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Lesco KC, Rowland SM, Ratanathanawongs Williams SK, Laurens LML. Single-filament imaging mass spectrometry lipidomics in Arthrospira platensis. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2023; 37:e9525. [PMID: 37062938 DOI: 10.1002/rcm.9525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 04/13/2023] [Accepted: 04/14/2023] [Indexed: 06/17/2023]
Abstract
RATIONALE Elucidating intra-organismal biochemical and lipid organization in photosynthetic biological cell factories of filamentous cyanobacteria, such as Arthrospira platensis (Spirulina), is important for tracking physiological response mechanisms during growth. Little is known about the filaments' biochemical organization and cellular structure and no label-free imaging techniques exist that provide molecular mapping. METHODS We applied ultrahigh-resolution mass spectrometry (MS) with matrix-assisted laser desorption ionization (MALDI) imaging to immobilized Spirulina filaments to investigate the localization of lipids across distinct physiological regions. We optimized matrix selection and deposition methods with the goal of facilitating high spatial, and intra-filament, resolution using untargeted multivariate statistical spectral deconvolution across MS pixels. RESULTS Our results demonstrate an improved two-step matrix application with an optimized procedure for intra-organismal lipid profiling to improve analyte sensitivity and achieve higher spatial resolution. We evaluate several conventional matrices, namely 2,5-dihydroxybenzoic acid (DHB), superDHB (sDHB), 1,5-diaminonaphthalene (DAN), and a 50:50 mix of DHB and sDHB, and compare delineation and pixel-based elucidation of intra-filament lipidomics. We identified a total of 1626 features that could be putatively assigned a lipid-like formula based on database query and 46 unique features, with associated lipid assignments that were significantly distinct in their intra-filament location. CONCLUSIONS MALDI imaging MS with untargeted statistical spectral deconvolution was used to visualize intra-filament lipidomics organization in Spirulina filaments. Improvements in matrix deposition, including sequential sublimation and pneumatic spraying, increased signal abundance at high spatial resolution and allowed for identification of distinct lipid composition regions. This work outlines a methodology that may be used for micro-ecological untargeted molecular phenotyping.
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Affiliation(s)
- Kaitlin C Lesco
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA
- Laboratory for Advanced Separation Technologies, Department of Chemistry, Colorado School of Mines, Golden, Colorado, USA
| | - Steven M Rowland
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA
| | | | - Lieve M L Laurens
- Bioenergy Science and Technology Directorate, National Renewable Energy Laboratory, Golden, Colorado, USA
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Cruz de Carvalho R, Feijão E, Matos AR, Cabrita MT, Utkin AB, Novais SC, Lemos MFL, Caçador I, Marques JC, Reis-Santos P, Fonseca VF, Duarte B. Ecotoxicological Effects of the Anionic Surfactant Sodium Dodecyl Sulfate (SDS) in Two Marine Primary Producers: Phaeodactylum tricornutum and Ulva lactuca. TOXICS 2022; 10:toxics10120780. [PMID: 36548613 PMCID: PMC9785791 DOI: 10.3390/toxics10120780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/08/2022] [Accepted: 12/11/2022] [Indexed: 05/14/2023]
Abstract
Sodium Dodecyl Sulfate (SDS) is an anionic surfactant, extensively used in detergents, household and personal care products, as well as in industrial processes. The present study aimed to disclose the potential toxicological effects of SDS exposure under environmentally relevant concentrations (0, 0.1, 1, 3, and 10 mg L-1) on the physiology and biochemistry (photosynthesis, pigment, and lipid composition, antioxidative systems, and energy balance) of two marine autotrophs: the diatom Phaeodactylum tricornutum and the macroalgae Ulva lactuca. A growth rate (GR) reduction in P. tricornutum was observed with a classic dose-response effect towards the highest applied concentration, while a GR increase occurred in U. lactuca. Regarding photochemistry, the decrease in the fluorescence of the OJIP curves and laser-induced fluorescence allowed a better separation between SDS treatments in U. lactuca compared with P. tricornutum. Although all pigments significantly decreased in U. lactuca at the highest concentrations (except for antheraxanthin), no significant variations occurred in P. tricornutum. On the other hand, changes in fatty acid content were observed in P. tricornutum but not in U. lactuca. In terms of classical biomarker assessment, a dose-effect relationship of individual biomarkers versus SDS dose applied; U. lactuca displayed a higher number of biomarker candidates, including those in distinct metabolic pathways, increasing its usefulness for ecotoxicological applications. By evaluating the potential application of optical and biochemical traits, it was evident that the fatty acid profiles of the different exposure groups are excellent candidates in P. tricornutum, concomitant with the characteristics of this anionic surfactant. On the other hand, the results presented by laser-induced fluorescence and some parameters of PAM fluorometry in U. lactuca may be an advantage in the field, offering non-invasive, fast, easy-to-use, high-throughput screening techniques as excellent tools for ecotoxicology assessment.
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Affiliation(s)
- Ricardo Cruz de Carvalho
- MARE–Marine and Environmental Sciences Centre, ARNET–Aquatic Research Network Associate Laboratory, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisbon, Portugal
- cE3c–Centre for Ecology, Evolution and Environmental Changes, Faculty of Sciences, University of Lisbon, Campo Grande, Edifício C2, Piso 5, 1749-016 Lisbon, Portugal
- Departamento de Biologia Vegetal, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
- Correspondence:
| | - Eduardo Feijão
- MARE–Marine and Environmental Sciences Centre, ARNET–Aquatic Research Network Associate Laboratory, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisbon, Portugal
| | - Ana Rita Matos
- Departamento de Biologia Vegetal, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
- BioISI–Instituto de Biosistemas e Ciências Integrativas, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - Maria Teresa Cabrita
- Centro de Estudos Geográficos (CEG), Instituto de Geografia e Ordenamento do Território (IGOT), Universidade de Lisboa, Rua Branca Edmée Marques, 1600-276 Lisboa, Portugal
- Laboratório Associado TERRA, Edifício Prof. Azevedo Gomes, Instituto Superior de Agronomia, Tapada da Ajuda, 1349-017 Lisboa, Portugal
| | - Andrei B. Utkin
- INOV-INESC, Rua Alves Redol 9, 1000-029 Lisboa, Portugal
- CeFEMA, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa, Portugal
| | - Sara C. Novais
- MARE–Marine and Environmental Sciences Centre, ARNET–Aquatic Research Network Associate Laboratory, ESTM, Polytechnic of Leiria, 2520-641 Peniche, Portugal
| | - Marco F. L. Lemos
- MARE–Marine and Environmental Sciences Centre, ARNET–Aquatic Research Network Associate Laboratory, ESTM, Polytechnic of Leiria, 2520-641 Peniche, Portugal
| | - Isabel Caçador
- MARE–Marine and Environmental Sciences Centre, ARNET–Aquatic Research Network Associate Laboratory, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisbon, Portugal
- Departamento de Biologia Vegetal, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
| | - João Carlos Marques
- MARE–Marine and Environmental Sciences Centre, ARNET–Aquatic Research Network, Department of Life Sciences, University of Coimbra, 3000 Coimbra, Portugal
| | - Patrick Reis-Santos
- MARE–Marine and Environmental Sciences Centre, ARNET–Aquatic Research Network Associate Laboratory, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisbon, Portugal
- Southern Seas Ecology Laboratories, School of Biological Sciences, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Vanessa F. Fonseca
- MARE–Marine and Environmental Sciences Centre, ARNET–Aquatic Research Network Associate Laboratory, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisbon, Portugal
- Departamento de Biologia Animal, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
| | - Bernardo Duarte
- MARE–Marine and Environmental Sciences Centre, ARNET–Aquatic Research Network Associate Laboratory, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisbon, Portugal
- Departamento de Biologia Vegetal, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
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Brady NG, Qian S, Nguyen J, O'Neill HM, Bruce BD. Small angle neutron scattering and lipidomic analysis of a native, trimeric PSI-SMALP from a thermophilic cyanobacteria. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2022; 1863:148596. [PMID: 35853496 PMCID: PMC10228149 DOI: 10.1016/j.bbabio.2022.148596] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 06/05/2022] [Accepted: 07/11/2022] [Indexed: 01/21/2023]
Abstract
The use of styrene-maleic acid copolymers (SMAs) to produce membrane protein-containing nanodiscs without the initial detergent isolation has gained significant interest over the last decade. We have previously shown that a Photosystem I SMALP from the thermophilic cyanobacterium, Thermosynechococcus elongatus (PSI-SMALP), has much more rapid energy transfer and charge separation in vitro than detergent isolated PSI complexes. In this study, we have utilized small-angle neutron scattering (SANS) to better understand the geometry of these SMALPs. These techniques allow us to investigate the size and shape of these particles in their fully solvated state. Further, the particle's proteolipid core and detergent shell or copolymer belt can be interrogated separately using contrast variation, a capability unique to SANS. Here we report the dimensions of the Thermosynechococcus elongatus PSI-SMALP containing a PSI trimer. At ~1.5 MDa, PSI-SMALP is the largest SMALP to be isolated; our lipidomic analysis indicates it contains ~1300 lipids/per trimeric particle, >40-fold more than the PSI-DDM particle and > 100 fold more than identified in the 1JB0 crystal structure. Interestingly, the lipid composition to the PSI trimer in the PSI-SMALP differs significantly from bulk thylakoid composition, being enriched ~50 % in the anionic sulfolipid, SQDG. Finally, utilizing the contrast match point for the SMA 1440 copolymer, we also can observe the ~1 nm SMA copolymer belt surrounding this SMALP for the first time, consistent with most models of SMA organization.
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Affiliation(s)
- Nathan G Brady
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Shuo Qian
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA; The Second Target Station Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Jon Nguyen
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Hugh M O'Neill
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Barry D Bruce
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA; Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996, USA; Department of Microbiology, University of Tennessee, Knoxville, TN 37996, USA.
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Ocean Acidification Alleviates Dwarf Eelgrass (Zostera noltii) Lipid Landscape Remodeling under Warming Stress. BIOLOGY 2022; 11:biology11050780. [PMID: 35625507 PMCID: PMC9138486 DOI: 10.3390/biology11050780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Revised: 05/17/2022] [Accepted: 05/17/2022] [Indexed: 11/17/2022]
Abstract
Coastal seagrass meadows provide a variety of essential ecological and economic services, including nursery grounds, sediment stabilization, nutrient cycling, coastal protection, and blue carbon sequestration. However, these ecosystems are highly threatened by ongoing climatic change. This study was aimed to understand how the dwarf eelgrass Zostera noltii leaf lipid landscapes are altered under predicted ocean warming (+4 °C) and hypercapnic (ΔpH 0.4) conditions. Warming and hypercapnic conditions were found to induce a severe reduction in the leaf total fatty acid, though the combined treatment substantially alleviated this depletion. The lipid discrimination revealed a significant increase in the relative monogalactosyldiacylglycerol (MGDG) content in both hypercapnic and warming conditions, allied to plastidial membrane stabilization mechanisms. Hypercapnia also promoted enhanced phosphatidylglycerol (PG) leaf contents, a mechanism often associated with thylakoid reinvigoration. In addition to changing the proportion of storage, galacto- and phospholipids, the tested treatments also impacted the FA composition of all lipid classes, with warming exposure leading to decreases in polyunsaturated fatty acids (PUFAs); however, the combination of both stress conditions alleviated this effect. The observed galactolipid and phospholipid PUFA decreases are compatible with a homeoviscous adaptation, allowing for the maintenance of membrane stability by counteracting excessive membrane fluidity. Neutral lipid contents were substantially increased under warming conditions, especially in C18 fatty acids (C18), impairing their use as substrates for fatty acylated derivatives essential for maintaining the osmotic balance of cells. An analysis of the phospholipid and galactolipid fatty acid profiles as a whole revealed a higher degree of discrimination, highlighting the higher impact of warming and the proposed stress alleviation effect induced by increased water-dissolved CO2 availability. Still, it is essential to remember that the pace at which the ocean is warming can overcome the ameliorative capacity induced by higher CO2 availability, leaving seagrasses under severe heat stress beyond their lipid remodeling capacity.
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Zhukova NV, Yakovleva IM. Low light acclimation strategy of the brown macroalga Undaria pinnatifida: Significance of lipid and fatty acid remodeling for photosynthetic competence. JOURNAL OF PHYCOLOGY 2021; 57:1792-1804. [PMID: 34486722 DOI: 10.1111/jpy.13209] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 08/10/2021] [Accepted: 08/21/2021] [Indexed: 06/13/2023]
Abstract
Brown macroalgae, being important components of benthic communities in temperate regions, are frequently subjected to light limitation. To extend our understanding of their low light acclimation strategies to the regulation of membrane lipid environment, photosynthetic characteristics, lipid class, fatty acid profiles and chloroplast ultrastructure were compared in Undaria pinnatifida (Phaeophyceae, Ochrophyta) after long-term exposure to low and moderate light intensities (LL, 100 and ML, 280 µmol photons · m-2 · s-1 ). We show that light limitation significantly increased PSII quantum efficiency and photosynthetic electron transport rate, enhanced pigment contents and concentration of thylakoid membranes in chloroplasts but decreased the distance between the thylakoid stacks. These physiological alterations at LL were accompanied by a selective remodeling of thylakoid membrane lipids driven by increases in monogalactosyldiacylglycerol (MGDG) and phosphatidylglycerol (PG) contents. Light limitation also induced active production of PG specific trans-Δ3 -hexadecenoic acid and accumulation of n-3 polyunsaturated fatty acids (PUFA) mostly in PG and MGDG at the expense of the rise in 18:3n-3 and 20:5n-3, 18:4n-3, respectively. These changes in lipid and FA profiles are apparently responsible for supporting thylakoid biogenesis and efficient photosynthesis at light limitation, thus contributing to photoacclimation strategies in brown algae. The content of triacylglycerols (TAG) and the level of their PUFA were decreased at LL, suggesting the consumption of TAG as a source of PUFA and energy reserves. Thus, U. pinnatifida is able to successfully overcome periods of low irradiance through the effective light harvesting and utilization that are provided by high flexibility of lipid biosynthesis.
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Affiliation(s)
- Natalia V Zhukova
- National Scientific Center of Marine Biology, Far East Branch of the Russian Academy of Sciences, Palchevskogo 17, Vladivostok, 690041, Russia
| | - Irina M Yakovleva
- National Scientific Center of Marine Biology, Far East Branch of the Russian Academy of Sciences, Palchevskogo 17, Vladivostok, 690041, Russia
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Duarte B, Feijão E, Cruz de Carvalho R, Duarte IA, Silva M, Matos AR, Cabrita MT, Novais SC, Lemos MFL, Marques JC, Caçador I, Reis-Santos P, Fonseca VF. Effects of Propranolol on Growth, Lipids and Energy Metabolism and Oxidative Stress Response of Phaeodactylum tricornutum. BIOLOGY 2020; 9:biology9120478. [PMID: 33353054 PMCID: PMC7766914 DOI: 10.3390/biology9120478] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 12/08/2020] [Accepted: 12/11/2020] [Indexed: 11/16/2022]
Abstract
Simple Summary In the past two decades, increasing attention has been directed to investigate the incidence and consequences of pharmaceuticals in the aquatic environment. Propranolol is a non-selective β-adrenoceptor blocker used in large quantities worldwide to treat cardiovascular conditions. Diatoms (model organism) exposed to this compound showed evident signs of oxidative stress, a significant reduction of the autotrophic O2 production and an increase in the heterotrophic mitochondrial respiration. Additionally, diatoms exposed to propranolol showed a consumption of its storage lipids. In ecological terms this will have cascading impacts in the marine trophic webs, where these organisms are key elements, through a reduction of the water column oxygenation and essential fatty acid availability to the heterotrophic organisms that depend on these primary producers. In ecotoxicological terms, diatoms photochemical and fatty acid traits showed to be potential good biomarkers for toxicity assessment of diatoms exposed to this widespread pharmaceutical compound. Abstract Present demographic trends suggest a rise in the contributions of human pharmaceuticals into coastal ecosystems, underpinning an increasing demand to evaluate the ecotoxicological effects and implications of drug residues in marine risk assessments. Propranolol, a non-selective β-adrenoceptor blocker, is used worldwide to treat high blood pressure conditions and other related cardiovascular conditions. Although diatoms lack β-adrenoceptors, this microalgal group presents receptor-like kinases and proteins with a functional analogy to the animal receptors and that can be targeted by propranolol. In the present work, the authors evaluated the effect of this non-selective β-adrenoceptor blocker in diatom cells using P. tricornutum as a model organism, to evaluate the potential effect of this compound in cell physiology (growth, lipids and energy metabolism and oxidative stress) and its potential relevance for marine ecosystems. Propranolol exposure leads to a significant reduction in diatom cell growth, more evident in the highest concentrations tested. This is likely due to the observed impairment of the main primary photochemistry processes and the enhancement of the mitochondrial respiratory activity. More specifically, propranolol decreased the energy transduction from photosystem II (PSII) to the electron transport chain, leading to an increase in oxidative stress levels. Cells exposed to propranolol also exhibited high-dissipated energy flux, indicating that this excessive energy is efficiently diverted, to some extent, from the photosystems, acting to prevent irreversible photoinhibition. As energy production is impaired at the PSII donor side, preventing energy production through the electron transport chain, diatoms appear to be consuming storage lipids as an energy backup system, to maintain essential cellular functions. This consumption will be attained by an increase in respiratory activity. Considering the primary oxygen production and consumption pathways, propranolol showed a significant reduction of the autotrophic O2 production and an increase in the heterotrophic mitochondrial respiration. Both mechanisms can have negative effects on marine trophic webs, due to a decrease in the energetic input from marine primary producers and a simultaneous oxygen production decrease for heterotrophic species. In ecotoxicological terms, bio-optical and fatty acid data appear as highly efficient tools for ecotoxicity assessment, with an overall high degree of classification when these traits are used to build a toxicological profile, instead of individually assessed.
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Affiliation(s)
- Bernardo Duarte
- MARE—Marine and Environmental Sciences Centre, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisbon, Portugal; (E.F.); (R.C.d.C.); (I.A.D.); (M.S.); (I.C.); (P.R.-S.); (V.F.F.)
- Departamento de Biologia Vegetal, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisbon, Portugal;
- Correspondence:
| | - Eduardo Feijão
- MARE—Marine and Environmental Sciences Centre, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisbon, Portugal; (E.F.); (R.C.d.C.); (I.A.D.); (M.S.); (I.C.); (P.R.-S.); (V.F.F.)
| | - Ricardo Cruz de Carvalho
- MARE—Marine and Environmental Sciences Centre, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisbon, Portugal; (E.F.); (R.C.d.C.); (I.A.D.); (M.S.); (I.C.); (P.R.-S.); (V.F.F.)
- cE3c, Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, Edifício C2, Piso 5, 1749-016 Lisbon, Portugal
| | - Irina A. Duarte
- MARE—Marine and Environmental Sciences Centre, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisbon, Portugal; (E.F.); (R.C.d.C.); (I.A.D.); (M.S.); (I.C.); (P.R.-S.); (V.F.F.)
| | - Marisa Silva
- MARE—Marine and Environmental Sciences Centre, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisbon, Portugal; (E.F.); (R.C.d.C.); (I.A.D.); (M.S.); (I.C.); (P.R.-S.); (V.F.F.)
| | - Ana Rita Matos
- Departamento de Biologia Vegetal, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisbon, Portugal;
- BioISI—Biosystems and Integrative Sciences Institute, Plant Functional Genomics Group, Departamento de Biologia Vegetal, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisbon, Portugal
| | - Maria Teresa Cabrita
- Centro de Estudos Geográficos (CEG), Instituto de Geografia e Ordenamento do Território (IGOT), Universidade de Lisboa, Rua Branca Edmée Marques, 1600-276 Lisbon, Portugal;
| | - Sara C. Novais
- MARE—Marine and Environmental Sciences Centre, ESTM, Politécnico de Leiria, 2520-641 Peniche, Portugal; (S.C.N.); (M.F.L.L.)
| | - Marco F. L. Lemos
- MARE—Marine and Environmental Sciences Centre, ESTM, Politécnico de Leiria, 2520-641 Peniche, Portugal; (S.C.N.); (M.F.L.L.)
| | - João Carlos Marques
- MARE—Marine and Environmental Sciences Centre, Department of Life Sciences, University of Coimbra, 3000 Coimbra, Portugal;
| | - Isabel Caçador
- MARE—Marine and Environmental Sciences Centre, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisbon, Portugal; (E.F.); (R.C.d.C.); (I.A.D.); (M.S.); (I.C.); (P.R.-S.); (V.F.F.)
- Departamento de Biologia Vegetal, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisbon, Portugal;
| | - Patrick Reis-Santos
- MARE—Marine and Environmental Sciences Centre, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisbon, Portugal; (E.F.); (R.C.d.C.); (I.A.D.); (M.S.); (I.C.); (P.R.-S.); (V.F.F.)
- Southern Seas Ecology Laboratories, School of Biological Sciences, The University of Adelaide, Aldeide, SA 5005, Australia
| | - Vanessa F. Fonseca
- MARE—Marine and Environmental Sciences Centre, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisbon, Portugal; (E.F.); (R.C.d.C.); (I.A.D.); (M.S.); (I.C.); (P.R.-S.); (V.F.F.)
- Departamento de Biologia Vegetal, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisbon, Portugal;
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Feijão E, Franzitta M, Cabrita MT, Caçador I, Duarte B, Gameiro C, Matos AR. Marine heat waves alter gene expression of key enzymes of membrane and storage lipids metabolism in Phaeodactylum tricornutum. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2020; 156:357-368. [PMID: 33002714 DOI: 10.1016/j.plaphy.2020.09.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Accepted: 09/16/2020] [Indexed: 06/11/2023]
Abstract
Across the globe, heat waves are getting more intense and frequent. Diatoms are a major group of microalgae at the base of the marine food webs and an important source of long chain polyunsaturated fatty acids that are transferred through the food web. The present study investigates the possible impacts of temperature increase on lipid classes and expression of genes encoding enzymes related to lipid metabolism in Phaeodactylum tricornutum. The heat wave exposure caused an increase in the relative amounts of plastidial lipids such as the glycolipids monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG) and sulphoquinovosyldiacylglycerol (SQDG) in parallel with a decrease in the neutral lipid fraction, which includes triacylglycerols. In agreement, gene expression analyses revealed an up-regulation of a gene encoding one MGDG synthase and down-regulation of a diacylglycerol acyltransferase (DGAT), a key enzyme in triacylglycerol synthesis. Our results show that heat waves not only negatively impact the abundance of unsaturated fatty acids such as eicosapentaenoic acid (20:5n-3, EPA) and hexadecatrienoic acid (16:3n-4) as observed by the decrease in their relative abundance in MGDG and neutral lipids, respectively, but also induce changes in the relative amounts of the diverse membrane lipids as well as the proportion of membrane/storage lipids. The expression study of key genes indicates that some of the aforementioned alterations are regulated at the transcription level whereas others appear to be post-transcriptional. The changes observed in plastidial lipids are related to negative impacts on the photosynthesis.
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Affiliation(s)
- Eduardo Feijão
- BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, 1749-016, Lisboa, Portugal; MARE - Marine and Environmental Sciences Centre, Faculty of Sciences of the University of Lisbon, Campo Grande, 1749-016, Lisbon, Portugal.
| | - Marco Franzitta
- BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, 1749-016, Lisboa, Portugal
| | - Maria Teresa Cabrita
- Centro de Estudos Geográficos (CEG), Instituto de Geografia e Ordenamento do Território (IGOT), Universidade de Lisboa, Rua Branca Edmée Marques, 1600-276, Lisboa, Portugal
| | - Isabel Caçador
- MARE - Marine and Environmental Sciences Centre, Faculty of Sciences of the University of Lisbon, Campo Grande, 1749-016, Lisbon, Portugal; Departamento de Biologia Vegetal, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016, Lisbon, Portugal
| | - Bernardo Duarte
- MARE - Marine and Environmental Sciences Centre, Faculty of Sciences of the University of Lisbon, Campo Grande, 1749-016, Lisbon, Portugal; Departamento de Biologia Vegetal, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016, Lisbon, Portugal
| | - Carla Gameiro
- IPMA, Instituto Português do Mar e Atmosfera, Div-RP - Divisão de Modelação e Gestão de Recursos de Pesca, 1495-165, Algés, Portugal
| | - Ana Rita Matos
- BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, 1749-016, Lisboa, Portugal; Departamento de Biologia Vegetal, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016, Lisbon, Portugal
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Glyphosate-Based Herbicide Toxicophenomics in Marine Diatoms: Impacts on Primary Production and Physiological Fitness. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10217391] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Glyphosate is the main active component of the commercial formulation Roundup®, the most widely used chemical herbicide worldwide. However, its potential high toxicity to the environment and throughout trophic webs has come under increasing scrutiny. The present study aims to investigate the application of bio-optical techniques and their correlation to physiological and biochemical processes, including primary productivity, oxidative stress, energy balance, and alterations in pigment and lipid composition in Phaeodactylum tricornutum, a representative species of marine diatoms, using the case study of its response to the herbicide glyphosate-based Roundup® formulation, at environmentally relevant concentrations. Cultures were exposed to the herbicide formulation representing effective glyphosate concentrations of 0, 10, 50, 100, 250, and 500 μg L−1. Results showed that high concentrations decreased cell density; furthermore, the inhibition of photosynthetic activity was not only caused by the impairment of electron transport in the thylakoids, but also by a decrease of antioxidant capacity and increased lipid peroxidation. Nevertheless, concentrations of one of the plastidial marker fatty acids had a positive correlation with the highest concentration as well as an increase in total protein. Cell energy allocation also increased with concentration, relative to control and the lowest concentration, although culture growth was inhibited. Pigment composition and fatty acid profiles proved to be efficient biomarkers for the highest glyphosate-based herbicide concentrations, while bio-optical data separated controls from intermediate concentrations and high concentrations.
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9
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Wilhelm C, Goss R, Garab G. The fluid-mosaic membrane theory in the context of photosynthetic membranes: Is the thylakoid membrane more like a mixed crystal or like a fluid? JOURNAL OF PLANT PHYSIOLOGY 2020; 252:153246. [PMID: 32777580 DOI: 10.1016/j.jplph.2020.153246] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/14/2020] [Accepted: 07/17/2020] [Indexed: 06/11/2023]
Abstract
Since the publication of the fluid-mosaic membrane theory by Singer and Nicolson in 1972 generations of scientists have adopted this fascinating concept for all biological membranes. Assuming the membrane as a fluid implies that the components embedded in the lipid bilayer can freely diffuse like swimmers in a water body. During the detailed biochemical analysis of the thylakoid protein components of chloroplasts from higher plants and algae, in the '80 s and '90 s it became clear that photosynthetic membranes are not homogeneous either in the vertical or the lateral directions. The lateral heterogeneity became obvious by the differentiation of grana and stroma thylakoids, but also the margins have been identified with a highly specific protein pattern. Further refinement of the fluid mosaic model was needed to take into account the presence of non-bilayer lipids, which are the most abundant lipids in all energy-converting membranes, and the polymorphism of lipid phases, which has also been documented in thylakoid membranes. These observations lead to the question, how mobile the components are in the lipid phase and how this ordering is made and maintained and how these features might be correlated with the non-bilayer propensity of the membrane lipids. Assuming instead of free diffusion, a "controlled neighborhood" replaced the model of fluidity by the model of a "mixed crystal structure". In this review we describe why basic photosynthetic regulation mechanisms depend on arrays of crystal-like lipid-protein macro-assemblies. The mechanisms which define the ordering in macrodomains are still not completely clear, but some recent experiments give an idea how this fascinating order is produced, adopted and maintained. We use the operation of the xanthophyll cycle as a rather well understood model challenging and complementing the standard Singer-Nicolson model via assigning special roles to non-bilayer lipids and non-lamellar lipid phases in the structure and function of thylakoid membranes.
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Affiliation(s)
- Christian Wilhelm
- Leipzig University, Institute of Biology, SenProf Algal Biotechnology, Permoserstr. 15, 04315, Leipzig, Germany; German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, D-04103, Leipzig, Germany.
| | - Reimund Goss
- Leipzig University, Institute of Biology, Department of Plant Physiology, Johannisallee 21-23, D-04103, Leipzig, Germany
| | - Gyözö Garab
- Biological Research Centre, Institute of Plant Biology, Temesvári körút 62, H-6726, Szeged, Hungary; University of Ostrava, Department of Physics, Faculty of Science, Chittussiho 10, CZ-710 00, Ostrava, Slezská Ostrava, Czech Republic
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10
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Vajravel S, Laczkó-Dobos H, Petrova N, Herman É, Kovács T, Zakar T, Todinova S, Taneva S, Kovács L, Gombos Z, Tóth T, Krumova S. Phycobilisome integrity and functionality in lipid unsaturation and xanthophyll mutants in Synechocystis. PHOTOSYNTHESIS RESEARCH 2020; 145:179-188. [PMID: 32720110 DOI: 10.1007/s11120-020-00776-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 07/19/2020] [Indexed: 06/11/2023]
Abstract
The major light-harvesting system in cyanobacteria, the phycobilisome, is an essential component of the photosynthetic apparatus that regulates the utilization of the natural light source-the Sun. Earlier works revealed that the thylakoid membrane composition and its physical properties might have an important role in antennas docking. Polyunsaturated lipids and xanthophylls are among the most significant modulators of the physical properties of thylakoid membranes. In the nature, the action of these molecules is orchestrated in response to environmental stimuli among which the growth temperature is the most influential. In order to further clarify the significance of thylakoid membrane physical properties for the phycobilisomes assembly (i.e. structural integrity) and their ability to efficiently direct the excitation energy towards the photosynthetic complexes, in this work, we utilize cyanobacterial Synechocystis sp. PCC 6803 mutants deficient in polyunsaturated lipids (AD mutant) and xanthophylls (RO mutant), as well as a strain depleted of both xanthophylls and polyunsaturated lipids (ROAD multiple mutant). For the first time, we discuss the effect of those mutations on the phycobilisomes assembly, integrity and functionality at optimal (30 °C) and moderate low (25 °C) and high (35 °C) temperatures. Our results show that xanthophyll depletion exerts a much stronger effect on both phycobilisome's integrity and the response of cells to growth at suboptimal temperatures than lipid unsaturation level. The strongest effects were observed for the combined ROAD mutant, which exhibited thermally destabilized phycobilisomes and a population of energetically uncoupled phycocyanin units.
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Affiliation(s)
- Sindhujaa Vajravel
- Institute of Plant Biology, Biological Research Centre, Szeged, Hungary
- Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku, Finland
| | | | - Nia Petrova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Éva Herman
- Institute of Plant Biology, Biological Research Centre, Szeged, Hungary
| | - Terézia Kovács
- Institute of Plant Biology, Biological Research Centre, Szeged, Hungary
- Department of Plant Biology, University of Szeged, Szeged, Hungary
| | - Tomas Zakar
- Institute of Plant Biology, Biological Research Centre, Szeged, Hungary
- Institute of Photonics and Electronics, The Czech Academy of Sciences, Prague, Czech Republic
| | - Svetla Todinova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Stefka Taneva
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Lászlo Kovács
- Institute of Plant Biology, Biological Research Centre, Szeged, Hungary
| | - Zoltan Gombos
- Institute of Plant Biology, Biological Research Centre, Szeged, Hungary
| | - Tünde Tóth
- Institute of Plant Biology, Biological Research Centre, Szeged, Hungary
| | - Sashka Krumova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria.
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11
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Feijão E, Cruz de Carvalho R, Duarte IA, Matos AR, Cabrita MT, Novais SC, Lemos MFL, Caçador I, Marques JC, Reis-Santos P, Fonseca VF, Duarte B. Fluoxetine Arrests Growth of the Model Diatom Phaeodactylum tricornutum by Increasing Oxidative Stress and Altering Energetic and Lipid Metabolism. Front Microbiol 2020; 11:1803. [PMID: 32849412 PMCID: PMC7411086 DOI: 10.3389/fmicb.2020.01803] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 07/09/2020] [Indexed: 11/13/2022] Open
Abstract
Pharmaceutical residues impose a new and emerging threat to aquatic environments and its biota. One of the most commonly prescribed pharmaceuticals is the antidepressant fluoxetine, a selective serotonin re-uptake inhibitor that has been frequently detected, in concentrations up to 40 μg L–1, in aquatic ecosystems. The present study aims to investigate the ecotoxicity of fluoxetine at environmentally relevant concentrations (0.3, 0.6, 20, 40, and 80 μg L–1) on cell energy and lipid metabolism, as well as oxidative stress biomarkers in the model diatom Phaeodactylum tricornutum. Exposure to higher concentrations of fluoxetine negatively affected cell density and photosynthesis through a decrease in the active PSII reaction centers. Stress response mechanisms, like β-carotene (β-car) production and antioxidant enzymes [superoxide dismutase (SOD) and ascorbate peroxidase (APX)] up-regulation were triggered, likely as a positive feedback mechanism toward formation of fluoxetine-induced reactive oxygen species. Lipid peroxidation products increased greatly at the highest fluoxetine concentration whereas no variation in the relative amounts of long chain polyunsaturated fatty acids (LC-PUFAs) was observed. However, monogalactosyldiacylglycerol-characteristic fatty acids such as C16:2 and C16:3 increased, suggesting an interaction between light harvesting pigments, lipid environment, and photosynthesis stabilization. Using a canonical multivariate analysis, it was possible to evaluate the efficiency of the application of bio-optical and biochemical techniques as potential fluoxetine exposure biomarkers in P. tricornutum. An overall classification efficiency to the different levels of fluoxetine exposure of 61.1 and 88.9% were obtained for bio-optical and fatty acids profiles, respectively, with different resolution degrees highlighting these parameters as potential efficient biomarkers. Additionally, the negative impact of this pharmaceutical molecule on the primary productivity is also evident alongside with an increase in respiratory oxygen consumption. From the ecological point of view, reduction in diatom biomass due to continued exposure to fluoxetine may severely impact estuarine and coastal trophic webs, by both a reduction in oxygen primary productivity and reduced availability of key fatty acids to the dependent heterotrophic upper levels.
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Affiliation(s)
- Eduardo Feijão
- MARE - Marine and Environmental Sciences Centre, Faculdade de Ciências da Universidade de Lisboa, Lisbon, Portugal
| | - Ricardo Cruz de Carvalho
- MARE - Marine and Environmental Sciences Centre, Faculdade de Ciências da Universidade de Lisboa, Lisbon, Portugal.,cE3c - Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
| | - Irina A Duarte
- MARE - Marine and Environmental Sciences Centre, Faculdade de Ciências da Universidade de Lisboa, Lisbon, Portugal
| | - Ana Rita Matos
- BioISI - Biosystems and Integrative Sciences Institute, Plant Functional Genomics Group, Departamento de Biologia Vegetal, Faculdade de Ciências da Universidade de Lisboa, Lisbon, Portugal
| | - Maria Teresa Cabrita
- Centro de Estudos Geográficos, Instituto de Geografia e Ordenamento do Território, University of Lisbon, Lisbon, Portugal
| | - Sara C Novais
- MARE - Marine and Environmental Sciences Centre, ESTM, Politécnico de Leiria, Peniche, Portugal
| | - Marco F L Lemos
- MARE - Marine and Environmental Sciences Centre, ESTM, Politécnico de Leiria, Peniche, Portugal
| | - Isabel Caçador
- MARE - Marine and Environmental Sciences Centre, Faculdade de Ciências da Universidade de Lisboa, Lisbon, Portugal
| | - João Carlos Marques
- MARE - Marine and Environmental Sciences Centre, Department of Zoology, Faculty of Sciences and Technology, University of Coimbra, Coimbra, Portugal
| | - Patrick Reis-Santos
- MARE - Marine and Environmental Sciences Centre, Faculdade de Ciências da Universidade de Lisboa, Lisbon, Portugal.,Southern Seas Ecology Laboratories, School of Biological Sciences, The University of Adelaide, Adelaide, SA, Australia
| | - Vanessa F Fonseca
- MARE - Marine and Environmental Sciences Centre, Faculdade de Ciências da Universidade de Lisboa, Lisbon, Portugal.,Departamento de Biologia Animal, Faculdade de Ciências da Universidade de Lisboa, Lisbon, Portugal
| | - Bernardo Duarte
- MARE - Marine and Environmental Sciences Centre, Faculdade de Ciências da Universidade de Lisboa, Lisbon, Portugal
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12
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From photosynthesis to photocatalysis: Dual catalytic oxidation/reduction in one system. Proc Natl Acad Sci U S A 2020; 117:8672-8673. [PMID: 32277026 DOI: 10.1073/pnas.2003512117] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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13
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Müh F, Zouni A. Structural basis of light-harvesting in the photosystem II core complex. Protein Sci 2020; 29:1090-1119. [PMID: 32067287 PMCID: PMC7184784 DOI: 10.1002/pro.3841] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Revised: 02/06/2020] [Accepted: 02/06/2020] [Indexed: 12/20/2022]
Abstract
Photosystem II (PSII) is a membrane-spanning, multi-subunit pigment-protein complex responsible for the oxidation of water and the reduction of plastoquinone in oxygenic photosynthesis. In the present review, the recent explosive increase in available structural information about the PSII core complex based on X-ray crystallography and cryo-electron microscopy is described at a level of detail that is suitable for a future structure-based analysis of light-harvesting processes. This description includes a proposal for a consistent numbering scheme of protein-bound pigment cofactors across species. The structural survey is complemented by an overview of the state of affairs in structure-based modeling of excitation energy transfer in the PSII core complex with emphasis on electrostatic computations, optical properties of the reaction center, the assignment of long-wavelength chlorophylls, and energy trapping mechanisms.
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Affiliation(s)
- Frank Müh
- Department of Theoretical Biophysics, Institute for Theoretical Physics, Johannes Kepler University Linz, Linz, Austria
| | - Athina Zouni
- Humboldt-Universität zu Berlin, Institute for Biology, Biophysics of Photosynthesis, Berlin, Germany
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14
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Azouz M, Gonin M, Fiedler S, Faherty J, Decossas M, Cullin C, Villette S, Lafleur M, D Alves I, Lecomte S, Ciaccafava A. Microfluidic diffusional sizing probes lipid nanodiscs formation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183215. [PMID: 32061645 DOI: 10.1016/j.bbamem.2020.183215] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 02/04/2020] [Accepted: 02/05/2020] [Indexed: 12/29/2022]
Abstract
The biophysical characterisation of membrane proteins and their interactions with lipids in native membrane habitat remains a major challenge. Indeed, traditional solubilisation procedures with detergents often causes the loss of native lipids surrounding membrane proteins, which ultimately impacts structural and functional properties. Recently, copolymer-based nanodiscs have emerged as a highly promising tool, thanks to their unique ability of solubilising membrane proteins directly from native membranes, in the shape of discoidal patches of lipid bilayers. While this methodology finally set us free from the use of detergents, some limitations are however associated with the use of such copolymers. Among them, one can cite the tedious control of the nanodiscs size, their instability in basic pH and in the presence of divalent cations. In this respect, many variants of the widely used Styrene Maleic Acid (SMA) copolymer have been developed to specifically address those limitations. With the multiplication of new SMA copolymer variants and the growing interest in copolymer-based nanodiscs for the characterisation of membrane proteins, there is a need to better understand and control their formation. Among the techniques used to characterise the solubilisation of lipid bilayer by amphipathic molecules, cryo-TEM, 31P NMR, DLS, ITC and fluorescence spectroscopy are the most widely used, with a consensus made in the sense that a combination of these techniques is required. In this work, we propose to evaluate the capacity of Microfluidic Diffusional Sizing (MDS) as a new method to follow copolymer nanodiscs formation. Originally designed to determine protein size through laminar flow diffusion, we present a novel application along with a protocol development to observe nanodiscs formation by MDS. We show that MDS allows to precisely measure the size of nanodiscs, and to determine the copolymer/lipid ratio at the onset of solubilisation. Finally, we use MDS to characterise peptide/nanodisc interaction. The technique shows a promising ability to highlight the pivotal role of lipids in promoting interactions through a case study with an aggregating peptide. This confirmed the relevance of using the MDS and nanodiscs as biomimetic models for such investigations.
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Affiliation(s)
- Mehdi Azouz
- Univ Bordeaux, CNRS, CBMN UMR 5248, Bat B14 Allée Geoffroy St Hilaire, F-33600 Pessac, France
| | - Mathilde Gonin
- Univ Bordeaux, CNRS, CBMN UMR 5248, Bat B14 Allée Geoffroy St Hilaire, F-33600 Pessac, France
| | - Sebastian Fiedler
- Fluidic Analytics Ltd, Unit A, The Paddocks Business Centre, Cherry Hinton Rd, Cambridge CB1 8DH, United Kingdom
| | - Jonathan Faherty
- Fluidic Analytics Ltd, Unit A, The Paddocks Business Centre, Cherry Hinton Rd, Cambridge CB1 8DH, United Kingdom
| | - Marion Decossas
- Univ Bordeaux, CNRS, CBMN UMR 5248, Bat B14 Allée Geoffroy St Hilaire, F-33600 Pessac, France
| | - Christophe Cullin
- Univ Bordeaux, CNRS, CBMN UMR 5248, Bat B14 Allée Geoffroy St Hilaire, F-33600 Pessac, France
| | - Sandrine Villette
- Univ Bordeaux, CNRS, CBMN UMR 5248, Bat B14 Allée Geoffroy St Hilaire, F-33600 Pessac, France
| | - Michel Lafleur
- Department of chemistry, Université de Montréal, 2900, Édouard-Montpetit blvd., Montréal, Québec, Canada
| | - Isabel D Alves
- Univ Bordeaux, CNRS, CBMN UMR 5248, Bat B14 Allée Geoffroy St Hilaire, F-33600 Pessac, France
| | - Sophie Lecomte
- Univ Bordeaux, CNRS, CBMN UMR 5248, Bat B14 Allée Geoffroy St Hilaire, F-33600 Pessac, France.
| | - Alexandre Ciaccafava
- Univ Bordeaux, CNRS, CBMN UMR 5248, Bat B14 Allée Geoffroy St Hilaire, F-33600 Pessac, France.
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15
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Hernando M, Orriss G, Perodeau J, Lei S, Ferens FG, Patel TR, Stetefeld J, Nieuwkoop AJ, O'Neil JD. Solution structure and oligomeric state of the E. coliglycerol facilitator. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183191. [PMID: 31953232 DOI: 10.1016/j.bbamem.2020.183191] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 12/05/2019] [Accepted: 01/10/2020] [Indexed: 12/11/2022]
Abstract
Protein dynamics at atomic resolution can provide deep insights into the biological activities of proteins and enzymes but they can also make structure and dynamics studies challenging. Despite their well-known biological and pharmaceutical importance, integral membrane protein structure and dynamics studies lag behind those of water-soluble proteins mainly owing to solubility problems that result upon their removal from the membrane. Escherichia coli glycerol facilitator (GF) is a member of the aquaglyceroporin family that allows for the highly selective passive diffusion of its substrate glycerol across the inner membrane of the bacterium. Previous molecular dynamics simulations and hydrogen-deuterium exchange studies suggested that protein dynamics play an important role in the passage of glycerol through the protein pore. With the aim of studying GF dynamics by solution and solid-state nuclear magnetic resonance (NMR) spectroscopy we optimized the expression of isotope-labelled GF and explored various solubilizing agents including detergents, osmolytes, amphipols, random heteropolymers, lipid nanodiscs, bicelles and other buffer additives to optimize the solubility and polydispersity of the protein. The GF protein is most stable and soluble in lauryl maltose neopentyl glycol (LMNG), where it exists in a tetramer-octamer equilibrium. The solution structures of the GF tetramer and octamer were determined by negative-stain transmission electron microscopy (TEM), size-exclusion chromatography small-angle X-ray scattering (SEC-SAXS) and solid-state magic-angle spinning NMR spectroscopy. Although NMR sample preparation still needs optimization for full structure and dynamics studies, negative stain TEM and SEC-SAXS revealed low-resolution structures of the detergent-solubilized tetramer and octamer particles. The non-native octamer appears to form from the association of the cytoplasmic faces of two tetramers, the interaction apparently mediated by their disordered N- and C-termini. This information may be useful in future studies directed at reducing the heterogeneity and self-association of the protein.
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Affiliation(s)
- Mary Hernando
- Department of Chemistry, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - George Orriss
- Department of Chemistry, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Jacqueline Perodeau
- Department of Chemistry and Chemical Biology, Rutgers School of Arts and Sciences, 123 Bevier Rd., Piscataway, NJ 08854, USA
| | - Shixing Lei
- Department of Chemistry, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Fraser G Ferens
- Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Trushar R Patel
- Alberta RNA Research & Training Institute, Department of Chemistry & Biochemistry, Lethbridge University, 4401 University Drive, Lethbridge, Alberta T1K 3M4, Canada
| | - Jörg Stetefeld
- Department of Chemistry, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Andrew J Nieuwkoop
- Department of Chemistry and Chemical Biology, Rutgers School of Arts and Sciences, 123 Bevier Rd., Piscataway, NJ 08854, USA
| | - Joe D O'Neil
- Department of Chemistry, University of Manitoba, Winnipeg, MB R3T 2N2, Canada.
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16
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Duarte B, Prata D, Matos AR, Cabrita MT, Caçador I, Marques JC, Cabral HN, Reis-Santos P, Fonseca VF. Ecotoxicity of the lipid-lowering drug bezafibrate on the bioenergetics and lipid metabolism of the diatom Phaeodactylum tricornutum. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 650:2085-2094. [PMID: 30290350 DOI: 10.1016/j.scitotenv.2018.09.354] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 09/24/2018] [Accepted: 09/28/2018] [Indexed: 06/08/2023]
Abstract
Pharmaceutical residues impose a new and emerging threat to the marine environment and its biota. In most countries, ecotoxicity tests are not required for all pharmaceutical residues classes and, even when mandatory, these tests are not performed using marine primary producers such as diatoms. These microalgae are among the most abundant class of primary producers in the marine realm and key players in the marine trophic web. Blood-lipid-lowering agents such as bezafibrate and its derivatives are among the most prescribed drugs and most frequently found human pharmaceuticals in aquatic environments. The present study aims to investigate the bezafibrate ecotoxicity and its effects on primary productivity and lipid metabolism, at environmentally relevant concentrations, using the model diatom Phaeodactylum tricornutum. Under controlled conditions, diatom cultures were exposed to bezafibrate at 0, 3, 6, 30 and 60 μg L-1, representing concentrations that can be found in the vicinity of discharges of wastewater treatment plants. High bezafibrate concentrations increased cell density and are suggested to promote a shift from autotrophic to mixotrophic metabolism, with diatoms using light energy generated redox potential to breakdown bezafibrate as carbon source. This was supported by an evident increase in cell density coupled with an impairment of the thylakoid electron transport and consequent photosynthetic activity reduction. In agreement, the concentrations of plastidial marker fatty acids showed negative correlations and Canonical Analysis of Principal coordinates of the relative abundances of fatty acid and photochemical data allowed the separation of controls and cells exposed to bezafibrate with high classification efficiency, namely for photochemical traits, suggesting their validity as suitable biomarkers of bezafibrate exposure. Further evaluations of the occurrence of a metabolic shift in diatoms due to exposure to bezafibrate is paramount, as ultimately it may reduce O2 generation and CO2 fixation in aquatic ecosystems with ensuing consequences for neighboring heterotrophic organisms.
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Affiliation(s)
- Bernardo Duarte
- MARE - Marine and Environmental Sciences Centre, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisbon, Portugal.
| | - Diogo Prata
- BioISI - Biosystems and Integrative Sciences Institute, Plant Functional Genomics Group, Departamento de Biologia Vegetal, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
| | - Ana Rita Matos
- BioISI - Biosystems and Integrative Sciences Institute, Plant Functional Genomics Group, Departamento de Biologia Vegetal, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
| | - Maria Teresa Cabrita
- Instituto do Mar e da Atmosfera (IPMA), Rua Alfredo Magalhães Ramalho, 6, 1495-006, Algés, Lisboa, Portugal
| | - Isabel Caçador
- MARE - Marine and Environmental Sciences Centre, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisbon, Portugal
| | - João Carlos Marques
- MARE - Marine and Environmental Sciences Centre, c/o Department of Zoology, Faculty of Sciences and Technology, University of Coimbra, 3000 Coimbra, Portugal
| | - Henrique N Cabral
- MARE - Marine and Environmental Sciences Centre, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisbon, Portugal; Irstea, UR EABX (Ecosystèmes Aquatiques et Changements Globaux), 50 avenue de Verdun, 33610 Cestas, France
| | - Patrick Reis-Santos
- MARE - Marine and Environmental Sciences Centre, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisbon, Portugal; Southern Seas Ecology Laboratories, School of Biological Sciences, The University of Adelaide, SA 5005, Australia
| | - Vanessa F Fonseca
- MARE - Marine and Environmental Sciences Centre, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisbon, Portugal
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17
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Yao M, Liu Y, Fei L, Zhou Y, Wang F, Chen J. Self-Adaptable Quinone-Quinol Exchange Mechanism of Photosystem II. J Phys Chem B 2018; 122:10478-10489. [PMID: 30380868 DOI: 10.1021/acs.jpcb.8b09641] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The step of plastoquinone (PQ) reduction to plastoquinol (PQH2) can regulate the photoreaction rate of photosystem II (PSII). To experimentally unravel the PQ-PQH2 exchange mechanism of PSII, we investigate the reaction kinetics of plant PSII membranes and the subunits-trimmed PSII core complexes with various PQ analogues and directly probe the reductions of PQ and other quinones by 257 nm resonance Raman scattering. Two phases of quinone concentration effect on the reaction rate originate from the quinone-quinol exchange mechanism. The results indicate that high concentrations of quinone, more than one movable quinone molecule per PSII reaction center, could trigger quinone-quinol exchange adapting to the unidirectional route: quinones enter through channel I and/or III, and quinols leave through channel II. A weak quinone binding site near QB probably plays a crucial role in pushing quinone-quinol exchange forward in the unidirectional route. Our work provides experimental proofs demonstrating a self-adaptable quinone-quinol exchange mechanism of PSII.
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Affiliation(s)
- Mingdong Yao
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics , Chinese Academy of Sciences , Dalian 116023 , China.,Key Laboratory of Systems Bioengineering (Ministry of Education) , Tianjin University , Tianjin 300072 , China
| | - Ying Liu
- Institute of Materials , China Academy of Engineering Physics , Mianyang 621907 , China
| | - Liping Fei
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics , Chinese Academy of Sciences , Dalian 116023 , China
| | - Ye Zhou
- Key Laboratory of Separation Sciences for Analytical Chemistry, National Chromatographic R&A Center, Dalian Institute of Chemical Physics , Chinese Academy of Sciences , Dalian 116023 , China
| | - Fangjun Wang
- Key Laboratory of Separation Sciences for Analytical Chemistry, National Chromatographic R&A Center, Dalian Institute of Chemical Physics , Chinese Academy of Sciences , Dalian 116023 , China
| | - Jun Chen
- Science and Technology on Surface Physics and Chemistry Laboratory , Jiangyou 621908 , China.,State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics , Chinese Academy of Sciences , Dalian 116023 , China
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Structural roles of lipid molecules in the assembly of plant PSII-LHCII supercomplex. BIOPHYSICS REPORTS 2018; 4:189-203. [PMID: 30310856 PMCID: PMC6153512 DOI: 10.1007/s41048-018-0068-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Accepted: 07/22/2018] [Indexed: 01/26/2023] Open
Abstract
In plants, photosystem II (PSII) associates with light-harvesting complexes II (LHCII) to form PSII–LHCII supercomplexes. They are multi-subunit supramolecular systems embedded in the thylakoid membrane of chloroplast, functioning as energy-converting and water-splitting machinery powered by light energy. The high-resolution structure of a PSII–LHCII supercomplex, previously solved through cryo-electron microscopy, revealed 34 well-defined lipid molecules per monomer of the homodimeric system. Here we characterize the distribution of lipid-binding sites in plant PSII–LHCII supercomplex and summarize their arrangement pattern within and across the membrane. These lipid molecules have crucial roles in stabilizing the oligomerization interfaces of plant PSII dimer and LHCII trimer. Moreover, they also mediate the interactions among PSII core subunits and contribute to the assembly between peripheral antenna complexes and PSII core. The detailed information of lipid-binding sites within PSII–LHCII supercomplex may serve as a framework for future researches on the functional roles of lipids in plant photosynthesis.
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Abstract
To study integral membrane proteins, one has to extract them from the membrane—the step that is typically achieved by the application of detergents. In this mini-review, we summarize the top 10 detergents used for the structural analysis of membrane proteins based on the published results. The aim of this study is to provide the reader with an overview of the main properties of available detergents (critical micelle concentration (CMC) value, micelle size, etc.) and provide an idea of what detergents to may merit further study. Furthermore, we briefly discuss alternative solubilization and stabilization agents, such as polymers.
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20
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Lipid and carotenoid cooperation-driven adaptation to light and temperature stress in Synechocystis sp. PCC6803. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2017; 1858:337-350. [PMID: 28188782 DOI: 10.1016/j.bbabio.2017.02.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 02/02/2017] [Accepted: 02/05/2017] [Indexed: 01/21/2023]
Abstract
Polyunsaturated lipids are important components of photosynthetic membranes. Xanthophylls are the main photoprotective agents, can assist in protection against light stress, and are crucial in the recovery from photoinhibition. We generated the xanthophyll- and polyunsaturated lipid-deficient ROAD mutant of Synechocystis sp. PCC6803 (Synechocystis) in order to study the little-known cooperative effects of lipids and carotenoids (Cars). Electron microscopic investigations confirmed that in the absence of xanthophylls the S-layer of the cellular envelope is missing. In wild-type (WT) cells, as well as the xanthophyll-less (RO), polyunsaturated lipid-less (AD), and the newly constructed ROAD mutants the lipid and Car compositions were determined by MS and HPLC, respectively. We found that, relative to the WT, the lipid composition of the mutants was remodeled and the Car content changed accordingly. In the mutants the ratio of non-bilayer-forming (NBL) to bilayer-forming (BL) lipids was found considerably lower. Xanthophyll to β-carotene ratio increased in the AD mutant. In vitro and in vivo methods demonstrated that saturated, monounsaturated lipids and xanthophylls may stabilize the trimerization of Photosystem I (PSI). Fluorescence induction and oxygen-evolving activity measurements revealed increased light sensitivity of RO cells compared to those of the WT. ROAD showed a robust increase in light susceptibility and reduced recovery capability, especially at moderate low (ML) and moderate high (MH) temperatures, indicating a cooperative effect of xanthophylls and polyunsaturated lipids. We suggest that both lipid unsaturation and xanthophylls are required for providing the proper structure and functioning of the membrane environment that protects against light and temperature stress.
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21
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Pospíšil P, Yamamoto Y. Damage to photosystem II by lipid peroxidation products. Biochim Biophys Acta Gen Subj 2017; 1861:457-466. [DOI: 10.1016/j.bbagen.2016.10.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 10/07/2016] [Accepted: 10/08/2016] [Indexed: 11/16/2022]
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22
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Zobnina V, Lambreva MD, Rea G, Campi G, Antonacci A, Scognamiglio V, Giardi MT, Polticelli F. The plastoquinol-plastoquinone exchange mechanism in photosystem II: insight from molecular dynamics simulations. PHOTOSYNTHESIS RESEARCH 2017; 131:15-30. [PMID: 27376842 DOI: 10.1007/s11120-016-0292-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 06/22/2016] [Indexed: 05/23/2023]
Abstract
In the photosystem II (PSII) of oxygenic photosynthetic organisms, the reaction center (RC) core mediates the light-induced electron transfer leading to water splitting and production of reduced plastoquinone molecules. The reduction of plastoquinone to plastoquinol lowers PSII affinity for the latter and leads to its release. However, little is known about the role of protein dynamics in this process. Here, molecular dynamics simulations of the complete PSII complex embedded in a lipid bilayer have been used to investigate the plastoquinol release mechanism. A distinct dynamic behavior of PSII in the presence of plastoquinol is observed which, coupled to changes in charge distribution and electrostatic interactions, causes disruption of the interactions seen in the PSII-plastoquinone complex and leads to the "squeezing out" of plastoquinol from the binding pocket. Displacement of plastoquinol closes the second water channel, recently described in a 2.9 Å resolution PSII structure (Guskov et al. in Nat Struct Mol Biol 16:334-342, 2009), allowing to rule out the proposed "alternating" mechanism of plastoquinol-plastoquinone exchange, while giving support to the "single-channel" one. The performed simulations indicated a pivotal role of D1-Ser264 in modulating the dynamics of the plastoquinone binding pocket and plastoquinol-plastoquinone exchange via its interaction with D1-His252 residue. The effects of the disruption of this hydrogen bond network on the PSII redox reactions were experimentally assessed in the D1 site-directed mutant Ser264Lys.
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Affiliation(s)
- Veranika Zobnina
- Theoretical Biology and Bioinformatics Laboratory, Department of Sciences, Roma Tre University, Viale G. Marconi 446, 00146, Rome, Italy
| | - Maya D Lambreva
- Institute of Crystallography CNR, 00015, Monterotondo Scalo, Rome, Italy
| | - Giuseppina Rea
- Institute of Crystallography CNR, 00015, Monterotondo Scalo, Rome, Italy
| | - Gaetano Campi
- Institute of Crystallography CNR, 00015, Monterotondo Scalo, Rome, Italy
| | - Amina Antonacci
- Institute of Crystallography CNR, 00015, Monterotondo Scalo, Rome, Italy
| | | | | | - Fabio Polticelli
- Theoretical Biology and Bioinformatics Laboratory, Department of Sciences, Roma Tre University, Viale G. Marconi 446, 00146, Rome, Italy.
- National Institute of Nuclear Physics, Roma Tre Section, 00146, Rome, Italy.
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23
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Endo K, Kobayashi K, Wada H. Sulfoquinovosyldiacylglycerol has an Essential Role in Thermosynechococcus elongatus BP-1 Under Phosphate-Deficient Conditions. PLANT & CELL PHYSIOLOGY 2016; 57:2461-2471. [PMID: 27615795 DOI: 10.1093/pcp/pcw159] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 09/07/2016] [Indexed: 06/06/2023]
Abstract
Anionic lipids, sulfoquinovosyldiacylglycerol (SQDG) and phosphatidylglycerol (PG), are major classes of the thylakoid membrane lipids in cyanobacteria and plant chloroplasts. PG is essential for growth and photosynthesis of cyanobacteria, algae and plants, but the requirement for SQDG differs even among cyanobacterial species. Although SQDG and PG can compensate each other in part presumably to maintain proper balance of anionic charge in lipid bilayers, the functional relationship of these lipids is largely unknown. In this study, we inactivated the sqdB gene, encoding a UDP-sulfoquinovose synthase and involved in SQDG biosynthesis, in Thermosynechococcus elongatus BP-1. In wild-type cells, PG accounted for only approximately 3.5 mol% of total membrane lipids, but its content was substantially increased along with complete loss of SQDG in the sqdB mutant. Under phosphate (Pi)-sufficient conditions, the growth rate and PSII activity were slightly lower in sqdB than in wild-type cells. In addition, the formation of PSI trimers and PSII dimers and energy transfer in phycobilisomes were perturbed in the mutant. Under Pi-deficient conditions, the growth of sqdB cells was severely impaired, with a decrease in PSII activity. PG supplementation could partially rescue the defective growth and PSII activity of Pi-deficient sqdB cells but fully recovered the impaired growth of the pgsA mutant of T. elongatus, which is deficient in PG biosynthesis. These data suggest that SQDG has a specific role in the growth and photosynthesis of T. elongatus, which cannot be complemented by PG, particularly under Pi-deficient conditions.
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Affiliation(s)
- Kaichiro Endo
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo, 153-8902 Japan
| | - Koichi Kobayashi
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo, 153-8902 Japan
| | - Hajime Wada
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo, 153-8902 Japan
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24
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van Eerden FJ, van den Berg T, Frederix PWJM, de Jong DH, Periole X, Marrink SJ. Molecular Dynamics of Photosystem II Embedded in the Thylakoid Membrane. J Phys Chem B 2016; 121:3237-3249. [PMID: 27624992 DOI: 10.1021/acs.jpcb.6b06865] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Photosystem II (PSII) is one of the key protein complexes in photosynthesis. We introduce a coarse grained model of PSII and present the analysis of 60 μs molecular dynamics simulations of PSII in both monomeric and dimeric form, embedded in a thylakoid membrane model that reflects its native lipid composition. We describe in detail the setup of the protein complex and the many natural cofactors and characterize their mobility. Overall we find that the protein subunits and cofactors are more flexible toward the periphery of the complex as well as near the PLQ exchange cavity and at the dimer interface. Of all cofactors, β-carotenes show the highest mobility. Some of the β-carotenes diffuse in and out of the protein complex via the thylakoid membrane. In contrast with the PSII dimer, the monomeric form adopts a tilted conformation in the membrane, with strong interactions between the soluble PsbO subunit and the glycolipid headgroups. Interestingly, the tilted conformation causes buckling of the membrane. Together, our results provide an unprecedented view of PSII dynamics on a microsecond time scale. Our data may be used as basis for the interpretation of experimental data as well as for theoretical models describing exciton energy transfer.
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Affiliation(s)
- Floris J van Eerden
- Groningen Biomolecular Sciences and Biotechnology Institute & Zernike Institute for Advanced Materials, University of Groningen , Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Tom van den Berg
- Department of Physics and Astronomy, Faculteit der Exacte Wetenschappen, Vrije Universiteit , De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Pim W J M Frederix
- Groningen Biomolecular Sciences and Biotechnology Institute & Zernike Institute for Advanced Materials, University of Groningen , Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Djurre H de Jong
- Groningen Biomolecular Sciences and Biotechnology Institute & Zernike Institute for Advanced Materials, University of Groningen , Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Xavier Periole
- Groningen Biomolecular Sciences and Biotechnology Institute & Zernike Institute for Advanced Materials, University of Groningen , Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Siewert J Marrink
- Groningen Biomolecular Sciences and Biotechnology Institute & Zernike Institute for Advanced Materials, University of Groningen , Nijenborgh 7, 9747 AG, Groningen, The Netherlands
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25
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Garab G, Ughy B, Goss R. Role of MGDG and Non-bilayer Lipid Phases in the Structure and Dynamics of Chloroplast Thylakoid Membranes. Subcell Biochem 2016; 86:127-57. [PMID: 27023234 DOI: 10.1007/978-3-319-25979-6_6] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In this chapter we focus our attention on the enigmatic structural and functional roles of the major, non-bilayer lipid monogalactosyl-diacylglycerol (MGDG) in the thylakoid membrane. We give an overview on the state of the art on the role of MGDG and non-bilayer lipid phases in the xanthophyll cycles in different organisms. We also discuss data on the roles of MGDG and other lipid molecules found in crystal structures of different photosynthetic protein complexes and in lipid-protein assemblies, as well as in the self-assembly of the multilamellar membrane system. Comparison and critical evaluation of different membrane models--that take into account and capitalize on the special properties of non-bilayer lipids and/or non-bilayer lipid phases, and thus to smaller or larger extents deviate from the 'standard' Singer-Nicolson model--will conclude this review. With this chapter the authors hope to further stimulate the discussion about, what we think, is perhaps the most exciting question of membrane biophysics: the why and wherefore of non-bilayer lipids and lipid phases in, or in association with, bilayer biological membranes.
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Affiliation(s)
- Győző Garab
- Biological Research Center, Hungarian Academy of Sciences, Szeged, Hungary.
| | - Bettina Ughy
- Biological Research Center, Hungarian Academy of Sciences, Szeged, Hungary
| | - Reimund Goss
- Institute of Biology, Department of Plant Physiology, University of Leipzig, Leipzig, Germany
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26
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The quest for energy traps in the CP43 antenna of photosystem II. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2015; 152:286-300. [DOI: 10.1016/j.jphotobiol.2015.05.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Revised: 05/13/2015] [Accepted: 05/28/2015] [Indexed: 01/08/2023]
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27
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Lambreva MD, Russo D, Polticelli F, Scognamiglio V, Antonacci A, Zobnina V, Campi G, Rea G. Structure/function/dynamics of photosystem II plastoquinone binding sites. Curr Protein Pept Sci 2015; 15:285-95. [PMID: 24678671 PMCID: PMC4030317 DOI: 10.2174/1389203715666140327104802] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Revised: 11/22/2013] [Accepted: 03/16/2014] [Indexed: 11/22/2022]
Abstract
Photosystem II (PSII)
continuously attracts the attention of researchers aiming to unravel the riddle
of its functioning and efficiency fundamental for all life on Earth. Besides, an
increasing number of biotechnological applications have been envisaged
exploiting and mimicking the unique properties of this macromolecular
pigment-protein complex. The PSII organization and working principles have
inspired the design of electrochemical water splitting schemes and charge
separating triads in energy storage systems as well as biochips and sensors for
environmental, agricultural and industrial screening of toxic compounds. An
intriguing opportunity is the development of sensor devices, exploiting native
or manipulated PSII complexes or ad hoc synthesized polypeptides
mimicking the PSII reaction centre proteins as bio-sensing elements. This review
offers a concise overview of the recent improvements in the understanding of
structure and function of PSII donor side, with focus on the interactions of the
plastoquinone cofactors with the surrounding environment and operational
features. Furthermore, studies focused on photosynthetic proteins
structure/function/dynamics and computational analyses aimed at rational design
of high-quality bio-recognition elements in biosensor devices are discussed.
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Affiliation(s)
| | | | | | | | | | | | | | - Giuseppina Rea
- Institute of Crystallography, National Research Council, Monterotondo, Italy.
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28
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Hellmich J, Bommer M, Burkhardt A, Ibrahim M, Kern J, Meents A, Müh F, Dobbek H, Zouni A. Native-like Photosystem II Superstructure at 2.44 Å Resolution through Detergent Extraction from the Protein Crystal. Structure 2014; 22:1607-15. [DOI: 10.1016/j.str.2014.09.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 08/26/2014] [Accepted: 09/10/2014] [Indexed: 10/24/2022]
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29
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Kansy M, Wilhelm C, Goss R. Influence of thylakoid membrane lipids on the structure and function of the plant photosystem II core complex. PLANTA 2014; 240:781-96. [PMID: 25063517 DOI: 10.1007/s00425-014-2130-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 07/14/2014] [Indexed: 05/18/2023]
Abstract
MGDG leads to a dimerization of isolated, monomeric PSII core complexes. SQDG and PG induce a detachment of CP43 from the PSII core, thereby disturbing the intrinsic PSII electron transport. The influence of the four thylakoid membrane lipids monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG), sulfoquinovosyldiacylglycerol (SQDG) and phosphatidylglycerol (PG) on the structure and function of isolated monomeric photosystem (PS) II core complexes was investigated. Incubation with the negatively charged lipids SQDG and PG led to a loss of the long-wavelength 77 K fluorescence emission at 693 nm that is associated with the inner antenna proteins. The neutral galactolipids DGDG and MGDG had no or only minor effects on the fluorescence emission spectra of the PSII core complexes, respectively. Pigment analysis, absorption and 77 K fluorescence excitation spectroscopy showed that incubation with SQDG and PG led to an exposure of chlorophyll molecules to the surrounding medium followed by conversion to pheophytin under acidic conditions. Size-exclusion chromatography and polypeptide analysis corroborated the findings of the spectroscopic measurements and pigment analysis. They showed that the negatively charged lipid SQDG led to a dissociation of the inner antenna protein CP43 and the 27- and 25-kDa apoproteins of the light-harvesting complex II, that were also associated with a part of the PSII core complexes used in the present study. Incubation of PSII core complexes with MGDG, on the other hand, induced an almost complete dimerization of the monomeric PSII. Measurements of the fast PSII fluorescence induction demonstrated that MGDG and DGDG only had a minor influence on the reduction kinetics of plastoquinone QA and the artificial PSII electron acceptor 2,5-dimethyl-p-benzoquinone (DMBQ). SQDG and, to a lesser extent, PG perturbed the intrinsic PSII electron transport significantly.
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Affiliation(s)
- Marcel Kansy
- Department of Plant Physiology, Institute of Biology, University of Leipzig, Johannisallee 21-23, 04103, Leipzig, Germany
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30
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Pogozheva ID, Mosberg HI, Lomize AL. Life at the border: adaptation of proteins to anisotropic membrane environment. Protein Sci 2014; 23:1165-96. [PMID: 24947665 DOI: 10.1002/pro.2508] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 06/17/2014] [Accepted: 06/18/2014] [Indexed: 12/25/2022]
Abstract
This review discusses main features of transmembrane (TM) proteins which distinguish them from water-soluble proteins and allow their adaptation to the anisotropic membrane environment. We overview the structural limitations on membrane protein architecture, spatial arrangement of proteins in membranes and their intrinsic hydrophobic thickness, co-translational and post-translational folding and insertion into lipid bilayers, topogenesis, high propensity to form oligomers, and large-scale conformational transitions during membrane insertion and transport function. Special attention is paid to the polarity of TM protein surfaces described by profiles of dipolarity/polarizability and hydrogen-bonding capacity parameters that match polarity of the lipid environment. Analysis of distributions of Trp resides on surfaces of TM proteins from different biological membranes indicates that interfacial membrane regions with preferential accumulation of Trp indole rings correspond to the outer part of the lipid acyl chain region-between double bonds and carbonyl groups of lipids. These "midpolar" regions are not always symmetric in proteins from natural membranes. We also examined the hydrophobic effect that drives insertion of proteins into lipid bilayer and different free energy contributions to TM protein stability, including attractive van der Waals forces and hydrogen bonds, side-chain conformational entropy, the hydrophobic mismatch, membrane deformations, and specific protein-lipid binding.
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Affiliation(s)
- Irina D Pogozheva
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, Michigan, 48109-1065
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31
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Gabdulkhakov AG, Dontsova MV. Structural studies on photosystem II of cyanobacteria. BIOCHEMISTRY (MOSCOW) 2014; 78:1524-38. [DOI: 10.1134/s0006297913130105] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- A G Gabdulkhakov
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
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32
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Lin CY, Chao L. Tunable nucleation time of functional sphingomyelinase--lipid features studied by membrane array statistic tool. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:13008-17. [PMID: 24059643 DOI: 10.1021/la401826b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Aggregation or assembly of lipids and proteins could significantly change the proteins' function. A peripheral membrane enzyme, sphingomyelinase (SMase), has been reported to be able to assemble to a functional feature with its lipid substrate, sphingomyelin (SM), and its lipid product, ceramide (Cer). SMase seems to processes its substrate more effectively in this feature. Here, we report that the functional feature has a tunable formation time. The peculiar behavior is that the feature formation has a time lag depending on the membrane composition. We hypothesized that the time lag is due to the significant nucleation energy barrier when the feature phase forms in its metastable parent phase in the 2-D lipid membrane. To study the stochastic nucleation of the feature, we built a corralled lipid membrane platform with numerous isolated membrane systems in parallel to capture the nucleation statistics. Using the high-throughput approach and the appropriate experimental design to circumvent the interplay of the complicated phase segregation in membranes induced by SMase, we found that the nucleation rate of the feature can be tuned by the supersaturation of the enzyme, the lipid substrate, and the lipid product, in the fluid phase of the membrane. The correlation between the supersaturation and the nucleation rate can be well described by the classical nucleation theory equation, suggesting that the feature formation follows the nucleation process with a certain component ratio specified in the equation. The certain relative component ratio suggests that the feature may have certain organization instead of being random aggregation. In addition, our finding suggests that nucleation could serve as a time lag control mechanism in this enzymatic system, and ways to reduce nucleation energy barrier could be used to shorten the aggregation time lag and vice versa.
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Affiliation(s)
- Charng-Yu Lin
- Department of Chemical Engineering, National Taiwan University , Taipei 106, Taiwan
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33
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Müh F, Zouni A. The nonheme iron in photosystem II. PHOTOSYNTHESIS RESEARCH 2013; 116:295-314. [PMID: 24077892 DOI: 10.1007/s11120-013-9926-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 09/17/2013] [Indexed: 06/02/2023]
Abstract
Photosystem II (PSII), the light-driven water:plastoquinone (PQ) oxidoreductase of oxygenic photosynthesis, contains a nonheme iron (NHI) at its electron acceptor side. The NHI is situated between the two PQs QA and QB that serve as one-electron transmitter and substrate of the reductase part of PSII, respectively. Among the ligands of the NHI is a (bi)carbonate originating from CO2, the substrate of the dark reactions of oxygenic photosynthesis. Based on recent advances in the crystallography of PSII, we review the structure of the NHI in PSII and discuss ideas concerning its function and the role of bicarbonate along with a comparison to the reaction center of purple bacteria and other enzymes containing a mononuclear NHI site.
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34
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Heyneke E, Luschin-Ebengreuth N, Krajcer I, Wolkinger V, Müller M, Zechmann B. Dynamic compartment specific changes in glutathione and ascorbate levels in Arabidopsis plants exposed to different light intensities. BMC PLANT BIOLOGY 2013; 13:104. [PMID: 23865417 PMCID: PMC3728233 DOI: 10.1186/1471-2229-13-104] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 07/16/2013] [Indexed: 05/03/2023]
Abstract
BACKGROUND Excess light conditions induce the generation of reactive oxygen species (ROS) directly in the chloroplasts but also cause an accumulation and production of ROS in peroxisomes, cytosol and vacuoles. Antioxidants such as ascorbate and glutathione occur in all cell compartments where they detoxify ROS. In this study compartment specific changes in antioxidant levels and related enzymes were monitored among Arabidopsis wildtype plants and ascorbate and glutathione deficient mutants (vtc2-1 and pad2-1, respectively) exposed to different light intensities (50, 150 which was considered as control condition, 300, 700 and 1,500 μmol m(-2) s(-1)) for 4 h and 14 d. RESULTS The results revealed that wildtype plants reacted to short term exposure to excess light conditions with the accumulation of ascorbate and glutathione in chloroplasts, peroxisomes and the cytosol and an increased activity of catalase in the leaves. Long term exposure led to an accumulation of ascorbate and glutathione mainly in chloroplasts. In wildtype plants an accumulation of ascorbate and hydrogen peroxide (H2O2) could be observed in vacuoles when exposed to high light conditions. The pad2-1 mutant reacted to long term excess light exposure with an accumulation of ascorbate in peroxisomes whereas the vtc2-1 mutant reacted with an accumulation of glutathione in the chloroplasts (relative to the wildtype) and nuclei during long term high light conditions indicating an important role of these antioxidants in these cell compartments for the protection of the mutants against high light stress. CONCLUSION The results obtained in this study demonstrate that the accumulation of ascorbate and glutathione in chloroplasts, peroxisomes and the cytosol is an important reaction of plants to short term high light stress. The accumulation of ascorbate and H2O2 along the tonoplast and in vacuoles during these conditions indicates an important route for H2O2 detoxification under these conditions.
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Affiliation(s)
- Elmien Heyneke
- Department of Lothar Willmitzer, Max-Planck-Institute of Molecular Plant Physiology, Golm, 14476, Germany
| | - Nora Luschin-Ebengreuth
- Institute for Electron Microscopy and Fine Structure Research, Graz University of Technology, Steyrergasse 17, Graz, 8010, Austria
- Institute of Plant Sciences, University of Graz, Schubertstrasse 51, Graz, 8010, Austria
| | - Iztok Krajcer
- Institute of Plant Sciences, University of Graz, Schubertstrasse 51, Graz, 8010, Austria
| | - Volker Wolkinger
- Institute of Plant Sciences, University of Graz, Schubertstrasse 51, Graz, 8010, Austria
| | - Maria Müller
- Institute of Plant Sciences, University of Graz, Schubertstrasse 51, Graz, 8010, Austria
| | - Bernd Zechmann
- Institute of Plant Sciences, University of Graz, Schubertstrasse 51, Graz, 8010, Austria
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Wu W, Ping W, Wu H, Li M, Gu D, Xu Y. Monogalactosyldiacylglycerol deficiency in tobacco inhibits the cytochrome b6f-mediated intersystem electron transport process and affects the photostability of the photosystem II apparatus. BIOCHIMICA ET BIOPHYSICA ACTA 2013; 1827:709-22. [PMID: 23466336 DOI: 10.1016/j.bbabio.2013.02.013] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 02/21/2013] [Accepted: 02/23/2013] [Indexed: 10/27/2022]
Abstract
Monogalactosyldiacylglycerol (MGDG) is the most abundant lipid component of the thylakoid membrane. Although MGDG is believed to be important in sustaining the structure and function of the photosynthetic membrane, its exact role in photosynthesis in vivo requires further investigation. In this study, the transgenic tobacco plant M18, which has an MGDG deficiency of approximately 53%, and which contains many fewer thylakoid membranes and exhibits retarded growth and a chlorotic phenotype, was used to investigate the role of MGDG. Chlorophyll fluorescence analysis of the M18 line revealed that PSII activity was inhibited when the plants were exposed to light. The inactive linear electron transport found in M18 plants was mainly attributed to a block in the intersystem electron transport process that was revealed by P700 redox kinetics and PSI light response analysis. Immunoblotting and Blue Native SDS-PAGE analysis suggested that a reduction in the accumulation of cytochrome b6f in M18 plants is a direct structural effect of MGDG deficiency, and this is likely to be responsible for the inefficiency observed in intersystem electron transport. Although drastic impairments of PSII subunits were detected in M18 plants grown under normal conditions, further investigations of low-light-grown M18 plants indicated that the impairments are not direct structural effects. Instead, they are likely to result from the cumulative photodamage that occurs due to impaired photostability under long-term exposure to relatively high light levels. The study suggests that MGDG plays important roles in maintaining both the linear electron transport process and the photostability of the PSII apparatus.
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Affiliation(s)
- Wang Wu
- Institute of Botany, Chinese Academy of Sciences, Beijing, China
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Kobayashi K, Narise T, Sonoike K, Hashimoto H, Sato N, Kondo M, Nishimura M, Sato M, Toyooka K, Sugimoto K, Wada H, Masuda T, Ohta H. Role of galactolipid biosynthesis in coordinated development of photosynthetic complexes and thylakoid membranes during chloroplast biogenesis in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 73:250-61. [PMID: 22978702 DOI: 10.1111/tpj.12028] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2011] [Revised: 08/21/2012] [Accepted: 09/10/2012] [Indexed: 05/17/2023]
Abstract
The galactolipids monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG) are the predominant lipids in thylakoid membranes and indispensable for photosynthesis. Among the three isoforms that catalyze MGDG synthesis in Arabidopsis thaliana, MGD1 is responsible for most galactolipid synthesis in chloroplasts, whereas MGD2 and MGD3 are required for DGDG accumulation during phosphate (Pi) starvation. A null mutant of Arabidopsis MGD1 (mgd1-2), which lacks both galactolipids and shows a severe defect in chloroplast biogenesis under nutrient-sufficient conditions, accumulated large amounts of DGDG, with a strong induction of MGD2/3 expression, during Pi starvation. In plastids of Pi-starved mgd1-2 leaves, biogenesis of thylakoid-like internal membranes, occasionally associated with invagination of the inner envelope, was observed, together with chlorophyll accumulation. Moreover, the mutant accumulated photosynthetic membrane proteins upon Pi starvation, indicating a compensation for MGD1 deficiency by Pi stress-induced galactolipid biosynthesis. However, photosynthetic activity in the mutant was still abolished, and light-harvesting/photosystem core complexes were improperly formed, suggesting a requirement for MGDG for proper assembly of these complexes. During Pi starvation, distribution of plastid nucleoids changed concomitantly with internal membrane biogenesis in the mgd1-2 mutant. Moreover, the reduced expression of nuclear- and plastid-encoded photosynthetic genes observed in the mgd1-2 mutant under Pi-sufficient conditions was restored after Pi starvation. In contrast, Pi starvation had no such positive effects in mutants lacking chlorophyll biosynthesis. These observations demonstrate that galactolipid biosynthesis and subsequent membrane biogenesis inside the plastid strongly influence nucleoid distribution and the expression of both plastid- and nuclear-encoded photosynthetic genes, independently of photosynthesis.
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Affiliation(s)
- Koichi Kobayashi
- Graduate School of Arts and Sciences, University of Tokyo, Komaba 3-8-1, Tokyo, 153-8902, Japan
- RIKEN Plant Science Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama, Kanagawa, 230-0045, Japan
| | - Takafumi Narise
- Center for Biological Resources and Informatics, Tokyo Institute of Technology, 4259-B-65 Nagatsuta-cho, Yokohama, 226-8501, Midori-ku, Japan
| | - Kintake Sonoike
- Faculty of Education and Integrated Arts and Sciences, Waseda University, 2-2 Wakamatsu-cho, Tokyo, 162-8480, Shinjuku-ku, Japan
| | - Haruki Hashimoto
- Graduate School of Arts and Sciences, University of Tokyo, Komaba 3-8-1, Tokyo, 153-8902, Japan
| | - Naoki Sato
- Graduate School of Arts and Sciences, University of Tokyo, Komaba 3-8-1, Tokyo, 153-8902, Japan
| | - Maki Kondo
- Department of Cell Biology, National Institute for Basic Biology, Okazaki, 444-8585, Japan
| | - Mikio Nishimura
- Department of Cell Biology, National Institute for Basic Biology, Okazaki, 444-8585, Japan
| | - Mayuko Sato
- RIKEN Plant Science Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama, Kanagawa, 230-0045, Japan
| | - Kiminori Toyooka
- RIKEN Plant Science Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama, Kanagawa, 230-0045, Japan
| | - Keiko Sugimoto
- RIKEN Plant Science Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama, Kanagawa, 230-0045, Japan
| | - Hajime Wada
- Graduate School of Arts and Sciences, University of Tokyo, Komaba 3-8-1, Tokyo, 153-8902, Japan
| | - Tatsuru Masuda
- Graduate School of Arts and Sciences, University of Tokyo, Komaba 3-8-1, Tokyo, 153-8902, Japan
| | - Hiroyuki Ohta
- Center for Biological Resources and Informatics, Tokyo Institute of Technology, 4259-B-65 Nagatsuta-cho, Yokohama, 226-8501, Midori-ku, Japan
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Evidence on the formation of singlet oxygen in the donor side photoinhibition of photosystem II: EPR spin-trapping study. PLoS One 2012; 7:e45883. [PMID: 23049883 PMCID: PMC3458798 DOI: 10.1371/journal.pone.0045883] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 08/27/2012] [Indexed: 11/19/2022] Open
Abstract
When photosystem II (PSII) is exposed to excess light, singlet oxygen (1O2) formed by the interaction of molecular oxygen with triplet chlorophyll. Triplet chlorophyll is formed by the charge recombination of triplet radical pair 3[P680•+Pheo•−] in the acceptor-side photoinhibition of PSII. Here, we provide evidence on the formation of 1O2 in the donor side photoinhibition of PSII. Light-induced 1O2 production in Tris-treated PSII membranes was studied by electron paramagnetic resonance (EPR) spin-trapping spectroscopy, as monitored by TEMPONE EPR signal. Light-induced formation of carbon-centered radicals (R•) was observed by POBN-R adduct EPR signal. Increased oxidation of organic molecules at high pH enhanced the formation of TEMPONE and POBN-R adduct EPR signals in Tris-treated PSII membranes. Interestingly, the scavenging of R• by propyl gallate significantly suppressed 1O2. Based on our results, it is concluded that 1O2 formation correlates with R• formation on the donor side of PSII due to oxidation of organic molecules (lipids and proteins) by long-lived P680•+/TyrZ•. It is proposed here that the Russell mechanism for the recombination of two peroxyl radicals formed by the interaction of R• with molecular oxygen is a plausible mechanism for 1O2 formation in the donor side photoinhibition of PSII.
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Ivanov AG, Allakhverdiev SI, Huner NPA, Murata N. Genetic decrease in fatty acid unsaturation of phosphatidylglycerol increased photoinhibition of photosystem I at low temperature in tobacco leaves. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1817:1374-9. [PMID: 22445720 DOI: 10.1016/j.bbabio.2012.03.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 03/02/2012] [Accepted: 03/07/2012] [Indexed: 11/28/2022]
Abstract
Leaves of transgenic tobacco plants with decreased levels of fatty acid unsaturation in phosphatidylglycerol (PG) exhibited a slightly lower level of the steady state oxidation of the photosystem I (PSI) reaction center P700 (P700(+)) than wild-type plants. The PSI photochemistry of wild-type plants was only marginally affected by high light treatments. Surprisingly, all plants of transgenic lines exhibited much higher susceptibility to photoinhibition of PSI than wild-type plants. This was accompanied by a 2.5-fold faster re-reduction rate of P700(+) in the dark, indicating a higher capacity for cyclic electron flow around PSI in high light treated transgenic leaves. This was associated with a much higher intersystem electron pool size suggesting over-reduction of the PQ pool in tobacco transgenic lines with altered PG unsaturation compared to wild-type plants. The physiological role of PG unsaturation in PSI down-regulation and modulation of the capacity of PSI-dependent cyclic electron flows and distribution of excitation light energy in tobacco plants under photoinhibitory conditions at low temperatures is discussed. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial.
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Affiliation(s)
- A G Ivanov
- Department of Biology, University of Western Ontario, London, Ontario, Canada.
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Najafpour MM, Moghaddam AN, Allakhverdiev SI, Govindjee. Biological water oxidation: lessons from nature. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:1110-21. [PMID: 22507946 DOI: 10.1016/j.bbabio.2012.04.002] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 04/02/2012] [Accepted: 04/04/2012] [Indexed: 01/03/2023]
Abstract
Hydrogen production by water splitting may be an appealing solution for future energy needs. To evolve hydrogen efficiently in a sustainable manner, it is necessary first to synthesize what we may call a 'super catalyst' for water oxidation, which is the more challenging half reaction of water splitting. An efficient system for water oxidation exists in the water oxidizing complex in cyanobacteria, algae and plants; further, recently published data on the Manganese-calcium cluster have provided details on the mechanism and structure of the water oxidizing complex. Here, we have briefly reviewed the characteristics of the natural system from the standpoint of what we could learn from it to produce an efficient artificial system. In short, to design an efficient water oxidizing complex for artificial photosynthesis, we must learn and use wisely the knowledge about water oxidation and the water oxidizing complex in the natural system. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial.
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