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Reber AS, Baluška F, Miller WB, Slijepčević P. The sensual cell: Feeling and affect in unicellular species. Biosystems 2024; 238:105197. [PMID: 38556108 DOI: 10.1016/j.biosystems.2024.105197] [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: 02/18/2024] [Revised: 03/21/2024] [Accepted: 03/22/2024] [Indexed: 04/02/2024]
Abstract
Our previous efforts to probe the complex, rich experiential lives of unicellular species have focused on the origins of consciousness (Reber, 2019) and the biomolecular processes that underlie sentience (Reber et al., 2023). Implied, but unexplored, was the assumption that these cognitive functions and associated unicellular organismal behaviors were linked with and often driven by affect, feelings, sensual experiences. In this essay we dig more deeply into these valenced (We're using the term valence here to cover the aspects of sensory experiences that have evaluative elements, are experienced as positive or negative ─ those where this affective, internal representation is an essential element in how the input is interpreted and responded to.) self-referencing features. In the first part, we examine the empirical evidence for various sensual experiences that have been identified. In the second part, we look at other features of prokaryote life that appear to also have affective, valenced elements but where the data to support the proposition aren't as strong. We engage in some informed speculation about these phenomena.
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Affiliation(s)
- Arthur S Reber
- Department of Psychology, University of British Columbia, Vancouver, BC, Canada.
| | - František Baluška
- Institute of Cellular and Molecular Botany, University of Bonn, Germany.
| | | | - Predrag Slijepčević
- Department of Life Sciences, College of Health, Medicine and Life Sciences, University of Brunel, UK.
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2
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Sharma S, Luo M, Patel H, Mueller DM, Liao M. Conformational ensemble of yeast ATP synthase at low pH reveals unique intermediates and plasticity in F 1-F o coupling. Nat Struct Mol Biol 2024; 31:657-666. [PMID: 38316880 DOI: 10.1038/s41594-024-01219-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 01/05/2024] [Indexed: 02/07/2024]
Abstract
Mitochondrial adenosine triphosphate (ATP) synthase uses the proton gradient across the inner mitochondrial membrane to synthesize ATP. Structural and single molecule studies conducted mostly at neutral or basic pH have provided details of the reaction mechanism of ATP synthesis. However, pH of the mitochondrial matrix is slightly acidic during hypoxia and pH-dependent conformational changes in the ATP synthase have been reported. Here we use single-particle cryo-EM to analyze the conformational ensemble of the yeast (Saccharomyces cerevisiae) ATP synthase at pH 6. Of the four conformations resolved in this study, three are reaction intermediates. In addition to canonical catalytic dwell and binding dwell structures, we identify two unique conformations with nearly identical positions of the central rotor but different catalytic site conformations. These structures provide new insights into the catalytic mechanism of the ATP synthase and highlight elastic coupling between the catalytic and proton translocating domains.
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Affiliation(s)
- Stuti Sharma
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, USA.
| | - Min Luo
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, Singapore
| | - Hiral Patel
- Center for Genetic Diseases, The Chicago Medical School, Rosalind Franklin University, North Chicago, IL, USA
| | - David M Mueller
- Center for Genetic Diseases, The Chicago Medical School, Rosalind Franklin University, North Chicago, IL, USA.
| | - Maofu Liao
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
- Department of Chemical Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China.
- Institute for Biological Electron Microscopy, Southern University of Science and Technology, Shenzhen, China.
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3
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Albaugh A, Fu RS, Gu G, Gingrich TR. Limits on the Precision of Catenane Molecular Motors: Insights from Thermodynamics and Molecular Dynamics Simulations. J Chem Theory Comput 2024; 20:1-6. [PMID: 38127444 DOI: 10.1021/acs.jctc.3c01201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
Thermodynamic uncertainty relations (TURs) relate precision to the dissipation rate, yet the inequalities can be far from saturation. Indeed, in catenane molecular motor simulations, we record precision far below the TUR limit. We further show that this inefficiency can be anticipated by four physical parameters: the thermodynamic driving force, fuel decomposition rate, coupling between fuel decomposition and motor motion, and rate of undriven motor motion. The physical insights might assist in designing molecular motors in the future.
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Affiliation(s)
- Alex Albaugh
- Department of Chemical Engineering and Materials Science, Wayne State University, 5050 Anthony Wayne Drive, Detroit, Michigan 48202, United States
| | - Rueih-Sheng Fu
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Geyao Gu
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Todd R Gingrich
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
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4
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Machida A, Kondo K, Wakabayashi KI, Tanaka K, Hisabori T. Molecular Bulkiness of a Single Amino Acid in the F1 α-Subunit Determines the Robustness of Cyanobacterial ATP Synthase. PLANT & CELL PHYSIOLOGY 2023; 64:1590-1600. [PMID: 37706547 DOI: 10.1093/pcp/pcad109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 08/18/2023] [Accepted: 09/12/2023] [Indexed: 09/15/2023]
Abstract
Cyanobacteria are promising photosynthetic organisms owing to their ease of genetic manipulation. Among them, Synechococcus elongatus UTEX 2973 exhibits faster growth, higher biomass production efficiency and more robust stress tolerance compared with S. elongatus PCC 7942. This is due to specific genetic differences, including four single-nucleotide polymorphisms (SNPs) in three genes. One of these SNPs alters an amino acid at position 252 of the FoF1 ATP synthase α-subunit from Tyr to Cys (αY252C) in S. elongatus 7942. This change has been shown to significantly affect growth rate and stress tolerance, specifically in S. elongatus. Furthermore, experimental substitutions with several other amino acids have been shown to alter the ATP synthesis rate in the cell. In the present study, we introduced identical amino acid substitutions into Synechocystis sp. PCC 6803 at position 252 to elucidate the amino acid's significance and generality across cyanobacteria. We investigated the resulting impact on growth, intracellular enzyme complex levels, intracellular ATP levels and enzyme activity. The results showed that the αY252C substitution decreased growth rate and high-light tolerance. This indicates that a specific bulkiness of this amino acid's side chain is important for maintaining cell growth. Additionally, a remarkable decrease in the membrane-bound enzyme complex level was observed. However, the αY252C substitution did not affect enzyme activity or intracellular ATP levels. Although the mechanism of growth suppression remains unknown, the amino acid at position 252 is expected to play an important role in enzyme complex formation.
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Affiliation(s)
- Akito Machida
- School of Life Science and Technology, Tokyo Institute of Technology, Nagatsuta-cho 4259, Midori-ku, Yokohama, 226-8501 Japan
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Nagatsuta-cho 4259-R1, Midori-Ku, Yokohama, 226-8501 Japan
| | - Kumiko Kondo
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Nagatsuta-cho 4259-R1, Midori-Ku, Yokohama, 226-8501 Japan
| | | | - Kan Tanaka
- School of Life Science and Technology, Tokyo Institute of Technology, Nagatsuta-cho 4259, Midori-ku, Yokohama, 226-8501 Japan
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Nagatsuta-cho 4259-R1, Midori-Ku, Yokohama, 226-8501 Japan
| | - Toru Hisabori
- School of Life Science and Technology, Tokyo Institute of Technology, Nagatsuta-cho 4259, Midori-ku, Yokohama, 226-8501 Japan
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Nagatsuta-cho 4259-R1, Midori-Ku, Yokohama, 226-8501 Japan
- International Research Frontiers Initiative (IRFI), Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8501 Japan
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Ray B, Roy KK. Deciphering insights into the binding mechanism and plasticity of Telacebec with M. tuberculosis cytochrome bcc-aa3 supercomplex through an unbiased molecular dynamics simulation, free-energy analysis, and DFT study. J Biomol Struct Dyn 2023:1-14. [PMID: 38111165 DOI: 10.1080/07391102.2023.2294833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 12/02/2023] [Indexed: 12/20/2023]
Abstract
The cytochrome bcc-aa3 supercomplex, a key component in the electron transport chain pathway involved in bacterial energy production and homeostasis, is a clinically validated target for tuberculosis (TB), leading to Telacebec (Q203). Telacebec is a potent candidate drug under Phase II clinical development for the treatment of drug-sensitive and drug-resistant TB. Recently, the cryo-electron microscopy structure of this supercomplex from Mycobacterium tuberculosis (Mtb) complexed with Q203 was resolved at 6.9 Å resolution (PDB ID: 7E1W). To understand the binding site (QP site) flexibility and Q203's stability at the QP site of the Mtb cytochrome bcc complex, we conducted molecular dynamics (MD) simulation and free energy analysis on this complex in an explicit hydrated lipid bilayer environment for 500 ns. Through this study, the persistence of a range of direct and indirect interactions was observed over the course of the simulation. The significance of the interactions with His375, Tyr161, Ala178, Ala179, Ile183, His355, Leu356, and Thr313 is underlined. Electrostatic energy was the primary source of the net binding free energy, regardless of the important interacting residues. The overall binding free energy for Q203 was -112.84 ± 7.73 kcal/mol, of which the electrostatic and lipophilic energy contributions were -116.31 ± 1.14 and -21.32 ± 2.35 kcal/mol, respectively. Meanwhile, DFT calculations were utilized to elucidate Q203's molecular properties. Overall, this study deciphers key insights into the cytochrome bcc-aa3 supercomplex with Q203 on the ground of molecular mechanics and quantum mechanics that may facilitate structure-based drug design and optimization for the discovery of the next-generation antitubercular drug(s).Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Bedabrata Ray
- Department of Pharmaceutical Sciences, School of Health Sciences and Technology, UPES, Dehradun, Uttarakhand, India
| | - Kuldeep K Roy
- Department of Pharmaceutical Sciences, School of Health Sciences and Technology, UPES, Dehradun, Uttarakhand, India
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6
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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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7
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Leighton MP, Sivak DA. Inferring Subsystem Efficiencies in Bipartite Molecular Machines. PHYSICAL REVIEW LETTERS 2023; 130:178401. [PMID: 37172234 DOI: 10.1103/physrevlett.130.178401] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Accepted: 03/20/2023] [Indexed: 05/14/2023]
Abstract
Molecular machines composed of coupled subsystems transduce free energy between different external reservoirs, in the process internally transducing energy and information. While subsystem efficiencies of these molecular machines have been measured in isolation, less is known about how they behave in their natural setting when coupled together and acting in concert. Here, we derive upper and lower bounds on the subsystem efficiencies of a bipartite molecular machine. We demonstrate their utility by estimating the efficiencies of the F_{o} and F_{1} subunits of ATP synthase and that of kinesin pulling a diffusive cargo.
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Affiliation(s)
- Matthew P Leighton
- Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - David A Sivak
- Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
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8
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Shivalkar S, Chowdhary P, Afshan T, Chaudhary S, Roy A, Samanta SK, Sahoo AK. Nanoengineering of biohybrid micro/nanobots for programmed biomedical applications. Colloids Surf B Biointerfaces 2023; 222:113054. [PMID: 36446238 DOI: 10.1016/j.colsurfb.2022.113054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 11/14/2022] [Accepted: 11/22/2022] [Indexed: 11/26/2022]
Abstract
Biohybrid micro/nanobots have emerged as an innovative resource to be employed in the biomedical field due to their biocompatible and biodegradable properties. These are tiny nanomaterial-based integrated structures engineered in a way that they can move autonomously and perform the programmed tasks efficiently even at hard-to-reach organ/tissues/cellular sites. The biohybrid micro/nanobots can either be cell/bacterial/enzyme-based or may mimic the properties of an active molecule. It holds the potential to change the landscape in various areas of biomedical including early diagnosis of disease, therapeutics, imaging, or precision surgery. The propulsion mechanism of the biohybrid micro/nanobots can be both fuel-based and fuel-free, but the most effective and easiest way to propel these micro/nanobots is via enzymes. Micro/nanobots possess the feature to adsorb/functionalize chemicals or drugs at their surfaces thus offering the scope of delivering drugs at the targeted locations. They also have shown immense potential in intracellular sensing of biomolecules and molecular events. Moreover, with recent progress in the material development and processing is required for enhanced activity and robustness the fabrication is done via various advanced techniques to avoid self-degradation and cause cellular toxicity during autonomous movement in biological medium. In this review, various approaches of design, architecture, and performance of such micro/nanobots have been illustrated along with their potential applications in controlled cargo release, therapeutics, intracellular sensing, and bioimaging. Furthermore, it is also foregrounding their advancement offering an insight into their future scopes, opportunities, and challenges involved in advanced biomedical applications.
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Affiliation(s)
- Saurabh Shivalkar
- Department of Applied Sciences, Indian Institute of Information Technology, Allahabad, UP, India.
| | - Pallabi Chowdhary
- Department of Biotechnology, MS Ramaiah University of Applied Sciences, Bengaluru, Karnataka, India
| | - Tayyaba Afshan
- Department of Applied Sciences, Indian Institute of Information Technology, Allahabad, UP, India
| | - Shrutika Chaudhary
- Department of Biotechnology, Delhi Technological University, Delhi, India
| | - Anwesha Roy
- Department of Biotechnology, Heritage Institute of Technology, Kolkata, West Bengal, India
| | - Sintu Kumar Samanta
- Department of Applied Sciences, Indian Institute of Information Technology, Allahabad, UP, India
| | - Amaresh Kumar Sahoo
- Department of Applied Sciences, Indian Institute of Information Technology, Allahabad, UP, India.
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9
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Nesci S. Bacterial and mammalian F1FO-ATPase: Structural similarities and divergences to exploit in the battle against Mycobacterium tuberculosis. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2023. [DOI: 10.1016/bs.ircmb.2023.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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10
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Abstract
F1-ATPase is a rotary molecular motor that in vivo is subject to strong nonequilibrium driving forces. There is great interest in understanding the operational principles governing its high efficiency of free-energy transduction. Here we use a near-equilibrium framework to design a nontrivial control protocol to minimize dissipation in rotating F1 to synthesize adenosine triphosphate. We find that the designed protocol requires much less work than a naive (constant-velocity) protocol across a wide range of protocol durations. Our analysis points to a possible mechanism for energetically efficient driving of F1 in vivo and provides insight into free-energy transduction for a broader class of biomolecular and synthetic machines.
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Affiliation(s)
- Deepak Gupta
- Department of Physics, Simon Fraser University, BurnabyV5A 1S6, British Columbia, Canada
- Institute for Theoretical Physics, Technical University of Berlin, Hardenbergstr. 36, BerlinD-10623, Germany
| | - Steven J Large
- Department of Physics, Simon Fraser University, BurnabyV5A 1S6, British Columbia, Canada
| | - Shoichi Toyabe
- Department of Applied Physics, Tohoku University, Aoba 6-6-05, Sendai980-8579, Japan
| | - David A Sivak
- Department of Physics, Simon Fraser University, BurnabyV5A 1S6, British Columbia, Canada
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11
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Bernardi P, Carraro M, Lippe G. The mitochondrial permeability transition: Recent progress and open questions. FEBS J 2022; 289:7051-7074. [PMID: 34710270 PMCID: PMC9787756 DOI: 10.1111/febs.16254] [Citation(s) in RCA: 71] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 10/27/2021] [Indexed: 01/13/2023]
Abstract
Major progress has been made in defining the basis of the mitochondrial permeability transition, a Ca2+ -dependent permeability increase of the inner membrane that has puzzled mitochondrial research for almost 70 years. Initially considered an artefact of limited biological interest by most, over the years the permeability transition has raised to the status of regulator of mitochondrial ion homeostasis and of druggable effector mechanism of cell death. The permeability transition is mediated by opening of channel(s) modulated by matrix cyclophilin D, the permeability transition pore(s) (PTP). The field has received new impulse (a) from the hypothesis that the PTP may originate from a Ca2+ -dependent conformational change of F-ATP synthase and (b) from the reevaluation of the long-standing hypothesis that it originates from the adenine nucleotide translocator (ANT). Here, we provide a synthetic account of the structure of ANT and F-ATP synthase to discuss potential and controversial mechanisms through which they may form high-conductance channels; and review some intriguing findings from the wealth of early studies of PTP modulation that still await an explanation. We hope that this review will stimulate new experiments addressing the many outstanding problems, and thus contribute to the eventual solution of the puzzle of the permeability transition.
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Affiliation(s)
- Paolo Bernardi
- Department of Biomedical Sciences and CNR Neuroscience InstituteUniversity of PadovaItaly
| | - Michela Carraro
- Department of Biomedical Sciences and CNR Neuroscience InstituteUniversity of PadovaItaly
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12
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Turina P. Modulation of the H +/ATP coupling ratio by ADP and ATP as a possible regulatory feature in the F-type ATP synthases. Front Mol Biosci 2022; 9:1023031. [PMID: 36275634 PMCID: PMC9583940 DOI: 10.3389/fmolb.2022.1023031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 09/12/2022] [Indexed: 11/13/2022] Open
Abstract
F-type ATP synthases are transmembrane enzymes, which play a central role in the metabolism of all aerobic and photosynthetic cells and organisms, being the major source of their ATP synthesis. Catalysis occurs via a rotary mechanism, in which the free energy of a transmembrane electrochemical ion gradient is converted into the free energy of ATP phosphorylation from ADP and Pi, and vice versa. An ADP, tightly bound to one of the three catalytic sites on the stator head, is associated with catalysis inhibition, which is relieved by the transmembrane proton gradient and by ATP. By preventing wasteful ATP hydrolysis in times of low osmotic energy and low ATP/ADP ratio, such inhibition constitutes a classical regulatory feedback effect, likely to be an integral component of in vivo regulation. The present miniview focuses on an additional putative regulatory phenomenon, which has drawn so far little attention, consisting in a substrate-induced tuning of the H+/ATP coupling ratio during catalysis, which might represent an additional key to energy homeostasis in the cell. Experimental pieces of evidence in support of such a phenomenon are reviewed.
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Affiliation(s)
- Paola Turina
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
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13
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Analytical Decomposition of Transition Flux to Cycle Durations via Integration of Transition Times. Symmetry (Basel) 2022. [DOI: 10.3390/sym14091857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Rigorous methods of decomposing kinetic networks to cycles are available, but the solutions usually contain entangled transition rates, which are difficult to analyze. This study proposes a new method of decomposing net transition flux to cycle durations, and the duration of each cycle is an integration of the transition times along the cycle. The method provides a series of neat dependences from the basic kinetic variables to the final flux, which support direct analysis based on the formulas. An assisting transformation diagram from symmetric conductivity to asymmetric conductivity is provided, which largely simplifies the application of the method. The method is likely a useful analytical tool for many studies relevant to kinetics and networks. Applications of the method shall provide new kinetic and thermodynamic information for the studied system.
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14
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Mitochondrial ATP synthase c-subunit leak channel triggers cell death upon loss of its F 1 subcomplex. Cell Death Differ 2022; 29:1874-1887. [PMID: 35322203 PMCID: PMC9433415 DOI: 10.1038/s41418-022-00972-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 02/16/2022] [Accepted: 02/28/2022] [Indexed: 02/03/2023] Open
Abstract
Mitochondrial ATP synthase is vital not only for cellular energy production but also for energy dissipation and cell death. ATP synthase c-ring was suggested to house the leak channel of mitochondrial permeability transition (mPT), which activates during excitotoxic ischemic insult. In this present study, we purified human c-ring from both eukaryotic and prokaryotic hosts to biophysically characterize its channel activity. We show that purified c-ring forms a large multi-conductance, voltage-gated ion channel that is inhibited by the addition of ATP synthase F1 subcomplex. In contrast, dissociation of F1 from FO occurs during excitotoxic neuronal death suggesting that the F1 constitutes the gate of the channel. mPT is known to dissipate the osmotic gradient across the inner membrane during cell death. We show that ATP synthase c-subunit knock down (KD) prevents the osmotic change in response to high calcium and eliminates large conductance, Ca2+ and CsA sensitive channel activity of mPT. These findings elucidate the gating mechanism of the ATP synthase c-subunit leak channel (ACLC) and suggest how ACLC opening is regulated by cell stress in a CypD-dependent manner.
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15
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Gerle C, Kishikawa JI, Yamaguchi T, Nakanishi A, Çoruh O, Makino F, Miyata T, Kawamoto A, Yokoyama K, Namba K, Kurisu G, Kato T. Structures of Multisubunit Membrane Complexes With the CRYO ARM 200. Microscopy (Oxf) 2022; 71:249-261. [PMID: 35861182 PMCID: PMC9535789 DOI: 10.1093/jmicro/dfac037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 07/18/2022] [Accepted: 07/20/2022] [Indexed: 11/18/2022] Open
Abstract
Progress in structural membrane biology has been significantly accelerated by the ongoing ‘Resolution Revolution’ in cryo-electron microscopy (cryo-EM). In particular, structure determination by single-particle analysis has evolved into the most powerful method for atomic model building of multisubunit membrane protein complexes. This has created an ever-increasing demand in cryo-EM machine time, which to satisfy is in need of new and affordable cryo-electron microscopes. Here, we review our experience in using the JEOL CRYO ARM 200 prototype for the structure determination by single-particle analysis of three different multisubunit membrane complexes: the Thermus thermophilus V-type ATPase VO complex, the Thermosynechococcus elongatus photosystem I monomer and the flagellar motor lipopolysaccharide peptidoglycan ring (LP ring) from Salmonella enterica.
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Affiliation(s)
- Christoph Gerle
- Institute for Protein Research, Osaka University, 3-2 Yamada Oka, Suita, Osaka 565-0871, Japan.,RIKEN SPring-8 Center, Life Science Research Infrastructure Group, Sayo-gun, Hyogo 679-5148, Japan
| | - Jun-Ichi Kishikawa
- Institute for Protein Research, Osaka University, 3-2 Yamada Oka, Suita, Osaka 565-0871, Japan
| | - Tomoko Yamaguchi
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Atsuko Nakanishi
- Department of Molecular Biosciences, Kyoto Sangyo University, Kamigamo-Motoyama, Kyoto, Japan.,Research Center for Ultra-High Voltage Electron Microscopy, Osaka, University, Ibaraki, Osaka 567-0047, Japan
| | - Orkun Çoruh
- Institute for Protein Research, Osaka University, 3-2 Yamada Oka, Suita, Osaka 565-0871, Japan.,Institute of Science and Technology Austria, Klosterneuburg, 3400 Austria
| | - Fumiaki Makino
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.,JEOL Ltd., Akishima, Tokyo, Japan
| | - Tomoko Miyata
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Akihiro Kawamoto
- Institute for Protein Research, Osaka University, 3-2 Yamada Oka, Suita, Osaka 565-0871, Japan
| | - Ken Yokoyama
- Department of Molecular Biosciences, Kyoto Sangyo University, Kamigamo-Motoyama, Kyoto, Japan
| | - Keiichi Namba
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.,RIKEN Center for Biosystems Dynamics Research, Suita, Osaka, Japan.,JEOL YOKOGUSHI Research Alliance Laboratories, Osaka University, Suita, Osaka, Japan
| | - Genji Kurisu
- Institute for Protein Research, Osaka University, 3-2 Yamada Oka, Suita, Osaka 565-0871, Japan
| | - Takayuki Kato
- Institute for Protein Research, Osaka University, 3-2 Yamada Oka, Suita, Osaka 565-0871, Japan.,Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
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16
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Abstract
ATP synthases are macromolecular machines consisting of an ATP-hydrolysis-driven F1 motor and a proton-translocation-driven FO motor. The F1 and FO motors oppose each other’s action on a shared rotor subcomplex and are held stationary relative to each other by a peripheral stalk. Structures of resting mitochondrial ATP synthases revealed a left-handed curvature of the peripheral stalk even though rotation of the rotor, driven by either ATP hydrolysis in F1 or proton translocation through FO, would apply a right-handed bending force to the stalk. We used cryoEM to image yeast mitochondrial ATP synthase under strain during ATP-hydrolysis-driven rotary catalysis, revealing a large deformation of the peripheral stalk. The structures show how the peripheral stalk opposes the bending force and suggests that during ATP synthesis proton translocation causes accumulation of strain in the stalk, which relaxes by driving the relative rotation of the rotor through six sub-steps within F1, leading to catalysis. CryoEM of mitochondrial ATP synthase frozen during rotary catalysis reveals dramatic conformational changes in the peripheral stalk subcomplex, which enable the enzyme’s efficient synthesis of ATP.
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17
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Marciniak A, Chodnicki P, Hossain KA, Slabonska J, Czub J. Determinants of Directionality and Efficiency of the ATP Synthase F o Motor at Atomic Resolution. J Phys Chem Lett 2022; 13:387-392. [PMID: 34985899 PMCID: PMC8762653 DOI: 10.1021/acs.jpclett.1c03358] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 01/03/2022] [Indexed: 05/27/2023]
Abstract
Fo subcomplex of ATP synthase is a membrane-embedded rotary motor that converts proton motive force into mechanical energy. Despite a rapid increase in the number of high-resolution structures, the mechanism of tight coupling between proton transport and motion of the rotary c-ring remains elusive. Here, using extensive all-atom free energy simulations, we show how the motor's directionality naturally arises from the interplay between intraprotein interactions and energetics of protonation of the c-ring. Notably, our calculations reveal that the strictly conserved arginine in the a-subunit (R176) serves as a jack-of-all-trades: it dictates the direction of rotation, controls the protonation state of the proton-release site, and separates the two proton-access half-channels. Therefore, arginine is necessary to avoid slippage between the proton flux and the mechanical output and guarantees highly efficient energy conversion. We also provide mechanistic explanations for the reported defective mutations of R176, reconciling the structural information on the Fo motor with previous functional and single-molecule data.
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Affiliation(s)
- Antoni Marciniak
- Department
of Physical Chemistry, Gdansk University
of Technology, Narutowicza St 11/12, 80-233 Gdansk, Poland
| | - Pawel Chodnicki
- Department
of Physical Chemistry, Gdansk University
of Technology, Narutowicza St 11/12, 80-233 Gdansk, Poland
| | - Kazi A Hossain
- Department
of Physical Chemistry, Gdansk University
of Technology, Narutowicza St 11/12, 80-233 Gdansk, Poland
| | - Joanna Slabonska
- Department
of Physical Chemistry, Gdansk University
of Technology, Narutowicza St 11/12, 80-233 Gdansk, Poland
| | - Jacek Czub
- Department
of Physical Chemistry, Gdansk University
of Technology, Narutowicza St 11/12, 80-233 Gdansk, Poland
- BioTechMed
Center, Gdansk University of Technology, Narutowicza St 11/12, 80-233, Gdansk, Poland
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18
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Schmidt CA, Fisher-Wellman KH, Neufer PD. From OCR and ECAR to energy: Perspectives on the design and interpretation of bioenergetics studies. J Biol Chem 2021; 297:101140. [PMID: 34461088 PMCID: PMC8479256 DOI: 10.1016/j.jbc.2021.101140] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 08/25/2021] [Accepted: 08/26/2021] [Indexed: 12/12/2022] Open
Abstract
Biological energy transduction underlies all physiological phenomena in cells. The metabolic systems that support energy transduction have been of great interest due to their association with numerous pathologies including diabetes, cancer, rare genetic diseases, and aberrant cell death. Commercially available bioenergetics technologies (e.g., extracellular flux analysis, high-resolution respirometry, fluorescent dye kits, etc.) have made practical assessment of metabolic parameters widely accessible. This has facilitated an explosion in the number of studies exploring, in particular, the biological implications of oxygen consumption rate (OCR) and substrate level phosphorylation via glycolysis (i.e., via extracellular acidification rate (ECAR)). Though these technologies have demonstrated substantial utility and broad applicability to cell biology research, they are also susceptible to historical assumptions, experimental limitations, and other caveats that have led to premature and/or erroneous interpretations. This review enumerates various important considerations for designing and interpreting cellular and mitochondrial bioenergetics experiments, some common challenges and pitfalls in data interpretation, and some potential "next steps" to be taken that can address these highlighted challenges.
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Affiliation(s)
- Cameron A Schmidt
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina, USA; Departments of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Kelsey H Fisher-Wellman
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina, USA; Departments of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA.
| | - P Darrell Neufer
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina, USA; Departments of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA; Departments of Biochemistry and Molecular Biology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA.
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19
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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: 2.3] [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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20
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Nakayama Y, Toyabe S. Optimal Rectification without Forward-Current Suppression by Biological Molecular Motor. PHYSICAL REVIEW LETTERS 2021; 126:208101. [PMID: 34110213 DOI: 10.1103/physrevlett.126.208101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 04/23/2021] [Indexed: 06/12/2023]
Abstract
We experimentally show that biological molecular motor F_{1}-ATPase (F_{1}) implements an optimal rectification mechanism. The rectification mechanism hardly suppresses the synthesis of adenosine triphosphate by F_{1}, which is F_{1}'s physiological role, while inhibiting the unfavorable hydrolysis of adenosine triphosphate. This optimal rectification contrasts highly with that of a simple ratchet model, where the inhibition of the backward current is inevitably accompanied by the suppression of the forward current. Our detailed analysis of single-molecule trajectories demonstrates a novel but simple rectification mechanism of F_{1} with parallel landscapes and asymmetric transition rates.
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Affiliation(s)
- Yohei Nakayama
- Department of Applied Physics, Graduate School of Engineering, Tohoku University, Aoba 6-6-05, Sendai 980-8579, Japan
| | - Shoichi Toyabe
- Department of Applied Physics, Graduate School of Engineering, Tohoku University, Aoba 6-6-05, Sendai 980-8579, Japan
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21
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Balasubramanian S, Chen J, Wigneswaran V, Bang-Berthelsen CH, Jensen PR. Droplet-Based Microfluidic High Throughput Screening of Corynebacterium glutamicum for Efficient Heterologous Protein Production and Secretion. Front Bioeng Biotechnol 2021; 9:668513. [PMID: 34026744 PMCID: PMC8137953 DOI: 10.3389/fbioe.2021.668513] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 04/12/2021] [Indexed: 11/17/2022] Open
Abstract
With emerging interests in heterologous production of proteins such as antibodies, growth factors, nanobodies, high-quality protein food ingredients, etc. the demand for efficient production hosts increases. Corynebacterium glutamicum is an attractive industrial host with great secretion capacity to produce therapeutics. It lacks extracellular protease and endotoxin activities and easily achieves high cell density. Therefore, this study focuses on improving protein production and secretion in C. glutamicum with the use of droplet-based microfluidic (DBM) high throughput screening. A library of C. glutamicum secreting β-glucosidase was generated using chemical mutagenesis coupled with DBM screening of 200,000 mutants in just 20 min. Among 100 recovered mutants, 16 mutants exhibited enhanced enzyme secretion capacity, 13 of which had unique mutation profiles. Whole-genome analysis showed that approximately 50–150 SNVs had occurred on the chromosome per mutant. Functional enrichment analysis of genes with non-synonymous mutations showed overrepresentation of genes involved in protein synthesis and secretion relevant biological processes, such as DNA and ribosome RNA synthesis, protein secretion and energy turnover. Two mutants JCMT1 and JCMT8 exhibited the highest secretion with a six and a fivefold increase in the β-glucosidase activity in the supernatant, respectively, relative to the reference strain JC0190. After plasmid curing, a new plasmid with the gene encoding α-amylase was cloned into these two mutants. The new strains SB024 and SB025 also exhibited a five and a sixfold increase in α-amylase activity in the supernatant, respectively, relative to the reference strain SB023. The results demonstrate how DBM screening can serve as a powerful development tool to improve cell factories for the production and secretion of heterologous proteins.
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Affiliation(s)
- Suvasini Balasubramanian
- Research Group for Microbial Biotechnology and Biorefining, National Food Institute, Technical University of Denmark, Kongens Lyngby, Denmark
| | | | - Vinoth Wigneswaran
- Research Group for Microbial Biotechnology and Biorefining, National Food Institute, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Claus Heiner Bang-Berthelsen
- Research Group for Microbial Biotechnology and Biorefining, National Food Institute, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Peter Ruhdal Jensen
- Research Group for Microbial Biotechnology and Biorefining, National Food Institute, Technical University of Denmark, Kongens Lyngby, Denmark
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22
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Abstract
Bacteria power their energy metabolism using membrane-bound respiratory enzymes that capture chemical energy and transduce it by pumping protons or Na+ ions across their cell membranes. Recent breakthroughs in molecular bioenergetics have elucidated the architecture and function of many bacterial respiratory enzymes, although key mechanistic principles remain debated. In this Review, we present an overview of the structure, function and bioenergetic principles of modular bacterial respiratory chains and discuss their differences from the eukaryotic counterparts. We also discuss bacterial supercomplexes, which provide central energy transduction systems in several bacteria, including important pathogens, and which could open up possible avenues for treatment of disease.
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23
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Kell DB. A protet-based, protonic charge transfer model of energy coupling in oxidative and photosynthetic phosphorylation. Adv Microb Physiol 2021; 78:1-177. [PMID: 34147184 DOI: 10.1016/bs.ampbs.2021.01.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Textbooks of biochemistry will explain that the otherwise endergonic reactions of ATP synthesis can be driven by the exergonic reactions of respiratory electron transport, and that these two half-reactions are catalyzed by protein complexes embedded in the same, closed membrane. These views are correct. The textbooks also state that, according to the chemiosmotic coupling hypothesis, a (or the) kinetically and thermodynamically competent intermediate linking the two half-reactions is the electrochemical difference of protons that is in equilibrium with that between the two bulk phases that the coupling membrane serves to separate. This gradient consists of a membrane potential term Δψ and a pH gradient term ΔpH, and is known colloquially as the protonmotive force or pmf. Artificial imposition of a pmf can drive phosphorylation, but only if the pmf exceeds some 150-170mV; to achieve in vivo rates the imposed pmf must reach 200mV. The key question then is 'does the pmf generated by electron transport exceed 200mV, or even 170mV?' The possibly surprising answer, from a great many kinds of experiment and sources of evidence, including direct measurements with microelectrodes, indicates it that it does not. Observable pH changes driven by electron transport are real, and they control various processes; however, compensating ion movements restrict the Δψ component to low values. A protet-based model, that I outline here, can account for all the necessary observations, including all of those inconsistent with chemiosmotic coupling, and provides for a variety of testable hypotheses by which it might be refined.
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Affiliation(s)
- Douglas B Kell
- Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative, Biology, University of Liverpool, Liverpool, United Kingdom; The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark.
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24
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Calisto F, Sousa FM, Sena FV, Refojo PN, Pereira MM. Mechanisms of Energy Transduction by Charge Translocating Membrane Proteins. Chem Rev 2021; 121:1804-1844. [PMID: 33398986 DOI: 10.1021/acs.chemrev.0c00830] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Life relies on the constant exchange of different forms of energy, i.e., on energy transduction. Therefore, organisms have evolved in a way to be able to harvest the energy made available by external sources (such as light or chemical compounds) and convert these into biological useable energy forms, such as the transmembrane difference of electrochemical potential (Δμ̃). Membrane proteins contribute to the establishment of Δμ̃ by coupling exergonic catalytic reactions to the translocation of charges (electrons/ions) across the membrane. Irrespectively of the energy source and consequent type of reaction, all charge-translocating proteins follow two molecular coupling mechanisms: direct- or indirect-coupling, depending on whether the translocated charge is involved in the driving reaction. In this review, we explore these two coupling mechanisms by thoroughly examining the different types of charge-translocating membrane proteins. For each protein, we analyze the respective reaction thermodynamics, electron transfer/catalytic processes, charge-translocating pathways, and ion/substrate stoichiometries.
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Affiliation(s)
- Filipa Calisto
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157, Oeiras, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, University of Lisboa, Faculty of Sciences, Campo Grande, 1749-016 Lisboa, Portugal
| | - Filipe M Sousa
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157, Oeiras, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, University of Lisboa, Faculty of Sciences, Campo Grande, 1749-016 Lisboa, Portugal
| | - Filipa V Sena
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157, Oeiras, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, University of Lisboa, Faculty of Sciences, Campo Grande, 1749-016 Lisboa, Portugal
| | - Patricia N Refojo
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157, Oeiras, Portugal
| | - Manuela M Pereira
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157, Oeiras, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, University of Lisboa, Faculty of Sciences, Campo Grande, 1749-016 Lisboa, Portugal
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25
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Kasper AKS, Sivak DA. Modeling work-speed-accuracy trade-offs in a stochastic rotary machine. Phys Rev E 2021; 101:032110. [PMID: 32289954 DOI: 10.1103/physreve.101.032110] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Accepted: 01/30/2020] [Indexed: 11/07/2022]
Abstract
Molecular machines are stochastic systems that catalyze the energetic processes keeping living cells alive and structured. Inspired by the examples of F_{1}-ATP synthase and the bacterial flagellum, we present a minimal model of an externally driven stochastic rotary machine. We explore the trade-offs of work, driving speed, and driving accuracy when changing driving strength, speed, and the underlying system dynamics. We find an upper bound on accuracy and work for a particular speed. Our results favor slow driving when tasked with minimizing the work-accuracy ratio and maximizing the rate of successful cycles. Finally, in the parameter regime mapping to the dynamics of F_{1}-ATP synthase, we find a significant decay of driving accuracy at physiological rotation rates, raising questions about how ATP synthase achieves reasonable or even remarkable efficiency in vivo.
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Affiliation(s)
- Alexandra K S Kasper
- Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada V5A1S6
| | - David A Sivak
- Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada V5A1S6
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26
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Hou R, Wang Z. Thermodynamic marking of F OF 1 ATP synthase. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2021; 1862:148369. [PMID: 33454313 DOI: 10.1016/j.bbabio.2021.148369] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 12/02/2020] [Accepted: 01/05/2021] [Indexed: 11/29/2022]
Abstract
FOF1 ATP synthase is a ~100% efficient molecular machine for energy conversion in biology, and holds great lessons for man-made energy technology and nanotechnology. In light of formidable biocomplexity of the FOF1 machinery, its modeling from pure physical principles remains difficult and rare. Here we construct a thermodynamic model of FOF1 from experimentally accessible quantities plus a single entropy production that generally has vanishingly small values (<1kB). Based on the physical inputs, this model captures FOF1 performance observed over an exhaustively wide range of proton-motive force and nucleotide concentrations. The model predicts a distinct 1/8kBT slope for ATP synthesis rate versus proton-motive force, which is verified by experimental data and represents a profound thermodynamic marking of this amazingly efficient machine operating near a universal limit of the 2nd law of thermodynamics. The model further predicts two symmetries of heat productions, which are testable by available experimental techniques and offer quantitative constraints on FOF1's possible mechanisms behind its ~100% efficiency.
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Affiliation(s)
- Ruizheng Hou
- Department of Applied Physics, School of Science, Xi'an University of Technology, Xi'an, Shaan Xi 710048, China.
| | - Zhisong Wang
- Department of Physics and NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 117542, Singapore
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27
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Basso L, Yamori W, Szabo I, Shikanai T. Collaboration between NDH and KEA3 Allows Maximally Efficient Photosynthesis after a Long Dark Adaptation. PLANT PHYSIOLOGY 2020; 184:2078-2090. [PMID: 32978277 PMCID: PMC7723091 DOI: 10.1104/pp.20.01069] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 09/16/2020] [Indexed: 05/10/2023]
Abstract
In angiosperms, the NADH dehydrogenase-like (NDH) complex mediates cyclic electron transport around PSI (CET). K+ Efflux Antiporter3 (KEA3) is a putative thylakoid H+/K+ antiporter and allows an increase in membrane potential at the expense of the ∆pH component of the proton motive force. In this study, we discovered that the chlororespiratory reduction2-1 (crr2-1) mutation, which abolished NDH-dependent CET, enhanced the kea3-1 mutant phenotypes in Arabidopsis (Arabidopsis thaliana). The NDH complex pumps protons during CET, further enhancing ∆pH, but its physiological function has not been fully clarified. The observed effect only took place upon exposure to light of 110 µmol photons m-2 s-1 after overnight dark adaptation. We propose two distinct modes of NDH action. In the initial phase, within 1 min after the onset of actinic light, the NDH-dependent CET engages with KEA3 to enhance electron transport efficiency. In the subsequent phase, in which the ∆pH-dependent down-regulation of the electron transport is relaxed, the NDH complex engages with KEA3 to relax the large ∆pH formed during the initial phase. We observed a similar impact of the crr2-1 mutation in the genetic background of the PROTON GRADIENT REGULATION5 overexpression line, in which the size of ∆pH was enhanced. When photosynthesis was induced at 300 µmol photons m-2 s-1, the contribution of KEA3 was negligible in the initial phase and the ∆pH-dependent down-regulation was not relaxed in the second phase. In the crr2-1 kea3-1 double mutant, the induction of CO2 fixation was delayed after overnight dark adaptation.
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Affiliation(s)
- Leonardo Basso
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502 Japan
| | - Wataru Yamori
- Institute for Sustainable Agro-Ecosystem Services, Graduate School of Agriculture and Life Science, University of Tokyo, Tokyo 188-0002 Japan
| | - Ildiko Szabo
- Department of Biology, University of Padova, 606-8502 Padova, Italy
| | - Toshiharu Shikanai
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502 Japan
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28
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Nath S. Molecular-level understanding of biological energy coupling and transduction: Response to "Chemiosmotic misunderstandings". Biophys Chem 2020; 268:106496. [PMID: 33160142 DOI: 10.1016/j.bpc.2020.106496] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 10/06/2020] [Accepted: 10/27/2020] [Indexed: 02/08/2023]
Abstract
In a recent paper entitled "Chemiosmotic misunderstandings", it is claimed that "enough shortcomings in Mitchell's chemiosmotic theory have not been found and that a novel paradigm that offers at least as much explanatory power as chemiosmosis is not ready." This view is refuted by a wealth of molecular-level experimental data and strong new theoretical and computational evidence. It is shown that the chemiosmotic theory was beset with a large number of major shortcomings ever since the time when it was first proposed in the 1960s. These multiple shortcomings and flaws of chemiosmosis were repeatedly pointed out in incisive critiques by biochemical authorities of the late 20th century. All the shortcomings and flaws have been shown to be rectified by a quantitative, unified molecular-level theory that leads to a deeper and far more accurate understanding of biological energy coupling and ATP synthesis. The new theory is shown to be consistent with pioneering X-ray and cryo-EM structures and validated by state-of-the-art single-molecule techniques. Several new biochemical experimental tests are proposed and constructive ways for providing a revitalizing conceptual background and theory for integration of the available experimental information are suggested.
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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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29
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Soga N, Ota A, Nakajima K, Watanabe R, Ueno H, Noji H. Monodisperse Liposomes with Femtoliter Volume Enable Quantitative Digital Bioassays of Membrane Transporters and Cell-Free Gene Expression. ACS NANO 2020; 14:11700-11711. [PMID: 32864949 DOI: 10.1021/acsnano.0c04354] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Digital bioassays have emerged as a new category of bioanalysis. However, digital bioassays for membrane transporter proteins have not been well established yet despite high demands in molecular physiology and molecular pharmacology due to the lack of biologically functional monodisperse liposomes with femtoliter volumes. Here, we established a simple and robust method to produce femtoliter-sized liposomes (femto-liposomes). We prepared 106 monodispersed water-in-oil droplets stabilized by a lipid monolayer using a polyethylene glycol-coated femtoliter reactor array device. Droplets were subjected to the optimized emulsion transfer process for femto-liposome production. Liposomes were monodispersed (coefficient of variation = 5-15%) and had suitable diameter (0.6-5.3 μm) and uniform volumes of subfemtoliter or a few femtoliters; thus, they were termed uniform femto-liposomes. The unilamellarity of uniform femto-liposomes allowed quantitative single-molecule analysis of passive and active transporter proteins: α-hemolysin and FoF1-ATPase. Digital gene expression in uniform femto-liposomes (cell-free transcription and translation from single DNA molecules) was also demonstrated, showing the versatility of digital assays for membrane transporter proteins and cell-free synthetic biology.
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Affiliation(s)
- Naoki Soga
- Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Akira Ota
- Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Kota Nakajima
- Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Rikiya Watanabe
- Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
- PRIME, Japan Agency for Medical Research and Development, 1-7-1 Otemachi, Chiyoda-ku, Tokyo 100-0004, Japan
| | - Hiroshi Ueno
- Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Hiroyuki Noji
- Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
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30
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Wikström M, Springett R. Thermodynamic efficiency, reversibility, and degree of coupling in energy conservation by the mitochondrial respiratory chain. Commun Biol 2020; 3:451. [PMID: 32811895 PMCID: PMC7434914 DOI: 10.1038/s42003-020-01192-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 07/30/2020] [Indexed: 11/23/2022] Open
Abstract
The protonmotive mitochondrial respiratory chain, comprising complexes I, III and IV, transduces free energy of the electron transfer reactions to an electrochemical proton gradient across the inner mitochondrial membrane. This gradient is used to drive synthesis of ATP and ion and metabolite transport. The efficiency of energy conversion is of interest from a physiological point of view, since the energy transduction mechanisms differ fundamentally between the three complexes. Here, we have chosen actively phosphorylating mitochondria as the focus of analysis. For all three complexes we find that the thermodynamic efficiency is about 80–90% and that the degree of coupling between the redox and proton translocation reactions is very high during active ATP synthesis. However, when net ATP synthesis stops at a high ATP/ADP.Pi ratio, and mitochondria reach “State 4” with an elevated proton gradient, the degree of coupling drops substantially. The mechanistic cause and the physiological implications of this effect are discussed. Wikström and Springett analyze the thermodynamic efficiency of redox reactions and proton translocation by the complexes of mitochondrial respiratory chain. They report that the thermodynamic efficiency is about 80–90% and that the degree of coupling between the redox and proton translocation reactions is very high during active ATP synthesis, but decreases when ATP synthesis stops.
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Affiliation(s)
- Mårten Wikström
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland.
| | - Roger Springett
- Cardiovascular Division, King's College London, British Heart Foundation Centre of Excellence, 125 Coldharbour Lane, London, SE5 9NU, UK
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31
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Lathouwers E, Lucero JNE, Sivak DA. Nonequilibrium Energy Transduction in Stochastic Strongly Coupled Rotary Motors. J Phys Chem Lett 2020; 11:5273-5278. [PMID: 32501698 DOI: 10.1021/acs.jpclett.0c01055] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Living systems at the molecular scale are composed of many constituents with strong and heterogeneous interactions, operating far from equilibrium, and subject to strong fluctuations. These conditions pose significant challenges to efficient, precise, and rapid free energy transduction, yet nature has evolved numerous molecular machines that do just this. Using a simple model of the ingenious rotary machine FoF1-ATP synthase, we investigate the interplay between nonequilibrium driving forces, thermal fluctuations, and interactions between strongly coupled subsystems. This model reveals design principles for effective free energy transduction. Most notably, while tight coupling is intuitively appealing, we find that output power is maximized at intermediate-strength coupling, which permits lubrication by stochastic fluctuations with only minimal slippage.
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Affiliation(s)
- Emma Lathouwers
- Department of Physics, Simon Fraser University, Burnaby, BC V5A1S6 Canada
| | - Joseph N E Lucero
- Department of Physics, Simon Fraser University, Burnaby, BC V5A1S6 Canada
| | - David A Sivak
- Department of Physics, Simon Fraser University, Burnaby, BC V5A1S6 Canada
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32
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Structural and functional properties of plant mitochondrial F-ATP synthase. Mitochondrion 2020; 53:178-193. [DOI: 10.1016/j.mito.2020.06.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 05/25/2020] [Accepted: 06/08/2020] [Indexed: 12/13/2022]
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33
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Halling PJ. Estimation of initial rate from discontinuous progress data. BIOCATAL BIOTRANSFOR 2020. [DOI: 10.1080/10242422.2020.1746771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Peter J. Halling
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, UK
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34
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Toyabe S, Li CB, Kinbara K. Session 2SDA-Nonequilibrium energetics of biological molecular machines. Biophys Rev 2020; 12:273-274. [PMID: 32108300 DOI: 10.1007/s12551-020-00634-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 02/03/2020] [Indexed: 11/26/2022] Open
Affiliation(s)
- Shoichi Toyabe
- Department of Applied Physics, Grad. Sch. of Engineering, Tohoku University, Aoba 6-6-05, Sendai, 980-8579, Japan.
| | - Chun-Biu Li
- Department of Mathematics, Stockholm University, 106 91, Stockholm, Sweden
| | - Kazushi Kinbara
- School of Life Science and Technology, Tokyo Institute of Technology, Nagatsuda-cho 4259 B58, Midori-ku, Yokohama, 226-8501, Japan
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35
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Affiliation(s)
- Ryota Iino
- Institute for Molecular Science and The Graduate University for
Advanced Studies (SOKENDAI)
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36
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Mnatsakanyan N, Llaguno MC, Yang Y, Yan Y, Weber J, Sigworth FJ, Jonas EA. A mitochondrial megachannel resides in monomeric F 1F O ATP synthase. Nat Commun 2019; 10:5823. [PMID: 31862883 PMCID: PMC6925261 DOI: 10.1038/s41467-019-13766-2] [Citation(s) in RCA: 108] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Accepted: 11/25/2019] [Indexed: 11/08/2022] Open
Abstract
Purified mitochondrial ATP synthase has been shown to form Ca2+-activated, large conductance channel activity similar to that of mitochondrial megachannel (MMC) or mitochondrial permeability transition pore (mPTP) but the oligomeric state required for channel formation is being debated. We reconstitute purified monomeric ATP synthase from porcine heart mitochondria into small unilamellar vesicles (SUVs) with the lipid composition of mitochondrial inner membrane and analyze its oligomeric state by electron cryomicroscopy. The cryo-EM density map reveals the presence of a single ATP synthase monomer with no density seen for a second molecule tilted at an 86o angle relative to the first. We show that this preparation of SUV-reconstituted ATP synthase monomers, when fused into giant unilamellar vesicles (GUVs), forms voltage-gated and Ca2+-activated channels with the key features of mPTP. Based on our findings we conclude that the ATP synthase monomer is sufficient, and dimer formation is not required, for mPTP activity.
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Affiliation(s)
- Nelli Mnatsakanyan
- Section of Endocrinology, Department of Internal Medicine, Yale University, New Haven, CT, USA.
| | - Marc C Llaguno
- Center for Cellular and Molecular Imaging, Yale University, New Haven, CT, USA
| | - Youshan Yang
- Department of Cellular and Molecular Physiology, Yale University, New Haven, CT, USA
| | - Yangyang Yan
- Department of Cellular and Molecular Physiology, Yale University, New Haven, CT, USA
| | - Joachim Weber
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, USA
| | - Fred J Sigworth
- Department of Cellular and Molecular Physiology, Yale University, New Haven, CT, USA
| | - Elizabeth A Jonas
- Section of Endocrinology, Department of Internal Medicine, Yale University, New Haven, CT, USA.
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37
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Novichkova NS, Malyan AN. The Effect of the Viscosity of a Trehalose Solution on ATP Hydrolysis by Chloroplast F1-ATPase. Biophysics (Nagoya-shi) 2019. [DOI: 10.1134/s0006350919060174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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38
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Wang C, Shikanai T. Modification of Activity of the Thylakoid H +/K + Antiporter KEA3 Disturbs ∆pH-Dependent Regulation of Photosynthesis. PLANT PHYSIOLOGY 2019; 181:762-773. [PMID: 31427465 PMCID: PMC6776848 DOI: 10.1104/pp.19.00766] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 08/07/2019] [Indexed: 05/19/2023]
Abstract
The thylakoid K+ efflux antiporter 3 (KEA3) is required for regulating components of the proton motive force (pmf), proton concentration gradient (ΔpH), and membrane potential (Δψ). The Arabidopsis (Arabidopsis thaliana) disturbed proton gradient regulation mutant (dpgr) is a dominant allele of KEA3, conferring disturbed transport activity. Here, we show that overexpressing the DPGR-type KEA3 (DPGRox) retarded plant growth, whereas overexpressing the wild-type KEA3 (KEA3ox) did not. In KEA3ox lines, the contribution of Δψ to pmf was enhanced, but in DPGRox lines, the size of pmf was reduced. In DPGRox plants, proton conductivity of the thylakoid membrane (g H +) was elevated under high light, implying disturbed stoichiometry of H+/K+ antiport through DPGR-type KEA3 rather than simply enhanced activity. The ΔpH-dependent regulation consisting of thermal dissipation of excessively absorbed light energy and downregulation of cytochrome b 6 f complex activity was severely and mildly affected in DPGRox and KEA3ox plants, respectively. Consequently, photosystem I was sensitive to fluctuating light in both transgenic plants. Both photosystems were sensitive to constant high light and were slightly photodamaged even at standard growth light intensity in DPGRox plants. KEA3 regulates the components of pmf and optimizes the operation of ∆pH-dependent regulation of electron transport.
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Affiliation(s)
- Caijuan Wang
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto, 606-8502 Japan
| | - Toshiharu Shikanai
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto, 606-8502 Japan
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39
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Marko JF, De Los Rios P, Barducci A, Gruber S. DNA-segment-capture model for loop extrusion by structural maintenance of chromosome (SMC) protein complexes. Nucleic Acids Res 2019; 47:6956-6972. [PMID: 31175837 PMCID: PMC6649773 DOI: 10.1093/nar/gkz497] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 05/20/2019] [Accepted: 06/06/2019] [Indexed: 01/08/2023] Open
Abstract
Cells possess remarkable control of the folding and entanglement topology of long and flexible chromosomal DNA molecules. It is thought that structural maintenance of chromosome (SMC) protein complexes play a crucial role in this, by organizing long DNAs into series of loops. Experimental data suggest that SMC complexes are able to translocate on DNA, as well as pull out lengths of DNA via a 'loop extrusion' process. We describe a Brownian loop-capture-ratchet model for translocation and loop extrusion based on known structural, catalytic, and DNA-binding properties of the Bacillus subtilis SMC complex. Our model provides an example of a new class of molecular motor where large conformational fluctuations of the motor 'track'-in this case DNA-are involved in the basic translocation process. Quantitative analysis of our model leads to a series of predictions for the motor properties of SMC complexes, most strikingly a strong dependence of SMC translocation velocity and step size on tension in the DNA track that it is moving along, with 'stalling' occuring at subpiconewton tensions. We discuss how the same mechanism might be used by structurally related SMC complexes (Escherichia coli MukBEF and eukaryote condensin, cohesin and SMC5/6) to organize genomic DNA.
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Affiliation(s)
- John F Marko
- Department of Molecular Biosciences and Department of Physics & Astronomy, Northwestern University, Evanston, IL 60208, USA
| | - Paolo De Los Rios
- Laboratory of Statistical Biophysics, Institute of Physics, School of Basic Sciences and Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne - EPFL, 1015 Lausanne, Switzerland
| | - Alessandro Barducci
- Centre de Biochimie Structurale, INSERM, CNRS, Université de Montpellier, 34090 Montpellier, France
| | - Stephan Gruber
- Départment de Microbiologie Fondamentale, Université de Lausanne, 1015 Lausanne, Switzerland
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40
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Murphy BJ, Klusch N, Langer J, Mills DJ, Yildiz Ö, Kühlbrandt W. Rotary substates of mitochondrial ATP synthase reveal the basis of flexible F1-Focoupling. Science 2019; 364:364/6446/eaaw9128. [DOI: 10.1126/science.aaw9128] [Citation(s) in RCA: 112] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 04/26/2019] [Indexed: 12/17/2022]
Abstract
F1Fo–adenosine triphosphate (ATP) synthases make the energy of the proton-motive force available for energy-consuming processes in the cell. We determined the single-particle cryo–electron microscopy structure of active dimeric ATP synthase from mitochondria ofPolytomellasp. at a resolution of 2.7 to 2.8 angstroms. Separation of 13 well-defined rotary substates by three-dimensional classification provides a detailed picture of the molecular motions that accompanyc-ring rotation and result in ATP synthesis. Crucially, the F1head rotates along with the central stalk andc-ring rotor for the first ~30° of each 120° primary rotary step to facilitate flexible coupling of the stoichiometrically mismatched F1and Fosubcomplexes. Flexibility is mediated primarily by the interdomain hinge of the conserved OSCP subunit. A conserved metal ion in the proton access channel may synchronizec-ring protonation with rotation.
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41
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Mitochondrial F-ATP Synthase and Its Transition into an Energy-Dissipating Molecular Machine. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:8743257. [PMID: 31178976 PMCID: PMC6501240 DOI: 10.1155/2019/8743257] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 03/18/2019] [Indexed: 01/27/2023]
Abstract
The mitochondrial F-ATP synthase is the principal energy-conserving nanomotor of cells that harnesses the proton motive force generated by the respiratory chain to make ATP from ADP and phosphate in a process known as oxidative phosphorylation. In the energy-converting membranes, F-ATP synthase is a multisubunit complex organized into a membrane-extrinsic F1 sector and a membrane-intrinsic FO domain, linked by central and peripheral stalks. Due to its essential role in the cellular metabolism, malfunction of F-ATP synthase has been associated with a variety of pathological conditions, and the enzyme is now considered as a promising drug target for multiple disease conditions and for the regulation of energy metabolism. We discuss structural and functional features of mitochondrial F-ATP synthase as well as several conditions that partially or fully inhibit the coupling between the F1 catalytic activities and the FO proton translocation, thus decreasing the cellular metabolic efficiency and transforming the enzyme into an energy-dissipating structure through molecular mechanisms that still remain to be defined.
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42
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Yamamoto H, Shikanai T. PGR5-Dependent Cyclic Electron Flow Protects Photosystem I under Fluctuating Light at Donor and Acceptor Sides. PLANT PHYSIOLOGY 2019; 179:588-600. [PMID: 30464024 PMCID: PMC6426425 DOI: 10.1104/pp.18.01343] [Citation(s) in RCA: 127] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 11/12/2018] [Indexed: 05/14/2023]
Abstract
In response to a sudden increase in light intensity, plants must cope with absorbed excess photon energy to protect photosystems from photodamage. Under fluctuating light, PSI is severely photodamaged in the Arabidopsis (Arabidopsis thaliana) proton gradient regulation5 (pgr5) mutant defective in the main pathway of PSI cyclic electron transport (CET). Here, we aimed to determine how PSI is protected by two proposed regulatory roles of CET via transthylakoid ΔpH formation: (1) reservation of electron sink capacity by adjusting the ATP/NADPH production ratio (acceptor-side regulation) and (2) down-regulation of the cytochrome b 6 f complex activity called photosynthetic control for slowing down the electron flow toward PSI (donor-side regulation). We artificially enhanced donor- and acceptor-side regulation in the wild-type and pgr5 backgrounds by introducing the pgr1 mutation conferring the hypersensitivity of the cytochrome b 6 f complex to luminal acidification and moss Physcomitrella patens flavodiiron protein genes, respectively. Enhanced photosynthetic control partially alleviated PSI photodamage in the pgr5 mutant background but restricted linear electron transport under constant high light, suggesting that the strength of photosynthetic control should be optimized. Flavodiiron protein-dependent oxygen photoreduction formed a large electron sink and alleviated PSI photoinhibition, accompanied by the induction of photosynthetic control. Thus, donor-side regulation is essential for PSI photoprotection but acceptor-side regulation also is important to rapidly induce donor-side regulation. In angiosperms, PGR5-dependent CET is required for both functions.
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Affiliation(s)
- Hiroshi Yamamoto
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502 Japan
| | - Toshiharu Shikanai
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502 Japan
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43
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Measuring the functionality of the mitochondrial pumping complexes with multi-wavelength spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:89-101. [DOI: 10.1016/j.bbabio.2018.11.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 10/04/2018] [Accepted: 11/07/2018] [Indexed: 12/24/2022]
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44
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Li Y, Feng X, Wang A, Yang Y, Fei J, Sun B, Jia Y, Li J. Supramolecularly Assembled Nanocomposites as Biomimetic Chloroplasts for Enhancement of Photophosphorylation. Angew Chem Int Ed Engl 2018; 58:796-800. [PMID: 30474178 DOI: 10.1002/anie.201812582] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Indexed: 11/07/2022]
Abstract
Prototypes of natural biosystems provide opportunities for artificial biomimetic systems to break the limits of natural reactions and achieve output control. However, mimicking unique natural structures and ingenious functions remains a challenge. Now, multiple biochemical reactions were integrated into artificially designed compartments via molecular assembly. First, multicompartmental silica nanoparticles with hierarchical structures that mimic the chloroplasts were obtained by a templated synthesis. Then, photoacid generators and ATPase-liposomes were assembled inside and outside of silica compartments, respectively. Upon light illumination, protons produced by a photoacid generator in the confined space can drive the liposome-embedded enzyme ATPase towards ATP synthesis, which mimics the photophosphorylation process in vitro. The method enables fabrication of bioinspired nanoreactors for photobiocatalysis and provides insight for understanding sophisticated biochemical reactions.
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Affiliation(s)
- Yue Li
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Lab of Colloid, Interface and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.,CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, Beijing, 100190, China
| | - Xiyun Feng
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Lab of Colloid, Interface and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.,Yunnan Normal University, Faculty of Chemistry and Chemical Engineering, Kunming, 650050, China
| | - Anhe Wang
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Lab of Colloid, Interface and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.,State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China
| | - Yang Yang
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, Beijing, 100190, China
| | - Jinbo Fei
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Lab of Colloid, Interface and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Bingbing Sun
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Lab of Colloid, Interface and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.,University of Chinese Academic of Sciences, Beijing, 100049, China
| | - Yi Jia
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Lab of Colloid, Interface and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Junbai Li
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Lab of Colloid, Interface and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.,University of Chinese Academic of Sciences, Beijing, 100049, China
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45
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Li Y, Feng X, Wang A, Yang Y, Fei J, Sun B, Jia Y, Li J. Supramolecularly Assembled Nanocomposites as Biomimetic Chloroplasts for Enhancement of Photophosphorylation. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201812582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Yue Li
- Beijing National Laboratory for Molecular Sciences (BNLMS)CAS Key Lab of Colloid, Interface and Chemical ThermodynamicsInstitute of ChemistryChinese Academy of Sciences Beijing 100190 China
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and NanosafetyNational Center for Nanoscience and Technology Beijing 100190 China
| | - Xiyun Feng
- Beijing National Laboratory for Molecular Sciences (BNLMS)CAS Key Lab of Colloid, Interface and Chemical ThermodynamicsInstitute of ChemistryChinese Academy of Sciences Beijing 100190 China
- Yunnan Normal UniversityFaculty of Chemistry and Chemical Engineering Kunming 650050 China
| | - Anhe Wang
- Beijing National Laboratory for Molecular Sciences (BNLMS)CAS Key Lab of Colloid, Interface and Chemical ThermodynamicsInstitute of ChemistryChinese Academy of Sciences Beijing 100190 China
- State Key Laboratory of Biochemical EngineeringInstitute of Process EngineeringChinese Academy of Sciences Beijing 100190 China
| | - Yang Yang
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and NanosafetyNational Center for Nanoscience and Technology Beijing 100190 China
| | - Jinbo Fei
- Beijing National Laboratory for Molecular Sciences (BNLMS)CAS Key Lab of Colloid, Interface and Chemical ThermodynamicsInstitute of ChemistryChinese Academy of Sciences Beijing 100190 China
| | - Bingbing Sun
- Beijing National Laboratory for Molecular Sciences (BNLMS)CAS Key Lab of Colloid, Interface and Chemical ThermodynamicsInstitute of ChemistryChinese Academy of Sciences Beijing 100190 China
- University of Chinese Academic of Sciences Beijing 100049 China
| | - Yi Jia
- Beijing National Laboratory for Molecular Sciences (BNLMS)CAS Key Lab of Colloid, Interface and Chemical ThermodynamicsInstitute of ChemistryChinese Academy of Sciences Beijing 100190 China
| | - Junbai Li
- Beijing National Laboratory for Molecular Sciences (BNLMS)CAS Key Lab of Colloid, Interface and Chemical ThermodynamicsInstitute of ChemistryChinese Academy of Sciences Beijing 100190 China
- University of Chinese Academic of Sciences Beijing 100049 China
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46
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47
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Li G, Fei J, Xu Y, Hong JD, Li J. Proton-consumed nanoarchitectures toward sustainable and efficient photophosphorylation. J Colloid Interface Sci 2018; 535:325-330. [PMID: 30316119 DOI: 10.1016/j.jcis.2018.09.082] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 09/24/2018] [Accepted: 09/24/2018] [Indexed: 12/01/2022]
Abstract
At present, photophosphorylation in natural or artificial systems is accomplished by the production of protons or their pumping across the biomembranes. Herein, different from this strategy above, we demonstrate a designed system which can effectively enhance photophosphorylation by photo-induced proton-scavenging through molecular assembly. Upon the introduction of photobase generators, a (photo-) chemical reaction occurs to produce hydroxyl ions. Accompanying the further extramembranous acid-base neutralization reaction, an outbound flow of protons is generated to drive the reconstituted adenosine triphosphate (ATP) synthase to produce ATP. That is, contrary to biochemistry, the proton gradient to drive photophosphorylation derives from the scavenging of protons present in the external medium by hydroxyl ions, produced by the partially photo-induced splitting of photobase generator. Such assembled system holds great potential in ATP-consuming bioapplications.
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Affiliation(s)
- Guangle Li
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Lab of Colloid, Interface and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jinbo Fei
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Lab of Colloid, Interface and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Youqian Xu
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Lab of Colloid, Interface and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jong-Dal Hong
- Department of Chemistry, Incheon National University, Incheon 21022, South Korea.
| | - Junbai Li
- Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Lab of Colloid, Interface and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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48
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Colina-Tenorio L, Dautant A, Miranda-Astudillo H, Giraud MF, González-Halphen D. The Peripheral Stalk of Rotary ATPases. Front Physiol 2018; 9:1243. [PMID: 30233414 PMCID: PMC6131620 DOI: 10.3389/fphys.2018.01243] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 08/16/2018] [Indexed: 12/18/2022] Open
Abstract
Rotary ATPases are a family of enzymes that are thought of as molecular nanomotors and are classified in three types: F, A, and V-type ATPases. Two members (F and A-type) can synthesize and hydrolyze ATP, depending on the energetic needs of the cell, while the V-type enzyme exhibits only a hydrolytic activity. The overall architecture of all these enzymes is conserved and three main sectors are distinguished: a catalytic core, a rotor and a stator or peripheral stalk. The peripheral stalks of the A and V-types are highly conserved in both structure and function, however, the F-type peripheral stalks have divergent structures. Furthermore, the peripheral stalk has other roles beyond its stator function, as evidenced by several biochemical and recent structural studies. This review describes the information regarding the organization of the peripheral stalk components of F, A, and V-ATPases, highlighting the key differences between the studied enzymes, as well as the different processes in which the structure is involved.
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Affiliation(s)
- Lilia Colina-Tenorio
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Alain Dautant
- CNRS, UMR5095, IBGC, Bordeaux, France.,Energy Transducing Systems and Mitochondrial Morphology, Université de Bordeaux, Bordeaux, France
| | - Héctor Miranda-Astudillo
- Genetics and Physiology of Microalgae, InBios, PhytoSYSTEMS, University of Liège, Liège, Belgium
| | - Marie-France Giraud
- CNRS, UMR5095, IBGC, Bordeaux, France.,Energy Transducing Systems and Mitochondrial Morphology, Université de Bordeaux, Bordeaux, France
| | - Diego González-Halphen
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
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49
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Nath S. Molecular mechanistic insights into coupling of ion transport to ATP synthesis. Biophys Chem 2018; 241:20-26. [PMID: 30081239 DOI: 10.1016/j.bpc.2018.07.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 07/26/2018] [Accepted: 07/26/2018] [Indexed: 12/22/2022]
Abstract
A wealth of molecular mechanistic insights has been provided into the coupling of ion transport to ATP synthesis based on a two-ion theory of biological energy coupling. A kinetic scheme that considers the mode of functioning of a single F1FO-ATP synthase molecule with H+-A- cotransport and unidirectional rotation of the c-rotor in the membrane-bound FO-portion of the enzyme has been developed. Mathematical analysis leads to a detailed enzyme kinetic model applicable to a population of molecules which is compared with experimental data on the pH dependence of ATP synthesis. The model agrees well with the experimental data, and a single equation with a single set of standard enzymological kinetic parameters has been shown to explain the experimental data over the entire range of conditions for the chloroplast ATP synthase. The analysis gives novel insights into kinetic and mechanistic characteristics of ATP synthesis in FO. These include an order imposed on ion binding and unbinding events in FO, the essential role of the anion in direct activation of the ATP synthase (in addition to its role as a permeant ion), and the integration in a novel way of the functions of cooperativity and cotransport of dicarboxylic acid anions and protons during physiological ATP synthesis. Further, Wyman's pioneering classical work on the thermodynamics of linked functions has been shown to offer a new approach to distinguish between various models of energy coupling in ATP synthesis. All these results have been found to be inconsistent with Mitchell's chemiosmotic theory and are shown to be in agreement with Nath's torsional mechanism of energy transduction and ATP synthesis.
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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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Nath S. Two-ion theory of energy coupling in ATP synthesis rectifies a fundamental flaw in the governing equations of the chemiosmotic theory. Biophys Chem 2017; 230:45-52. [PMID: 28882384 DOI: 10.1016/j.bpc.2017.08.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 08/08/2017] [Accepted: 08/17/2017] [Indexed: 10/19/2022]
Abstract
The vital coupled processes of oxidative phosphorylation and photosynthetic phosphorylation synthesize molecules of adenosine-5'-triphosphate (ATP), the universal biological energy currency, and sustain all life on our planet. The chemiosmotic theory of energy coupling in oxidative and photophosphorylation was proposed by Mitchell >50years ago. It has had a contentious history, with part of the accumulated body of experimental evidence supporting it, and part of it in conflict with the theory. Although the theory was strongly criticized by many prominent scientists, the controversy has never been resolved. Here, the mathematical steps of Mitchell's original derivation leading to the principal equation of the chemiosmotic theory are scrutinized, and a fundamental flaw in them has been identified. Surprisingly, this flaw had not been detected earlier. Discovery of such a defect negates, or at least considerably weakens, the theoretical foundations on which the chemiosmotic theory is based. Ad hoc or simplistic ways to remedy this defect are shown to be scientifically unproductive and sterile. A novel two-ion theory of biological energy coupling salvages the situation by rectifying the fundamental flaw in the chemiosmotic theory, and the governing equations of the new theory have been shown to accurately quantify and predict extensive recent experimental data on ATP synthesis by F1FO-ATP synthase without using adjustable parameters. Some major biological implications arising from the new thinking are discussed. The principles of energy transduction and coupling proposed in the new paradigm are shown to be of a very general and universal nature. It is concluded that the timely availability after a 25-year research struggle of Nath's torsional mechanism of energy transduction and ATP synthesis is a rational alternative that has the power to solve the problems arising from the past, and also meet present and future challenges in this important interdisciplinary field of research.
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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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