1
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Nath S. Coupling and biological free-energy transduction processes as a bridge between physics and life: Molecular-level instantiation of Ervin Bauer's pioneering concepts in biological thermodynamics. Biosystems 2024; 236:105134. [PMID: 38301737 DOI: 10.1016/j.biosystems.2024.105134] [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: 12/28/2023] [Revised: 01/28/2024] [Accepted: 01/29/2024] [Indexed: 02/03/2024]
Abstract
The nonequilibrium coupled processes of oxidation and ATP synthesis in the biological process of oxidative phosphorylation (OXPHOS) are fundamental to all life on our planet. These steady-state energy transduction processes ‒ coupled by proton and anion/counter-cation concentration gradients in the OXPHOS pathway ‒ generate ∼95 % of the ATP requirement of aerobic systems for cellular function. The rapid energy cycling and homeostasis of metabolites involved in this coupling are shown to be responsible for maintenance and regulation of stable nonequilibrium states, the latter first postulated in pioneering biothermodynamics work by Ervin Bauer between 1920 and 1935. How exactly does this occur? This is shown to be answered by molecular considerations arising from Nath's torsional mechanism of ATP synthesis and two-ion theory of energy coupling developed in 25 years of research work on the subject. A fresh analysis of the biological thermodynamics of coupling that goes beyond the previous work of Stucki and others and shows how the system functions at the molecular level has been carried out. Thermodynamic parameters, such as the overall degree of coupling, q of the coupled system are evaluated for the state 4 to state 3 transition in animal mitochondria with succinate as substrate. The actual or operative P to O ratio, the efficiency of the coupled reactions, η, and the Gibbs energy dissipation, Φ have been calculated and shown to be in good agreement with experimental data. Novel mechanistic insights arising from the above have been discussed. A fourth law/principle of thermodynamics is formulated for a sub-class of physical and biological systems. The critical importance of constraints and time-varying boundary conditions for function and regulation is discussed in detail. Dynamic internal structural changes essential for torsional energy storage within the γ-subunit in a single molecule of the FOF1-ATP synthase and its transduction have been highlighted. These results provide a molecular-level instantiation of Ervin Bauer's pioneering concepts in biological thermodynamics.
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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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2
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Nath S. Phosphorus Chemistry at the Roots of Bioenergetics: Ligand Permutation as the Molecular Basis of the Mechanism of ATP Synthesis/Hydrolysis by F OF 1-ATP Synthase. Molecules 2023; 28:7486. [PMID: 38005208 PMCID: PMC10673332 DOI: 10.3390/molecules28227486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 11/04/2023] [Accepted: 11/06/2023] [Indexed: 11/26/2023] Open
Abstract
The integration of phosphorus chemistry with the mechanism of ATP synthesis/hydrolysis requires dynamical information during ATP turnover and catalysis. Oxygen exchange reactions occurring at β-catalytic sites of the FOF1-ATP synthase/F1-ATPase imprint a unique record of molecular events during the catalytic cycle of ATP synthesis/hydrolysis. They have been shown to provide valuable time-resolved information on enzyme catalysis during ATP synthesis and ATP hydrolysis. The present work conducts new experiments on oxygen exchange catalyzed by submitochondrial particles designed to (i) measure the relative rates of Pi-ATP, Pi-HOH, and ATP-HOH isotope exchanges; (ii) probe the effect of ADP removal on the extent of inhibition of the exchanges, and (iii) test their uncoupler sensitivity/resistance. The objectives have been realized based on new experiments on submitochondrial particles, which show that both the Pi-HOH and ATP-HOH exchanges occur at a considerably higher rate relative to the Pi-ATP exchange, an observation that cannot be explained by previous mechanisms. A unifying explanation of the kinetic data that rationalizes these observations is given. The experimental results in (ii) show that ADP removal does not inhibit the intermediate Pi-HOH exchange when ATP and submitochondrial particles are incubated, and that the nucleotide requirement of the intermediate Pi-HOH exchange is adequately met by ATP, but not by ADP. These results contradicts the central postulate in Boyer's binding change mechanism of reversible catalysis at a F1 catalytic site with Keq~1 that predicts an absolute requirement of ADP for the occurrence of the Pi-HOH exchange. The prominent intermediate Pi-HOH exchange occurring under hydrolytic conditions is shown to be best explained by Nath's torsional mechanism of energy transduction and ATP synthesis/hydrolysis, which postulates an essentially irreversible cleavage of ATP by mitochondria/particles, independent from a reversible formation of ATP from ADP and Pi. The explanation within the torsional mechanism is also shown to rationalize the relative insensitivity of the intermediate Pi-HOH exchange to uncouplers observed in the experiments in (iii) compared to the Pi-ATP and ATP-HOH exchanges. This is shown to lead to new concepts and perspectives based on ligand displacement/substitution and ligand permutation for the elucidation of the oxygen exchange reactions within the framework of fundamental phosphorus chemistry. Fast mechanisms that realize the rotation/twist, tilt, permutation and switch of ligands, as well as inversion at the γ-phosphorus synchronously and simultaneously and in a concerted manner, have been proposed, and their stereochemical consequences have been analyzed. These considerations take us beyond the binding change mechanism of ATP synthesis/hydrolysis in bioenergetics.
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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; or
- Institute of Molecular Psychiatry, Rheinische-Friedrichs-Wilhelm Universität Bonn, D-53127 Bonn, Germany
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3
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Nath S. Elucidating Events within the Black Box of Enzyme Catalysis in Energy Metabolism: Insights into the Molecular Mechanism of ATP Hydrolysis by F 1-ATPase. Biomolecules 2023; 13:1596. [PMID: 38002278 PMCID: PMC10669602 DOI: 10.3390/biom13111596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Revised: 10/23/2023] [Accepted: 10/26/2023] [Indexed: 11/26/2023] Open
Abstract
Oxygen exchange reactions occurring at β-catalytic sites of the FOF1-ATP synthase/F1-ATPase imprint a unique record of molecular events during the catalytic cycle of ATP synthesis/hydrolysis. This work presents a new theory of oxygen exchange and tests it on oxygen exchange data recorded on ATP hydrolysis by mitochondrial F1-ATPase (MF1). The apparent rate constant of oxygen exchange governing the intermediate Pi-HOH exchange accompanying ATP hydrolysis is determined by kinetic analysis over a ~50,000-fold range of substrate ATP concentration (0.1-5000 μM) and a corresponding ~200-fold range of reaction velocity (3.5-650 [moles of Pi/{moles of F1-ATPase}-1 s-1]). Isotopomer distributions of [18O]Pi species containing 0, 1, 2, and 3 labeled oxygen atoms predicted by the theory have been quantified and shown to be in perfect agreement with the experimental distributions over the entire range of medium ATP concentrations without employing adjustable parameters. A novel molecular mechanism of steady-state multisite ATP hydrolysis by the F1-ATPase has been proposed. Our results show that steady-state ATP hydrolysis by F1-ATPase occurs with all three sites occupied by Mg-nucleotide. The various implications arising from models of energy coupling in ATP synthesis/hydrolysis by the ATP synthase/F1-ATPase have been discussed. Current models of ATP hydrolysis by F1-ATPase, including those postulated from single-molecule data, are shown to be effectively bisite models that contradict the data. The trisite catalysis formulated by Nath's torsional mechanism of energy transduction and ATP synthesis/hydrolysis since its first appearance 25 years ago is shown to be in better accord with the experimental record. The total biochemical information on ATP hydrolysis is integrated into a consistent model by the torsional mechanism of ATP synthesis/hydrolysis and shown to elucidate the elementary chemical and mechanical events within the black box of enzyme catalysis in energy metabolism by F1-ATPase.
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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; or
- Institute of Molecular Psychiatry, Rheinische-Friedrichs-Wilhelm Universität Bonn, D–53127 Bonn, Germany
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4
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Nesterov SV, Yaguzhinsky LS. Directed proton transfer from F o to F 1 extends the multifaceted proton functions in ATP synthase. Biophys Rev 2023; 15:859-873. [PMID: 37975013 PMCID: PMC10643803 DOI: 10.1007/s12551-023-01132-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 08/30/2023] [Indexed: 11/19/2023] Open
Abstract
The role of protons in ATP synthase is typically considered to be energy storage in the form of an electrochemical potential, as well as an operating element proving rotation. However, this review emphasizes that protons also act as activators of conformational changes in F1 and as direct participants in phosphorylation reaction. The protons transferred through Fo do not immediately leave to the bulk aqueous phase, but instead provide for the formation of a pH gradient between acidifying Fo and alkalizing F1. It facilitates a directed inter-subunit proton transfer to F1, where they are used in the ATP synthesis reaction. This ensures that the enzyme activity is not limited by a lack of protons in the alkaline mitochondrial matrix or chloroplast stroma. Up to one hundred protons bind to the carboxyl groups of the F1 subunit, altering the electrical interactions between the amino acids of the enzyme. This removes the inhibition of ATP synthase caused by the electrostatic attraction of charged amino acids of the stator and rotor and also makes the enzyme more prone to conformational changes. Protonation occurs during ATP synthesis initiation and during phosphorylation, while deprotonation blocks the rotation inhibiting both synthesis and hydrolysis. Thus, protons participate in the functioning of all main components of ATP synthase molecular machine making it effectively a proton-driven electric machine. The review highlights the key role of protons as a coupling factor in ATP synthase with multifaceted functions, including charge and energy transport, torque generation, facilitation of conformational changes, and participation in the ATP synthesis reaction.
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Affiliation(s)
- Semen V. Nesterov
- Kurchatov Complex of NBICS-Technologies, National Research Center Kurchatov Institute, 123182 Moscow, Russia
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, 141701 Dolgoprudny, Russia
| | - Lev S. Yaguzhinsky
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, 141701 Dolgoprudny, Russia
- Belozersky Research Institute for Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia
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5
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Waite KA, Roelofs J. Proteasome granule formation is regulated through mitochondrial respiration and kinase signaling. J Cell Sci 2022; 135:jcs259778. [PMID: 35975718 PMCID: PMC9482347 DOI: 10.1242/jcs.259778] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 08/03/2022] [Indexed: 11/20/2022] Open
Abstract
In the yeast Saccharomyces cerevisiae, proteasomes are enriched in cell nuclei, in which they execute important cellular functions. Nutrient stress can change this localization, indicating that proteasomes respond to the metabolic state of the cell. However, the signals that connect these processes remain poorly understood. Carbon starvation triggers a reversible translocation of proteasomes to cytosolic condensates known as proteasome storage granules. Surprisingly, we observed strongly reduced levels of proteasome granules when cells had active cellular respiration prior to starvation. This suggests that the mitochondrial activity of cells is a determining factor in the response of proteasomes to carbon starvation. Consistent with this, upon inhibition of mitochondrial function, we observed that proteasomes relocalize to granules. These links between proteasomes and metabolism involve specific signaling pathways, as we identified a mitogen-activated protein kinase (MAPK) cascade that is critical to the formation of proteasome granules after respiratory growth but not following glycolytic growth. Furthermore, the yeast homolog of AMP kinase, Snf1, is important for proteasome granule formation induced by mitochondrial inhibitors, but it is dispensable for granule formation following carbon starvation. We propose a model in which mitochondrial activity promotes nuclear localization of the proteasome. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
| | - Jeroen Roelofs
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, 3901 Rainbow Blvd., HLSIC 1077, Kansas City, KS 66160-7421, USA
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6
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Samuel TA, Awobajo FO, Akinsanya TH, Oyediran HS, Egege IE, Egede CB, Timothy BO. Modulatory role of genistein on placenta and maternal bone minerals composition: further insight into its influence on pregnancy and foetal development. Biol Futur 2021; 71:223-230. [PMID: 34554508 DOI: 10.1007/s42977-020-00017-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 05/24/2020] [Indexed: 01/04/2023]
Abstract
Pregnancy is a crucial period with an increased need to supply necessary minerals for both the mother and the developing foetus and with a tendency of altering the maternal bone mineral density when there is no balance between demand and supply of these minerals. This study evaluated the influence of genistein on the maternal bone and placenta mineral composition. Pregnant rats were grouped into control, 2 mg/kg and 4 mg/kg genistein groups, dosed accordingly till sacrificed at different gestation days (GD). Body and placenta weights, right femur bone and placenta mineral composition were analysed. A significant decrease in body weight and percentage relative right femur bone weight at GD-20 was recorded in the 2-mg group with the reverse occurring in the 4-mg genistein group. The right femur bone Ca2+ and Zn2+ was reduced towards GD-20 in both 2-mg and 4-mg genistein groups. Genistein had no influence on placenta selenium and cadmium level, but significantly decreased zinc and lead level concentration as the gestation progressed towards GD-20. Copper level was increased at GD-16 at the doses used. Genistein modulated maternal bone mineral composition and placenta capability in retaining some heavy metals at various stages of pregnancy.
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Affiliation(s)
| | | | | | | | - Ikechukwu Eric Egege
- Department of Biochemistry, College of Medicine, University of Lagos, Lagos, Nigeria
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7
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Galera-Laporta L, Comerci CJ, Garcia-Ojalvo J, Süel GM. IonoBiology: The functional dynamics of the intracellular metallome, with lessons from bacteria. Cell Syst 2021; 12:497-508. [PMID: 34139162 PMCID: PMC8570674 DOI: 10.1016/j.cels.2021.04.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 04/16/2021] [Accepted: 04/28/2021] [Indexed: 12/29/2022]
Abstract
Metal ions are essential for life and represent the second most abundant constituent (after water) of any living cell. While the biological importance of inorganic ions has been appreciated for over a century, we are far from a comprehensive understanding of the functional roles that ions play in cells and organisms. In particular, recent advances are challenging the traditional view that cells maintain constant levels of ion concentrations (ion homeostasis). In fact, the ionic composition (metallome) of cells appears to be purposefully dynamic. The scientific journey that started over 60 years ago with the seminal work by Hodgkin and Huxley on action potentials in neurons is far from reaching its end. New evidence is uncovering how changes in ionic composition regulate unexpected cellular functions and physiology, especially in bacteria, thereby hinting at the evolutionary origins of the dynamic metallome. It is an exciting time for this field of biology, which we discuss and refer to here as IonoBiology.
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Affiliation(s)
- Leticia Galera-Laporta
- Molecular Biology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Colin J Comerci
- Molecular Biology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jordi Garcia-Ojalvo
- Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona 08003, Spain
| | - Gürol M Süel
- Molecular Biology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA; San Diego Center for Systems Biology, University of California, San Diego, La Jolla, CA 92093- 0380, USA; Center for Microbiome Innovation, University of California, San Diego, La Jolla, CA 92093-0380, USA.
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8
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Ohtsuka H, Kobayashi M, Shimasaki T, Sato T, Akanuma G, Kitaura Y, Otsubo Y, Yamashita A, Aiba H. Magnesium depletion extends fission yeast lifespan via general amino acid control activation. Microbiologyopen 2021; 10:e1176. [PMID: 33970532 PMCID: PMC8088111 DOI: 10.1002/mbo3.1176] [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: 12/30/2020] [Revised: 02/09/2021] [Accepted: 02/11/2021] [Indexed: 12/31/2022] Open
Abstract
Nutrients including glucose, nitrogen, sulfur, zinc, and iron are involved in the regulation of chronological lifespan (CLS) of yeast, which serves as a model of the lifespan of differentiated cells of higher organisms. Herein, we show that magnesium (Mg2+) depletion extends CLS of the fission yeast Schizosaccharomyces pombe through a mechanism involving the Ecl1 gene family. We discovered that ecl1+ expression, which extends CLS, responds to Mg2+ depletion. Therefore, we investigated the underlying intracellular responses. In amino acid auxotrophic strains, Mg2+ depletion robustly induces ecl1+ expression through the activation of the general amino acid control (GAAC) pathway—the equivalent of the amino acid response of mammals. Polysome analysis indicated that the expression of Ecl1 family genes was required for regulating ribosome amount when cells were starved, suggesting that Ecl1 family gene products control the abundance of ribosomes, which contributes to longevity through the activation of the evolutionarily conserved GAAC pathway. The present study extends our understanding of the cellular response to Mg2+ depletion and its influence on the mechanism controlling longevity.
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Affiliation(s)
- Hokuto Ohtsuka
- Laboratory of Molecular Microbiology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Japan
| | - Mikuto Kobayashi
- Laboratory of Molecular Microbiology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Japan
| | - Takafumi Shimasaki
- Laboratory of Molecular Microbiology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Japan
| | - Teppei Sato
- Laboratory of Molecular Microbiology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Japan
| | - Genki Akanuma
- Department of Life Science, College of Sciences, Rikkyo University, Tokyo, Japan.,Department of Life Science, Graduate School of Science, Gakushuin University, Tokyo, Japan
| | - Yasuyuki Kitaura
- Laboratory of Nutritional Biochemistry, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Yoko Otsubo
- Laboratory of Cell Responses, National Institute for Basic Biology, Okazaki, Japan.,National Institute for Fusion Science, Toki, Japan.,Center for Novel Science Initiatives, National Institutes of Natural Sciences, Okazaki, Japan
| | - Akira Yamashita
- Laboratory of Cell Responses, National Institute for Basic Biology, Okazaki, Japan.,Center for Novel Science Initiatives, National Institutes of Natural Sciences, Okazaki, Japan.,Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies, Okazaki, Japan
| | - Hirofumi Aiba
- Laboratory of Molecular Microbiology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Japan
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9
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Sassani M, Alix JJ, McDermott CJ, Baster K, Hoggard N, Wild JM, Mortiboys HJ, Shaw PJ, Wilkinson ID, Jenkins TM. Magnetic resonance spectroscopy reveals mitochondrial dysfunction in amyotrophic lateral sclerosis. Brain 2021; 143:3603-3618. [PMID: 33439988 DOI: 10.1093/brain/awaa340] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 07/16/2020] [Accepted: 08/08/2020] [Indexed: 12/16/2022] Open
Abstract
Mitochondrial dysfunction is postulated to be central to amyotrophic lateral sclerosis (ALS) pathophysiology. Evidence comes primarily from disease models and conclusive data to support bioenergetic dysfunction in vivo in patients is currently lacking. This study is the first to assess mitochondrial dysfunction in brain and muscle in individuals living with ALS using 31P-magnetic resonance spectroscopy (MRS), the modality of choice to assess energy metabolism in vivo. We recruited 20 patients and 10 healthy age and gender-matched control subjects in this cross-sectional clinico-radiological study. 31P-MRS was acquired from cerebral motor regions and from tibialis anterior during rest and exercise. Bioenergetic parameter estimates were derived including: ATP, phosphocreatine, inorganic phosphate, adenosine diphosphate, Gibbs free energy of ATP hydrolysis (ΔGATP), phosphomonoesters, phosphodiesters, pH, free magnesium concentration, and muscle dynamic recovery constants. Linear regression was used to test for associations between brain data and clinical parameters (revised amyotrophic functional rating scale, slow vital capacity, and upper motor neuron score) and between muscle data and clinico-neurophysiological measures (motor unit number and size indices, force of contraction, and speed of walking). Evidence for primary dysfunction of mitochondrial oxidative phosphorylation was detected in the brainstem where ΔGATP and phosphocreatine were reduced. Alterations were also detected in skeletal muscle in patients where resting inorganic phosphate, pH, and phosphomonoesters were increased, whereas resting ΔGATP, magnesium, and dynamic phosphocreatine to inorganic phosphate recovery were decreased. Phosphocreatine in brainstem correlated with respiratory dysfunction and disability; in muscle, energy metabolites correlated with motor unit number index, muscle power, and speed of walking. This study provides in vivo evidence for bioenergetic dysfunction in ALS in brain and skeletal muscle, which appears clinically and electrophysiologically relevant. 31P-MRS represents a promising technique to assess the pathophysiology of mitochondrial function in vivo in ALS and a potential tool for future clinical trials targeting bioenergetic dysfunction.
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Affiliation(s)
- Matilde Sassani
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, UK
| | - James J Alix
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, UK
| | - Christopher J McDermott
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, UK
| | - Kathleen Baster
- Statistical Service Unit, University of Sheffield, Sheffield, UK
| | - Nigel Hoggard
- Academic Unit of Radiology, University of Sheffield, Sheffield, UK
| | - Jim M Wild
- Academic Unit of Radiology, University of Sheffield, Sheffield, UK
| | - Heather J Mortiboys
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, UK
| | - Pamela J Shaw
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, UK
| | - Iain D Wilkinson
- Academic Unit of Radiology, University of Sheffield, Sheffield, UK
| | - Thomas M Jenkins
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, UK
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10
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Xu D, Kleineberg C, Vidaković-Koch T, Wegner SV. Multistimuli Sensing Adhesion Unit for the Self-Positioning of Minimal Synthetic Cells. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e2002440. [PMID: 32776424 DOI: 10.1002/smll.202002440] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 06/16/2020] [Indexed: 06/11/2023]
Abstract
Cells have the ability to sense different environmental signals and position themselves accordingly in order to support their survival. Introducing analogous capabilities to the bottom-up assembled minimal synthetic cells is an important step for their autonomy. Here, a minimal synthetic cell which combines a multistimuli sensitive adhesion unit with an energy conversion module is reported, such that it can adhere to places that have the right environmental parameters for ATP production. The multistimuli sensitive adhesion unit senses light, pH, oxidative stress, and the presence of metal ions and can regulate the adhesion of synthetic cells to substrates in response to these stimuli following a chemically coded logic. The adhesion unit is composed of the light and redox responsive protein interaction of iLID and Nano and the pH sensitive and metal ion mediated binding of protein His-tags to Ni2+ -NTA complexes. Integration of the adhesion unit with a light to ATP conversion module into one synthetic cell allows it to adhere to places under blue light illumination, non-oxidative conditions, at neutral pH and in the presence of metal ions, which are the right conditions to synthesize ATP. Thus, the multistimuli responsive adhesion unit allows synthetic cells to self-position and execute their functions.
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Affiliation(s)
- Dongdong Xu
- Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz, 55128, Germany
| | - Christin Kleineberg
- Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstraße 1, Magdeburg, 39106, Germany
| | - Tanja Vidaković-Koch
- Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstraße 1, Magdeburg, 39106, Germany
| | - Seraphine V Wegner
- Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz, 55128, Germany
- Institute of Physiological Chemistry and Pathobiochemistry, University of Münster, Waldeyerstraße 15, Münster, 48149, Germany
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11
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Mehta R, Singh J, Nath S. Time-Resolved Oxygen Exchange Measurements Offer Novel Mechanistic Insights into Enzyme-Catalyzed ATP Synthesis during Photophosphorylation. J Phys Chem B 2020; 124:5139-5148. [PMID: 32484674 DOI: 10.1021/acs.jpcb.0c03505] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Techniques to probe molecular mechanistic events occurring at a single catalytic site of multi-subunit enzymes in real time are few and are still under development. Here time-resolved information is extracted from measurements of the extensive oxygen exchange that occurs at an intermediate stage of adenosine triphosphate (ATP) synthesis during photophosphorylation by chloroplast thylakoids. A stochastic process-based approach for modeling exchange reactions is formulated that provides a physical basis for the kinetic theory. Compatible with the assumptions made in such a model of randomness, the formulation is shown to lead to a Poisson-type theory that enables kinetic analysis of oxygen-exchange data and offers novel physical insights. Parameters such as the apparent rate constant of exchange and the average lifetime of the exchanging intermediates during the synthesis of ATP by the chloroplast F1FO-ATP synthase have been determined over a 5000-fold range of ADP concentration. Experimental isotopomer distributions of [18O]ATP at high (0.5 mM), intermediate (10 μM), and low (0.2 μM) ADP concentrations have been quantified and compared to expected distributions from the theory. The observed distributions are shown to closely match the predicted distributions. A wealth of novel mechanistic insights such as the number of sites/pathways of oxygen exchange, the order of substrate binding steps at the enzyme catalytic site, and regulation of the process of energy coupling have been deduced, and the results are interpreted with the help of available high-resolution X-ray structures. The various biological implications for models of energy coupling have been discussed. Permutation of oxygen ligands about the phosphorus center is proposed as a possible and general but not well-recognized mechanism for oxygen exchange that is consistent with the principal results of this work, and several suggestions for future research are offered.
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Affiliation(s)
- Ritu Mehta
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Jitendra Singh
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Sunil Nath
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
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12
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Nutritional Deficiencies, Bariatric Surgery, and Serum Homocysteine Level: Review of Current Literature. Obes Surg 2020; 29:3735-3742. [PMID: 31471768 DOI: 10.1007/s11695-019-04100-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Obesity is currently one of the biggest global health problems. In the case of severe obesity, bariatric surgeries are considered to be the most important method of treatment. The 2 most commonly performed bariatric surgery procedures include Roux-en-Y gastric bypass and sleeve gastrectomy. However, these methods are not free from complications, and the most common ones (moderately long or long term) are micronutrient deficiencies. The deficiency of vitamins B6, B12, and folic acid as cofactors of the folate cycle contributes to the development of hyperhomocysteinemia. It seems that apart from nutritional factors, there are other aspects that have a significant influence on the concentration of homocysteine in blood, such as the type of conducted bariatric surgery, the post-surgical concentration of betaine and creatinine, and the clearance of methionine (i.e., the mutations of the gene that encodes the MTHFR reductase as well as other genes associated with the process of methylation, e.g., methionine synthase). Their presence might be one of the causes of the increased concentration of homocysteine after surgery despite the fact that patients take vitamin-mineral supplementation.
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Cheung MM, DeLuccia R, Ramadoss RK, Aljahdali A, Volpe SL, Shewokis PA, Sukumar D. Low dietary magnesium intake alters vitamin D-parathyroid hormone relationship in adults who are overweight or obese. Nutr Res 2019; 69:82-93. [PMID: 31675537 DOI: 10.1016/j.nutres.2019.08.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 05/16/2019] [Accepted: 08/02/2019] [Indexed: 01/10/2023]
Abstract
Vitamin D metabolism is dependent on magnesium (Mg) as a cofactor; therefore, poor Mg status may alter the relationship between vitamin D metabolite serum 25-hydroxyvitamin D (s25OHD) and serum parathyroid hormone (sPTH). We hypothesized that low dietary Mg intake may alter sPTH response to s25OHD in a population with excess body weight, thereby leading to a worsening of cardiometabolic health. To explore this hypothesis, we conducted a cross-sectional study on adults who were either overweight or obese (owt/ob). Dietary Mg intake was measured using a Mg food frequency questionnaire (MgFFQ). Body composition information was measured using Dual Energy X-ray Absorptiometry (DXA). Blood samples were obtained for all biochemical analyses. A total of 57 participants, 22 to 65 years of age, with a body mass index between 25 to 45 kg/m2 were divided into 3 groups, according to dietary Mg intake percentiles (Low Mg Group = <33 percentile, Medium Mg Group = 33 to 66 percentile, High Mg Group = >66 percentile). Higher s25OHD was negatively associated with lower sPTH in the High Mg Intake group (r = -0.472, P = .041), but not in other groups. A positive relationship between s25OHD and serum high-molecular weight adiponectin concentrations was observed in the High Mg Group (r = 0.532, r = 0.022), but not in other groups. Serum Interleukin-6 concentrations were negatively associated with s25OHD (r = -0.316, P = .017) for the entire study group. Based on these results, our study demonstrated that a low dietary Mg intake may alter PTH response to 25OHD.
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Affiliation(s)
- May M Cheung
- Department of Nutrition Sciences, College of Nursing and Health Professions, Drexel University, 1601 Cherry St., Philadelphia, PA 19102.
| | - Rosemary DeLuccia
- Department of Nutrition Sciences, College of Nursing and Health Professions, Drexel University, 1601 Cherry St., Philadelphia, PA 19102.
| | - Rohit Kumar Ramadoss
- Department of Culinary Arts and Food Sciences, College of Nursing and Health Professions, Drexel University, 1601 Cherry St., Philadelphia, PA 19102.
| | - Abeer Aljahdali
- Department of Nutrition Sciences, College of Nursing and Health Professions, Drexel University, 1601 Cherry St., Philadelphia, PA 19102.
| | - Stella L Volpe
- Department of Nutrition Sciences, College of Nursing and Health Professions, Drexel University, 1601 Cherry St., Philadelphia, PA 19102.
| | - Patricia A Shewokis
- Department of Nutrition Sciences, College of Nursing and Health Professions, School of Biomedical Engineering, Science and Health System, Drexel University, 1601 Cherry St., Philadelphia, PA 19102.
| | - Deeptha Sukumar
- Department of Nutrition Sciences, College of Nursing and Health Professions, Drexel University, 1601 Cherry St., Philadelphia, PA 19102.
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14
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Tomas C, Lodge TA, Potter M, Elson JL, Newton JL, Morten KJ. Assessing cellular energy dysfunction in CFS/ME using a commercially available laboratory test. Sci Rep 2019; 9:11464. [PMID: 31391529 PMCID: PMC6686017 DOI: 10.1038/s41598-019-47966-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 07/11/2019] [Indexed: 12/26/2022] Open
Abstract
The mitochondrial energy score (MES) protocol, developed by the Myhill group, is marketed as a diagnostic test for chronic fatigue syndrome/Myalgic Encephalomyelitis (CFS/ME). This study assessed the reliability and reproducibility of the test, currently provided by private clinics, to assess its potential to be developed as an NHS accredited laboratory test. We replicated the MES protocol using neutrophils and peripheral blood mononuclear cells (PBMCs) from CFS/ME patients (10) and healthy controls (13). The protocol was then repeated in PBMCs and neutrophils from healthy controls to investigate the effect of delayed sample processing time used by the Myhill group. Experiments using the established protocol showed no differences between CFS/ME patients and healthy controls in any of the components of the MES (p ≥ 0.059). Delaying blood sample processing by 24 hours (well within the 72 hour time frame quoted by the Myhill group) significantly altered many of the parameters used to calculate the MES in both neutrophils and PBMCs. The MES test does not have the reliability and reproducibility required of a diagnostic test and therefore should not currently be offered as a diagnostic test for CFS/ME. The differences observed by the Myhill group may be down to differences in sample processing time between cohorts.
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Affiliation(s)
- Cara Tomas
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Tiffany A Lodge
- Nuffield Department of Women's and Reproductive Health, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Michelle Potter
- Nuffield Department of Women's and Reproductive Health, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Joanna L Elson
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
- Centre for Human Metabolomics, North-West University, Potchefstroom, South Africa
| | - Julia L Newton
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK.
- Newcastle upon Tyne Hospitals, NHS Foundation Trust, Newcastle upon Tyne, UK.
| | - Karl J Morten
- Nuffield Department of Women's and Reproductive Health, University of Oxford, John Radcliffe Hospital, Oxford, UK
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15
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Santra B, Narayanan RS, Kalita P, Kumar V, Mandal D, Gupta V, Zimmer M, Huch V, Chandrasekhar V, Scheschkewitz D, Schulzke C, Jana A. Modulation of the nuclearity of molecular Mg(ii)-phosphates: solid-state structural change involving coordinating solvents. Dalton Trans 2019; 48:8853-8860. [PMID: 31139786 DOI: 10.1039/c9dt00687g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Herein, we report the synthesis and molecular structures of various magnesium(ii)-phosphate monoesters. By using a bulky aryl substituted phosphate monoester, ArOPO3H2 (Ar = 2,6-(CHPh2)2-4-tBu-C6H2), we have reproducibly assembled mono-, di-, tetra- (cage and ring), hexa-, and polynuclear magnesium(ii)-phosphate monoesters. Interestingly, the hexanuclear magnesium(ii)-phosphate monoester encapsulates an open-cage dodecanuclear water cluster.
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Affiliation(s)
- Biswajit Santra
- Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad-500107, Telangana, India.
| | | | - Pankaj Kalita
- School of Chemical Sciences, National Institute of Science Education and Research, HBNI, Bhubaneswar-752050, India
| | - Vierandra Kumar
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, India.
| | - Debdeep Mandal
- Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad-500107, Telangana, India.
| | - Vivek Gupta
- Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad-500107, Telangana, India.
| | - Michael Zimmer
- Krupp-Chair of General and Inorganic Chemistry, Saarland University, 66123 Saarbrücken, Germany.
| | - Volker Huch
- Krupp-Chair of General and Inorganic Chemistry, Saarland University, 66123 Saarbrücken, Germany.
| | - Vadapalli Chandrasekhar
- Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad-500107, Telangana, India. and Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, India.
| | - David Scheschkewitz
- Krupp-Chair of General and Inorganic Chemistry, Saarland University, 66123 Saarbrücken, Germany.
| | - Carola Schulzke
- Institut für Biochemie, Universität Greifswald, Felix-Hausdorff-Straße 4, D-17487, Greifswald, Germany.
| | - Anukul Jana
- Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad-500107, Telangana, India.
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16
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Martínez Sánchez AH, Omidi M, Wurlitzer M, Fuh MM, Feyerabend F, Schlüter H, Willumeit-Römer R, Luthringer BJ. Proteome analysis of human mesenchymal stem cells undergoing chondrogenesis when exposed to the products of various magnesium-based materials degradation. Bioact Mater 2019; 4:168-188. [PMID: 31049466 PMCID: PMC6482314 DOI: 10.1016/j.bioactmat.2019.04.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 03/20/2019] [Accepted: 04/09/2019] [Indexed: 12/23/2022] Open
Abstract
Treatment of physeal fractures (15%–30% of all paediatric fractures) remains a challenge as in approximately 10% of the cases, significant growth disturbance may occur. Bioresorbable Magnesium-based implants represent a strategy to minimize damage (i.e., load support until bone healing without second surgery). Nevertheless, the absence of harmful effects of magnesium-implants and their degradation products on the growth plate should be confirmed. Here, the proteome of human mesenchymal stem cells undergoing chondrogenesis was evaluated when exposed to the products of various Magnesium-based materials degradation. The results of this study indicate that the materials induced regulation of proteins associated with cell chondrogenesis and cartilage formation, which should be beneficial for cartilage regeneration. Degradation products from Mg-based materials generated changes in protein expression. Relevant proteins involved in cartilage formation were upregulated. Potential application of especially Pure-Mg and Mg-10Gd for cartilage regeneration.
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Affiliation(s)
- Adela Helvia Martínez Sánchez
- Division of Metallic Biomaterials, Institute of Material Research, Helmholtz-Zentrum Geesthacht, Max Planck Strasse 1, 21502, Geesthacht, Germany
| | - Maryam Omidi
- Institute of Clinical Chemistry and Laboratory Medicine, Mass Spectrometric Proteomics, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
| | - Marcus Wurlitzer
- Institute of Clinical Chemistry and Laboratory Medicine, Mass Spectrometric Proteomics, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
| | - Marceline Manka Fuh
- Institute of Clinical Chemistry and Laboratory Medicine, Mass Spectrometric Proteomics, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
| | - Frank Feyerabend
- Division of Metallic Biomaterials, Institute of Material Research, Helmholtz-Zentrum Geesthacht, Max Planck Strasse 1, 21502, Geesthacht, Germany
| | - Hartmut Schlüter
- Institute of Clinical Chemistry and Laboratory Medicine, Mass Spectrometric Proteomics, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
| | - Regine Willumeit-Römer
- Division of Metallic Biomaterials, Institute of Material Research, Helmholtz-Zentrum Geesthacht, Max Planck Strasse 1, 21502, Geesthacht, Germany
| | - Bérengère J.C. Luthringer
- Division of Metallic Biomaterials, Institute of Material Research, Helmholtz-Zentrum Geesthacht, Max Planck Strasse 1, 21502, Geesthacht, Germany
- Corresponding author.
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Thangarasa T, Gotfrit J, Goodwin RA, Tang PA, Clemons M, Imbulgoda A, Vickers MM. Epidermal growth factor receptor inhibitor-induced hypomagnesemia: a survey of practice patterns among Canadian gastrointestinal medical oncologists. ACTA ACUST UNITED AC 2019; 26:e162-e166. [PMID: 31043822 DOI: 10.3747/co.26.4591] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Background The optimal management of hypomagnesemia (hMg) induced by epidermal growth factor receptor inhibitors (egfris) for advanced colorectal cancer is unclear. We surveyed gastrointestinal medical oncologists in Canada to determine practice patterns for the management of egfri-induced hMg. Methods Based on distribution lists from the Eastern Canadian Colorectal Cancer Consensus Conference and the Western Canadian Gastrointestinal Cancer Consensus Conference, medical oncologists were invited to participate in an online questionnaire between November 2013 and February 2014. Results From the 104 eligible physicians, 40 responses were obtained (38.5%). Panitumumab was more commonly prescribed than cetuximab by 70% of respondents, with 25% prescribing cetuximab and panitumumab equally. Most respondents obtain a serum magnesium level before initiating a patient on an egfri (92.5%) and before every treatment (90%). Most use a reactive strategy for magnesium supplementation (90%) and, when using supplementation, favour intravenous (iv) alone (40%) or iv and oral (45%) dosing. Magnesium sulfate was used for iv replacement, and the most common oral strategies were magnesium oxide (36.4%) and magnesium rougier (18.2%). Under the reactive strategy, intervention occurred at hMg grade 1 (70.3%) or grade 2 (27%). Of the survey respondents, 45% felt that 1-5 of their patients have ever developed symptoms attributable to hMg, and 35% have had to interrupt egfri therapy because of this toxicity, most commonly at grade 3 (30%) or grade 4 (45%) hMg. The most important question about egfri-induced hMg was its relevance to clinical outcomes (45%) and its symptoms (37.5%). Conclusions In Canada, various strategies are used in the management of egfri-induced hMg, including prophylactic and reactive approaches that incorporate iv, oral, or a combination of iv and oral supplementation. Clinicians are concerned about the effect of hMg on clinical outcomes and about the symptoms that patients experience as a result of this toxicity.
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Affiliation(s)
- T Thangarasa
- The Ottawa Hospital Cancer Centre and University of Ottawa, Ottawa, ON
| | - J Gotfrit
- The Ottawa Hospital Cancer Centre and University of Ottawa, Ottawa, ON
| | - R A Goodwin
- The Ottawa Hospital Cancer Centre and University of Ottawa, Ottawa, ON
| | - P A Tang
- Tom Baker Cancer Centre and University of Calgary, Calgary, AB
| | - M Clemons
- The Ottawa Hospital Cancer Centre and University of Ottawa, Ottawa, ON
| | - A Imbulgoda
- Jack Ady Cancer Centre and Alberta Health Services, Lethbridge, AB
| | - M M Vickers
- The Ottawa Hospital Cancer Centre and University of Ottawa, Ottawa, ON
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18
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Zoroddu MA, Aaseth J, Crisponi G, Medici S, Peana M, Nurchi VM. The essential metals for humans: a brief overview. J Inorg Biochem 2019; 195:120-129. [PMID: 30939379 DOI: 10.1016/j.jinorgbio.2019.03.013] [Citation(s) in RCA: 413] [Impact Index Per Article: 82.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 02/25/2019] [Accepted: 03/18/2019] [Indexed: 12/11/2022]
Abstract
The human body needs about 20 essential elements in order to function properly and among them, for certain, 10 are metal elements, though for every metal we do need, there is another one in our body we could do without it. Until about 1950 poor attention was given to the so-called "inorganic elements" and while researches on "organic elements" (C, N, O and H) and organic compounds were given high priority, studies on essential inorganic elements were left aside. Base on current knowledge it is ascertained today that metals such as Na, K, Mg, Ca, Fe, Mn, Co, Cu, Zn and Mo are essential elements for life and our body must have appropriate amounts of them. Here a brief overview to highlight their importance and current knowledge about their essentiality.
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Affiliation(s)
| | - Jan Aaseth
- Research Department, Innlandet Hospital, Brumunddal, Norway; Inland Norway University of Applied Sciences, Elverum, Norway
| | - Guido Crisponi
- Department of Life and Environmental Sciences, University of Cagliari, Italy
| | - Serenella Medici
- Department of Chemistry and Pharmacy, University of Sassari, Italy
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19
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Lebre PH, Cowan DA. Genomics of Alkaliphiles. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2019; 172:135-155. [PMID: 30796503 DOI: 10.1007/10_2018_83] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Alkalinicity presents a challenge for life due to a "reversed" proton gradient that is unfavourable to many bioenergetic processes across the membranes of microorganisms. Despite this, many bacteria, archaea, and eukaryotes, collectively termed alkaliphiles, are adapted to life in alkaline ecosystems and are of great scientific and biotechnological interest due to their niche specialization and ability to produce highly stable enzymes. Advances in next-generation sequencing technologies have propelled not only the genomic characterization of many alkaliphilic microorganisms that have been isolated from nature alkaline sources but also our understanding of the functional relationships between different taxa in microbial communities living in these ecosystems. In this review, we discuss the genetics and molecular biology of alkaliphiles from an "omics" point of view, focusing on how metagenomics and transcriptomics have contributed to our understanding of these extremophiles. Graphical Abstract.
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Affiliation(s)
- Pedro H Lebre
- Centre for Microbial Ecology and Genomics, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
| | - Don A Cowan
- Centre for Microbial Ecology and Genomics, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa.
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20
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van Niekerk G, Mitchell M, Engelbrecht AM. Bone resorption: supporting immunometabolism. Biol Lett 2018; 14:rsbl.2017.0783. [PMID: 29491030 DOI: 10.1098/rsbl.2017.0783] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 02/01/2018] [Indexed: 12/21/2022] Open
Abstract
Activation of the immune system is associated with an increase in the breakdown of various peripheral tissues, including bone. Despite the widely appreciated role of inflammatory mediators in promoting bone resorption, the functional value behind this process is not completely understood. Recent advances in the field of immunometabolism have highlighted the metabolic reprogramming that takes place in activated immune cells. It is now believed that the breakdown of peripheral tissue provides metabolic substrates to fuel metabolic anabolism in activated immune cells. We argue that phosphate, liberated by bone resorption, plays an indispensable role in sustaining immune cell metabolism. The liberated phosphate is then incorporated into macromolecules such as nucleotides and phospholipids, and is also used for the phosphorylation of metabolites (e.g. glycolytic intermediates). In addition, magnesium, also liberated during the breakdown of bone, is an essential cofactor required by various metabolic enzymes which are upregulated in activated immune cells. Finally, calcium activates various additional molecules involved in immune cell migration. Taken together, these factors suggest a key role for bone resorption during infection.
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Affiliation(s)
- Gustav van Niekerk
- Department of Physiological Sciences, Stellenbosch University, Stellenbosch, South Africa
| | - Megan Mitchell
- Department of Physiological Sciences, Stellenbosch University, Stellenbosch, South Africa
| | - Anna-Mart Engelbrecht
- Department of Physiological Sciences, Stellenbosch University, Stellenbosch, South Africa
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21
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22
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Duboué-Dijon E, Mason PE, Fischer HE, Jungwirth P. Hydration and Ion Pairing in Aqueous Mg2+ and Zn2+ Solutions: Force-Field Description Aided by Neutron Scattering Experiments and Ab Initio Molecular Dynamics Simulations. J Phys Chem B 2017; 122:3296-3306. [DOI: 10.1021/acs.jpcb.7b09612] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Elise Duboué-Dijon
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 2, 16610 Prague 6, Czech Republic
| | - Philip E. Mason
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 2, 16610 Prague 6, Czech Republic
| | - Henry E. Fischer
- Institut Laue-Langevin, 71 Avenue des Martyrs, CS 20156, 38042 Grenoble Cedex 9, France
| | - Pavel Jungwirth
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 2, 16610 Prague 6, Czech Republic
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Rigo J, Pieltain C, Christmann V, Bonsante F, Moltu SJ, Iacobelli S, Marret S. Serum Magnesium Levels in Preterm Infants Are Higher Than Adult Levels: A Systematic Literature Review and Meta-Analysis. Nutrients 2017; 9:nu9101125. [PMID: 29035309 PMCID: PMC5691741 DOI: 10.3390/nu9101125] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 09/06/2017] [Accepted: 10/07/2017] [Indexed: 12/20/2022] Open
Abstract
Magnesium (Mg) is an essential mineral in the body, impacting the synthesis of biomacromolecules, bone matrix development, energy production, as well as heart, nerve, and muscle function. Although the importance of Mg is evident, reference values for serum Mg (sMg) in pediatric patients (more specifically, in neonates) are not well established. This systematic literature review and meta-analysis (using 47 eligible studies) aims to quantify normal and tolerable ranges of sMg concentrations during the neonatal period and to highlight the factors influencing Mg levels and the importance of regulating sMg levels during pregnancy and birth. In newborns without Mg supplementation during pregnancy, magnesium levels at birth (0.76 (95% CI: 0.52, 0.99) mmol/L) were similar to that of mothers during pregnancy (0.74 (95% CI: 0.43, 1.04) mmol/L), but increased during the first week of life (0.91 (95% CI: 0.55, 1.26) mmol/L) before returning to adult levels. This pattern was also seen in newborns with Mg supplementation during pregnancy, where the average was 1.29 (95% CI: 0.50, 2.08) mmol/L at birth and 1.44 (95% CI: 0.61, 2.27) mmol/L during the first week of life. Factors influencing these levels include prenatal Mg supplementation, gestational age, birth weight, renal maturity/function, and postnatal Mg intake. Elevated Mg levels (>2.5 mmol/L) have been associated with an increased risk of mortality, admission into intensive care, hypotonia, hypotension, and respiratory depression but sMg concentrations up to 2.0 mmol/L appear to be well tolerated in neonates, requiring adequate survey and minimal intervention.
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Affiliation(s)
- Jacques Rigo
- Department of Neonatology, Université de Liège, CHR Citadelle, 4000 Liège, Belgium.
| | - Catherine Pieltain
- Department of Neonatology, Université de Liège, CHR Citadelle, 4000 Liège, Belgium.
| | - Viola Christmann
- Radboudumc Amalia Children's Hospital, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands.
| | - Francesco Bonsante
- Centre d'Etudes Périnatales de l'Océan Indien (EA 7388), CHU La Réunion-Site Sud Saint Pierre, BP 350 97448 Saint Pierre CEDEX, France.
- Réanimation Néonatale et Pédiatrique, Néonatologie, CHU La Réunion-Site Sud Saint Pierre, BP 350 97448 Saint Pierre CEDEX, France.
| | - Sissel J Moltu
- Department of Neonatal Intensive Care, Oslo University Hospital, 0318 Oslo, Norway.
| | - Silvia Iacobelli
- Centre d'Etudes Périnatales de l'Océan Indien (EA 7388), CHU La Réunion-Site Sud Saint Pierre, BP 350 97448 Saint Pierre CEDEX, France.
- Réanimation Néonatale et Pédiatrique, Néonatologie, CHU La Réunion-Site Sud Saint Pierre, BP 350 97448 Saint Pierre CEDEX, France.
| | - Stéphane Marret
- Department of Neonatal Pediatrics and Intensive Care and Neuropediatrics, Rouen University Hospital, and INSERM, Laboratoire NeoVasc ERI28, Normandy University, 76000 Rouen, France.
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Schwalfenberg GK, Genuis SJ. The Importance of Magnesium in Clinical Healthcare. SCIENTIFICA 2017; 2017:4179326. [PMID: 29093983 PMCID: PMC5637834 DOI: 10.1155/2017/4179326] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 06/25/2017] [Accepted: 08/07/2017] [Indexed: 05/12/2023]
Abstract
The scientific literature provides extensive evidence of widespread magnesium deficiency and the potential need for magnesium repletion in diverse medical conditions. Magnesium is an essential element required as a cofactor for over 300 enzymatic reactions and is thus necessary for the biochemical functioning of numerous metabolic pathways. Inadequate magnesium status may impair biochemical processes dependent on sufficiency of this element. Emerging evidence confirms that nearly two-thirds of the population in the western world is not achieving the recommended daily allowance for magnesium, a deficiency problem contributing to various health conditions. This review assesses available medical and scientific literature on health issues related to magnesium. A traditional integrated review format was utilized for this study. Level I evidence supports the use of magnesium in the prevention and treatment of many common health conditions including migraine headache, metabolic syndrome, diabetes, hyperlipidemia, asthma, premenstrual syndrome, preeclampsia, and various cardiac arrhythmias. Magnesium may also be considered for prevention of renal calculi and cataract formation, as an adjunct or treatment for depression, and as a therapeutic intervention for many other health-related disorders. In clinical practice, optimizing magnesium status through diet and supplementation appears to be a safe, useful, and well-documented therapy for several medical conditions.
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Affiliation(s)
- Gerry K. Schwalfenberg
- Department of Family Medicine, University of Alberta, No. 301, 9509-156 Street, Edmonton, AB, Canada T5P 4J5
| | - Stephen J. Genuis
- Faculty of Medicine, University of Alberta, 2935-66 Street, Edmonton, AB, Canada T6K 4C1
- University of Calgary, Calgary, AB, Canada
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25
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Chen ZC, Peng WT, Li J, Liao H. Functional dissection and transport mechanism of magnesium in plants. Semin Cell Dev Biol 2017; 74:142-152. [PMID: 28822768 DOI: 10.1016/j.semcdb.2017.08.005] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 07/24/2017] [Accepted: 08/01/2017] [Indexed: 01/15/2023]
Abstract
Magnesium (Mg) is the second most abundant cation in plants, and, as such, is involved in numerous physiological and biochemical processes, including photosynthesis, enzyme activation, and synthesis of nucleic acids and proteins. Due to its relatively small ionic radius and large hydrated radius, Mg binds weakly to soil and root surfaces, and thereby is easily leached from soil. Mg deficiency not only affects crop productivity and quality, but also contributes to numerous chronic human diseases. Therefore, Mg nutrition in plants is an important issue in nutrition and food security. To acquire and maintain high concentrations of Mg, plants have evolved highly-efficient systems for Mg uptake, storage and translocation. Advances in the understanding of fundamental principles of Mg nutrition and physiology are required in order to improve Mg nutrient management, Mg stress diagnosis, and genetic marker assisted breeding efforts. The aims of this review are to highlight physiological and molecular mechanisms underlying Mg biological functions and to summarize recent developments in the elucidation of Mg transport systems in plants.
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Affiliation(s)
- Zhi Chang Chen
- Root Biology Center, Fujian Agriculture and Forestry University, Fujian, Fuzhou 350002, China.
| | - Wen Ting Peng
- Root Biology Center, Fujian Agriculture and Forestry University, Fujian, Fuzhou 350002, China; College of Resources and Environment, Fujian Agriculture and Forestry University, Fujian, Fuzhou 350002, China
| | - Jian Li
- Root Biology Center, Fujian Agriculture and Forestry University, Fujian, Fuzhou 350002, China; College of Life Sciences, Fujian Agriculture and Forestry University, Fujian, Fuzhou 350002, China
| | - Hong Liao
- Root Biology Center, Fujian Agriculture and Forestry University, Fujian, Fuzhou 350002, China
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Tomita A, Zhang M, Jin F, Zhuang W, Takeda H, Maruyama T, Osawa M, Hashimoto KI, Kawasaki H, Ito K, Dohmae N, Ishitani R, Shimada I, Yan Z, Hattori M, Nureki O. ATP-dependent modulation of MgtE in Mg 2+ homeostasis. Nat Commun 2017; 8:148. [PMID: 28747715 PMCID: PMC5529423 DOI: 10.1038/s41467-017-00082-w] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 05/26/2017] [Indexed: 11/09/2022] Open
Abstract
Magnesium is an essential ion for numerous physiological processes. MgtE is a Mg2+ selective channel involved in the maintenance of intracellular Mg2+ homeostasis, whose gating is regulated by intracellular Mg2+ levels. Here, we report that ATP binds to MgtE, regulating its Mg2+-dependent gating. Crystal structures of MgtE–ATP complex show that ATP binds to the intracellular CBS domain of MgtE. Functional studies support that ATP binding to MgtE enhances the intracellular domain affinity for Mg2+ within physiological concentrations of this divalent cation, enabling MgtE to function as an in vivo Mg2+ sensor. ATP dissociation from MgtE upregulates Mg2+ influx at both high and low intracellular Mg2+ concentrations. Using site-directed mutagenesis and structure based-electrophysiological and biochemical analyses, we identify key residues and main structural changes involved in the process. This work provides the molecular basis of ATP-dependent modulation of MgtE in Mg2+ homeostasis. MgtE is an Mg2+ transporter involved in Mg2+ homeostasis. Here, the authors report that ATP regulates the Mg+2-dependent gating of MgtE and use X-ray crystallography combined with functional studies to propose the molecular mechanisms involved in this process.
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Affiliation(s)
- Atsuhiro Tomita
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, 113-0032, Japan
| | - Mingfeng Zhang
- State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center of Genetics and Development, Institute of Brain Science, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, 2005 Songhu Road, Yangpu District, Shanghai, 200438, China
| | - Fei Jin
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, 2005 Songhu Road, Yangpu District, Shanghai, 200438, China
| | - Wenhui Zhuang
- State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center of Genetics and Development, Institute of Brain Science, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, 2005 Songhu Road, Yangpu District, Shanghai, 200438, China
| | - Hironori Takeda
- Faculty of Life Science, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan
| | - Tatsuro Maruyama
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Masanori Osawa
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Ken-Ichi Hashimoto
- Department of Green and Sustainable Chemistry, Tokyo Denki University, 5 Asahi-cho, Senju, Adachi-ku, Tokyo, 120-8551, Japan
| | - Hisashi Kawasaki
- Department of Green and Sustainable Chemistry, Tokyo Denki University, 5 Asahi-cho, Senju, Adachi-ku, Tokyo, 120-8551, Japan
| | - Koichi Ito
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba, 277-8562, Japan
| | - Naoshi Dohmae
- Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako-shi, Saitama, 351-0198, Japan
| | - Ryuichiro Ishitani
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, 113-0032, Japan
| | - Ichio Shimada
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Zhiqiang Yan
- State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center of Genetics and Development, Institute of Brain Science, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, 2005 Songhu Road, Yangpu District, Shanghai, 200438, China. .,Department of Human Anatomy, School of Basic Medicine Sciences, Southwest Medical University, Luzhou, Sichuan, 646000, China.
| | - Motoyuki Hattori
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, 2005 Songhu Road, Yangpu District, Shanghai, 200438, China.
| | - Osamu Nureki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, 113-0032, Japan.
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Biasutto L, Azzolini M, Szabò I, Zoratti M. The mitochondrial permeability transition pore in AD 2016: An update. BIOCHIMICA ET BIOPHYSICA ACTA 2016; 1863:2515-30. [PMID: 26902508 DOI: 10.1016/j.bbamcr.2016.02.012] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 02/04/2016] [Accepted: 02/05/2016] [Indexed: 12/13/2022]
Abstract
Over the past 30years the mitochondrial permeability transition - the permeabilization of the inner mitochondrial membrane due to the opening of a wide pore - has progressed from being considered a curious artifact induced in isolated mitochondria by Ca(2+) and phosphate to a key cell-death-inducing process in several major pathologies. Its relevance is by now universally acknowledged and a pharmacology targeting the phenomenon is being developed. The molecular nature of the pore remains to this day uncertain, but progress has recently been made with the identification of the FOF1 ATP synthase as the probable proteic substrate. Researchers sharing this conviction are however divided into two camps: these believing that only the ATP synthase dimers or oligomers can form the pore, presumably in the contact region between monomers, and those who consider that the ring-forming c subunits in the FO sector actually constitute the walls of the pore. The latest development is the emergence of a new candidate: Spastic Paraplegia 7 (SPG7), a mitochondrial AAA-type membrane protease which forms a 6-stave barrel. This review summarizes recent developments of research on the pathophysiological relevance and on the molecular nature of the mitochondrial permeability transition pore. This article is part of a Special Issue entitled: Mitochondrial Channels edited by Pierre Sonveaux, Pierre Maechler and Jean-Claude Martinou.
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Affiliation(s)
- Lucia Biasutto
- CNR Neuroscience Institute, Viale G. Colombo 3, 35121 Padova, Italy; University of Padova, Department of Biomedical Sciences, Viale G. Colombo 3, 35121 Padova, Italy
| | - Michele Azzolini
- CNR Neuroscience Institute, Viale G. Colombo 3, 35121 Padova, Italy; University of Padova, Department of Biomedical Sciences, Viale G. Colombo 3, 35121 Padova, Italy
| | - Ildikò Szabò
- CNR Neuroscience Institute, Viale G. Colombo 3, 35121 Padova, Italy; University of Padova, Department of Biology, Viale G. Colombo 3, 35121 Padova, Italy
| | - Mario Zoratti
- CNR Neuroscience Institute, Viale G. Colombo 3, 35121 Padova, Italy; University of Padova, Department of Biomedical Sciences, Viale G. Colombo 3, 35121 Padova, Italy.
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Singh SS, Roy A, Lee B, Banerjee I, Kumta PN. Synthesis, characterization, and in-vitro cytocompatibility of amorphous β-tri-calcium magnesium phosphate ceramics. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2016; 67:636-645. [PMID: 27287163 DOI: 10.1016/j.msec.2016.04.076] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2015] [Revised: 03/15/2016] [Accepted: 04/21/2016] [Indexed: 11/19/2022]
Abstract
Biphasic mixtures of crystalline β-tricalcium magnesium phosphate (β-TCMP) and an amorphous calcium magnesium phosphate have been synthesized and reported to support enhanced hMSC differentiation in comparison to β-tricalcium phosphate (β-TCP) due to the release of increased amounts of bioactive ions. In the current study, completely amorphous β-TCMP has been synthesized which is capable of releasing increased amounts of Mg(2+) and PO4(3-) ions, rather than a biphasic mixture as earlier reported. The amorphous phase formed was observed to crystallize between temperatures of 400-600°C. The scaffolds prepared with amorphous β-TCMP were capable of supporting enhanced hMSC proliferation and differentiation in comparison to commercially available β-TCP. However, a similar gene expression of mature osteoblast markers, OCN and COL-1, in comparison to biphasic β-TCMP was observed. To further study the role of Mg(2+) and PO4(3-) ions in regulating hMSC osteogenic differentiation, the capability of hMSCs to mineralize in growth media supplemented with Mg(2+) and PO4(3-) ions was studied. Interestingly, 5mM PO4(3-) supported mineralization while the addition of 5mM Mg(2+) to 5mM PO4(3-) inhibited mineralization. It was therefore concluded that the release of Ca(2+) ions from β-TCMP scaffolds also plays a role in regulating osteogenic differentiation on these scaffolds and it is noted that further work is required to more accurately determine the exact role of Mg(2+) in regulating hMSC osteogenic differentiation.
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Affiliation(s)
- Satish S Singh
- Department of Chemical & Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA.
| | - Abhijit Roy
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261, USA.
| | - Boeun Lee
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261, USA.
| | - Ipsita Banerjee
- Department of Chemical & Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Prashant N Kumta
- Department of Chemical & Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261, USA; Center for Craniofacial Regeneration, University of Pittsburgh, Pittsburgh, PA 15261, USA; Department of Mechanical Engineering and Materials Science, University of Pittsburgh, PA 15261, USA.
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Stanec Z, Halambek J, Maldini K, Balog M, Križik P, Schauperl Z, Ćatić A. Titanium Ions Release from an Innovative Titanium-Magnesium Composite: an in Vitro Study. Acta Stomatol Croat 2016; 50:40-8. [PMID: 27688425 DOI: 10.15644/asc50/1/6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
BACKGROUND The innovative titanium-magnesium composite (Ti-Mg) was produced by powder metallurgy (P/M) method and is characterized in terms of corrosion behavior. MATERIAL AND METHODS Two groups of experimental material, 1 mass% (Ti-1Mg) and 2 mass% (Ti-2Mg) of magnesium in titanium matrix, were tested and compared to commercially pure titanium (CP Ti). Immersion test and chemical analysis of four solutions: artificial saliva; artificial saliva pH 4; artificial saliva with fluoride and Hank balanced salt solution were performed after 42 days of immersion, using inductively coupled plasma mass spectrometry (ICP-MS) to detect the amount of released titanium ions (Ti). SEM and EDS analysis were used for surface characterization. RESULTS The difference between the results from different test solutions was assessed by ANOVA and Newman-Keuls test at p<0.05. The influence of predictor variables was found by multiple regression analysis. The results of the present study revealed a low corrosion rate of titanium from the experimental Ti-Mg group. Up to 46 and 23 times lower dissolution of Ti from Ti-1Mg and Ti-2Mg, respectively was observed compared to the control group. Among the tested solutions, artificial saliva with fluorides exhibited the highest corrosion effect on all specimens tested. SEM micrographs showed preserved dual phase surface structure and EDS analysis suggested a favorable surface bioactivity. CONCLUSION In conclusion, Ti-Mg produced by P/M as a material with better corrosion properties when compared to CP Ti is suggested.
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Affiliation(s)
- Zlatko Stanec
- Private Dental Office Zlatko Stanec, DMD, Samobor, Croatia
| | - Jasna Halambek
- Karlovac University of Applied Sciences, Department for general and organic chemistry, Karlovac, Croatia
| | | | - Martin Balog
- Slovak Academy of Sciences, Institute of materials and machine mechanics, Bratislava, Slovakia
| | - Peter Križik
- Slovak Academy of Sciences, Institute of materials and machine mechanics, Bratislava, Slovakia
| | - Zdravko Schauperl
- University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture, Zagreb, Croatia
| | - Amir Ćatić
- University of Zagreb, School of Dental Medicine, Department of Prosthodontics, Zagreb, Croatia
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30
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Xu Z, Xu L. Fluorescent probes for the selective detection of chemical species inside mitochondria. Chem Commun (Camb) 2016; 52:1094-119. [DOI: 10.1039/c5cc09248e] [Citation(s) in RCA: 220] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
This feature article systematically summarizes the development of fluorescent probes for the selective detection of chemical species inside mitochondria.
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Affiliation(s)
- Zheng Xu
- Chongqing Key Laboratory of Environmental Materials and Remediation Technology
- College of Materials and Chemical Engineering
- Chongqing University of Arts and Sciences
- Chongqing
- China
| | - Lin Xu
- School of Chemistry and Molecular Engineering
- East China Normal University
- Shanghai
- China
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31
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Martins IJ. Magnesium Therapy Prevents Senescence with the Reversal of Diabetes and Alzheimer’s Disease. Health (London) 2016. [DOI: 10.4236/health.2016.87073] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Abstract
The F1F0-ATP synthase (EC 3.6.1.34) is a remarkable enzyme that functions as a rotary motor. It is found in the inner membranes of Escherichia coli and is responsible for the synthesis of ATP in response to an electrochemical proton gradient. Under some conditions, the enzyme functions reversibly and uses the energy of ATP hydrolysis to generate the gradient. The ATP synthase is composed of eight different polypeptide subunits in a stoichiometry of α3β3γδεab2c10. Traditionally they were divided into two physically separable units: an F1 that catalyzes ATP hydrolysis (α3β3γδε) and a membrane-bound F0 sector that transports protons (ab2c10). In terms of rotary function, the subunits can be divided into rotor subunits (γεc10) and stator subunits (α3β3δab2). The stator subunits include six nucleotide binding sites, three catalytic and three noncatalytic, formed primarily by the β and α subunits, respectively. The stator also includes a peripheral stalk composed of δ and b subunits, and part of the proton channel in subunit a. Among the rotor subunits, the c subunits form a ring in the membrane, and interact with subunit a to form the proton channel. Subunits γ and ε bind to the c-ring subunits, and also communicate with the catalytic sites through interactions with α and β subunits. The eight subunits are expressed from a single operon, and posttranscriptional processing and translational regulation ensure that the polypeptides are made at the proper stoichiometry. Recent studies, including those of other species, have elucidated many structural and rotary properties of this enzyme.
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Costa Pessoa J, Garribba E, Santos MF, Santos-Silva T. Vanadium and proteins: Uptake, transport, structure, activity and function. Coord Chem Rev 2015. [DOI: 10.1016/j.ccr.2015.03.016] [Citation(s) in RCA: 141] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Igamberdiev AU, Kleczkowski LA. Optimization of ATP synthase function in mitochondria and chloroplasts via the adenylate kinase equilibrium. FRONTIERS IN PLANT SCIENCE 2015; 6:10. [PMID: 25674099 PMCID: PMC4309032 DOI: 10.3389/fpls.2015.00010] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 01/06/2015] [Indexed: 05/09/2023]
Abstract
The bulk of ATP synthesis in plants is performed by ATP synthase, the main bioenergetics engine of cells, operating both in mitochondria and in chloroplasts. The reaction mechanism of ATP synthase has been studied in detail for over half a century; however, its optimal performance depends also on the steady delivery of ATP synthase substrates and the removal of its products. For mitochondrial ATP synthase, we analyze here the provision of stable conditions for (i) the supply of ADP and Mg(2+), supported by adenylate kinase (AK) equilibrium in the intermembrane space, (ii) the supply of phosphate via membrane transporter in symport with H(+), and (iii) the conditions of outflow of ATP by adenylate transporter carrying out the exchange of free adenylates. We also show that, in chloroplasts, AK equilibrates adenylates and governs Mg(2+) contents in the stroma, optimizing ATP synthase and Calvin cycle operation, and affecting the import of inorganic phosphate in exchange with triose phosphates. It is argued that chemiosmosis is not the sole component of ATP synthase performance, which also depends on AK-mediated equilibrium of adenylates and Mg(2+), adenylate transport, and phosphate release and supply.
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Affiliation(s)
- Abir U. Igamberdiev
- Department of Biology, Memorial University of Newfoundland, St. John’s, NL, Canada
- *Correspondence: Abir U. Igamberdiev, Department of Biology, Memorial University of Newfoundland, St. John’s, NL A1B3X9, Canada e-mail:
| | - Leszek A. Kleczkowski
- Department of Plant Physiology, Umeå Plant Science Centre, University of Umeå, Umeå, Sweden
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Moncayo R, Moncayo H. The WOMED model of benign thyroid disease: Acquired magnesium deficiency due to physical and psychological stressors relates to dysfunction of oxidative phosphorylation. BBA CLINICAL 2014; 3:44-64. [PMID: 26675817 PMCID: PMC4661500 DOI: 10.1016/j.bbacli.2014.11.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Revised: 10/15/2014] [Accepted: 11/04/2014] [Indexed: 12/11/2022]
Abstract
BACKGROUND The aim of this study was to discern whether a relation between biochemical parameters, sonography and musculoskeletal data exists in cases of hyperthyroidism and whether they are modifiable through supplementation with selenomethionine and magnesium citrate as well as by acupuncture and manual medicine methods. RESULTS A direct correlation between whole blood selenium and serum magnesium was found in subjects without thyroid disease and in menopausal women while it was reversed in cases of thyroid diseases as well as in patients with depression, infection, and in infertile women. Vascularization indices were elevated in cases of newly diagnosed benign thyroid diseases. Musculoskeletal changes i.e. lateral tension and idiopathic moving toes, as well as situations of physical and psychological stress and minor trauma and infection led to an increase of vascularization. Magnesium levels correlated negatively with these two conditions. The supplementation brought a reduction of the vascularization indices and reduced the incidence of idiopathic moving toes. Treatment of lateral tension required manual medicine methods and acupuncture (gastrocnemius). A small subgroup of patients showed a further reduction of hyper-vascularization after receiving coenzyme Q10. CONCLUSIONS We interpret the elevated thyroid vascularization and low magnesium levels as signs of an inflammatory process related to the musculoskeletal changes. Improvement of thyroid function and morphology can be achieved after correcting the influence of stressors together with the supplementation regime. We hypothesize that the central biochemical event in thyroid disease is that of an acquired, altered mitochondrial function due to deficiency of magnesium, selenium, and coenzyme Q10.
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Affiliation(s)
- Roy Moncayo
- WOMED, Karl-Kapferer-Strasse 5, AT-6020 Innsbruck, Austria
| | - Helga Moncayo
- WOMED, Karl-Kapferer-Strasse 5, AT-6020 Innsbruck, Austria
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Bojovschi A, Liu MS, Sadus RJ. Mg²⁺ coordinating dynamics in Mg:ATP fueled motor proteins. J Chem Phys 2014; 140:115102. [PMID: 24655204 DOI: 10.1063/1.4867898] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The coordination of Mg(2+) with the triphosphate group of adenosine triphosphate (ATP) in motor proteins is investigated using data mining and molecular dynamics. The possible coordination structures available from crystal data for actin, myosin, RNA polymerase, DNA polymerase, DNA helicase, and F1-ATPase are verified and investigated further by molecular dynamics. Coordination states are evaluated using structural analysis and quantified by radial distribution functions, coordination numbers, and pair interaction energy calculations. The results reveal a diverse range of both transitory and stable coordination arrangements between Mg(2+) and ATP. The two most stable coordinating states occur when Mg(2+) coordinates two or three oxygens from the triphosphate group of ATP. Evidence for five-site coordination is also reported involving water in addition to the triphosphate group. The stable states correspond to a pair interaction energy of either ∼-2750 kJ/mol or -3500 kJ/mol. The role of water molecules in the hydration shell surrounding Mg(2+) is also reported.
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Affiliation(s)
- A Bojovschi
- Centre for Molecular Simulation, Swinburne University of Technology, P.O. Box 218, Hawthorn, Victoria 3122, Australia
| | - Ming S Liu
- Centre for Molecular Simulation, Swinburne University of Technology, P.O. Box 218, Hawthorn, Victoria 3122, Australia
| | - Richard J Sadus
- Centre for Molecular Simulation, Swinburne University of Technology, P.O. Box 218, Hawthorn, Victoria 3122, Australia
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Environmental dependence of stationary-phase metabolism in Bacillus subtilis and Escherichia coli. Appl Environ Microbiol 2014; 80:2901-9. [PMID: 24584250 DOI: 10.1128/aem.00061-14] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
When microbes lack the nutrients necessary for growth, they enter stationary phase. In cases when energy sources are still present in the environment, they must decide whether to continue to use their metabolic program to harvest the available energy. Here we characterized the metabolic response to a variety of types of nutrient starvation in Escherichia coli and Bacillus subtilis. We found that E. coli exhibits a range of phenotypes, with the lowest metabolic rates under nitrogen starvation and highest rates under magnesium starvation. In contrast, the phenotype of B. subtilis was dominated by its decision to form metabolically inactive endospores. While its metabolic rates under most conditions were thus lower than those of E. coli, when sporulation was suppressed by a genetic perturbation or an unnatural starvation condition, the situation was reversed. To further probe stationary-phase metabolism, we used quantitative metabolomics to investigate possible small-molecule signals that may regulate the metabolic rate of E. coli and initiate sporulation in B. subtilis. We hypothesize a role for phosphoenolpyruvate (PEP) in regulating E. coli glucose uptake and for the redox cofactors NAD(H) and NADP(H) in initiation of sporulation. Our work is directly relevant to synthetic biology and metabolic engineering, where active metabolism during stationary phase, which uncouples production from growth, remains an elusive goal.
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Galli S, Naito Y, Karlsson J, He W, Andersson M, Wennerberg A, Jimbo R. Osteoconductive Potential of Mesoporous Titania Implant Surfaces Loaded with Magnesium: An Experimental Study in the Rabbit. Clin Implant Dent Relat Res 2014; 17:1048-59. [PMID: 25178845 DOI: 10.1111/cid.12211] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Mesoporous coatings enable incorporation of functional substances and sustainedly release them at the implant site. One bioactive substance that can be incorporated in mesoporous is magnesium, which is strongly involved in bone metabolism and in osteoblast interaction. PURPOSE The aim of this experimental study was to evaluate the effect of incorporation of magnesium into mesoporous coatings of oral implants on early stages of osseointegration. MATERIAL AND METHODS Titanium implants were coated with thin films of mesoporous TiO2 having pore diameters of 6 nm and were loaded with magnesium. The implant surfaces were extensively characterized by means of interferometry, atomic force microscopy, scanning electron microscopy, and energy-dispersive spectroscopy and then placed in the tibiae of 10 rabbits. After 3 weeks of healing, osseointegration was evaluated by means of removal torque testing and histology and histomorphometry. RESULTS Histological and biomechanical analyses revealed no side effects and successful osseointegration of the implants. The biomechanical evaluation evidenced a significant effect of magnesium doping on strengthening the implant-bone interface. CONCLUSIONS A local release of magnesium from the implant surfaces enhances implant retention at the early stage of healing (3 weeks after implantation), which is highly desirable for early loading of the implant.
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Affiliation(s)
- Silvia Galli
- Department of Prosthodontics, Faculty of Odontology, Malmö University, Malmö, Sweden
| | - Yoshihito Naito
- Department of Oral and Maxillofacial Prosthodontics and Oral Implantology, Institute of Health Biosciences, University of Tokushima Graduate School, Tokushima, Japan
| | - Johan Karlsson
- Applied Surface Chemistry Research Group, Department of Chemical and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Wenxiao He
- Applied Surface Chemistry Research Group, Department of Chemical and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Martin Andersson
- Applied Surface Chemistry Research Group, Department of Chemical and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Ann Wennerberg
- Department of Prosthodontics, Faculty of Odontology, Malmö University, Malmö, Sweden
| | - Ryo Jimbo
- Department of Prosthodontics, Faculty of Odontology, Malmö University, Malmö, Sweden
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Bojovschi A, Liu MS, Sadus RJ. Conformational dynamics of ATP/Mg:ATP in motor proteins via data mining and molecular simulation. J Chem Phys 2013; 137:075101. [PMID: 22920142 DOI: 10.1063/1.4739308] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The conformational diversity of ATP/Mg:ATP in motor proteins was investigated using molecular dynamics and data mining. Adenosine triphosphate (ATP) conformations were found to be constrained mostly by inter cavity motifs in the motor proteins. It is demonstrated that ATP favors extended conformations in the tight pockets of motor proteins such as F(1)-ATPase and actin whereas compact structures are favored in motor proteins such as RNA polymerase and DNA helicase. The incorporation of Mg(2+) leads to increased flexibility of ATP molecules. The differences in the conformational dynamics of ATP/Mg:ATP in various motor proteins was quantified by the radius of gyration. The relationship between the simulation results and those obtained by data mining of motor proteins available in the protein data bank is analyzed. The data mining analysis of motor proteins supports the conformational diversity of the phosphate group of ATP obtained computationally.
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Affiliation(s)
- A Bojovschi
- Centre for Molecular Simulation, Swinburne University of Technology, P.O. Box 218, Hawthorn, Victoria 3122, Australia.
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40
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Blum DJ, Ko YH, Pedersen PL. Mitochondrial ATP Synthase Catalytic Mechanism: A Novel Visual Comparative Structural Approach Emphasizes Pivotal Roles for Mg2+ and P-Loop Residues in Making ATP. Biochemistry 2012; 51:1532-46. [DOI: 10.1021/bi201595v] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- David J. Blum
- Department of Biological Chemistry, The Johns Hopkins University, School of Medicine, 725
North Wolfe Street, Baltimore, Maryland 21205-2185, United States
| | - Young H. Ko
- Cancer Cure Med, LLC, 300 Redland Court, Suite 212, Owings Mills, Maryland
21117, United States
| | - Peter L. Pedersen
- Department of Biological Chemistry, The Johns Hopkins University, School of Medicine, 725
North Wolfe Street, Baltimore, Maryland 21205-2185, United States
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Sell H, Gehl A, Sönnichsen FD, Herges R. Thermodynamic and kinetic stabilization of divanadate in the monovanadate/divanadate equilibrium using a Zn-cyclene derivative: Towards a simple ATP synthase model. Beilstein J Org Chem 2012; 8:81-9. [PMID: 22423274 PMCID: PMC3302101 DOI: 10.3762/bjoc.8.8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Accepted: 12/21/2011] [Indexed: 01/12/2023] Open
Abstract
For the condensation of anions such as phosphate and ADP to form ATP and water, nature employs sophisticated supramolecular systems to overcome coulomb repulsion and activation barriers. For an attempt to create a simple, analogous chemical system, the dimerization of vanadate is probably the simplest model. We have investigated Zn-benzylcyclene which favors the dimerization thermodynamically as shown by NMR titration. Moreover, EXSY NMR experiments reveal that the vanadate dimer is also kinetically stabilized with respect to hydrolysis by complexation with Zn-cyclene.
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Affiliation(s)
- Hanno Sell
- Otto-Diels Institut für Organische Chemie, Christian-Albrechts-Universität zu Kiel, Otto-Hahn-Platz 4, 24418 Kiel, Germany
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Shindo Y, Fujii T, Komatsu H, Citterio D, Hotta K, Suzuki K, Oka K. Newly developed Mg2+-selective fluorescent probe enables visualization of Mg2+ dynamics in mitochondria. PLoS One 2011; 6:e23684. [PMID: 21858208 PMCID: PMC3156752 DOI: 10.1371/journal.pone.0023684] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Accepted: 07/22/2011] [Indexed: 12/27/2022] Open
Abstract
Mg(2+) plays important roles in numerous cellular functions. Mitochondria take part in intracellular Mg(2+) regulation and the Mg(2+) concentration in mitochondria affects the synthesis of ATP. However, there are few methods to observe Mg(2+) in mitochondria in intact cells. Here, we have developed a novel Mg(2+)-selective fluorescent probe, KMG-301, that is functional in mitochondria. This probe changes its fluorescence properties solely depending on the Mg(2+) concentration in mitochondria under physiologically normal conditions. Simultaneous measurements using this probe together with a probe for cytosolic Mg(2+), KMG-104, enabled us to compare the dynamics of Mg(2+) in the cytosol and in mitochondria. With this method, carbonyl cyanide p-(trifluoromethoxy) phenylhydrazone (FCCP)-induced Mg(2+) mobilization from mitochondria to the cytosol was visualized. Although a FCCP-induced decrease in the Mg(2+) concentration in mitochondria and an increase in the cytosol were observed both in differentiated PC12 cells and in hippocampal neurons, the time-courses of concentration changes varied with cell type. Moreover, the relationship between mitochondrial Mg(2+) and Parkinson's disease was analyzed in a cellular model of Parkinson's disease by using the 1-methyl-4-phenylpyridinium ion (MPP(+)). A gradual decrease in the Mg(2+) concentration in mitochondria was observed in response to MPP(+) in differentiated PC12 cells. These results indicate that KMG-301 is useful for investigating Mg(2+) dynamics in mitochondria. All animal procedures to obtain neurons from Wistar rats were approved by the ethical committee of Keio University (permit number is 09106-(1)).
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Affiliation(s)
- Yutaka Shindo
- Center for Biosciences and Informatics, School of Fundamental Science and Technology, Graduate School of Science and Technology, Keio University, Yokohama, Kanagawa, Japan
| | - Tomohiko Fujii
- Center for Biosciences and Informatics, School of Fundamental Science and Technology, Graduate School of Science and Technology, Keio University, Yokohama, Kanagawa, Japan
| | - Hirokazu Komatsu
- Center for Science and Technology for Designing Functions, School of Integrated Design Engineering, Graduate School of Science and Technology, Keio University, Yokohama, Kanagawa, Japan
| | - Daniel Citterio
- Center for Science and Technology for Designing Functions, School of Integrated Design Engineering, Graduate School of Science and Technology, Keio University, Yokohama, Kanagawa, Japan
| | - Kohji Hotta
- Center for Biosciences and Informatics, School of Fundamental Science and Technology, Graduate School of Science and Technology, Keio University, Yokohama, Kanagawa, Japan
| | - Koji Suzuki
- Center for Science and Technology for Designing Functions, School of Integrated Design Engineering, Graduate School of Science and Technology, Keio University, Yokohama, Kanagawa, Japan
| | - Kotaro Oka
- Center for Biosciences and Informatics, School of Fundamental Science and Technology, Graduate School of Science and Technology, Keio University, Yokohama, Kanagawa, Japan
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Manimekalai MSS, Kumar A, Jeyakanthan J, Grüber G. The transition-like state and Pi entrance into the catalytic a subunit of the biological engine A-ATP synthase. J Mol Biol 2011; 408:736-54. [PMID: 21396943 DOI: 10.1016/j.jmb.2011.03.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2011] [Revised: 03/02/2011] [Accepted: 03/03/2011] [Indexed: 11/18/2022]
Abstract
Archaeal A-ATP synthases catalyze the formation of the energy currency ATP. The chemical mechanisms of ATP synthesis in A-ATP synthases are unknown. We have determined the crystal structure of a transition-like state of the vanadate-bound form of catalytic subunit A (A(Vi)) of the A-ATP synthase from Pyrococcus horikoshii OT3. Two orthovanadate molecules were observed in the A(Vi) structure, one of which interacts with the phosphate binding loop through residue S238. The second vanadate is positioned in the transient binding site, implicating for the first time the pathway for phosphate entry to the catalytic site. Moreover, since residues K240 and T241 are proposed to be essential for catalysis, the mutant structures of K240A and T241A were also determined. The results demonstrate the importance of these two residues for transition-state stabilization. The structures presented shed light on the diversity of catalytic mechanisms used by the biological motors A- and F-ATP synthases and eukaryotic V-ATPases.
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Pulido NO, Salcedo G, Pérez-Hernández G, José-Núñez C, Velázquez-Campoy A, García-Hernández E. Energetic effects of magnesium in the recognition of adenosine nucleotides by the F(1)-ATPase beta subunit. Biochemistry 2010; 49:5258-68. [PMID: 20518490 DOI: 10.1021/bi1006767] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Nucleotide-induced conformational changes of the catalytic beta subunits play a crucial role in the rotary mechanism of F(1)-ATPase. To gain insights into the energetic bases that govern the recognition of nucleotides by the isolated beta subunit from thermophilic Bacillus PS3 (Tbeta), the binding of this monomer to Mg(II)-free and Mg(II)-bound adenosine nucleotides was characterized using high-precision isothermal titration calorimetry. The interactions of Mg(II) with free ATP or ADP were also measured calorimetrically. A model that considers simultaneously the interactions of Tbeta with Mg.ATP or with ATP and in which ATP is able to bind two Mg(II) atoms sequentially was used to determine the formation parameters of the Tbeta-Mg.ATP complex from calorimetric data. This analysis yielded significantly different DeltaH(b) and DeltaS(b) values in relation to those obtained using a single-binding site model, while DeltaG(b) was almost unchanged. Published calorimetric data for the titration of Tbeta with Mg.ADP [Perez-Hernandez, G., et al. (2002) Arch. Biochem. Biophys. 408, 177-183] were reanalyzed with the ternary model to determine the corresponding true binding parameters. Interactions of Tbeta with Mg.ATP, ATP, Mg.ADP, or ADP were enthalpically driven. Larger differences in thermodynamic properties were observed between Tbeta-Mg.ATP and Tbeta-ATP complexes than between Tbeta-Mg.ADP and Tbeta-ADP complexes or between Tbeta-Mg.ATP and Tbeta-Mg.ADP complexes. These binding data, in conjunction with those for the association of Mg(II) with free nucleotides, allowed for a determination of the energetic effects of the metal ion on the recognition of adenosine nucleotides by Tbeta [i.e., Tbeta.AT(D)P + Mg(II) right harpoon over left harpoon Tbeta.AT(D)P-Mg]. Because of a more favorable binding enthalpy, Mg(II) is recognized more avidly by the Tbeta.ATP complex, indicating better stereochemical complementarity than in the Tbeta.ADP complex. Furthermore, a structural-energetic analysis suggests that Tbeta adopts a more closed conformation when it is bound to Mg.ATP than to ATP or Mg.ADP, in agreement with recently published NMR data [Yagi, H., et al. (2009) J. Biol. Chem. 284, 2374-2382]. Using published binding data, a similar analysis of Mg(II) energetic effects was performed for the free energy change of F(1) catalytic sites, in the framework of bi- or tri-site binding models.
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Affiliation(s)
- Nancy O Pulido
- Instituto de Quimica, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, Mexico
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45
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Kominkova V, Malekova L, Tomaskova Z, Slezak P, Szewczyk A, Ondrias K. Modulation of intracellular chloride channels by ATP and Mg2+. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:1300-12. [PMID: 20206596 DOI: 10.1016/j.bbabio.2010.02.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2009] [Revised: 02/03/2010] [Accepted: 02/26/2010] [Indexed: 12/15/2022]
Abstract
We report the effects of ATP and Mg2+ on the activity of intracellular chloride channels. Mitochondrial and lysosomal membrane vesicles isolated from rat hearts were incorporated into bilayer lipid membranes, and single chloride channel currents were measured. The observed chloride channels (n=112) possessed a wide variation in single channel parameters and sensitivities to ATP. ATP (0.5-2 mmol/l) modulated and/or inhibited the chloride channel activities (n=38/112) in a concentration-dependent manner. The inhibition effect was irreversible (n=5/93) or reversible (n=15/93). The non-hydrolysable ATP analogue AMP-PNP had a similar inhibition effect as ATP, indicating that phosphorylation did not play a role in the ATP inhibition effect. ATP modulated the gating properties of the channels (n=6/93), decreased the channels' open dwell times and increased the gating transition rates. ATP (0.5-2 mmol/l) without the presence of Mg2+ decreased the chloride channel current (n=12/14), whereas Mg2+ significantly reversed the effect (n=4/4). We suggest that ATP-intracellular chloride channel interactions and Mg2+ modulation of these interactions may regulate different physiological and pathological processes.
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Affiliation(s)
- Viera Kominkova
- Institute of Molecular Physiology and Genetics, Centre of Excellence for Cardiovascular Research, Slovak Academy of Sciences, 83334 Bratislava, Slovakia
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Kawahara K, Sato R, Iwabuchi S, Matsuyama D. Rhythmic Fluctuations in the Concentration of Intracellular Mg2+in Association with Spontaneous Rhythmic Contraction in Cultured Cardiac Myocytes. Chronobiol Int 2009; 25:868-81. [DOI: 10.1080/07420520802536387] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Hypertonic stress increased extracellular ATP levels and the expression of stress-responsive genes in Arabidopsis thaliana seedlings. Biosci Biotechnol Biochem 2009; 73:1252-6. [PMID: 19502745 DOI: 10.1271/bbb.80660] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Arabidopsis seedlings increased extracellular ATP (exATP) concentrations transiently in extracellular matrix (ECM) under hypertonic stresses. The increased transcription levels of two apyrase genes, AtAPY1 and AtAPY2, in accordance with exATP accumulation, suggests active regulation of exATP concentration. Arabidopsis seedlings subjected to hypertonic stresses survived after incubation with beta,gamma-methyleneadenosine-5'-triphosphate, which usually causes cell death through competitive exclusion of ATP. This confirms that the enhanced viability was due to accumulated exATP. The increased concentration of hydrogen peroxide through NADPH oxidase expression suggests the possible importance of exATP in stress response under hypertonic stresses. The mRNA levels of exATP inducible genes (AtMAPK3, AtACS6, and AtERF4) and the reactive oxygen species inducible gene (AtPAL1) were increased by hypertonic stresses. We suggest that exATP accumulation plays a role as a regulatory mechanism in the hypertonic stress response in Arabidopsis seedlings.
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Abstract
The experimentally measured mechanical efficiency of the F(1)-ATPase under viscous loading is nearly 100%, far higher than any other hydrolysis-driven molecular motor (Yasuda et al., 1998). Here we give a molecular explanation for this remarkable property.
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Affiliation(s)
- G Oster
- Department of Molecular and Cellular Biology, University of California, Berkeley, California 94720-3112, USA
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49
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Pedersen PL, Ko YH, Hong S. ATP synthases in the year 2000: defining the different levels of mechanism and getting a grip on each. J Bioenerg Biomembr 2009; 32:423-32. [PMID: 15254377 DOI: 10.1023/a:1005652605340] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
ATP synthases are unusually complex molecules, which fractionate most readily into two major units, one a water soluble unit called F(1) and the other a detergent soluble unit called F(0). In almost all known species the F(1) unit consists of 5 subunit types in the stoichiometric ratio alpha(3)beta(3)gammadeltaepsilon while the F(0) unit contains 3 subunit types (a, b, and c) in E. coli, and at least 10 subunit types (a, b, c, and others) in higher animals. It is now believed by many investigators that during the synthesis of ATP, protons derived from an electrochemical gradient generated by an electron transport chain are directed through the F(0) unit in such a way as to drive the rotation of the single gamma subunit, which extends from an oligomeric ring of at least 10 c subunits in F(0) through the center of F(1). It is further believed by many that the rotating gamma subunit, by interacting sequentially with the 3 alphabeta pairs of F(1) (360 degrees cycle) in the presence of ADP, P(i), and Mg++, brings about via "power strokes" conformational/binding changes in these subunits that promote the synthesis of ATP and its release on each alphabeta pair. In support of these views, studies in several laboratories either suggest or demonstrate that F(0) consists in part of a proton gradient driven motor while F(1) consists of an ATP hydrolysis driven motor, and that the gamma subunit does rotate during F(1) function. Therefore, current implications are that during ATP synthesis the former motor drives the latter in reverse via the gamma subunit. This would suggest that the process of understanding the mechanism of ATP synthases can be subdivided into three major levels, which include elucidating those chemical and/or biophysical events involved in (1) inducing rotation of the gamma subunit, (2) coupling rotation of this subunit to conformational/binding changes in each of the 3 alphabeta pairs, and (3) forming ATP and water (from ADP, P(i), and Mg(++)) and then releasing these products from each of the 3 catalytic sites. Significantly, it is at the final level of mechanism where the bond breaking/making events of ATP synthesis occur in the transition state, with the former two levels of mechanism setting the stage for this critical payoff event. Nevertheless, in order to get a better grip in this new century on how ATP synthases make ATP and then release it, we must take on the difficult challenge of elucidating each of the three levels of mechanism.
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Affiliation(s)
- P L Pedersen
- Department of Biological Chemistry, Johns Hopkins University, School of Medicine, 725 North Wolfe Street, Baltimore, Maryland 21205-2185, USA.
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Hong S, Pedersen PL. ATP synthase and the actions of inhibitors utilized to study its roles in human health, disease, and other scientific areas. Microbiol Mol Biol Rev 2008; 72:590-641, Table of Contents. [PMID: 19052322 PMCID: PMC2593570 DOI: 10.1128/mmbr.00016-08] [Citation(s) in RCA: 236] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
ATP synthase, a double-motor enzyme, plays various roles in the cell, participating not only in ATP synthesis but in ATP hydrolysis-dependent processes and in the regulation of a proton gradient across some membrane-dependent systems. Recent studies of ATP synthase as a potential molecular target for the treatment of some human diseases have displayed promising results, and this enzyme is now emerging as an attractive molecular target for the development of new therapies for a variety of diseases. Significantly, ATP synthase, because of its complex structure, is inhibited by a number of different inhibitors and provides diverse possibilities in the development of new ATP synthase-directed agents. In this review, we classify over 250 natural and synthetic inhibitors of ATP synthase reported to date and present their inhibitory sites and their known or proposed modes of action. The rich source of ATP synthase inhibitors and their known or purported sites of action presented in this review should provide valuable insights into their applications as potential scaffolds for new therapeutics for human and animal diseases as well as for the discovery of new pesticides and herbicides to help protect the world's food supply. Finally, as ATP synthase is now known to consist of two unique nanomotors involved in making ATP from ADP and P(i), the information provided in this review may greatly assist those investigators entering the emerging field of nanotechnology.
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Affiliation(s)
- Sangjin Hong
- Department of Biological Chemistry, Johns Hopkins University, School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205-2185, USA
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