant strains lacking the β-hairpin structure, which provided novel insights into the regulatory mechanisms of FoF1 ATP synthase in cyanobacteria via the phototroph-specific region of the γ subunit. Our results indicated that this structure critically contributes to ATP synthesis and suppresses ATP hydrolysis.
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Affiliation(s)
- Kumiko Kondo
- Laboratory for Chemistry and Life Science, Tokyo Institute of Technology, Midori-ku, Yokohama, Japan
| | - Masayuki Izumi
- Laboratory for Chemistry and Life Science, Tokyo Institute of Technology, Midori-ku, Yokohama, Japan
| | - Kosuke Inabe
- Laboratory for Chemistry and Life Science, Tokyo Institute of Technology, Midori-ku, Yokohama, Japan
| | - Keisuke Yoshida
- Laboratory for Chemistry and Life Science, Tokyo Institute of Technology, Midori-ku, Yokohama, Japan
| | - Mari Imashimizu
- Laboratory for Chemistry and Life Science, Tokyo Institute of Technology, Midori-ku, Yokohama, Japan
| | - Toshiharu Suzuki
- Laboratory for Chemistry and Life Science, Tokyo Institute of Technology, Midori-ku, Yokohama, Japan
| | - Toru Hisabori
- Laboratory for Chemistry and Life Science, Tokyo Institute of Technology, Midori-ku, Yokohama, Japan.
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10
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de Jong SI, van den Broek MA, Merkel AY, de la Torre Cortes P, Kalamorz F, Cook GM, van Loosdrecht MCM, McMillan DGG. Genomic analysis of Caldalkalibacillus thermarum TA2.A1 reveals aerobic alkaliphilic metabolism and evolutionary hallmarks linking alkaliphilic bacteria and plant life. Extremophiles 2020; 24:923-935. [PMID: 33030592 PMCID: PMC7561548 DOI: 10.1007/s00792-020-01205-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Accepted: 09/23/2020] [Indexed: 12/28/2022]
Abstract
The aerobic thermoalkaliphile Caldalkalibacillus thermarum strain TA2.A1 is a member of a separate order of alkaliphilic bacteria closely related to the Bacillales order. Efforts to relate the genomic information of this evolutionary ancient organism to environmental adaptation have been thwarted by the inability to construct a complete genome. The existing draft genome is highly fragmented due to repetitive regions, and gaps between and over repetitive regions were unbridgeable. To address this, Oxford Nanopore Technology's MinION allowed us to span these repeats through long reads, with over 6000-fold coverage. This resulted in a single 3.34 Mb circular chromosome. The profile of transporters and central metabolism gives insight into why the organism prefers glutamate over sucrose as carbon source. We propose that the deamination of glutamate allows alkalization of the immediate environment, an excellent example of how an extremophile modulates environmental conditions to suit its own requirements. Curiously, plant-like hallmark electron transfer enzymes and transporters are found throughout the genome, such as a cytochrome b6c1 complex and a CO2-concentrating transporter. In addition, multiple self-splicing group II intron-encoded proteins closely aligning to those of a telomerase reverse transcriptase in Arabidopsis thaliana were revealed. Collectively, these features suggest an evolutionary relationship to plant life.
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Affiliation(s)
- Samuel I de Jong
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | | | - Alexander Y Merkel
- Winogradsky Institute of Microbiology, Research Center of Biotechnology, Russian Academy of Sciences, Moscow, Russia
| | | | - Falk Kalamorz
- The New Zealand Institute for Plant and Food Research, Lincoln, New Zealand
| | - Gregory M Cook
- Department of Microbiology and Immunology, The University of Otago, Dunedin, New Zealand
| | | | - Duncan G G McMillan
- Department of Biotechnology, Delft University of Technology, Delft, The Netherlands.
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11
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Flygaard RK, Mühleip A, Tobiasson V, Amunts A. Type III ATP synthase is a symmetry-deviated dimer that induces membrane curvature through tetramerization. Nat Commun 2020; 11:5342. [PMID: 33093501 PMCID: PMC7583250 DOI: 10.1038/s41467-020-18993-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 09/24/2020] [Indexed: 01/01/2023] Open
Abstract
Mitochondrial ATP synthases form functional homodimers to induce cristae curvature that is a universal property of mitochondria. To expand on the understanding of this fundamental phenomenon, we characterized the unique type III mitochondrial ATP synthase in its dimeric and tetrameric form. The cryo-EM structure of a ciliate ATP synthase dimer reveals an unusual U-shaped assembly of 81 proteins, including a substoichiometrically bound ATPTT2, 40 lipids, and co-factors NAD and CoQ. A single copy of subunit ATPTT2 functions as a membrane anchor for the dimeric inhibitor IF1. Type III specific linker proteins stably tie the ATP synthase monomers in parallel to each other. The intricate dimer architecture is scaffolded by an extended subunit-a that provides a template for both intra- and inter-dimer interactions. The latter results in the formation of tetramer assemblies, the membrane part of which we determined to 3.1 Å resolution. The structure of the type III ATP synthase tetramer and its associated lipids suggests that it is the intact unit propagating the membrane curvature.
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Affiliation(s)
- Rasmus Kock Flygaard
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, 17165, Solna, Sweden
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, 17177, Stockholm, Sweden
| | - Alexander Mühleip
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, 17165, Solna, Sweden
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, 17177, Stockholm, Sweden
| | - Victor Tobiasson
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, 17165, Solna, Sweden
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, 17177, Stockholm, Sweden
| | - Alexey Amunts
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, 17165, Solna, Sweden.
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, 17177, Stockholm, Sweden.
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12
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Krah A, Marzinek JK, Bond PJ. Characterizing the Hydration Properties of Proton Binding Sites in the ATP Synthase c-Rings of Bacillus Species. J Phys Chem B 2020; 124:7176-7183. [PMID: 32687713 DOI: 10.1021/acs.jpcb.0c03896] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The membrane-embedded domain of ATP synthases contains the c-ring, which translocates ions across the membrane, and its resultant rotation is coupled to ATP synthesis in the extramembranous domain. During rotation, the c-ring becomes accessible on both sides of the lipid bilayer to solvent via channels connected to the other membrane-embedded component, the a subunit, and thereby allows the ion to be released into the solvent environment. In recent times, many experimental structures of c-rings from different species have been solved. In some of these, a water molecule with a proposed "structural role" has been identified within the c-ring ion binding site, but in general, the requirement for high resolution to resolve specific water densities complicates their interpretation. In the present study, we use molecular dynamics (MD) simulations and rigorous free energy calculations to characterize the dynamics and energetics of a water molecule within the ion binding site of the c-ring from Bacillus pseudofirmus OF4, in its wild type (WT) and P51A mutant forms, along with the c-ring from thermophilic Bacillus PS3. Our data suggest that a water molecule stably binds to the P51A mutant, as well as helping to identify a bound water molecule in Bacillus PS3 whose presence was previously overlooked due to the limited resolution of the structural data. Sequence analysis further identifies a novel conserved sequence motif that is likely required to harbor a water molecule for stable ion coordination in the binding site of such proteins.
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Affiliation(s)
- Alexander Krah
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, #07-01 Matrix, Singapore 138671
| | - Jan K Marzinek
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, #07-01 Matrix, Singapore 138671
| | - Peter J Bond
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, #07-01 Matrix, Singapore 138671.,Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543
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13
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Imaging and Force Spectroscopy of Single Transmembrane Proteins with the Atomic Force Microscope. Methods Mol Biol 2020. [PMID: 31218616 DOI: 10.1007/978-1-4939-9512-7_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
The atomic force microscope (AFM) has opened avenues and provided opportunities to investigate biological soft matter and processes ranging from nanometer (nm) to millimeter (mm). The high temporal (millisecond) and spatial (nanometer) resolutions of the AFM are suited for studying many biological processes in their native conditions. The AFM cantilever-aptly termed as a "lab on a tip"-can be used as an imaging tool as well as a handle to manipulate single bonds and proteins. Recent examples have convincingly established AFM as a tool to study the mechanical properties and monitor processes of single proteins and cells with high sensitivity, thus affording insight into important mechanistic details. This chapter specifically focuses on practical and analytical protocols of single-molecule AFM methodologies related to high-resolution imaging and single-molecule force spectroscopy of transmembrane proteins in a lipid bilayer (reconstituted or native). Both these techniques are operator oriented, and require specialized working knowledge of the instrument, theory and practical skills.
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14
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Zhou L, Sazanov LA. Structure and conformational plasticity of the intact Thermus thermophilus V/A-type ATPase. Science 2020; 365:365/6455/eaaw9144. [PMID: 31439765 DOI: 10.1126/science.aaw9144] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 07/10/2019] [Indexed: 12/21/2022]
Abstract
V (vacuolar)/A (archaeal)-type adenosine triphosphatases (ATPases), found in archaea and eubacteria, couple ATP hydrolysis or synthesis to proton translocation across the plasma membrane using the rotary-catalysis mechanism. They belong to the V-type ATPase family, which differs from the mitochondrial/chloroplast F-type ATP synthases in overall architecture. We solved cryo-electron microscopy structures of the intact Thermus thermophilus V/A-ATPase, reconstituted into lipid nanodiscs, in three rotational states and two substates. These structures indicate substantial flexibility between V1 and Vo in a working enzyme, which results from mechanical competition between central shaft rotation and resistance from the peripheral stalks. We also describe details of adenosine diphosphate inhibition release, V1-Vo torque transmission, and proton translocation, which are relevant for the entire V-type ATPase family.
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Affiliation(s)
- Long Zhou
- Institute of Science and Technology Austria, Klosterneuberg 3400, Austria
| | - Leonid A Sazanov
- Institute of Science and Technology Austria, Klosterneuberg 3400, Austria.
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15
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Davis GA, Kramer DM. Optimization of ATP Synthase c-Rings for Oxygenic Photosynthesis. FRONTIERS IN PLANT SCIENCE 2020; 10:1778. [PMID: 32082344 PMCID: PMC7003800 DOI: 10.3389/fpls.2019.01778] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 12/20/2019] [Indexed: 05/10/2023]
Abstract
The conversion of sunlight into useable cellular energy occurs via the proton-coupled electron transfer reactions of photosynthesis. Light is absorbed by photosynthetic pigments and transferred to photochemical reaction centers to initiate electron and proton transfer reactions to store energy in a redox gradient and an electrochemical proton gradient (proton motive force, pmf), composed of a concentration gradient (ΔpH) and an electric field (Δψ), which drives the synthesis of ATP through the thylakoid FoF1-ATP synthase. Although ATP synthase structure and function are conserved across biological kingdoms, the number of membrane-embedded ion-binding c subunits varies between organisms, ranging from 8 to 17, theoretically altering the H+/ATP ratio for different ATP synthase complexes, with profound implications for the bioenergetic processes of cellular metabolism. Of the known c-ring stoichiometries, photosynthetic c-rings are among the largest identified stoichiometries, and it has been proposed that decreasing the c-stoichiometry could increase the energy conversion efficiency of photosynthesis. Indeed, there is strong evidence that the high H+/ATP of the chloroplast ATP synthase results in a low ATP/nicotinamide adenine dinucleotide phosphate (NADPH) ratio produced by photosynthetic linear electron flow, requiring secondary processes such as cyclic electron flow to support downstream metabolism. We hypothesize that the larger c subunit stoichiometry observed in photosynthetic ATP synthases was selected for because it allows the thylakoid to maintain pmf in a range where ATP synthesis is supported, but avoids excess Δψ and ΔpH, both of which can lead to production of reactive oxygen species and subsequent photodamage. Numerical kinetic simulations of the energetics of chloroplast photosynthetic reactions with altered c-ring size predicts the energy storage of pmf and its effects on the photochemical reaction centers strongly support this hypothesis, suggesting that, despite the low efficiency and suboptimal ATP/NADPH ratio, a high H+/ATP is favored to avoid photodamage. This has important implications for the evolution and regulation of photosynthesis as well as for synthetic biology efforts to alter photosynthetic efficiency by engineering the ATP synthase.
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Affiliation(s)
- Geoffry A. Davis
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, United States
| | - David M. Kramer
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI, United States
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, United States
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16
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Novitskaia O, Buslaev P, Gushchin I. Assembly of Spinach Chloroplast ATP Synthase Rotor Ring Protein-Lipid Complex. Front Mol Biosci 2019; 6:135. [PMID: 31850368 PMCID: PMC6896225 DOI: 10.3389/fmolb.2019.00135] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 11/13/2019] [Indexed: 11/19/2022] Open
Abstract
Rotor ATPases are large multisubunit membrane protein complexes found in all kingdoms of life. The membrane parts of these ATPases include a ring-like assembly, so-called c-ring, consisting of several subunits c, plugged by a patch of phospholipids. In this report, we use a nature-inspired approach to model the assembly of the spinach (Spinacia oleracea) c14 ring protein-lipid complex, where partially assembled oligomers are pulled toward each other using a biasing potential. The resulting assemblies contain 23 to 26 encapsulated plug lipids, general position of which corresponds well to experimental maps. However, best fit to experimental data is achieved with 15 to 17 lipids inside the c-ring. In all of the simulations, the lipids from one leaflet (loop side of the c subunit) are ordered and static, whereas the lipids from the other leaflet are disordered and dynamic. Spontaneous permeation of water molecules toward Glu61 at the active site is also observed. The presented assembly approach is expected to be generalizable to other protein complexes with encapsulated lipid patches.
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Affiliation(s)
- Olga Novitskaia
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Pavel Buslaev
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia.,Nanoscience Center, Department of Chemistry, University of Jyväskylä, Jyväskylä, Finland
| | - Ivan Gushchin
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
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17
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Sikkema HR, Gaastra BF, Pols T, Poolman B. Cell Fuelling and Metabolic Energy Conservation in Synthetic Cells. Chembiochem 2019; 20:2581-2592. [PMID: 31381223 DOI: 10.1002/cbic.201900398] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Indexed: 12/14/2022]
Abstract
We are aiming for a blue print for synthesizing (moderately complex) subcellular systems from molecular components and ultimately for constructing life. However, without comprehensive instructions and design principles, we rely on simple reaction routes to operate the essential functions of life. The first forms of synthetic life will not make every building block for polymers de novo according to complex pathways, rather they will be fed with amino acids, fatty acids and nucleotides. Controlled energy supply is crucial for any synthetic cell, no matter how complex. Herein, we describe the simplest pathways for the efficient generation of ATP and electrochemical ion gradients. We have estimated the demand for ATP by polymer synthesis and maintenance processes in small cell-like systems, and we describe circuits to control the need for ATP. We also present fluorescence-based sensors for pH, ionic strength, excluded volume, ATP/ADP, and viscosity, which allow the major physicochemical conditions inside cells to be monitored and tuned.
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Affiliation(s)
- Hendrik R Sikkema
- Department of Biochemistry, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Bauke F Gaastra
- Department of Biochemistry, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Tjeerd Pols
- Department of Biochemistry, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Bert Poolman
- Department of Biochemistry, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
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18
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Versantvoort W, Guerrero-Castillo S, Wessels HJCT, van Niftrik L, Jetten MSM, Brandt U, Reimann J, Kartal B. Complexome analysis of the nitrite-dependent methanotroph Methylomirabilis lanthanidiphila. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:734-744. [PMID: 31376363 DOI: 10.1016/j.bbabio.2019.07.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 07/05/2019] [Accepted: 07/29/2019] [Indexed: 01/31/2023]
Abstract
The atmospheric concentration of the potent greenhouse gases methane and nitrous oxide (N2O) has increased drastically during the last century. Methylomirabilis bacteria can play an important role in controlling the emission of these two gases from natural ecosystems, by oxidizing methane to CO2 and reducing nitrite to N2 without producing N2O. These bacteria have an anaerobic metabolism, but are proposed to possess an oxygen-dependent pathway for methane activation. Methylomirabilis bacteria reduce nitrite to NO, and are proposed to dismutate NO into O2 and N2 by a putative NO dismutase (NO-D). The O2 produced in the cell can then be used to activate methane by a particulate methane monooxygenase. So far, the metabolic model of Methylomirabilis bacteria was based mainly on (meta)genomics and physiological experiments. Here we applied a complexome profiling approach to determine which of the proposed enzymes are actually expressed in Methylomirabilis lanthanidiphila. To validate the proposed metabolic model, we focused on enzymes involved in respiration, as well as nitrogen and carbon transformation. All complexes suggested to be involved in nitrite-dependent methane oxidation, were identified in M. lanthanidiphila, including the putative NO-D. Furthermore, several complexes involved in nitrate reduction/nitrite oxidation and NO reduction were detected, which likely play a role in detoxification and redox homeostasis. In conclusion, complexome profiling validated the expression and composition of enzymes hypothesized to be involved in the energy, methane and nitrogen metabolism of M. lanthanidiphila, thereby further corroborating their unique metabolism involved in the environmentally relevant process of nitrite-dependent methane oxidation.
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Affiliation(s)
- Wouter Versantvoort
- Department of Microbiology, IWWR, Faculty of Science, Radboud University, Nijmegen, the Netherlands.
| | - Sergio Guerrero-Castillo
- Molecular Bioenergetics Group, Radboud Institute for Molecular Life Sciences, Department of Pediatrics, Radboud University Medical Center, Geert-Grooteplein Zuid 10, 6525 GA Nijmegen, the Netherlands
| | - Hans J C T Wessels
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud University Medical Center, Geert-Grooteplein Zuid 10, 6525 GA Nijmegen, the Netherlands
| | - Laura van Niftrik
- Department of Microbiology, IWWR, Faculty of Science, Radboud University, Nijmegen, the Netherlands
| | - Mike S M Jetten
- Department of Microbiology, IWWR, Faculty of Science, Radboud University, Nijmegen, the Netherlands
| | - Ulrich Brandt
- Molecular Bioenergetics Group, Radboud Institute for Molecular Life Sciences, Department of Pediatrics, Radboud University Medical Center, Geert-Grooteplein Zuid 10, 6525 GA Nijmegen, the Netherlands; KPA Aging-Associated Diseases, CECAD Research Center, University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany
| | - Joachim Reimann
- Department of Microbiology, IWWR, Faculty of Science, Radboud University, Nijmegen, the Netherlands
| | - Boran Kartal
- Microbial Physiology Group, Max Planck Institute for Marine Microbiology, Bremen, Germany.
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19
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Abstract
F1Fo ATP synthases produce most of the ATP in the cell. F-type ATP synthases have been investigated for more than 50 years, but a full understanding of their molecular mechanisms has become possible only with the recent structures of complete, functionally competent complexes determined by electron cryo-microscopy (cryo-EM). High-resolution cryo-EM structures offer a wealth of unexpected new insights. The catalytic F1 head rotates with the central γ-subunit for the first part of each ATP-generating power stroke. Joint rotation is enabled by subunit δ/OSCP acting as a flexible hinge between F1 and the peripheral stalk. Subunit a conducts protons to and from the c-ring rotor through two conserved aqueous channels. The channels are separated by ∼6 Å in the hydrophobic core of Fo, resulting in a strong local field that generates torque to drive rotary catalysis in F1. The structure of the chloroplast F1Fo complex explains how ATPase activity is turned off at night by a redox switch. Structures of mitochondrial ATP synthase dimers indicate how they shape the inner membrane cristae. The new cryo-EM structures complete our picture of the ATP synthases and reveal the unique mechanism by which they transform an electrochemical membrane potential into biologically useful chemical energy.
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Affiliation(s)
- Werner Kühlbrandt
- Department of Structural Biology, Max Planck Institute of Biophysics, 60438 Frankfurt, Germany;
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20
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Lebre PH, Cowan DA. Genomics of Alkaliphiles. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2019; 172:135-155. [PMID: 30796503 DOI: 10.1007/10_2018_83] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Alkalinicity presents a challenge for life due to a "reversed" proton gradient that is unfavourable to many bioenergetic processes across the membranes of microorganisms. Despite this, many bacteria, archaea, and eukaryotes, collectively termed alkaliphiles, are adapted to life in alkaline ecosystems and are of great scientific and biotechnological interest due to their niche specialization and ability to produce highly stable enzymes. Advances in next-generation sequencing technologies have propelled not only the genomic characterization of many alkaliphilic microorganisms that have been isolated from nature alkaline sources but also our understanding of the functional relationships between different taxa in microbial communities living in these ecosystems. In this review, we discuss the genetics and molecular biology of alkaliphiles from an "omics" point of view, focusing on how metagenomics and transcriptomics have contributed to our understanding of these extremophiles. Graphical Abstract.
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Affiliation(s)
- Pedro H Lebre
- Centre for Microbial Ecology and Genomics, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
| | - Don A Cowan
- Centre for Microbial Ecology and Genomics, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa.
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21
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Sielaff H, Yanagisawa S, Frasch WD, Junge W, Börsch M. Structural Asymmetry and Kinetic Limping of Single Rotary F-ATP Synthases. Molecules 2019; 24:E504. [PMID: 30704145 PMCID: PMC6384691 DOI: 10.3390/molecules24030504] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 01/23/2019] [Accepted: 01/29/2019] [Indexed: 12/12/2022] Open
Abstract
F-ATP synthases use proton flow through the FO domain to synthesize ATP in the F₁ domain. In Escherichia coli, the enzyme consists of rotor subunits γεc10 and stator subunits (αβ)₃δab₂. Subunits c10 or (αβ)₃ alone are rotationally symmetric. However, symmetry is broken by the b₂ homodimer, which together with subunit δa, forms a single eccentric stalk connecting the membrane embedded FO domain with the soluble F₁ domain, and the central rotating and curved stalk composed of subunit γε. Although each of the three catalytic binding sites in (αβ)₃ catalyzes the same set of partial reactions in the time average, they might not be fully equivalent at any moment, because the structural symmetry is broken by contact with b₂δ in F₁ and with b₂a in FO. We monitored the enzyme's rotary progression during ATP hydrolysis by three single-molecule techniques: fluorescence video-microscopy with attached actin filaments, Förster resonance energy transfer between pairs of fluorescence probes, and a polarization assay using gold nanorods. We found that one dwell in the three-stepped rotary progression lasting longer than the other two by a factor of up to 1.6. This effect of the structural asymmetry is small due to the internal elastic coupling.
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Affiliation(s)
- Hendrik Sielaff
- Single-Molecule Microscopy Group, Jena University Hospital, Friedrich Schiller University, 07743 Jena, Germany.
| | - Seiga Yanagisawa
- School of Life Sciences, Arizona State University, Tempe, Arizona, AZ 85287, USA.
| | - Wayne D Frasch
- School of Life Sciences, Arizona State University, Tempe, Arizona, AZ 85287, USA.
| | - Wolfgang Junge
- Department of Biology & Chemistry, University of Osnabrück, 49076 Osnabrück, Germany.
| | - Michael Börsch
- Single-Molecule Microscopy Group, Jena University Hospital, Friedrich Schiller University, 07743 Jena, Germany.
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22
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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: 2.4] [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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23
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Kondo K, Takeyama Y, Sunamura EI, Madoka Y, Fukaya Y, Isu A, Hisabori T. Amputation of a C-terminal helix of the γ subunit increases ATP-hydrolysis activity of cyanobacterial F 1 ATP synthase. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:319-325. [PMID: 29470949 DOI: 10.1016/j.bbabio.2018.02.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 02/09/2018] [Accepted: 02/14/2018] [Indexed: 12/01/2022]
Abstract
F1 is a soluble part of FoF1-ATP synthase and performs a catalytic process of ATP hydrolysis and synthesis. The γ subunit, which is the rotary shaft of F1 motor, is composed of N-terminal and C-terminal helices domains, and a protruding Rossman-fold domain located between the two major helices parts. The N-terminal and C-terminal helices domains of γ assemble into an antiparallel coiled-coil structure, and are almost embedded into the stator ring composed of α3β3 hexamer of the F1 molecule. Cyanobacterial and chloroplast γ subunits harbor an inserted sequence of 30 or 39 amino acids length within the Rossman-fold domain in comparison with bacterial or mitochondrial γ. To understand the structure-function relationship of the γ subunit, we prepared a mutant F1-ATP synthase of a thermophilic cyanobacterium, Thermosynechococcus elongatus BP-1, in which the γ subunit is split into N-terminal α-helix along with the inserted sequence and the remaining C-terminal part. The obtained mutant showed higher ATP-hydrolysis activities than those containing the wild-type γ. Contrary to our expectation, the complexes containing the split γ subunits were mostly devoid of the C-terminal helix. We further investigated the effect of post-assembly cleavage of the γ subunit. We demonstrate that insertion of the nick between two helices of the γ subunit imparts resistance to ADP inhibition, and the C-terminal α-helix is dispensable for ATP-hydrolysis activity and plays a crucial role in the assembly of F1-ATP synthase.
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Affiliation(s)
- Kumiko Kondo
- Laboratory for Chemistry and Life Science, Tokyo Institute of Technology, Nagatsuta 4259-R1-8, Midori-Ku, Yokohama 226-8503, Japan; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo 102-0075, Japan
| | - Yu Takeyama
- Laboratory for Chemistry and Life Science, Tokyo Institute of Technology, Nagatsuta 4259-R1-8, Midori-Ku, Yokohama 226-8503, Japan
| | - Ei-Ichiro Sunamura
- Laboratory for Chemistry and Life Science, Tokyo Institute of Technology, Nagatsuta 4259-R1-8, Midori-Ku, Yokohama 226-8503, Japan; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo 102-0075, Japan
| | - Yuka Madoka
- Laboratory for Chemistry and Life Science, Tokyo Institute of Technology, Nagatsuta 4259-R1-8, Midori-Ku, Yokohama 226-8503, Japan; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo 102-0075, Japan
| | - Yuki Fukaya
- Laboratory for Chemistry and Life Science, Tokyo Institute of Technology, Nagatsuta 4259-R1-8, Midori-Ku, Yokohama 226-8503, Japan
| | - Atsuko Isu
- Laboratory for Chemistry and Life Science, Tokyo Institute of Technology, Nagatsuta 4259-R1-8, Midori-Ku, Yokohama 226-8503, Japan; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo 102-0075, Japan
| | - Toru Hisabori
- Laboratory for Chemistry and Life Science, Tokyo Institute of Technology, Nagatsuta 4259-R1-8, Midori-Ku, Yokohama 226-8503, Japan; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo 102-0075, Japan.
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24
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Abstract
Mitochondria are the power stations of the eukaryotic cell, using the energy released by the oxidation of glucose and other sugars to produce ATP. Electrons are transferred from NADH, produced in the citric acid cycle in the mitochondrial matrix, to oxygen by a series of large protein complexes in the inner mitochondrial membrane, which create a transmembrane electrochemical gradient by pumping protons across the membrane. The flow of protons back into the matrix via a proton channel in the ATP synthase leads to conformational changes in the nucleotide binding pockets and the formation of ATP. The three proton pumping complexes of the electron transfer chain are NADH-ubiquinone oxidoreductase or complex I, ubiquinone-cytochrome c oxidoreductase or complex III, and cytochrome c oxidase or complex IV. Succinate dehydrogenase or complex II does not pump protons, but contributes reduced ubiquinone. The structures of complex II, III and IV were determined by x-ray crystallography several decades ago, but complex I and ATP synthase have only recently started to reveal their secrets by advances in x-ray crystallography and cryo-electron microscopy. The complexes I, III and IV occur to a certain extent as supercomplexes in the membrane, the so-called respirasomes. Several hypotheses exist about their function. Recent cryo-electron microscopy structures show the architecture of the respirasome with near-atomic detail. ATP synthase occurs as dimers in the inner mitochondrial membrane, which by their curvature are responsible for the folding of the membrane into cristae and thus for the huge increase in available surface that makes mitochondria the efficient energy plants of the eukaryotic cell.
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Affiliation(s)
- Joana S Sousa
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Edoardo D'Imprima
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Janet Vonck
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany.
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25
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Noji H, Ueno H, McMillan DGG. Catalytic robustness and torque generation of the F 1-ATPase. Biophys Rev 2017; 9:103-118. [PMID: 28424741 PMCID: PMC5380711 DOI: 10.1007/s12551-017-0262-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 03/13/2017] [Indexed: 12/28/2022] Open
Abstract
The F1-ATPase is the catalytic portion of the FoF1 ATP synthase and acts as a rotary molecular motor when it hydrolyzes ATP. Two decades have passed since the single-molecule rotation assay of F1-ATPase was established. Although several fundamental issues remain elusive, basic properties of F-type ATPases as motor proteins have been well characterized, and a large part of the reaction scheme has been revealed by the combination of extensive structural, biochemical, biophysical, and theoretical studies. This review is intended to provide a concise summary of the fundamental features of F1-ATPases, by use of the well-described model F1 from the thermophilic Bacillus PS3 (TF1). In the last part of this review, we focus on the robustness of the rotary catalysis of F1-ATPase to provide a perspective on the re-designing of novel molecular machines.
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Affiliation(s)
- Hiroyuki Noji
- Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, Tokyo, 113-8656 Japan
| | - Hiroshi Ueno
- Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, Tokyo, 113-8656 Japan
| | - Duncan G. G. McMillan
- Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, Tokyo, 113-8656 Japan
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26
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Schulz S, Wilkes M, Mills DJ, Kühlbrandt W, Meier T. Molecular architecture of the N-type ATPase rotor ring from Burkholderia pseudomallei. EMBO Rep 2017; 18:526-535. [PMID: 28283532 PMCID: PMC5376962 DOI: 10.15252/embr.201643374] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 02/02/2017] [Accepted: 02/09/2017] [Indexed: 11/09/2022] Open
Abstract
The genome of the highly infectious bacterium Burkholderia pseudomallei harbors an atp operon that encodes an N‐type rotary ATPase, in addition to an operon for a regular F‐type rotary ATPase. The molecular architecture of N‐type ATPases is unknown and their biochemical properties and cellular functions are largely unexplored. We studied the B. pseudomallei N1No‐type ATPase and investigated the structure and ion specificity of its membrane‐embedded c‐ring rotor by single‐particle electron cryo‐microscopy. Of several amphiphilic compounds tested for solubilizing the complex, the choice of the low‐density, low‐CMC detergent LDAO was optimal in terms of map quality and resolution. The cryoEM map of the c‐ring at 6.1 Å resolution reveals a heptadecameric oligomer with a molecular mass of ~141 kDa. Biochemical measurements indicate that the c17 ring is H+ specific, demonstrating that the ATPase is proton‐coupled. The c17 ring stoichiometry results in a very high ion‐to‐ATP ratio of 5.7. We propose that this N‐ATPase is a highly efficient proton pump that helps these melioidosis‐causing bacteria to survive in the hostile, acidic environment of phagosomes.
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Affiliation(s)
- Sarah Schulz
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Martin Wilkes
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Deryck J Mills
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Werner Kühlbrandt
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Thomas Meier
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
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27
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Dannheim H, Will SE, Schomburg D, Neumann-Schaal M. Clostridioides difficile 630Δ erm in silico and in vivo - quantitative growth and extensive polysaccharide secretion. FEBS Open Bio 2017; 7:602-615. [PMID: 28396843 PMCID: PMC5377389 DOI: 10.1002/2211-5463.12208] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 02/09/2017] [Accepted: 02/10/2017] [Indexed: 12/15/2022] Open
Abstract
Antibiotic-associated infections with Clostridioides difficile are a severe and often lethal risk for hospitalized patients, and can also affect populations without these classical risk factors. For a rational design of therapeutical concepts, a better knowledge of the metabolism of the pathogen is crucial. Metabolic modeling can provide a simulation of quantitative growth and usage of metabolic pathways, leading to a deeper understanding of the organism. Here, we present an elaborate genome-scale metabolic model of C. difficile 630Δerm. The model iHD992 includes experimentally determined product and substrate uptake rates and is able to simulate the energy metabolism and quantitative growth of C. difficile. Dynamic flux balance analysis was used for time-resolved simulations of the quantitative growth in two different media. The model predicts oxidative Stickland reactions and glucose degradation as main sources of energy, while the resulting reduction potential is mostly used for acetogenesis via the Wood-Ljungdahl pathway. Initial modeling experiments did not reproduce the observed growth behavior before the production of large quantities of a previously unknown polysaccharide was detected. Combined genome analysis and laboratory experiments indicated that the polysaccharide is an acetylated glucose polymer. Time-resolved simulations showed that polysaccharide secretion was coupled to growth even during unstable glucose uptake in minimal medium. This is accomplished by metabolic shifts between active glycolysis and gluconeogenesis which were also observed in laboratory experiments.
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Affiliation(s)
- Henning Dannheim
- Braunschweig Integrated Centre of Systems Biology (BRICS) Department of Bioinformatics and Biochemistry Technische Universität Braunschweig Braunschweig Germany
| | - Sabine E Will
- Braunschweig Integrated Centre of Systems Biology (BRICS) Department of Bioinformatics and Biochemistry Technische Universität Braunschweig Braunschweig Germany
| | - Dietmar Schomburg
- Braunschweig Integrated Centre of Systems Biology (BRICS) Department of Bioinformatics and Biochemistry Technische Universität Braunschweig Braunschweig Germany
| | - Meina Neumann-Schaal
- Braunschweig Integrated Centre of Systems Biology (BRICS) Department of Bioinformatics and Biochemistry Technische Universität Braunschweig Braunschweig Germany
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Vershubskii AV, Trubitsin BV, Priklonskii VI, Tikhonov AN. Lateral heterogeneity of the proton potential along the thylakoid membranes of chloroplasts. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:388-401. [DOI: 10.1016/j.bbamem.2016.11.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 11/20/2016] [Accepted: 11/29/2016] [Indexed: 02/06/2023]
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29
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Zhou W, Marinelli F, Nief C, Faraldo-Gómez JD. Atomistic simulations indicate the c-subunit ring of the F 1F o ATP synthase is not the mitochondrial permeability transition pore. eLife 2017; 6. [PMID: 28186490 PMCID: PMC5323039 DOI: 10.7554/elife.23781] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 02/09/2017] [Indexed: 12/03/2022] Open
Abstract
Pathological metabolic conditions such as ischemia induce the rupture of the mitochondrial envelope and the release of pro-apoptotic proteins, leading to cell death. At the onset of this process, the inner mitochondrial membrane becomes depolarized and permeable to osmolytes, proposedly due to the opening of a non-selective protein channel of unknown molecular identity. A recent study purports that this channel, referred to as Mitochondrial Permeability Transition Pore (MPTP), is formed within the c-subunit ring of the ATP synthase, upon its dissociation from the catalytic domain of the enzyme. Here, we examine this claim for two c-rings of different lumen width, through calculations of their ion conductance and selectivity based on all-atom molecular dynamics simulations. We also quantify the likelihood that the lumen of these c-rings is in a hydrated, potentially conducting state rather than empty or blocked by lipid molecules. These calculations demonstrate that the structure and biophysical properties of a correctly assembled c-ring are inconsistent with those attributed to the MPTP. DOI:http://dx.doi.org/10.7554/eLife.23781.001
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Affiliation(s)
- Wenchang Zhou
- Theoretical Molecular Biophysics Section, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, United States
| | - Fabrizio Marinelli
- Theoretical Molecular Biophysics Section, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, United States
| | - Corrine Nief
- Theoretical Molecular Biophysics Section, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, United States
| | - José D Faraldo-Gómez
- Theoretical Molecular Biophysics Section, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, United States
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30
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Nath S. The thermodynamic efficiency of ATP synthesis in oxidative phosphorylation. Biophys Chem 2016; 219:69-74. [PMID: 27770651 DOI: 10.1016/j.bpc.2016.10.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 10/12/2016] [Accepted: 10/12/2016] [Indexed: 12/20/2022]
Abstract
As the chief energy source of eukaryotic cells, it is important to determine the thermodynamic efficiency of ATP synthesis in oxidative phosphorylation (OX PHOS). Previous estimates of the thermodynamic efficiency of this vital process have ranged from Lehninger's original back-of-the-envelope calculation of 38% to the often quoted value of 55-60% in current textbooks of biochemistry, to high values of 90% from recent information theoretic considerations, and reports of realizations of close to ideal 100% efficiencies by single molecule experiments. Hence this problem has been reinvestigated from first principles. The overall thermodynamic efficiency of ATP synthesis in the mitochondrial energy transduction OX PHOS process has been found to lie between 40 and 41% from four different approaches based on a) estimation using structural and biochemical data, b) fundamental nonequilibrium thermodynamic analysis, c) novel insights arising from Nath's torsional mechanism of energy transduction and ATP synthesis, and d) the overall balance of cellular energetics. The torsional mechanism also offers an explanation for the observation of a thermodynamic efficiency approaching 100% in some experiments. Applications of the unique, molecular machine mode of functioning of F1FO-ATP synthase involving direct inter-conversion of chemical and mechanical energies in the design and fabrication of novel, man-made mechanochemical devices have been envisaged, and some new ways to exorcise Maxwell's demon have been proposed. It is hoped that analysis of the fundamental problem of energy transduction in OX PHOS from a fresh perspective will catalyze new avenues of research in this interdisciplinary field.
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Affiliation(s)
- Sunil Nath
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110016, India.
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31
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McMillan DGG, Watanabe R, Ueno H, Cook GM, Noji H. Biophysical Characterization of a Thermoalkaliphilic Molecular Motor with a High Stepping Torque Gives Insight into Evolutionary ATP Synthase Adaptation. J Biol Chem 2016; 291:23965-23977. [PMID: 27624936 DOI: 10.1074/jbc.m116.743633] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 09/12/2016] [Indexed: 11/06/2022] Open
Abstract
F1F0 ATP synthases are bidirectional molecular motors that translocate protons across the cell membrane by either synthesizing or hydrolyzing ATP. Alkaliphile ATP synthases are highly adapted, performing oxidative phosphorylation at high pH against an inverted pH gradient (acidin/alkalineout). Unlike mesophilic ATP synthases, alkaliphilic enzymes have tightly regulated ATP hydrolysis activity, which can be relieved in the presence of lauryldimethylamine oxide. Here, we characterized the rotary dynamics of the Caldalkalibacillus thermarum TA2.A1 F1 ATPase (TA2F1) with two forms of single molecule analysis, a magnetic bead duplex and a gold nanoparticle. TA2F1 rotated in a counterclockwise direction in both systems, adhering to Michaelis-Menten kinetics with a maximum rotation rate (Vmax) of 112.4 revolutions/s. TA2F1 displayed 120° unitary steps coupled with ATP hydrolysis. Torque measurements revealed the highest torque (52.4 piconewtons) derived from an F1 molecule using fluctuation theorem. The implications of high torque in terms of extreme environment adaptation are discussed.
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Affiliation(s)
- Duncan G G McMillan
- From the Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan and
| | - Rikiya Watanabe
- From the Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan and
| | - Hiroshi Ueno
- From the Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan and
| | - Gregory M Cook
- the Department of Microbiology and Immunology, Otago School of Medical Sciences, University of Otago, P. O. Box 56, Dunedin 9054, New Zealand
| | - Hiroyuki Noji
- From the Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan and
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Siniauskaya MG, Danilenko NG, Lukhanina NV, Shymkevich AM, Davydenko OG. Expression of the chloroplast genome: Modern concepts and experimental approaches. ACTA ACUST UNITED AC 2016. [DOI: 10.1134/s2079059716050117] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Nesci S, Trombetti F, Ventrella V, Pagliarani A. The c-Ring of the F1FO-ATP Synthase: Facts and Perspectives. J Membr Biol 2016; 249:11-21. [PMID: 26621635 DOI: 10.1007/s00232-015-9860-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 11/19/2015] [Indexed: 10/22/2022]
Abstract
The F1FO-ATP synthase is the only enzyme in nature endowed with bi-functional catalytic mechanism of synthesis and hydrolysis of ATP. The enzyme functions, not only confined to energy transduction, are tied to three intrinsic features of the annular arrangement of c subunits which constitutes the so-called c-ring, the core of the membrane-embedded FO domain: (i) the c-ring constitution is linked to the number of ions (H(+) or Na(+)) channeled across the membrane during the dissipation of the transmembrane electrochemical gradient, which in turn determines the species-specific bioenergetic cost of ATP, the "molecular currency unit" of energy transfer in all living beings; (ii) the c-ring is increasingly involved in the mitochondrial permeability transition, an event linked to cell death and to most mitochondrial dysfunctions; (iii) the c subunit species-specific amino acid sequence and susceptibility to post-translational modifications can address antibacterial drug design according to the model of enzyme inhibitors which target the c subunits. Therefore, the simple c-ring structure not only allows the F1FO-ATP synthase to perform the two opposite tasks of molecular machine of cell life and death, but it also amplifies the enzyme's potential role as a drug target.
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Affiliation(s)
- Salvatore Nesci
- Department of Veterinary Medical Sciences (DIMEVET), University of Bologna, Via Tolara di Sopra, 50, 40064, Ozzano Emilia, Bologna, Italy
| | - Fabiana Trombetti
- Department of Veterinary Medical Sciences (DIMEVET), University of Bologna, Via Tolara di Sopra, 50, 40064, Ozzano Emilia, Bologna, Italy
| | - Vittoria Ventrella
- Department of Veterinary Medical Sciences (DIMEVET), University of Bologna, Via Tolara di Sopra, 50, 40064, Ozzano Emilia, Bologna, Italy
| | - Alessandra Pagliarani
- Department of Veterinary Medical Sciences (DIMEVET), University of Bologna, Via Tolara di Sopra, 50, 40064, Ozzano Emilia, Bologna, Italy.
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Turina P, Petersen J, Gräber P. Thermodynamics of proton transport coupled ATP synthesis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:653-64. [PMID: 26940516 DOI: 10.1016/j.bbabio.2016.02.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 01/16/2016] [Accepted: 02/28/2016] [Indexed: 10/22/2022]
Abstract
The thermodynamic H(+)/ATP ratio of the H(+)-ATP synthase from chloroplasts was measured in proteoliposomes after energization of the membrane by an acid base transition (Turina et al. 2003 [13], 418-422). The method is discussed, and all published data obtained with this system are combined and analyzed as a single dataset. This meta-analysis led to the following results. 1) At equilibrium, the transmembrane ΔpH is energetically equivalent to the transmembrane electric potential difference. 2) The standard free energy for ATP synthesis (reference reaction) is ΔG°(ref)=33.8±1.3kJ/mol. 3) The thermodynamic H(+)/ATP ratio, as obtained from the shift of the ATP synthesis equilibrium induced by changing the transmembrane ΔpH (varying either pH(in) or pH(out)) is 4.0±0.1. The structural H(+)/ATP ratio, calculated from the ratio of proton binding sites on the c-subunit-ring in F(0) to the catalytic nucleotide binding sites on the β-subunits in F(1), is c/β=14/3=4.7. We infer that the energy of 0.7 protons per ATP that flow through the enzyme, but do not contribute to shifting the ATP/(ADP·Pi) ratio, is used for additional processes within the enzyme, such as activation, and/or energy dissipation, due e.g. to internal uncoupling. The ratio between the thermodynamic and the structural H(+)/ATP values is 0.85, and we conclude that this value represents the efficiency of the chemiosmotic energy conversion within the chloroplast H(+)-ATP synthase.
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Affiliation(s)
- Paola Turina
- Department of Biology, BiGeA, University of Bologna, Via Irnerio 42, I-40126 Bologna, Italy
| | - Jan Petersen
- Biomedicine Discovery Institute, Monash University, 1 Wellington Rd., Clayton, Vic 3800, Australia
| | - Peter Gräber
- Institut für Physikalische Chemie, University of Freiburg, Albertstr, 23a, D-79104 Freiburg, Germany.
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35
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Nadeau VG, Deber CM. Structural impact of proline mutations in the loop region of an ancestral membrane protein. Biopolymers 2016; 106:37-42. [DOI: 10.1002/bip.22765] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 10/29/2015] [Accepted: 11/02/2015] [Indexed: 01/24/2023]
Affiliation(s)
- Vincent G. Nadeau
- Program in Molecular Structure & Function; Research Institute, Hospital for Sick Children; Toronto, M5G 1X8 Ontario Canada
- Department of Biochemistry; University of Toronto; Toronto, M5S 1A8 Ontario Canada
| | - Charles M. Deber
- Program in Molecular Structure & Function; Research Institute, Hospital for Sick Children; Toronto, M5G 1X8 Ontario Canada
- Department of Biochemistry; University of Toronto; Toronto, M5S 1A8 Ontario Canada
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36
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Structure-Function of the Cytochrome b 6 f Lipoprotein Complex. ADVANCES IN PHOTOSYNTHESIS AND RESPIRATION 2016. [DOI: 10.1007/978-94-017-7481-9_9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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37
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Abstract
The F1F0-ATP synthase (EC 3.6.1.34) is a remarkable enzyme that functions as a rotary motor. It is found in the inner membranes of Escherichia coli and is responsible for the synthesis of ATP in response to an electrochemical proton gradient. Under some conditions, the enzyme functions reversibly and uses the energy of ATP hydrolysis to generate the gradient. The ATP synthase is composed of eight different polypeptide subunits in a stoichiometry of α3β3γδεab2c10. Traditionally they were divided into two physically separable units: an F1 that catalyzes ATP hydrolysis (α3β3γδε) and a membrane-bound F0 sector that transports protons (ab2c10). In terms of rotary function, the subunits can be divided into rotor subunits (γεc10) and stator subunits (α3β3δab2). The stator subunits include six nucleotide binding sites, three catalytic and three noncatalytic, formed primarily by the β and α subunits, respectively. The stator also includes a peripheral stalk composed of δ and b subunits, and part of the proton channel in subunit a. Among the rotor subunits, the c subunits form a ring in the membrane, and interact with subunit a to form the proton channel. Subunits γ and ε bind to the c-ring subunits, and also communicate with the catalytic sites through interactions with α and β subunits. The eight subunits are expressed from a single operon, and posttranscriptional processing and translational regulation ensure that the polypeptides are made at the proper stoichiometry. Recent studies, including those of other species, have elucidated many structural and rotary properties of this enzyme.
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38
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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: 1.5] [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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39
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Preiss L, Langer JD, Yildiz Ö, Eckhardt-Strelau L, Guillemont JEG, Koul A, Meier T. Structure of the mycobacterial ATP synthase Fo rotor ring in complex with the anti-TB drug bedaquiline. SCIENCE ADVANCES 2015; 1:e1500106. [PMID: 26601184 PMCID: PMC4640650 DOI: 10.1126/sciadv.1500106] [Citation(s) in RCA: 203] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 04/04/2015] [Indexed: 05/12/2023]
Abstract
Multidrug-resistant tuberculosis (MDR-TB) is more prevalent today than at any other time in human history. Bedaquiline (BDQ), a novel Mycobacterium-specific adenosine triphosphate (ATP) synthase inhibitor, is the first drug in the last 40 years to be approved for the treatment of MDR-TB. This bactericidal compound targets the membrane-embedded rotor (c-ring) of the mycobacterial ATP synthase, a key metabolic enzyme required for ATP generation. We report the x-ray crystal structures of a mycobacterial c9 ring without and with BDQ bound at 1.55- and 1.7-Å resolution, respectively. The structures and supporting functional assays reveal how BDQ specifically interacts with the rotor ring via numerous interactions and thereby completely covers the c-ring's ion-binding sites. This prevents the rotor ring from acting as an ion shuttle and stalls ATP synthase operation. The structures explain how diarylquinoline chemicals specifically inhibit the mycobacterial ATP synthase and thus enable structure-based drug design of next-generation ATP synthase inhibitors against Mycobacterium tuberculosis and other bacterial pathogens.
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Affiliation(s)
- Laura Preiss
- Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438 Frankfurt am Main, Germany
| | - Julian D. Langer
- Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
| | - Özkan Yildiz
- Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438 Frankfurt am Main, Germany
| | - Luise Eckhardt-Strelau
- Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438 Frankfurt am Main, Germany
| | - Jérôme E. G. Guillemont
- Johnson & Johnson Pharmaceutical Research and Development, Campus de Maigremont-BP615, 27106 Val de Reuil Cedex, France
| | - Anil Koul
- Department of Respiratory Infections, Infectious Diseases and Vaccines Group, Janssen Research and Development, Johnson & Johnson, Turnhoutseweg 30, B-2340 Beerse, Belgium
| | - Thomas Meier
- Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438 Frankfurt am Main, Germany
- Corresponding author: E-mail:
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40
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Walpole TB, Palmer DN, Jiang H, Ding S, Fearnley IM, Walker JE. Conservation of complete trimethylation of lysine-43 in the rotor ring of c-subunits of metazoan adenosine triphosphate (ATP) synthases. Mol Cell Proteomics 2015; 14:828-40. [PMID: 25608518 PMCID: PMC4390263 DOI: 10.1074/mcp.m114.047456] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 01/13/2015] [Indexed: 11/06/2022] Open
Abstract
The rotors of ATP synthases turn about 100 times every second. One essential component of the rotor is a ring of hydrophobic c-subunits in the membrane domain of the enzyme. The rotation of these c-rings is driven by a transmembrane proton-motive force, and they turn against a surface provided by another membrane protein, known as subunit a. Together, the rotating c-ring and the static subunit a provide a pathway for protons through the membrane in which the c-ring and subunit a are embedded. Vertebrate and invertebrate c-subunits are well conserved. In the structure of the bovine F1-ATPase-c-ring subcomplex, the 75 amino acid c-subunit is folded into two transmembrane α-helices linked by a short loop. Each bovine rotor-ring consists of eight c-subunits with the N- and C-terminal α-helices forming concentric inner and outer rings, with the loop regions exposed to the phospholipid head-group region on the matrix side of the inner membrane. Lysine-43 is in the loop region and its ε-amino group is completely trimethylated. The role of this modification is unknown. If the trimethylated lysine-43 plays some important role in the functioning, assembly or degradation of the c-ring, it would be expected to persist throughout vertebrates and possibly invertebrates also. Therefore, we have carried out a proteomic analysis of c-subunits across representative species from different classes of vertebrates and from invertebrate phyla. In the twenty-nine metazoan species that have been examined, the complete methylation of lysine-43 is conserved, and it is likely to be conserved throughout the more than two million extant metazoan species. In unicellular eukaryotes and prokaryotes, when the lysine is conserved it is unmethylated, and the stoichiometries of c-subunits vary from 9-15. One possible role for the trimethylated residue is to provide a site for the specific binding of cardiolipin, an essential component of ATP synthases in mitochondria.
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Affiliation(s)
- Thomas B Walpole
- From the ‡Mitochondrial Biology Unit, Medical Research Council, Hills Road, Cambridge, CB2 0XY, United Kingdom and
| | - David N Palmer
- From the ‡Mitochondrial Biology Unit, Medical Research Council, Hills Road, Cambridge, CB2 0XY, United Kingdom and the §Agriculture and Life Sciences Faculty, Lincoln University, 7647, New Zealand
| | - Huibing Jiang
- From the ‡Mitochondrial Biology Unit, Medical Research Council, Hills Road, Cambridge, CB2 0XY, United Kingdom and the §Agriculture and Life Sciences Faculty, Lincoln University, 7647, New Zealand
| | - Shujing Ding
- From the ‡Mitochondrial Biology Unit, Medical Research Council, Hills Road, Cambridge, CB2 0XY, United Kingdom and
| | - Ian M Fearnley
- From the ‡Mitochondrial Biology Unit, Medical Research Council, Hills Road, Cambridge, CB2 0XY, United Kingdom and
| | - John E Walker
- From the ‡Mitochondrial Biology Unit, Medical Research Council, Hills Road, Cambridge, CB2 0XY, United Kingdom and
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41
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Abstract
Oxygenic photosynthesis is the principal converter of sunlight into chemical energy. Cyanobacteria and plants provide aerobic life with oxygen, food, fuel, fibers, and platform chemicals. Four multisubunit membrane proteins are involved: photosystem I (PSI), photosystem II (PSII), cytochrome b6f (cyt b6f), and ATP synthase (FOF1). ATP synthase is likewise a key enzyme of cell respiration. Over three billion years, the basic machinery of oxygenic photosynthesis and respiration has been perfected to minimize wasteful reactions. The proton-driven ATP synthase is embedded in a proton tight-coupling membrane. It is composed of two rotary motors/generators, FO and F1, which do not slip against each other. The proton-driven FO and the ATP-synthesizing F1 are coupled via elastic torque transmission. Elastic transmission decouples the two motors in kinetic detail but keeps them perfectly coupled in thermodynamic equilibrium and (time-averaged) under steady turnover. Elastic transmission enables operation with different gear ratios in different organisms.
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Affiliation(s)
- Wolfgang Junge
- Department of Biophysics, Universität Osnabrück, DE-49069 Osnabrück, Germany;
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42
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Rühle T, Leister D. Assembly of F1F0-ATP synthases. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:849-60. [PMID: 25667968 DOI: 10.1016/j.bbabio.2015.02.005] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Revised: 01/28/2015] [Accepted: 02/02/2015] [Indexed: 12/31/2022]
Abstract
F1F0-ATP synthases are multimeric protein complexes and common prerequisites for their correct assembly are (i) provision of subunits in appropriate relative amounts, (ii) coordination of membrane insertion and (iii) avoidance of assembly intermediates that uncouple the proton gradient or wastefully hydrolyse ATP. Accessory factors facilitate these goals and assembly occurs in a modular fashion. Subcomplexes common to bacteria and mitochondria, but in part still elusive in chloroplasts, include a soluble F1 intermediate, a membrane-intrinsic, oligomeric c-ring, and a membrane-embedded subcomplex composed of stator subunits and subunit a. The final assembly step is thought to involve association of the preformed F1-c10-14 with the ab2 module (or the ab8-stator module in mitochondria)--mediated by binding of subunit δ in bacteria or OSCP in mitochondria, respectively. Despite the common evolutionary origin of F1F0-ATP synthases, the set of auxiliary factors required for their assembly in bacteria, mitochondria and chloroplasts shows clear signs of evolutionary divergence. This article is part of a Special Issue entitled: Chloroplast Biogenesis.
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Affiliation(s)
- Thilo Rühle
- Plant Molecular Biology (Botany), Department Biology I, Ludwig-Maximilians-Universität München (LMU), Großhaderner Straße 2, 82152 Planegg-Martinsried, Germany.
| | - Dario Leister
- Plant Molecular Biology (Botany), Department Biology I, Ludwig-Maximilians-Universität München (LMU), Großhaderner Straße 2, 82152 Planegg-Martinsried, Germany.
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43
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Rawson S, Phillips C, Huss M, Tiburcy F, Wieczorek H, Trinick J, Harrison MA, Muench SP. Structure of the vacuolar H+-ATPase rotary motor reveals new mechanistic insights. Structure 2015; 23:461-471. [PMID: 25661654 PMCID: PMC4353692 DOI: 10.1016/j.str.2014.12.016] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2014] [Revised: 12/05/2014] [Accepted: 12/06/2014] [Indexed: 01/08/2023]
Abstract
Vacuolar H(+)-ATPases are multisubunit complexes that operate with rotary mechanics and are essential for membrane proton transport throughout eukaryotes. Here we report a ∼ 1 nm resolution reconstruction of a V-ATPase in a different conformational state from that previously reported for a lower-resolution yeast model. The stator network of the V-ATPase (and by implication that of other rotary ATPases) does not change conformation in different catalytic states, and hence must be relatively rigid. We also demonstrate that a conserved bearing in the catalytic domain is electrostatic, contributing to the extraordinarily high efficiency of rotary ATPases. Analysis of the rotor axle/membrane pump interface suggests how rotary ATPases accommodate different c ring stoichiometries while maintaining high efficiency. The model provides evidence for a half channel in the proton pump, supporting theoretical models of ion translocation. Our refined model therefore provides new insights into the structure and mechanics of the V-ATPases.
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Affiliation(s)
- Shaun Rawson
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Clair Phillips
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Markus Huss
- Abteilung Tierphysiologie, Fachbereich Biologie/Chemie, Universität Osnabrück, 49069 Osnabrück, Germany
| | - Felix Tiburcy
- Abteilung Tierphysiologie, Fachbereich Biologie/Chemie, Universität Osnabrück, 49069 Osnabrück, Germany
| | - Helmut Wieczorek
- Abteilung Tierphysiologie, Fachbereich Biologie/Chemie, Universität Osnabrück, 49069 Osnabrück, Germany
| | - John Trinick
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Michael A Harrison
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Stephen P Muench
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
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44
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Bosshart PD, Engel A, Fotiadis D. High-resolution atomic force microscopy imaging of rhodopsin in rod outer segment disk membranes. Methods Mol Biol 2015; 1271:189-203. [PMID: 25697525 DOI: 10.1007/978-1-4939-2330-4_13] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Atomic force microscopy (AFM) is a powerful imaging technique that allows recording topographical information of membrane proteins under near-physiological conditions. Remarkable results have been obtained on membrane proteins that were reconstituted into lipid bilayers. High-resolution AFM imaging of native disk membranes from vertebrate rod outer segments has unveiled the higher-order oligomeric state of the G protein-coupled receptor rhodopsin, which is highly expressed in disk membranes. Based on AFM imaging, it has been demonstrated that rhodopsin assembles in rows of dimers and paracrystals and that the rhodopsin dimer is the fundamental building block of higher-order structures.
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Affiliation(s)
- Patrick D Bosshart
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, Bern, CH-3012, Switzerland
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Richardson RA, Papachristos K, Read DJ, Harlen OG, Harrison M, Paci E, Muench SP, Harris SA. Understanding the apparent stator-rotor connections in the rotary ATPase family using coarse-grained computer modeling. Proteins 2014; 82:3298-311. [PMID: 25174610 DOI: 10.1002/prot.24680] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 07/14/2014] [Accepted: 08/06/2014] [Indexed: 11/12/2022]
Abstract
Advances in structural biology, such as cryo-electron microscopy (cryo-EM) have allowed for a number of sophisticated protein complexes to be characterized. However, often only a static snapshot of a protein complex is visualized despite the fact that conformational change is frequently inherent to biological function, as is the case for molecular motors. Computer simulations provide valuable insights into the different conformations available to a particular system that are not accessible using conventional structural techniques. For larger proteins and protein complexes, where a fully atomistic description would be computationally prohibitive, coarse-grained simulation techniques such as Elastic Network Modeling (ENM) are often employed, whereby each atom or group of atoms is linked by a set of springs whose properties can be customized according to the system of interest. Here we compare ENM with a recently proposed continuum model known as Fluctuating Finite Element Analysis (FFEA), which represents the biomolecule as a viscoelastic solid subject to thermal fluctuations. These two complementary computational techniques are used to answer a critical question in the rotary ATPase family; implicit within these motors is the need for a rotor axle and proton pump to rotate freely of the motor domain and stator structures. However, current single particle cryo-EM reconstructions have shown an apparent connection between the stators and rotor axle or pump region, hindering rotation. Both modeling approaches show a possible role for this connection and how it would significantly constrain the mobility of the rotary ATPase family.
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Affiliation(s)
- Robin A Richardson
- School of Physics and Astronomy, University of Leeds, Leeds, United Kingdom
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Matthies D, Zhou W, Klyszejko AL, Anselmi C, Yildiz Ö, Brandt K, Müller V, Faraldo-Gómez JD, Meier T. High-resolution structure and mechanism of an F/V-hybrid rotor ring in a Na⁺-coupled ATP synthase. Nat Commun 2014; 5:5286. [PMID: 25381992 PMCID: PMC4228694 DOI: 10.1038/ncomms6286] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 09/16/2014] [Indexed: 01/03/2023] Open
Abstract
All rotary ATPases catalyse the interconversion of ATP and ADP-Pi through a mechanism that is coupled to the transmembrane flow of H(+) or Na(+). Physiologically, however, F/A-type enzymes specialize in ATP synthesis driven by downhill ion diffusion, while eukaryotic V-type ATPases function as ion pumps. To begin to rationalize the molecular basis for this functional differentiation, we solved the crystal structure of the Na(+)-driven membrane rotor of the Acetobacterium woodii ATP synthase, at 2.1 Å resolution. Unlike known structures, this rotor ring is a 9:1 heteromer of F- and V-type c-subunits and therefore features a hybrid configuration of ion-binding sites along its circumference. Molecular and kinetic simulations are used to dissect the mechanisms of Na(+) recognition and rotation of this c-ring, and to explain the functional implications of the V-type c-subunit. These structural and mechanistic insights indicate an evolutionary path between synthases and pumps involving adaptations in the rotor ring.
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Affiliation(s)
- Doreen Matthies
- Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Str. 3, 60438 Frankfurt am Main, Germany
| | - Wenchang Zhou
- Theoretical Molecular Biophysics Section, National Heart, Lung and Blood Institute, National Institutes of Health, Building 5635FL, Suite T-800, Bethesda, Maryland 20892, USA
| | - Adriana L Klyszejko
- Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Str. 3, 60438 Frankfurt am Main, Germany
| | - Claudio Anselmi
- Theoretical Molecular Biophysics Section, National Heart, Lung and Blood Institute, National Institutes of Health, Building 5635FL, Suite T-800, Bethesda, Maryland 20892, USA
| | - Özkan Yildiz
- Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Str. 3, 60438 Frankfurt am Main, Germany
| | - Karsten Brandt
- Department of Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University Frankfurt am Main, Max-von-Laue-Str. 9, 60438 Frankfurt am Main, Germany
| | - Volker Müller
- Department of Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University Frankfurt am Main, Max-von-Laue-Str. 9, 60438 Frankfurt am Main, Germany
| | - José D Faraldo-Gómez
- 1] Theoretical Molecular Biophysics Section, National Heart, Lung and Blood Institute, National Institutes of Health, Building 5635FL, Suite T-800, Bethesda, Maryland 20892, USA [2] Cluster of Excellence Macromolecular Complexes, Max-von-Laue-Str. 15, 60438 Frankfurt am Main, Germany
| | - Thomas Meier
- 1] Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Str. 3, 60438 Frankfurt am Main, Germany [2] Cluster of Excellence Macromolecular Complexes, Max-von-Laue-Str. 15, 60438 Frankfurt am Main, Germany
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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: 6.5] [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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Stewart AG, Laming EM, Sobti M, Stock D. Rotary ATPases--dynamic molecular machines. Curr Opin Struct Biol 2013; 25:40-8. [PMID: 24878343 DOI: 10.1016/j.sbi.2013.11.013] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 11/20/2013] [Accepted: 11/26/2013] [Indexed: 01/14/2023]
Abstract
Recent work has provided the detailed overall architecture and subunit composition of three subtypes of rotary ATPases. Composite models of F-type, V-type and A-type ATPases have been constructed by fitting high-resolution X-ray structures of individual components into electron microscopy derived envelopes of the intact enzymes. Electron cryo-tomography has provided new insights into the supra-molecular arrangement of eukaryotic ATP synthases within mitochondria. An inherent flexibility in rotary ATPases observed by different techniques suggests greater dynamics during operation than previously envisioned. The concerted movement of subunits within the complex might provide means of regulation and information transfer between distant parts of rotary ATPases thereby fine tuning these molecular machines to their cellular environment, while optimizing their efficiency.
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Affiliation(s)
- Alastair G Stewart
- The Victor Chang Cardiac Research Institute, Sydney, NSW, Australia; The University of New South Wales, Sydney, NSW, Australia.
| | - Elise M Laming
- The Victor Chang Cardiac Research Institute, Sydney, NSW, Australia; The University of New South Wales, Sydney, NSW, Australia
| | - Meghna Sobti
- The Victor Chang Cardiac Research Institute, Sydney, NSW, Australia; The University of New South Wales, Sydney, NSW, Australia
| | - Daniela Stock
- The Victor Chang Cardiac Research Institute, Sydney, NSW, Australia; The University of New South Wales, Sydney, NSW, Australia
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Flexibility within the rotor and stators of the vacuolar H+-ATPase. PLoS One 2013; 8:e82207. [PMID: 24312643 PMCID: PMC3846802 DOI: 10.1371/journal.pone.0082207] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 10/21/2013] [Indexed: 11/19/2022] Open
Abstract
The V-ATPase is a membrane-bound protein complex which pumps protons across the membrane to generate a large proton motive force through the coupling of an ATP-driven 3-stroke rotary motor (V1) to a multistroke proton pump (Vo). This is done with near 100% efficiency, which is achieved in part by flexibility within the central rotor axle and stator connections, allowing the system to flex to minimise the free energy loss of conformational changes during catalysis. We have used electron microscopy to reveal distinctive bending along the V-ATPase complex, leading to angular displacement of the V1 domain relative to the Vo domain to a maximum of ~30°. This has been complemented by elastic network normal mode analysis that shows both flexing and twisting with the compliance being located in the rotor axle, stator filaments, or both. This study provides direct evidence of flexibility within the V-ATPase and by implication in related rotary ATPases, a feature predicted to be important for regulation and their high energetic efficiencies.
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Steed PR, Fillingame RH. Residues in the polar loop of subunit c in Escherichia coli ATP synthase function in gating proton transport to the cytoplasm. J Biol Chem 2013; 289:2127-38. [PMID: 24297166 DOI: 10.1074/jbc.m113.527879] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Rotary catalysis in F1F0 ATP synthase is powered by proton translocation through the membrane-embedded F0 sector. Proton binding and release occur in the middle of the membrane at Asp-61 on the second transmembrane helix (TMH) of subunit c, which folds in a hairpin-like structure with two TMHs. Previously, the aqueous accessibility of Cys substitutions in the transmembrane regions of subunit c was probed by testing the inhibitory effects of Ag(+) or Cd(2+) on function, which revealed extensive aqueous access in the region around Asp-61 and on the half of TMH2 extending to the cytoplasm. In the current study, we surveyed the Ag(+) and Cd(2+) sensitivity of Cys substitutions in the loop of the helical hairpin and used a variety of assays to categorize the mechanisms by which Ag(+) or Cd(2+) chelation with the Cys thiolates caused inhibition. We identified two distinct metal-sensitive regions in the cytoplasmic loop where function was inhibited by different mechanisms. Metal binding to Cys substitutions in the N-terminal half of the loop resulted in an uncoupling of F1 from F0 with release of F1 from the membrane. In contrast, substitutions in the C-terminal half of the loop retained membrane-bound F1 after metal treatment. In several of these cases, inhibition was shown to be due to blockage of passive H(+) translocation through F0 as assayed with F0 reconstituted into liposomes. The results suggest that the C-terminal domain of the cytoplasmic loop may function in gating H(+) translocation to the cytoplasm.
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Affiliation(s)
- P Ryan Steed
- From the Department of Biomolecular Chemistry, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin 53706
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