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Calvaruso C, Stefanidis K, Büchel C. Photoacclimation impacts the molecular features of photosystem supercomplexes in the centric diatom Thalassiosira pseudonana. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2022; 1863:148589. [PMID: 35779585 DOI: 10.1016/j.bbabio.2022.148589] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Revised: 06/10/2022] [Accepted: 06/24/2022] [Indexed: 06/15/2023]
Abstract
In diatoms, light-harvesting processes take place in a specific group of proteins, called fucoxanthin chlorophyll a/c proteins (FCP). This group includes many members and represents the major characteristic of the diatom photosynthetic apparatus, with specific pigments bound (chlorophyll c, fucoxanthin, diadino- and diatoxanthin besides chlorophyll a). In thylakoids, FCP and photosystems (PS) form multimeric supercomplexes. In this study, we compared the biochemical properties of PS supercomplexes isolated from Thalassiosira pseudonana cells grown under low light or high light conditions, respectively. High light acclimation changed the molecular features of the PS and their ratio in thylakoids. In PSII, no obvious changes in polypeptide composition were observed, whereas for PSI changes in one specific group of FCP proteins were detected. As reported before, the amount of xanthophyll cycle pigments and their de-epoxidation ratio was increased in PSI under HL. In PSII, however, no additional xanthophyll cycle pigments occurred, but the de-epoxidation ratio was increased as well. This comparison suggests how mechanisms of photoprotection might take place within and in the proximity of the PS, which gives new insights into the capacity of diatoms to adapt to different conditions and in different environments.
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Affiliation(s)
- Claudio Calvaruso
- Institute of Molecular Biosciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Konstantinos Stefanidis
- Institute of Molecular Biosciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Claudia Büchel
- Institute of Molecular Biosciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany.
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2
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Thangaraj S, Palanisamy SK, Zhang G, Sun J. Quantitative Proteomic Profiling of Marine Diatom Skeletonema dohrnii in Response to Temperature and Silicate Induced Environmental Stress. Front Microbiol 2021; 11:554832. [PMID: 33519723 PMCID: PMC7841394 DOI: 10.3389/fmicb.2020.554832] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 12/23/2020] [Indexed: 11/17/2022] Open
Abstract
Global warming is expected to reduce the nutrient concentration in the upper ocean and affect the physiology of marine diatoms, but the underlying molecular mechanisms controlling these physiological changes are currently unknown. To understand these mechanisms, here we investigated iTRAQ based proteomic profiling of diatom Skeletonema dohrnii in a multifactorial experimental with a combining change of temperature and silicate concentrations. In total, 3369 differently abundant proteins were detected in four different environmental conditions, and the function of all proteins was identified using Gene Ontology and KEGG pathway analysis. For discriminating the proteome variation among samples, multivariate statistical analysis (PCA, PLS-DA) was performed by comparing the protein ratio differences. Further, performing pathway analysis on diatom proteomes, we here demonstrated downregulation of photosynthesis, carbon metabolism, and ribosome biogenesis in the cellular process that leads to decrease the oxidoreductase activity and affects the cell cycle of the diatom. Using PLS-DA VIP score plot analysis, we identified 15 protein biomarkers for discriminating studied samples. Of these, five proteins or gene (rbcL, PRK, atpB, DNA-binding, and signal transduction) identified as key biomarkers, induced by temperature and silicate stress in diatom metabolism. Our results show that proteomic finger-printing of S. dohrnii with different environmental conditions adds biological information that strengthens marine phytoplankton proteome analysis.
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Affiliation(s)
| | - Satheesh Kumar Palanisamy
- Department of Zoology, School of Natural Science, Ryan Institute, National University of Ireland, Galway, Ireland
| | - Guicheng Zhang
- Research Center for Indian Ocean Ecosystem, Tianjin University of Science and Technology, Tianjin, China.,Tianjin Key Laboratory of Marine Resources and Chemistry, Tianjin University of Science and Technology, Tianjin, China
| | - Jun Sun
- College of Marine Science and Technology, China University of Geosciences, Wuhan, China
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3
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Chetouhi C, Masseret E, Satta CT, Balliau T, Laabir M, Jean N. Intraspecific variability in membrane proteome, cell growth, and morphometry of the invasive marine neurotoxic dinoflagellate Alexandrium pacificum grown in metal-contaminated conditions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 715:136834. [PMID: 32014766 DOI: 10.1016/j.scitotenv.2020.136834] [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: 11/08/2019] [Revised: 01/03/2020] [Accepted: 01/19/2020] [Indexed: 06/10/2023]
Abstract
Over the past decades, the occurrence, distribution and intensity of harmful algal blooms involving the dinoflagellate Alexandrium pacificum have increased in marine coastal areas disturbed by anthropogenic inputs. This invasive species produces saxitoxin, which causes the paralytic shellfish poisoning syndrome in humans upon consumption of contaminated seafood. Blooms of A. pacificum have been reported in metal-contaminated coastal ecosystems, suggesting some ability of these microorganisms to adapt to and/or resist in metal stress conditions. This study seeks to characterize the modifications in membrane proteomes (by 2-D electrophoresis coupled to LC-MS/MS), cell growth and morphometry (measured with an inverted microscope), in response to metal stress (addition of Zn2+, Pb2+, Cu2+ and Cd2+), in two Mediterranean A. pacificum strains: SG C10-3 and TAR C5-4F, respectively isolated from the Santa Giusta Lagoon (Sardinia, Italy) and from the Tarragona seaport (Spain), both metal-contaminated ecosystems. In the SG C10-3 cultures grown in a metal cocktail, cell growth was significantly delayed, and cell size increased (22% of 37.5 μm cells after 25 days of growth). Conversely, no substantial change was observed for cell growth or cell size in the TAR C5-4F cultures grown in a metal cocktail (P > 0.10), thus indicating intraspecific variability in the responses of A. pacificum strains to metal contamination. Regardless of the conditions tested, the total number of proteins constituting the membrane proteome was significantly higher for TAR C5-4F than for SG C10-3, which may help TAR C5-4F to thrive better in contaminated conditions. For both strains, the total number of proteins constituting the membrane proteomes was significantly lower in response to metal stress (29% decrease in the SG C10-3 proteome: 82 ± 12 proteins for controls, and 58 ± 12 in metal-contaminated cultures; 17% decrease in the TAR C5-4F proteome: 101 ± 8 proteins for controls, and 84 ± 5 in metal-contaminated cultures). Moreover, regardless of the strain, proteins with significantly modified expression in response to stress were mainly down-regulated (representing 45% of the proteome for SG C10-3 and 38% for TAR C5-4F), clearly showing the harmful effects of the metals. Protein down-regulation may affect cell transport (actin and phospholipid scramblase in SG C10-3), photosynthesis (RUBISCO in SG C10-3, light-harvesting protein in TAR C5-4F, and high-CO2-inducing periplasmic protein in both strains), and finally energy metabolism (ATP synthase in both strains). However, other modifications in protein expression may confer to these A. pacificum strains a capacity for adaptation and/or resistance to metal stress conditions, for example by (i) limiting the metal entry through the plasma membrane of the SG C10-3 cells (via the down-regulation of scramblase) and/or (ii) reducing the oxidative stress generated by metals in SG C10-3 and TAR C5-4F cells (due to down-regulation of ATP-synthase).
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Affiliation(s)
- Cherif Chetouhi
- Mediterranean Institute of Oceanography, Equipe Microbiologie Environnementale et Biotechnologie, UM 110 CNRS/IRD Aix-Marseille Université, Université de Toulon, CS 60584, 83 041 Toulon Cedex 9, France
| | - Estelle Masseret
- Marbec, University of Montpellier, IRD, Ifremer, CNRS, 34 095 Montpellier Cedex 5, France
| | - Cecilia Teodora Satta
- University of Sassari, via Piandanna 4, Agenzia Regionale per la Ricerca in Agricoltura, Loc. Bonassai, Olmedo, 07 100 Sassari, Italy
| | - Thierry Balliau
- PAPPSO-GQE-Le Moulon, INRA, Université Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 91 190 Gif-sur-Yvette, France
| | - Mohamed Laabir
- Marbec, University of Montpellier, IRD, Ifremer, CNRS, 34 095 Montpellier Cedex 5, France
| | - Natacha Jean
- Mediterranean Institute of Oceanography, Equipe Microbiologie Environnementale et Biotechnologie, UM 110 CNRS/IRD Aix-Marseille Université, Université de Toulon, CS 60584, 83 041 Toulon Cedex 9, France.
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Biomimetic Membranes with Transmembrane Proteins: State-of-the-Art in Transmembrane Protein Applications. Int J Mol Sci 2019; 20:ijms20061437. [PMID: 30901910 PMCID: PMC6472214 DOI: 10.3390/ijms20061437] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 02/26/2019] [Accepted: 03/13/2019] [Indexed: 12/14/2022] Open
Abstract
In biological cells, membrane proteins are the most crucial component for the maintenance of cell physiology and processes, including ion transportation, cell signaling, cell adhesion, and recognition of signal molecules. Therefore, researchers have proposed a number of membrane platforms to mimic the biological cell environment for transmembrane protein incorporation. The performance and selectivity of these transmembrane proteins based biomimetic platforms are far superior to those of traditional material platforms, but their lack of stability and scalability rule out their commercial presence. This review highlights the development of transmembrane protein-based biomimetic platforms for four major applications, which are biosensors, molecular interaction studies, energy harvesting, and water purification. We summarize the fundamental principles and recent progress in transmembrane protein biomimetic platforms for each application, discuss their limitations, and present future outlooks for industrial implementation.
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Lee SH, Matula AJ, Hu G, Troiano JL, Karpovich CJ, Crabtree RH, Batista VS, Brudvig GW. Strongly Coupled Phenazine-Porphyrin Dyads: Light-Harvesting Molecular Assemblies with Broad Absorption Coverage. ACS APPLIED MATERIALS & INTERFACES 2019; 11:8000-8008. [PMID: 30698407 DOI: 10.1021/acsami.8b20996] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The development of light-harvesting architectures with broad absorption coverage in the visible region continues to be an important research area in the field of artificial photosynthesis. Here, we introduce a new class of ethynyl-linked panchromatic dyads composed of dibenzophenazines coupled ortho and meta to tetrapyrroles with an anchoring group that can be grafted onto metal oxide surfaces. Quantum chemical calculations and photophysical measurements of the synthesized materials reveal that both of the dibenzophenazine dyads absorb broadly from 300 to 636 nm and exhibit absorption bands different from those of the constituent chromophore units. Moreover, the different points of attachment of dibenzophenazines to tetrapyrroles give different absorption profiles which computations suggest result from differences in the planarity of the two dyads. Applicability of the dyads in artificial photosynthesis systems was assessed by their incorporation and characterization of their performance in dye-sensitized solar cells.
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Affiliation(s)
- Shin Hee Lee
- Department of Chemistry, and Yale Energy Sciences Institute , Yale University , New Haven , Connecticut 06520-8107 , United States
| | - Adam J Matula
- Department of Chemistry, and Yale Energy Sciences Institute , Yale University , New Haven , Connecticut 06520-8107 , United States
| | - Gongfang Hu
- Department of Chemistry, and Yale Energy Sciences Institute , Yale University , New Haven , Connecticut 06520-8107 , United States
| | - Jennifer L Troiano
- Department of Chemistry, and Yale Energy Sciences Institute , Yale University , New Haven , Connecticut 06520-8107 , United States
| | - Christopher J Karpovich
- Department of Chemistry, and Yale Energy Sciences Institute , Yale University , New Haven , Connecticut 06520-8107 , United States
| | - Robert H Crabtree
- Department of Chemistry, and Yale Energy Sciences Institute , Yale University , New Haven , Connecticut 06520-8107 , United States
| | - Victor S Batista
- Department of Chemistry, and Yale Energy Sciences Institute , Yale University , New Haven , Connecticut 06520-8107 , United States
| | - Gary W Brudvig
- Department of Chemistry, and Yale Energy Sciences Institute , Yale University , New Haven , Connecticut 06520-8107 , United States
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Is the protection of photosynthesis related to the mechanism of quinclorac resistance in Echinochloa crus-galli var. zelayensis? Gene 2019; 683:133-148. [DOI: 10.1016/j.gene.2018.10.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 09/12/2018] [Accepted: 10/09/2018] [Indexed: 01/16/2023]
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Kemmler L, Ibrahim M, Dobbek H, Zouni A, Bondar AN. Dynamic water bridging and proton transfer at a surface carboxylate cluster of photosystem II. Phys Chem Chem Phys 2019; 21:25449-25466. [DOI: 10.1039/c9cp03926k] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A hydrogen-bond cluster at a negatively-charged protein interface with a bound protein and long-lived waters might be a proton storage site.
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Affiliation(s)
- Lukas Kemmler
- Freie Universität Berlin
- Department of Physics
- Theoretical Molecular Biophysics Group
- D-14195 Berlin
- Germany
| | - Mohamed Ibrahim
- Humboldt Universtät zu Berlin
- Institute for Biology, Structural Biology and Biochemistry
- Berlin
- Germany
| | - Holger Dobbek
- Humboldt Universtät zu Berlin
- Institute for Biology, Structural Biology and Biochemistry
- Berlin
- Germany
| | - Athina Zouni
- Humboldt Universtät zu Berlin
- Institute for Biology, Biophysics of Photosynthesis
- Berlin
- Germany
| | - Ana-Nicoleta Bondar
- Freie Universität Berlin
- Department of Physics
- Theoretical Molecular Biophysics Group
- D-14195 Berlin
- Germany
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8
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Adam S, Bondar AN. Mechanism by which water and protein electrostatic interactions control proton transfer at the active site of channelrhodopsin. PLoS One 2018; 13:e0201298. [PMID: 30086158 PMCID: PMC6080761 DOI: 10.1371/journal.pone.0201298] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 07/12/2018] [Indexed: 12/31/2022] Open
Abstract
Channelrhodopsins are light-sensitive ion channels whose reaction cycles involve conformation-coupled transfer of protons. Understanding how channelrhodopsins work is important for applications in optogenetics, where light activation of these proteins triggers changes in the transmembrane potential across excitable membranes. A fundamental open question is how the protein environment ensures that unproductive proton transfer from the retinal Schiff base to the nearby carboxylate counterion is avoided in the resting state of the channel. To address this question, we performed combined quantum mechanical/molecular mechanical proton transfer calculations with explicit treatment of the surrounding lipid membrane. The free energy profiles computed for proton transfer to the counterion, either via a direct jump or mediated by a water molecule, demonstrate that, when retinal is all-trans, water and protein electrostatic interactions largely favour the protonated retinal Schiff base state. We identified a conserved lysine group as an essential structural element for the proton transfer energetics in channelrhodopsins.
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Affiliation(s)
- Suliman Adam
- Freie Universität Berlin, Department of Physics, Theoretical Molecular Biophysics Group, Berlin, Germany
| | - Ana-Nicoleta Bondar
- Freie Universität Berlin, Department of Physics, Theoretical Molecular Biophysics Group, Berlin, Germany
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Wang YX, Hu Y, Zhu YF, Baloch AW, Jia XM, Guo AX. Transcriptional and physiological analyses of short-term Iron deficiency response in apple seedlings provide insight into the regulation involved in photosynthesis. BMC Genomics 2018; 19:461. [PMID: 29902966 PMCID: PMC6003109 DOI: 10.1186/s12864-018-4846-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 05/31/2018] [Indexed: 12/29/2022] Open
Abstract
Background Iron (Fe) is an essential micronutrient for plants. Utilization of Fe deficiency-tolerant rootstock is an effective strategy to prevent Fe deficiency problems in fruit trees production. Malus halliana is an apple rootstock that is resistant to Fe deficiency; however, few molecular studies have been conducted on M. halliana. Results To evaluate short-term molecular response of M. halliana leaves under Fe deficiency condition, RNA sequencing (RNA-Seq) analyses were conducted at 0 (T1), 0.5 (T2) and 3 d (T3) after Fe-deficiency stress, and the timepoints were determined with a preliminary physiological experiment. In all, 6907, 5328, and 3593 differentially expressed genes (DEGs) were identified in pairs of T2 vs. T1, T3 vs. T1, and T3 vs. T2. Several of the enriched DEGs were related to heme binding, Fe ion binding, thylakoid membranes, photosystem II, photosynthesis-antenna protein, porphyrin and chlorophyll metabolism and carotenoid biosynthesis under Fe deficiency, which suggests that Fe deficiency mainly affects the photosynthesis of M. halliana. Additionally, we found that Fe deficiency induced significant down-regulation in genes involved in photosynthesis at T2 when seedlings were treated with Fe-deficient solution for 0.5 d, indicating that there was a rapid response of M. halliana to Fe deficiency. A strong up-regulation of photosynthesis genes was detected at T3, which suggested that M. halliana was able to recover photosynthesis after prolonged Fe starvation. A similar expression pattern was found in pigment regulation, including genes for coding chlorophyllide a oxygenase (CAO), β-carotene hydroxylase (β-OHase), zeaxanthin epoxidase (ZEP) and 9-cis-epoxycarotenoid dioxygenase (NCED). Our results suggest that pigment regulation plays an important role in the Fe deficiency response. In addition, we verified sixteen genes related to photosynthesis-antenna protein, porphyrin and chlorophyll metabolism and carotenoid biosynthesis pathways using quantitative real-time PCR (qRT-PCR) to ensure the accuracy of transcriptome data. Photosynthetic parameters, Chl fluorescence parameters and the activity of Chlase were also determined. Conclusions This study broadly characterizes a molecular mechanism in which pigment and photosynthesis-related regulations play indispensable roles in the response of M. halliana to short-term Fe deficiency and provides a basis for future analyses of the key genes involved in the tolerance of Fe deficiency. Electronic supplementary material The online version of this article (10.1186/s12864-018-4846-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yan-Xiu Wang
- College of Horticulture, Gansu Agricultural University, Lanzhou, Gansu, China.
| | - Ya Hu
- College of Horticulture, Gansu Agricultural University, Lanzhou, Gansu, China
| | - Yan-Fang Zhu
- College of Horticulture, Gansu Agricultural University, Lanzhou, Gansu, China
| | - Abdul Wahid Baloch
- Department of Plant Breeding & Genetics, Faculty of Crop Production, Sindh Agriculture University, Tandojam, Pakistan
| | - Xu-Mei Jia
- College of Horticulture, Gansu Agricultural University, Lanzhou, Gansu, China
| | - Ai-Xia Guo
- College of Horticulture, Gansu Agricultural University, Lanzhou, Gansu, China
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Giovanardi M, Poggioli M, Ferroni L, Lespinasse M, Baldisserotto C, Aro EM, Pancaldi S. Higher packing of thylakoid complexes ensures a preserved Photosystem II activity in mixotrophic Neochloris oleoabundans. ALGAL RES 2017. [DOI: 10.1016/j.algal.2017.05.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Chang R, Lv B, Li B. Quantitative proteomics analysis by iTRAQ revealed underlying changes in thermotolerance of Arthrospira platensis. J Proteomics 2017. [PMID: 28645570 DOI: 10.1016/j.jprot.2017.06.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Growth temperature is a critical factor that affects cultivation of Arthrospira platensis which is a type of cyanobacterium widely known as Spirulina that has significant commercial value. To investigate the molecular mechanism underlying the thermotolerance of Spirulina, differential protein expression profiling was carried out using iTRAQ-based quantitative proteomic analysis. This study only analyzed changes in thylakoids. Among the 2085 proteins quantified, 43 differentially expressed proteins were selected based on the fold change cutoff scores of ≥2 or ≤0.5 for up-regulation or down-regulation, respectively. An analysis of these 43 proteins found that 23% of them are photosynthetic system proteins which include photosynthetic enzymes and pigment proteins. The dynamic change of these proteins indicates that photosynthetic system functions were profoundly affected under heat stress and the light-dependent reactions were probably the most sensitive to temperature changes. Meanwhile, to cope with the low energy production due to impaired photosynthesis there was a considerable down-shift in protein synthesis which is a very energy demanding process. The impaired photosynthesis led to low energy generation that was compensated by a down-shift in translation (the most energy-demanding process) and an up-shift of glycolysis. The reduction of many ribosome proteins may lead to a loss in translation efficiency; therefore, Spirulina may adopted a different mechanism to increase translational elongation under heat stress to compensate for this loss, such as elevate L7/L12 proteins. Changes were also found in the classical heat shock proteins, the ROS scavenging system, DNA-binding proteins, and some membrane proteins. In conclusion, this research demonstrate that heat stress induces profound changes in cellular physiology and shed light on the mechanism of the heat stress response and thermotolerance of Arthrospira platensis. BIOLOGICAL SIGNIFICANCE Arthrospira platensis, widely known as Spirulina, is a type of cyanobacteria which is cultivated at large scale for it great commercial value. It has become a consensus that continually increasing temperature due to global warming is bringing serious threat to agriculture, including the Spirulina cultivation. High temperature not only limits biomass accumulation by Spirulina, but also changes the composition of nutrition. Therefore there is a greater need than ever before to understand how Spirulina tolerates and cope with high temperature. In this study, we for the first time applied the iTRAQ-based quantitative proteomic technology to investigate the thermotolerance of Spirulina. Our results showed that many biological processes were altered by heat stress. Most significantly, we found that heat stress harmed the photosynthesis ability and caused low energy production, and to deal with this situation, energy demanding processes like protein synthesis were down-shifted and the alternative energy metabolism process glycolysis was up-shifted. Our results also show other important proteins, like the classical heat shock proteins and some antioxidant proteins, are also increased. Thus our study sheds light to our understanding of the mechanism underlying the thermotolerance of Spirulina.
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Affiliation(s)
- Rong Chang
- College of Biological Sciences and Technology, Beijing Forestry University, No. 35 Qinghua east road, Haidian District, Beijing, China
| | - Bingxin Lv
- College of Biological Sciences and Technology, Beijing Forestry University, No. 35 Qinghua east road, Haidian District, Beijing, China
| | - Bosheng Li
- College of Biological Sciences and Technology, Beijing Forestry University, No. 35 Qinghua east road, Haidian District, Beijing, China.
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12
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Alderman NP, Sommers JM, Viasus CJ, Wang CHT, Peneau V, Gambarotta S, Vidjayacoumar B, Al-Bahily KA. Photochemical water splitting mediated by a C1 shuttle. Dalton Trans 2016; 46:49-54. [PMID: 27841421 DOI: 10.1039/c6dt03658a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The possibility of performing photochemical water splitting in a two-stage system, separately releasing the H2 and O2 components, has been probed with two separate catalysts and in combination with a formaldehyde/formate shuttling redox couple. In the first stage, formaldehyde releases hydrogen vigorously in the presence of an Na4[Fe(CN)6]·10H2O catalyst, selectively affording the formate anion. In the second stage, the formate anion is hydro-genated back to formaldehyde by water and in the presence of a Bi2WO6 photocatalyst whilst releasing oxygen. Both stages operate at room temperature and under visible light irradiation. The two separate photocatalysts are compatible since water splitting can also be obtained in one-pot experiments with simultaneous H2/O2 evolution.
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Affiliation(s)
- N P Alderman
- Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.
| | - J M Sommers
- Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.
| | - C J Viasus
- Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.
| | - C H T Wang
- Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.
| | - V Peneau
- Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.
| | - S Gambarotta
- Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.
| | - B Vidjayacoumar
- Advanced Catalysis SABIC CDR Centre at KAUST, Thuwal, 23955, Saudi Arabia
| | - K A Al-Bahily
- Advanced Catalysis SABIC CDR Centre at KAUST, Thuwal, 23955, Saudi Arabia
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13
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Carvalho FEL, Ware MA, Ruban AV. Quantifying the dynamics of light tolerance in Arabidopsis plants during ontogenesis. PLANT, CELL & ENVIRONMENT 2015; 38:2603-2617. [PMID: 26012511 DOI: 10.1111/pce.12574] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 05/14/2015] [Indexed: 06/04/2023]
Abstract
The amount of light plants can tolerate during different phases of ontogenesis remains largely unknown. This was addressed here employing a novel methodology that uses the coefficient of photochemical quenching (qP) to assess the intactness of photosystem II reaction centres. Fluorescence quenching coefficients, total chlorophyll content and concentration of anthocyanins were determined weekly during the juvenile, adult, reproductive and senescent phases of plant ontogenesis. This enabled quantification of the protective effectiveness of non-photochemical fluorescence quenching (NPQ) and determination of light tolerance. The light intensity that caused photoinhibition in 50% of leaf population increased from ∼70 μmol m(-2) s(-1) , for 1-week-old seedlings, to a maximum of 1385 μmol m(-2) s(-1) for 8-week-old plants. After 8 weeks, the tolerated light intensity started to gradually decline, becoming only 332 μmol m(-2) s(-1) for 13-week-old plants. The dependency of light tolerance on plant age was well-related to the amplitude of protective NPQ (pNPQ) and the electron transport rates (ETRs). Light tolerance did not, however, show a similar trend to chlorophyll a/b ratios and content of anthocyanins. Our data suggest that pNPQ is crucial in defining the capability of high light tolerance by Arabidopsis plants during ontogenesis.
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Affiliation(s)
- Fabricio E L Carvalho
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
| | - Maxwell A Ware
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
| | - Alexander V Ruban
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
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Zhang SF, Zhang Y, Xie ZX, Zhang H, Lin L, Wang DZ. iTRAQ-based quantitative proteomic analysis of a toxigenic dinoflagellate Alexandrium catenella and its non-toxic mutant. Proteomics 2015; 15:4041-50. [PMID: 26417864 DOI: 10.1002/pmic.201500156] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Revised: 09/01/2015] [Accepted: 09/22/2015] [Indexed: 11/06/2022]
Abstract
Paralytic shellfish toxins (PSTs) are a group of potent neurotoxic alkaloids produced by cyanobacteria and dinoflagellates. The PST biosynthesis gene cluster and several toxin-related proteins have been unveiled in cyanobacteria, yet little is known about dinoflagellates. Here, we compared the protein profiles of a toxin-producing dinoflagellate Alexandrium catenella (ACHK-T) and its non-toxic mutant (ACHK-NT), and characterized differentially displayed proteins using a combination of the iTRAQ-based proteomic approach and the transcriptomic database. Totally 3488 proteins were identified from A. catenella, and proteins involved in carbohydrate, amino acid and energy metabolism were the most abundant. Among them, 185 proteins were differentially displayed: proteins involved in amino acid biosynthesis, protein and carbohydrate metabolism and bioluminescence were more abundant in ACHK-T, while proteins participating in photosynthesis, fatty acid biosynthesis, and the processes occurring in peroxisome displayed higher abundances in ACHK-NT. Seven toxin-related proteins were identified but they varied insignificantly between the two strains. Different carbon and energy utilization strategies were potentially related to the toxin producing ability, and the regulation mechanism of PST biosynthesis was more complex in dinoflagellates. Our study provides the first comprehensive dataset on the dinoflagellate proteome and lays the groundwork for future proteomic study.
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Affiliation(s)
- Shu-Fei Zhang
- State Key Laboratory of Marine Environmental Science/College of the Environment and Ecology, Xiamen University, Xiamen, P. R. China
| | - Yong Zhang
- State Key Laboratory of Marine Environmental Science/College of the Environment and Ecology, Xiamen University, Xiamen, P. R. China
| | - Zhang-Xian Xie
- State Key Laboratory of Marine Environmental Science/College of the Environment and Ecology, Xiamen University, Xiamen, P. R. China
| | - Hao Zhang
- State Key Laboratory of Marine Environmental Science/College of the Environment and Ecology, Xiamen University, Xiamen, P. R. China
| | - Lin Lin
- State Key Laboratory of Marine Environmental Science/College of the Environment and Ecology, Xiamen University, Xiamen, P. R. China
| | - Da-Zhi Wang
- State Key Laboratory of Marine Environmental Science/College of the Environment and Ecology, Xiamen University, Xiamen, P. R. China
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15
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High JS, Virgil KA, Jakubikova E. Electronic Structure and Absorption Properties of Strongly Coupled Porphyrin–Perylene Arrays. J Phys Chem A 2015; 119:9879-88. [DOI: 10.1021/acs.jpca.5b05600] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Judah S. High
- Department
of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Kyle A. Virgil
- Department
of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Elena Jakubikova
- Department
of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
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16
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Giovagnetti V, Ware MA, Ruban AV. Assessment of the impact of photosystem I chlorophyll fluorescence on the pulse-amplitude modulated quenching analysis in leaves of Arabidopsis thaliana. PHOTOSYNTHESIS RESEARCH 2015; 125:179-89. [PMID: 25613087 DOI: 10.1007/s11120-015-0087-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 01/12/2015] [Indexed: 05/03/2023]
Abstract
In their natural environment, plants are exposed to varying light conditions, which can lead to a build-up of excitation energy in photosystem (PS) II. Non-photochemical quenching (NPQ) is the primary defence mechanism employed to dissipate this excess energy. Recently, we developed a fluorescence-quenching analysis procedure that enables the protective effectiveness of NPQ in intact Arabidopsis leaves to be determined. However, pulse-amplitude modulation measurements do not currently allow distinguishing between PSII and PSI fluorescence levels. Failure to account for PSI contribution is suggested to lead to inaccurate measurements of NPQ and, particularly, maximum PSII yield (F v/F m). Recently, Pfündel et al. (Photosynth Res 114:189-206, 2013) proposed a method that takes into account PSI contribution in the measurements of F o fluorescence level. However, when PSI contribution was assumed to be constant throughout the induction of NPQ, we observed lower values of the measured minimum fluorescence level ([Formula: see text]) than those calculated according to the formula of Oxborough and Baker (Photosynth Res 54:135-142 1997) ([Formula: see text]), regardless of the light intensity. Therefore, in this work, we propose a refined model to correct for the presence of PSI fluorescence, which takes into account the previously observed NPQ in PSI. This method efficiently resolves the discrepancies between measured and calculated F o' produced by assuming a constant PSI fluorescence contribution, whilst allowing for the correction of the maximum PSII yield.
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Affiliation(s)
- Vasco Giovagnetti
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
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Abstract
Oxygenic photosynthesis is the principal converter of sunlight into chemical energy on Earth. Cyanobacteria and plants provide the oxygen, food, fuel, fibers, and platform chemicals for life on Earth. The conversion of solar energy into chemical energy is catalyzed by two multisubunit membrane protein complexes, photosystem I (PSI) and photosystem II (PSII). Light is absorbed by the pigment cofactors, and excitation energy is transferred among the antennae pigments and converted into chemical energy at very high efficiency. Oxygenic photosynthesis has existed for more than three billion years, during which its molecular machinery was perfected to minimize wasteful reactions. Light excitation transfer and singlet trapping won over fluorescence, radiation-less decay, and triplet formation. Photosynthetic reaction centers operate in organisms ranging from bacteria to higher plants. They are all evolutionarily linked. The crystal structure determination of photosynthetic protein complexes sheds light on the various partial reactions and explains how they are protected against wasteful pathways and why their function is robust. This review discusses the efficiency of photosynthetic solar energy conversion.
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Affiliation(s)
- Nathan Nelson
- Department of Biochemistry, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel;
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Ware MA, Belgio E, Ruban AV. Comparison of the protective effectiveness of NPQ in Arabidopsis plants deficient in PsbS protein and zeaxanthin. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:1259-70. [PMID: 25429003 PMCID: PMC4339590 DOI: 10.1093/jxb/eru477] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The efficiency of protective energy dissipation by non-photochemical quenching (NPQ) in photosystem II (PSII) has been recently quantified by a new non-invasive photochemical quenching parameter, qPd. PSII yield (ФPSII) was expressed in terms of NPQ, and the extent of damage to the reaction centres (RCIIs) was calculated via qPd as: ФPSII=qPd×(F v/F m)/{1+[1-(F v/F m)]×NPQ}. Here this approach was used to determine the amount of NPQ required to protect all PSII reaction centres (pNPQ) under a gradually increasing light intensity, in the zeaxanthin-deficient (npq1) Arabidopsis mutant, compared with PsbS protein-deficient (npq4) and wild-type plants. The relationship between maximum pNPQ and tolerated light intensity for all plant genotypes followed similar trends. These results suggest that under a gradually increasing light intensity, where pNPQ is allowed to develop, it is only the amplitude of pNPQ which is the determining factor for protection. However, the use of a sudden constant high light exposure routine revealed that the presence of PsbS, not zeaxanthin, offered better protection for PSII. This was attributed to a slower development of pNPQ in plants lacking PsbS in comparison with plants that lacked zeaxanthin. This research adds further support to the value of pNPQ and qPd as effective parameters for assessing NPQ effectiveness in different types of plants.
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Affiliation(s)
- Maxwell A Ware
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - Erica Belgio
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - Alexander V Ruban
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
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19
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Dong L, Tu W, Liu K, Sun R, Liu C, Wang K, Yang C. The PsbS protein plays important roles in photosystem II supercomplex remodeling under elevated light conditions. JOURNAL OF PLANT PHYSIOLOGY 2015; 172:33-41. [PMID: 25047739 DOI: 10.1016/j.jplph.2014.06.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Revised: 06/05/2014] [Accepted: 06/05/2014] [Indexed: 06/03/2023]
Abstract
Leaves from three different Arabidopsis lines with different expression levels of PsbS protein showed different levels of non-photochemical quenching. The PsbS deficient plant npq4 showed remarkable reduction of electron transport rate, while the other two lines with a moderate amount (wild type) or an overexpression of PsbS (L17) presented unchanged electron transport rates under the same range of high light intensities. Biochemical investigation revealed that the plant with the highest PsbS content (L17) sustained the highest level of stable PSII-LHCII supercomplex structure, and displayed the smallest fluorescence quenching in the thylakoid membranes, the most efficient linear electron transport and the smallest cyclic electron transport. Based on these observations, it is proposed that the remodeling of PSII-LHCII supercomplexes affected by PsbS plays important roles in regulating the energy balance in thylakoid membrane and in ensuring the sophisticated coordination between energy excitation and dissipation.
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Affiliation(s)
- Lianqing Dong
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenfeng Tu
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Kun Liu
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Ruixue Sun
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Cheng Liu
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Ke Wang
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Chunhong Yang
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
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20
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Chen K, Sun X, Amombo E, Zhu Q, Zhao Z, Chen L, Xu Q, Fu J. High correlation between thermotolerance and photosystem II activity in tall fescue. PHOTOSYNTHESIS RESEARCH 2014; 122:305-14. [PMID: 25145554 DOI: 10.1007/s11120-014-0035-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Accepted: 08/11/2014] [Indexed: 05/20/2023]
Abstract
Heat stress affects a broad spectrum of cellular components and metabolism. The objectives of this study were to investigate the behavior of Photosystem II (PSII) in tall fescue (Festuca arundinacea Schreb) with various thermotolerance capacities and to broaden our comprehension about the relationship between thermotolerance and PSII function. Heat-tolerant and heat-sensitive accessions were incubated at 24 °C (control) and 46 °C (heat stress) for 5 h. The fluorescence transient curves (OJIP curves), slow Chl fluorescence kinetic, and light response curve were employed to study the behavior of PSII subjected to heat stress. After heat stress, performance index for energy conservation from photons absorbed by PSII antenna until the reduction of PSI acceptors (PITotal), the value of electrons produced per photon (a), and the maximal rate of electron transport (ETRmax) of heat-tolerant accessions were lower than those of heat-sensitive accessions. Relatively lower reactive oxygen species (ROS) contents were detected in heat-tolerant accessions. Simultaneously, there was a significant decline in the quantum yield of photochemical energy conversion in PS II (Y(II)), probability that a PSII Chl molecule functions as reaction center (γRC), and the increase of quantum yield for non-regulated non-photochemical energy loss (Y(NO)) in heat-tolerant accessions. Moreover, a significant inverse correlation between heat tolerance indexes (HTI) and Y(II) was observed. Therefore, maintaining a lower photochemical activity in heat-tolerant accessions could be a crucial strategy to improve their thermotolerance. This finding could be attributed to the structural difference in the reaction center, and for heat-tolerant accessions, it could simultaneously limit energy input into linear electron transport, and dissipate more energy through non-regulated non-photochemical energy loss processes.
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Affiliation(s)
- Ke Chen
- Key Laboratory of Plant Germplasm Enhancement and Speciality Agriculture, Wuhan Botanical Garden,, Chinese Academy of Science, Wuhan City, 430074, Hubei, People's Republic of China,
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21
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Najafpour MM, Ghobadi MZ, Haghighi B, Tomo T, Carpentier R, Shen JR, Allakhverdiev SI. A nano-sized manganese oxide in a protein matrix as a natural water-oxidizing site. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2014; 81:3-15. [PMID: 24560883 DOI: 10.1016/j.plaphy.2014.01.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Accepted: 01/26/2014] [Indexed: 06/03/2023]
Abstract
The purpose of this review is to present recent advances in the structural and functional studies of water-oxidizing center of Photosystem II and its surrounding protein matrix in order to synthesize artificial catalysts for production of clean and efficient hydrogen fuel.
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Affiliation(s)
- Mohammad Mahdi Najafpour
- Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731, Iran; Center of Climate Change and Global Warming, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731, Iran.
| | - Mohadeseh Zarei Ghobadi
- Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731, Iran
| | - Behzad Haghighi
- Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731, Iran; Center of Climate Change and Global Warming, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731, Iran
| | - Tatsuya Tomo
- Department of Biology, Faculty of Science, Tokyo University of Science, Kagurazaka 1-3, Shinjuku-ku, Tokyo 162-8601, Japan; PRESTO, Japan Science and Technology Agency (JST), Saitama 332-0012, Japan
| | - Robert Carpentier
- Departement de Chimie Biochimie et Physique, Université du Québec à Trois Rivières, C.P. 500, Québec G9A 5H7, Canada
| | - Jian-Ren Shen
- Graduate School of Natural Science and Technology, Faculty of Science, Okayama University, Okayama 700-8530, Japan
| | - Suleyman I Allakhverdiev
- Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow 127276, Russia; Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow Region 142290, Russia.
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22
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Yu F, Cangelosi VM, Zastrow ML, Tegoni M, Plegaria JS, Tebo AG, Mocny CS, Ruckthong L, Qayyum H, Pecoraro VL. Protein design: toward functional metalloenzymes. Chem Rev 2014; 114:3495-578. [PMID: 24661096 PMCID: PMC4300145 DOI: 10.1021/cr400458x] [Citation(s) in RCA: 329] [Impact Index Per Article: 32.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Fangting Yu
- University of Michigan, Ann Arbor, Michigan 48109, United States
| | | | | | | | | | - Alison G. Tebo
- University of Michigan, Ann Arbor, Michigan 48109, United States
| | | | - Leela Ruckthong
- University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Hira Qayyum
- University of Michigan, Ann Arbor, Michigan 48109, United States
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23
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Yu F, Pecoraro VL. Use of the mechanistic probe 2-methyl-1-phenylpropan-2-yl hydroperoxide (MPPH) to discriminate between the formation of MnIVMnIV(OH) and MnIVMnVO species. Polyhedron 2013. [DOI: 10.1016/j.poly.2013.02.074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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24
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van Amerongen H, Croce R. Light harvesting in photosystem II. PHOTOSYNTHESIS RESEARCH 2013; 116:251-63. [PMID: 23595278 PMCID: PMC3824292 DOI: 10.1007/s11120-013-9824-3] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2013] [Accepted: 04/08/2013] [Indexed: 05/18/2023]
Abstract
Water oxidation in photosynthesis takes place in photosystem II (PSII). This photosystem is built around a reaction center (RC) where sunlight-induced charge separation occurs. This RC consists of various polypeptides that bind only a few chromophores or pigments, next to several other cofactors. It can handle far more photons than the ones absorbed by its own pigments and therefore, additional excitations are provided by the surrounding light-harvesting complexes or antennae. The RC is located in the PSII core that also contains the inner light-harvesting complexes CP43 and CP47, harboring 13 and 16 chlorophyll pigments, respectively. The core is surrounded by outer light-harvesting complexes (Lhcs), together forming the so-called supercomplexes, at least in plants. These PSII supercomplexes are complemented by some "extra" Lhcs, but their exact location in the thylakoid membrane is unknown. The whole system consists of many subunits and appears to be modular, i.e., both its composition and organization depend on environmental conditions, especially on the quality and intensity of the light. In this review, we will provide a short overview of the relation between the structure and organization of pigment-protein complexes in PSII, ranging from individual complexes to entire membranes and experimental and theoretical results on excitation energy transfer and charge separation. It will become clear that time-resolved fluorescence data can provide invaluable information about the organization and functioning of thylakoid membranes. At the end, an overview will be given of unanswered questions that should be addressed in the near future.
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Affiliation(s)
- Herbert van Amerongen
- Laboratory of Biophysics, Wageningen University, P. O. Box 8128, 6700 ET, Wageningen, The Netherlands,
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25
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Gunner MR, Amin M, Zhu X, Lu J. Molecular mechanisms for generating transmembrane proton gradients. BIOCHIMICA ET BIOPHYSICA ACTA 2013; 1827:892-913. [PMID: 23507617 PMCID: PMC3714358 DOI: 10.1016/j.bbabio.2013.03.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 01/28/2013] [Accepted: 03/01/2013] [Indexed: 01/02/2023]
Abstract
Membrane proteins use the energy of light or high energy substrates to build a transmembrane proton gradient through a series of reactions leading to proton release into the lower pH compartment (P-side) and proton uptake from the higher pH compartment (N-side). This review considers how the proton affinity of the substrates, cofactors and amino acids are modified in four proteins to drive proton transfers. Bacterial reaction centers (RCs) and photosystem II (PSII) carry out redox chemistry with the species to be oxidized on the P-side while reduction occurs on the N-side of the membrane. Terminal redox cofactors are used which have pKas that are strongly dependent on their redox state, so that protons are lost on oxidation and gained on reduction. Bacteriorhodopsin is a true proton pump. Light activation triggers trans to cis isomerization of a bound retinal. Strong electrostatic interactions within clusters of amino acids are modified by the conformational changes initiated by retinal motion leading to changes in proton affinity, driving transmembrane proton transfer. Cytochrome c oxidase (CcO) catalyzes the reduction of O2 to water. The protons needed for chemistry are bound from the N-side. The reduction chemistry also drives proton pumping from N- to P-side. Overall, in CcO the uptake of 4 electrons to reduce O2 transports 8 charges across the membrane, with each reduction fully coupled to removal of two protons from the N-side, the delivery of one for chemistry and transport of the other to the P-side.
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Affiliation(s)
- M R Gunner
- Department of Physics, City College of New York, New York, NY 10031, USA.
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26
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Emek SC, Åkerlund HE, Erlanson-Albertsson C, Albertsson PÅ. Pancreatic lipase-colipase binds strongly to the thylakoid membrane surface. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2013; 93:2254-8. [PMID: 23355304 DOI: 10.1002/jsfa.6034] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 11/30/2012] [Accepted: 12/11/2012] [Indexed: 05/05/2023]
Abstract
BACKGROUND Isolated thylakoid membranes, i.e. the photosynthetic membranes of green leaves, inhibit the activity of pancreatic lipase and colipase during hydrolysis of fat in vitro. This inhibition has been demonstrated to cause reduced food intake and improved hormonal and lipid profile in vivo. One of the reasons suggested for the inhibiting effect is binding of lipase-colipase to the thylakoid membrane surface. This prompted a study of the binding of lipase and colipase to thylakoids. RESULTS The results showed that lipase and colipase strongly bind to the thylakoid membrane surface. The dissociation constant was determined at 1.2 × 10⁻⁸ mol L⁻¹; binding decreased after treatment of thylakoids with pepsin/trypsin to 1.0 × 10⁻⁷ and to 0.6 × 10⁻⁷ mol L⁻¹ after treatment with pancreatic juice. Similarly, delipidation of thylakoids caused a decrease in binding, the dissociation constant being 2.0 × 10⁻⁷ mol L⁻¹. CONCLUSION The binding of pancreatic lipase-colipase to the thylakoid membrane is strong and may explain the inhibition of lipase-colipase activity by thylakoids. After treatment with proteases to mimic intestinal digestion binding is decreased, but is still high enough to explain the observed metabolic effects of thylakoids in vivo.
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Affiliation(s)
- Sinan Cem Emek
- Department of Biochemistry and Structural Biology, Chemical Centre, Lund University, SE-221 00, Lund, Sweden
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Singh S, de Tacconi NR, Diaz N, Lezna RO, Muñoz Zuñiga J, Abayan K, MacDonnell FM. Photochemical Two-Electron Reduction of a Dinuclear Ruthenium Complex Containing a Bent Tetraazatetrapyridopentacene Bridging Ligand: Pushing Up the LUMO for Storing More Energy. Inorg Chem 2011; 50:9318-28. [DOI: 10.1021/ic2006698] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Shreeyukta Singh
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019-0065, United States
| | - Norma R. de Tacconi
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019-0065, United States
| | - N.R.G. Diaz
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019-0065, United States
| | - Reynaldo O. Lezna
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA, UNLP, CCT La Plata-CONICET), Sucursal 4, C.C. 16, (B1906ZAA) La Plata, Argentina
| | - Jackeline Muñoz Zuñiga
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA, UNLP, CCT La Plata-CONICET), Sucursal 4, C.C. 16, (B1906ZAA) La Plata, Argentina
| | - Kenneth Abayan
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019-0065, United States
| | - Frederick M. MacDonnell
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019-0065, United States
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29
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Emek SC, Åkerlund HE, Clausén M, Ohlsson L, Weström B, Erlanson-Albertsson C, Albertsson PÅ. Pigments protect the light harvesting proteins of chloroplast thylakoid membranes against digestion by gastrointestinal proteases. Food Hydrocoll 2011. [DOI: 10.1016/j.foodhyd.2010.12.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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30
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Croce R, van Amerongen H. Light-harvesting and structural organization of Photosystem II: From individual complexes to thylakoid membrane. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2011; 104:142-53. [DOI: 10.1016/j.jphotobiol.2011.02.015] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Revised: 02/16/2011] [Accepted: 02/17/2011] [Indexed: 10/18/2022]
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31
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Ferroni L, Baldisserotto C, Giovanardi M, Pantaleoni L, Morosinotto T, Pancaldi S. Revised assignment of room-temperature chlorophyll fluorescence emission bands in single living cells of Chlamydomonas reinhardtii. J Bioenerg Biomembr 2011; 43:163-73. [PMID: 21336619 DOI: 10.1007/s10863-011-9343-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Accepted: 01/08/2011] [Indexed: 10/18/2022]
Abstract
Room temperature (RT) microspectrofluorimetry in vivo of single cells has a great potential in photosynthesis studies. In order to get new information on RT chlorophyll fluorescence bands, we analyzed the spectra of Chlamydomonas reinhardtii mutants lacking fundamental proteins of the thylakoid membrane and spectra of photoinhibited WT cells. RT spectra of single living cells were characterized thorough derivative analyses and Gaussian deconvolution. The results obtained suggest that the dynamism in LHCII assembly could be sufficient to explain the variations in amplitudes of F680 (free LHCII), F694 (LHCII-PSII) and F702 (LHCII aggregates); F686 was assigned to the PSII core. Based on the revised assignments and on the variations observed, we discuss the meaning of the two fluorescence emission ratios F680/(F686 + F694) and F702/(F686 + F694), showing that these are sensitive parameters under moderate photoinhibition. In the most photoinhibited samples, the RT spectra tended to degenerate, showing characteristics of mutants that are partly depleted in PSII.
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Affiliation(s)
- Lorenzo Ferroni
- Laboratory of Plant Cytophysiology, Department of Biology and Evolution, University of Ferrara, Italy
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32
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Kochubey SM. Changes in antenna of photosystem II induced by short-term heating. PHOTOSYNTHESIS RESEARCH 2010; 106:239-46. [PMID: 21140217 DOI: 10.1007/s11120-010-9599-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Accepted: 11/12/2010] [Indexed: 05/30/2023]
Abstract
Changes in antenna of photosystem II, induced by short-term heating, were studied using characteristics of a short-wavelength band in low-temperature fluorescence spectra (77 K) of pea chloroplasts. Heating for 5 min was carried out at 25 and 45°C in the darkness or in the presence of white light with intensity of 260 or 1,400 μmol/m(2)s. Most modes of thermal treating induced a decrease in integral intensity of the band and an increase of its half-width. The changes were more prominent at high-temperature heating. The second derivative of the contour of a short-wavelength band showed its three components around 680, 685, and 693 nm, the first of which belongs to emission of the outer antenna of Photosystem II, and the other two to its inner antenna. As the fourth derivative shows, high-temperature heating in the presence of light evokes an appearance of some additional components in a short-wavelength region (654, 658, 661, 666, 672, and 675 nm) as well as of two additional components, 682 and 689 nm, in the region of 685-nm peak. Two subcomponents, 692 and 694 nm, can be detected in the 693-nm component. The results are discussed on the basis of the data concerning energy levels and pathways of energy transfer in pigment-protein complexes of the outer and the inner antennas of photosystem II. It is assumed that a protective role of low light relates to inducing of an essential disarrangement in the outer and the inner antennas and of a subsequent decrease in energy funneling to reaction centers, which, in turn, lowers the extent of photoinhibition.
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Affiliation(s)
- Svetlana M Kochubey
- Institute of Plant Physiology, National Academy of Sciences of Ukraine, Vasylkivska Str. 31/17, Kiev, Ukraine.
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33
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Shutilova NI, Moiseev DN. The mechanism and quantum-chemical modeling of the photosynthetic water oxidation and oxygen formation reaction. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY B 2010. [DOI: 10.1134/s1990793110050179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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34
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TaNF-YC11, one of the light-upregulated NF-YC members in Triticum aestivum, is co-regulated with photosynthesis-related genes. Funct Integr Genomics 2010; 10:265-76. [PMID: 20111976 DOI: 10.1007/s10142-010-0158-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Revised: 12/27/2009] [Accepted: 01/01/2010] [Indexed: 10/19/2022]
Abstract
Nuclear factor Y (NF-Y) is a heterotrimeric transcription factor complex. Each of the NF-Y subunits (NF-YA, NF-YB and NF-YC) in plants is encoded by multiple genes. Quantitative RT-PCR analysis revealed that five wheat NF-YC members (TaNF-YC5, 8, 9, 11 and 12) were upregulated by light in both the leaf and seedling shoot. Co-expression analysis of Affymetrix wheat genome array datasets revealed that transcript levels of a large number of genes were consistently correlated with those of the TaNF-YC11 and TaNF-YC8 genes in three to four separate Affymetrix array datasets. TaNF-YC11-correlated transcripts were significantly enriched with the Gene Ontology term photosynthesis. Sequence analysis in the promoters of TaNF-YC11-correlated genes revealed the presence of putative NF-Y complex binding sites (CCAAT motifs). Quantitative RT-PCR analysis of a subset of potential TaNF-YC11 target genes showed that ten out of the 13 genes were also light-upregulated in both the leaf and seedling shoot and had significantly correlated expression profiles with TaNF-YC11. The potential target genes for TaNF-YC11 include subunit members from all four thylakoid membrane-bound complexes required for the conversion of solar energy into chemical energy and rate-limiting enzymes in the Calvin cycle. These data indicate that TaNF-YC11 is potentially involved in regulation of photosynthesis-related genes.
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McLuskey K, Roszak AW, Zhu Y, Isaacs NW. Crystal structures of all-alpha type membrane proteins. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2009; 39:723-55. [DOI: 10.1007/s00249-009-0546-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2009] [Revised: 08/19/2009] [Accepted: 08/26/2009] [Indexed: 01/05/2023]
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36
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Sobolewski AL, Domcke W. Ab initio study of the energetics of photoinduced electron and proton transfer processes in a bio-inspired model of photochemical water splitting. Chem Phys Lett 2009. [DOI: 10.1016/j.cplett.2009.07.098] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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37
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Chen S, Gollop N, Heuer B. Proteomic analysis of salt-stressed tomato ( Solanum lycopersicum) seedlings: effect of genotype and exogenous application of glycinebetaine. JOURNAL OF EXPERIMENTAL BOTANY 2009; 60:2005-19. [PMID: 19336390 PMCID: PMC2682497 DOI: 10.1093/jxb/erp075] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
An investigation aimed at a better understanding of the molecular adaptation mechanisms of salt stress was carried out in 7-d-old tomato Solanum lycopersicum (L.) Mill cultivars Patio and ‘F144’, using a proteomic approach. Total proteins were extracted from radicles and hypocotyls collected from both non-saline control and salt-stressed seedlings, and separated by two-dimensional gel electrophoresis. Liqud chromatography-electron spray ionization tandem mass spectrometry (LC-ESI-MS/MS) identified 23 salt stress response proteins, classified into six functional categories. The effect of exogenously applied glycinebetaine (GB) on the salt stress-induced inhibition of growth in tomato seedlings of cultivars Patio and ‘F144’ and on the protein profile was investigated. It was found that GB could alleviate the inhibition of tomato growth induced by salt stress through changing the expression abundance of six proteins in Patio and two proteins in ‘F144’ more than twice compared with salt-stressed seedlings. Furthermore, the interaction analysis based on computational bioinformatics reveals major regulating networks: photosystem II (PSII), Rubisco, and superoxide dismutase (SOD). The results suggest that it is likely that improvement of salt tolerance in tomato might be achieved through the application of exogenous compatible solutes, such as GB. Moreover, quantitative and qualitative analysis of the differentially expressed proteins of tomato under salt stress is an important step towards further elucidation of mechanisms of salt stress resistance.
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Affiliation(s)
- Songbi Chen
- Tropical Crops Genetic Resources Institute, Chinese Academy of Tropical Agricultural Sciences, Hainan, China
- To whom correspondence should be addressed. E-mail: or
| | - Natan Gollop
- Department of Food Science, ARO, Volcani Center, Bet-Dagan, Israel
| | - Bruria Heuer
- Department of Soil, Water and Environmental Sciences, ARO, Volcani Center, Bet-Dagan, Israel
- To whom correspondence should be addressed. E-mail: or
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38
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Kurashov VN, Allakhverdiev SI, Zharmukhamedov SK, Nagata T, Klimov VV, Semenov AY, Mamedov MD. Electrogenic reactions on the donor side of Mn-depleted photosystem II core particles in the presence of MnCl2and synthetic trinuclear Mn-complexes. Photochem Photobiol Sci 2009; 8:162-6. [DOI: 10.1039/b813981d] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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39
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Abstract
The oxygen in the atmosphere is derived from light-driven oxidation of water at a catalytic centre contained within a multi-subunit enzyme known as photosystem II (PSII). PSII is located in the photosynthetic membranes of plants, algae and cyanobacteria and its oxygen-evolving centre (OEC) consists of four manganese ions and a calcium ion surrounded by a highly conserved protein environment. Recently, the structure of PSII was elucidated by X-ray crystallography thus revealing details of the molecular architecture of the OEC. This structural information, coupled with an extensive knowledge base derived from a wide range of biophysical, biochemical and molecular biological studies, has provided a framework for understanding the chemistry of photosynthetic oxygen generation as well as opening up debate about its evolutionary origin.
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Vassiliev S, Bruce D. Toward understanding molecular mechanisms of light harvesting and charge separation in photosystem II. PHOTOSYNTHESIS RESEARCH 2008; 97:75-89. [PMID: 18443918 DOI: 10.1007/s11120-008-9303-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2007] [Accepted: 03/31/2008] [Indexed: 05/26/2023]
Abstract
Conversion of light energy in photosynthesis is extremely fast and efficient, and understanding the nature of this complex photophysical process is challenging. This review describes current progress in understanding molecular mechanisms of light harvesting and charge separation in photosystem II (PSII). Breakthroughs in X-ray crystallography have allowed the development and testing of more detailed kinetic models than have previously been possible. However, due to the complexity of the light conversion processes, satisfactory descriptions remain elusive. Recent advances point out the importance of variations in the photochemical properties of PSII in situ in different thylakoid membrane regions as well as the advantages of combining sophisticated time-resolved spectroscopic experiments with atomic level computational modeling which includes the effects of molecular dynamics.
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Affiliation(s)
- Serguei Vassiliev
- Department of Biology, Brock University, St. Catharines, ON, Canada L2S 3A1.
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41
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Abstract
The oxygen in our atmosphere is derived from and maintained by the water-splitting process of photosynthesis. The enzyme that facilitates this reaction and therefore underpins virtually all life on our planet is known as photosystem II (PSII). It is a multisubunit enzyme embedded in the lipid environment of the thylakoid membranes of plants, algae, and cyanobacteria. Powered by light, PSII catalyzes the chemically and thermodynamically demanding reaction of water splitting. In so doing, it releases molecular oxygen into the atmosphere and provides the reducing equivalents required for the conversion of carbon dioxide into the organic molecules of life. Recently, a fully refined structure of an isolated 700 kDa cyanobacterial dimeric PSII complex was elucidated by X-ray crystallography, which gave organizational and structural details of the 19 subunits (16 intrinsic and 3 extrinsic) that make up each monomer and provided information about the position and protein environments of the many different cofactors it binds. The water-splitting site was revealed as a cluster of four Mn ions and a Ca ion surrounded by amino acid side chains, of which six or seven form direct ligands to the metals. The metal cluster was originally modeled as a cubane-like structure composed of three Mn ions and the Ca (2+) linked by oxo bonds and the fourth Mn attached to the cubane via one of its O atoms. New data from X-ray diffraction and X-ray spectroscopy suggest some alternative arrangements. Nevertheless, all of the models are sufficiently similar to provide a basis for discussing the chemistry by which PSII splits water and makes oxygen.
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Affiliation(s)
- James Barber
- Division of Molecular Biosciences, Faculty of Natural Sciences, Imperial College London, London, UK.
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42
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Hammarström L, Styring S. Coupled electron transfers in artificial photosynthesis. Philos Trans R Soc Lond B Biol Sci 2008; 363:1283-91; discussion 1291. [PMID: 17954432 DOI: 10.1098/rstb.2007.2225] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Light-induced charge separation in molecular assemblies has been widely investigated in the context of artificial photosynthesis. Important progress has been made in the fundamental understanding of electron and energy transfer and in stabilizing charge separation by multi-step electron transfer. In the Swedish Consortium for Artificial Photosynthesis, we build on principles from the natural enzyme photosystem II and Fe-hydrogenases. An important theme in this biomimetic effort is that of coupled electron-transfer reactions, which have so far received only little attention. (i) Each absorbed photon leads to charge separation on a single-electron level only, while catalytic water splitting and hydrogen production are multi-electron processes; thus there is the need for controlling accumulative electron transfer on molecular components. (ii) Water splitting and proton reduction at the potential catalysts necessarily require the management of proton release and/or uptake. Far from being just a stoichiometric requirement, this controls the electron transfer processes by proton-coupled electron transfer (PCET). (iii) Redox-active links between the photosensitizers and the catalysts are required to rectify the accumulative electron-transfer reactions, and will often be the starting points of PCET.
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Affiliation(s)
- Leif Hammarström
- Department of Photochemistry and Molecular Science, Uppsala University, PO Box 523, 751 20 Uppsala, Sweden.
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43
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Barber J, Murray JW. The structure of the Mn4Ca2+ cluster of photosystem II and its protein environment as revealed by X-ray crystallography. Philos Trans R Soc Lond B Biol Sci 2008; 363:1129-38; discussion 1137-8. [PMID: 17971332 DOI: 10.1098/rstb.2007.2208] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The location, structure and protein environment of the Mn4Ca2+ cluster, which catalyses the light-driven, water-splitting reaction of photosystem II, has been revealed by X-ray crystallography. However, owing to the low resolutions of the crystal structures reported to date, and the possibility of radiation damage at the catalytic centre, the precise position of each metal ion remains unknown. To some extent, these problems have been overcome by applying spectroscopic techniques like extended X-ray absorption fine structure. Taking into account the most recent results obtained with these two X-ray-based techniques, we have attempted to refine models of the structure of the Mn4Ca2+ cluster and its protein environment.
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Affiliation(s)
- James Barber
- Division of Molecular Biosciences, Imperial College London, London SW7 2AZ, UK.
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44
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Mamedov F, Danielsson R, Gadjieva R, Albertsson PA, Styring S. EPR characterization of photosystem II from different domains of the thylakoid membrane. Biochemistry 2008; 47:3883-91. [PMID: 18303856 DOI: 10.1021/bi701913k] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report electron paramagnetic resonance (EPR) studies on photosystem II (PSII) from higher plants in five different domains of the thylakoid membrane prepared by sonication and two-phase partitioning. The domains studied were the grana core, the entire grana stack, the grana margins, the stroma lamellae and the purified stromal fraction, Y100. The electron transport properties of both donor and acceptor sides of PSII such as oxygen evolution, cofactors Y D, Q A, the CaMn 4-cluster, and Cytb 559 were investigated. The PSII content was estimated on the basis of oxidized Y D and Q A (-) Fe (2+) signal from the acceptor side vs Chl content (100% in the grana core fraction). It was found to be about 82% in the grana, 59% in the margins, 35% in the stroma and 15% in the Y100 fraction. The most active PSII centers were found in the granal fractions as was estimated from the rates of electron transfer and the S 2 state multiline EPR signal. In the margin and stroma fractions the multiline signal was smaller (40 and 33%, respectively). The S 2 state multiline could not be induced in the Y100 fraction. In addition, the oxidized LP Cytb 559 prevailed in the stromal fractions while the HP form dominated in the grana core. The margins and entire grana fractions have Cytb 559 in both potential forms. These data together with previous analyses indicate that the sequence of activation of the PSII properties can be represented as: PSII content > oxygen evolution > reduced Cytb 559 > dimerization of PSII centers in all fractions of the thylakoid membrane with the gradual increase from stromal fractions via margin to the grana core fraction. The results further support the existence of a PSII activity gradient which reflects lateral movement and photoactivation of PSII centers in the thylakoid membrane. The possible role of the PSII redox components in this process is discussed.
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Affiliation(s)
- Fikret Mamedov
- Molecular Biomimetics, Department of Photochemistry and Molecular Science, Angström Laboratory, Box 523, Uppsala University, Sweden.
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45
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Kas OY, Charati MB, Rothberg LJ, Galvin ME, Kiick KL. Regulation of electronic behavior via confinement of PPV-based oligomers on peptide scaffolds. ACTA ACUST UNITED AC 2008. [DOI: 10.1039/b800860d] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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46
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Affiliation(s)
- Arthur J. Esswein
- Department of Chemistry 6-335, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139-4307
| | - Daniel G. Nocera
- Department of Chemistry 6-335, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139-4307
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47
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Petros AK, Reddi AR, Kennedy ML, Hyslop AG, Gibney BR. Femtomolar Zn(II) affinity in a peptide-based ligand designed to model thiolate-rich metalloprotein active sites. Inorg Chem 2007; 45:9941-58. [PMID: 17140191 DOI: 10.1021/ic052190q] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Metal-ligand interactions are critical components of metalloprotein assembly, folding, stability, electrochemistry, and catalytic function. Research over the past 3 decades on the interaction of metals with peptide and protein ligands has progressed from the characterization of amino acid-metal and polypeptide-metal complexes to the design of folded protein scaffolds containing multiple metal cofactors. De novo metalloprotein design has emerged as a valuable tool both for the modular synthesis of these complex metalloproteins and for revealing the fundamental tenets of metalloprotein structure-function relationships. Our research has focused on using the coordination chemistry of de novo designed metalloproteins to probe the interactions of metal cofactors with protein ligands relevant to biological phenomena. Herein, we present a detailed thermodynamic analysis of Fe(II), Co(II), Zn(II), and[4Fe-4S]2(+/+) binding to IGA, a 16 amino acid peptide ligand containing four cysteine residues, H2N-KLCEGG-CIGCGAC-GGW-CONH2. These studies were conducted to delineate the inherent metal-ion preferences of this unfolded tetrathiolate peptide ligand as well as to evaluate the role of the solution pH on metal-peptide complex speciation. The [4Fe-4S]2(+/+)-IGA complex is both an excellent peptide-based synthetic analogue for natural ferredoxins and is flexible enough to accommodate mononuclear metal-ion binding. Incorporation of a single ferrous ion provides the FeII-IGA complex, a spectroscopic model of a reduced rubredoxin active site that possesses limited stability in aqueous buffers. As expected based on the Irving-Williams series and hard-soft acid-base theory, the Co(II) and Zn(II) complexes of IGA are significantly more stable than the Fe(II) complex. Direct proton competition experiments, coupled with determinations of the conditional dissociation constants over a range of pH values, fully define the thermodynamic stabilities and speciation of each MII-IGA complex. The data demonstrate that FeII-IGA and CoII-IGA have formation constant values of 5.0 x 10(8) and 4.2 x 10(11) M-1, which are highly attenuated at physiological pH values. The data also evince that the formation constant for ZnII-IGA is 8.0 x 10(15) M-1, a value that exceeds the tightest natural protein Zn(II)-binding affinities. The formation constant demonstrates that the metal-ligand binding energy of a ZnII(S-Cys)4 site can stabilize a metalloprotein by -21.6 kcal/mol. Rigorous thermodynamic analyses such as those demonstrated here are critical to current research efforts in metalloprotein design, metal-induced protein folding, and metal-ion trafficking.
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Affiliation(s)
- Amy K Petros
- Department of Chemistry, Columbia University, MC 3121, New York, New York 10027, USA
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48
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Abstract
Photosystem II (PSII) is a multisubunit enzyme embedded in the lipid environment of the thylakoid membranes of plants, algae and cyanobacteria. Powered by light, this enzyme catalyses the chemically and thermodynamically demanding reaction of water splitting. In so doing, it releases dioxygen into the atmosphere and provides the reducing equivalents required for the conversion of CO2 into the organic molecules of life. Recently, a fully refined structure of a 700 kDa cyanobacterial dimeric PSII complex was elucidated by X-ray crystallography which gave organizational and structural details of the 19 subunits (16 intrinsic and three extrinsic) which make up each monomer and provided information about the position and protein environments of 57 different cofactors. The water-splitting site was revealed as a cluster of four Mn ions and a Ca2+ ion surrounded by amino acid side chains, of which six or seven form direct ligands to the metals. The metal cluster was modelled as a cubane-like structure composed of three Mn ions and the Ca2+ linked by oxo-bonds with the fourth Mn attached to the cubane via one of its oxygens. The overall structure of the catalytic site is providing a framework to develop a mechanistic scheme for the water-splitting process, knowledge which could have significant implications for mimicking the reaction in an artificial chemical system.
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Affiliation(s)
- J Barber
- Division of Molecular Biosciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK.
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49
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Kargul J, Maghlaoui K, Murray JW, Deak Z, Boussac A, Rutherford AW, Vass I, Barber J. Purification, crystallization and X-ray diffraction analyses of the T. elongatus PSII core dimer with strontium replacing calcium in the oxygen-evolving complex. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2007; 1767:404-13. [PMID: 17321490 DOI: 10.1016/j.bbabio.2007.01.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2006] [Revised: 01/05/2007] [Accepted: 01/09/2007] [Indexed: 11/17/2022]
Abstract
The core complex of photosystem II (PSII) was purified from thermophilic cyanobacterium Thermosynechococcus elongatus grown in Sr(2+)-containing and Ca(2+)-free medium. Functional in vivo incorporation of Sr(2+) into the oxygen-evolving complex (OEC) was confirmed by EPR analysis of the isolated and highly purified SrPSII complex in agreement with the previous study of Boussac et al. [J. Biol. Chem. 279 (2004) 22809-22819]. Three-dimensional crystals of SrPSII complex were obtained which diffracted to 3.9 A and belonged to the orthorhombic space group P2(1)2(1)2(1) with unit cell dimensions of a=133.6 A, b=236.6 A, c=307.8 A. Anomalous diffraction data collected at the Sr K-X-ray absorption edge identified a novel Sr(2+)-binding site which, within the resolution of these data (6.5 A), is consistent with the positioning of Ca(2+) in the recent crystallographic models of PSII [Ferreira et al. Science 303 (2004) 1831-1838, Loll et al. Nature 438 (2005) 1040-1044]. Fluorescence measurements on SrPSII crystals confirmed that crystallized SrPSII was active in transferring electrons from the OEC to the acceptor site of the reaction centre. However, SrPSII showed altered functional properties of its modified OEC in comparison with that of the CaPSII counterpart: slowdown of the Q(A)-to-Q(B) electron transfer and stabilized S(2)Q(A)(-) charge recombination.
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Affiliation(s)
- Joanna Kargul
- Wolfson Laboratories, Division of Molecular Biosciences, Faculty of Natural Sciences, Imperial College London, London, UK
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50
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Song J, Lee MS, Carlberg I, Vener AV, Markley JL. Micelle-induced folding of spinach thylakoid soluble phosphoprotein of 9 kDa and its functional implications. Biochemistry 2006; 45:15633-43. [PMID: 17176085 PMCID: PMC2533273 DOI: 10.1021/bi062148m] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Thylakoid soluble phosphoprotein of 9 kDa (TSP9) has been identified as a plant-specific protein in the photosynthetic thylakoid membrane (Carlberg et al. (2003) Proc. Natl. Acad. Sci. 100, 757-762). Nonphosphorylated TSP9 is associated with the membrane, whereas, after light-induced phosphorylation, a fraction of the phosphorylated TSP9 is released into the aqueous stroma. By NMR spectroscopy, we have determined the structural features of nonphosphorylated TSP9 both in aqueous solution and in membrane mimetic micelles. The results show that both wild type nonphosphorylated TSP9 and a triple-mutant (T46E + T53E + T60E) mimic of the triphosphorylated form of TSP9 are disordered under aqueous conditions, but adopt an ordered conformation in the presence of detergent micelles. The micelle-induced structural features, which are similar in micelles either of SDS or dodecylphosphocholine (DPC), consist of an N-terminal alpha-helix, which may represent the primary site of interaction between TSP9 and binding partners, and a less structured helical turn near the C-terminus. These structured elements contain mainly hydrophobic residues. NMR relaxation data for nonphosphorylated TSP9 in SDS micelles indicated that the molecule is highly flexible with the highest order in the N-terminal alpha-helix. Intermolecular NOE signals, as well as spin probe-induced broadening of NMR signals, demonstrated that the SDS micelles contact both the structured and a portion of the unstructured regions of TSP9, in particular, those containing the three phosphorylation sites (T46, T53, and T60). This interaction may explain the selective dissociation of phosphorylated TSP9 from the membrane. Our study presents a structural model for the role played by the structured and unstructured regions of TSP9 in its membrane association and biological function.
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Affiliation(s)
| | | | | | | | - John L Markley
- * To whom correspondence should be addressed: Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706. Telephone: (608) 263-9349. Fax: (608) 262-3759. E-mail:
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