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Charras Q, Rey P, Guillemain D, Dourguin F, Laganier H, Peschoux S, Molinié R, Ismaël M, Caffarri S, Rayon C, Jungas C. An efficient protocol for extracting thylakoid membranes and total leaf proteins from Posidonia oceanica and other polyphenol-rich plants. Plant Methods 2024; 20:38. [PMID: 38468328 DOI: 10.1186/s13007-024-01166-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 02/28/2024] [Indexed: 03/13/2024]
Abstract
BACKGROUND The extraction of thylakoids is an essential step in studying the structure of photosynthetic complexes and several other aspects of the photosynthetic process in plants. Conventional protocols have been developed for selected land plants grown in controlled conditions. Plants accumulate defensive chemical compounds such as polyphenols to cope with environmental stresses. When the polyphenol levels are high, their oxidation and cross-linking properties prevent thylakoid extraction. RESULTS In this study, we developed a method to counteract the hindering effects of polyphenols by modifying the grinding buffer with the addition of both vitamin C (VitC) and polyethylene glycol (PEG4000). This protocol was first applied to the marine plant Posidonia oceanica and then extended to other plants synthesizing substantial amounts of polyphenols, such as Quercus pubescens (oak) and Vitis vinifera (grapevine). Native gel analysis showed that photosynthetic complexes (PSII, PSI, and LHCII) can be extracted from purified membranes and fractionated comparably to those extracted from the model plant Arabidopsis thaliana. Moreover, total protein extraction from frozen P. oceanica leaves was also efficiently carried out using a denaturing buffer containing PEG and VitC. CONCLUSIONS Our work shows that the use of PEG and VitC significantly improves the isolation of native thylakoids, native photosynthetic complexes, and total proteins from plants containing high amounts of polyphenols and thus enables studies on photosynthesis in various plant species grown in natural conditions.
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Affiliation(s)
- Quentin Charras
- CEA, CNRS, BIAM, LGBP Team, Aix-Marseille University, Marseille, France
- Science for Life Laboratory, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH-Royal Institute of Technology, KTH University, Stockholm, Sweden
| | - Pascal Rey
- CEA, CNRS, BIAM, P&E Team, Aix-Marseille University, Saint Paul-Lez-Durance, France
| | - Dorian Guillemain
- CNRS, IRD, IRSTEA, OSU Institut Pythéas, Aix-Marseille University, Marseille, France
| | - Fabian Dourguin
- CEA, CNRS, BIAM, LGBP Team, Aix-Marseille University, Marseille, France
| | - Hugo Laganier
- CEA, CNRS, BIAM, LGBP Team, Aix-Marseille University, Marseille, France
| | - Sacha Peschoux
- UFR Informatique, mathématiques et mathématiques appliquées (IM2AG), Université Grenoble Alpes, Saint Martin d'Heres, France
| | - Roland Molinié
- UMR INRAE 1158 Transfrontalière BioEcoAgro, BIOlogie des Plantes et Innovation (BIOPI), UPJV, Amiens, France
| | - Marwa Ismaël
- UMR INRAE 1158 Transfrontalière BioEcoAgro, BIOlogie des Plantes et Innovation (BIOPI), UPJV, Amiens, France
| | - Stefano Caffarri
- CEA, CNRS, BIAM, LGBP Team, Aix-Marseille University, Marseille, France
| | - Catherine Rayon
- UMR INRAE 1158 Transfrontalière BioEcoAgro, BIOlogie des Plantes et Innovation (BIOPI), UPJV, Amiens, France
| | - Colette Jungas
- CEA, CNRS, BIAM, LGBP Team, Aix-Marseille University, Marseille, France.
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Ismael M, Charras Q, Leschevin M, Herfurth D, Roulard R, Quéro A, Rusterucci C, Domon JM, Jungas C, Vermerris W, Rayon C. Seasonal Variation in Cell Wall Composition and Carbohydrate Metabolism in the Seagrass Posidonia oceanica Growing at Different Depths. Plants (Basel) 2023; 12:3155. [PMID: 37687400 PMCID: PMC10490095 DOI: 10.3390/plants12173155] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 08/26/2023] [Accepted: 08/28/2023] [Indexed: 09/10/2023]
Abstract
Posidonia oceanica is a common seagrass in the Mediterranean Sea that is able to sequester large amounts of carbon. The carbon assimilated during photosynthesis can be partitioned into non-structural sugars and cell-wall polymers. In this study, we investigated the distribution of carbon in starch, soluble carbohydrates and cell-wall polymers in leaves and rhizomes of P. oceanica. Analyses were performed during summer and winter in meadows located south of the Frioul archipelago near Marseille, France. The leaves and rhizomes were isolated from plants collected in shallow (2 m) and deep water (26 m). Our results showed that P. oceanica stores more carbon as starch, sucrose and cellulose in summer and that this is more pronounced in rhizomes from deep-water plants. In winter, the reduction in photoassimilates was correlated with a lower cellulose content, compensated with a greater lignin content, except in rhizomes from deep-water plants. The syringyl-to-guaiacyl (S/G) ratio in the lignin was higher in leaves than in rhizomes and decreased in rhizomes in winter, indicating a change in the distribution or structure of the lignin. These combined data show that deep-water plants store more carbon during summer, while in winter the shallow- and deep-water plants displayed a different cell wall composition reflecting their environment.
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Affiliation(s)
- Marwa Ismael
- UMR-INRAE 1158 Transfrontalière BioEcoAgro, BIOlogie des Plantes et Innovation (BIOPI), Université de Picardie Jules Verne, 80039 Amiens, France; (M.I.); (M.L.); (D.H.); (R.R.); (A.Q.); (C.R.); (J.-M.D.)
| | - Quentin Charras
- Aix-Marseille University, CEA, CNRS, BIAM, LGBP Team, 13009 Marseille, France; (Q.C.); (C.J.)
| | - Maïté Leschevin
- UMR-INRAE 1158 Transfrontalière BioEcoAgro, BIOlogie des Plantes et Innovation (BIOPI), Université de Picardie Jules Verne, 80039 Amiens, France; (M.I.); (M.L.); (D.H.); (R.R.); (A.Q.); (C.R.); (J.-M.D.)
- Aix-Marseille University, CEA Cadarache, Zone Cité des Énergies BIAM, Bâtiment 1900, 13108 Saint-Paul-lez-Durance, France
| | - Damien Herfurth
- UMR-INRAE 1158 Transfrontalière BioEcoAgro, BIOlogie des Plantes et Innovation (BIOPI), Université de Picardie Jules Verne, 80039 Amiens, France; (M.I.); (M.L.); (D.H.); (R.R.); (A.Q.); (C.R.); (J.-M.D.)
| | - Romain Roulard
- UMR-INRAE 1158 Transfrontalière BioEcoAgro, BIOlogie des Plantes et Innovation (BIOPI), Université de Picardie Jules Verne, 80039 Amiens, France; (M.I.); (M.L.); (D.H.); (R.R.); (A.Q.); (C.R.); (J.-M.D.)
| | - Anthony Quéro
- UMR-INRAE 1158 Transfrontalière BioEcoAgro, BIOlogie des Plantes et Innovation (BIOPI), Université de Picardie Jules Verne, 80039 Amiens, France; (M.I.); (M.L.); (D.H.); (R.R.); (A.Q.); (C.R.); (J.-M.D.)
| | - Christine Rusterucci
- UMR-INRAE 1158 Transfrontalière BioEcoAgro, BIOlogie des Plantes et Innovation (BIOPI), Université de Picardie Jules Verne, 80039 Amiens, France; (M.I.); (M.L.); (D.H.); (R.R.); (A.Q.); (C.R.); (J.-M.D.)
| | - Jean-Marc Domon
- UMR-INRAE 1158 Transfrontalière BioEcoAgro, BIOlogie des Plantes et Innovation (BIOPI), Université de Picardie Jules Verne, 80039 Amiens, France; (M.I.); (M.L.); (D.H.); (R.R.); (A.Q.); (C.R.); (J.-M.D.)
| | - Colette Jungas
- Aix-Marseille University, CEA, CNRS, BIAM, LGBP Team, 13009 Marseille, France; (Q.C.); (C.J.)
| | - Wilfred Vermerris
- Department of Microbiology & Cell Science and UF Genetics Institute, University of Florida, Gainesville, FL 32610, USA;
| | - Catherine Rayon
- UMR-INRAE 1158 Transfrontalière BioEcoAgro, BIOlogie des Plantes et Innovation (BIOPI), Université de Picardie Jules Verne, 80039 Amiens, France; (M.I.); (M.L.); (D.H.); (R.R.); (A.Q.); (C.R.); (J.-M.D.)
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Lapieza MP, Jungas C, Savirón M, Jarne C, Membrado L, Vela J, Orduna J, Garriga R, Galbán J, Cebolla VL. HPTLC coupled to ESI-Tandem MS for identifying phospholipids associated to membrane proteins in photosynthetic purple bacteria. J LIQ CHROMATOGR R T 2019. [DOI: 10.1080/10826076.2018.1561465] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- María P. Lapieza
- Instituto de Carboquímica, ICB-CSIC, C/Miguel Luesma, 4, 50018 Zaragoza, Spain
| | - Colette Jungas
- Cadarache‐DSV‐DEVM Laboratoire de Bioenergetique Cellulaire, CEA, St Paul‐lez‐Durance, France
| | - María Savirón
- Facultad de Ciencias, Instituto de Ciencia de Materiales de Aragón (UZ-CSIC), Zaragoza, Spain
| | - Carmen Jarne
- Instituto de Carboquímica, ICB-CSIC, C/Miguel Luesma, 4, 50018 Zaragoza, Spain
| | - Luis Membrado
- Instituto de Carboquímica, ICB-CSIC, C/Miguel Luesma, 4, 50018 Zaragoza, Spain
| | - Jesús Vela
- Departamento de Química Analítica, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain
| | - Jesús Orduna
- Facultad de Ciencias, Instituto de Ciencia de Materiales de Aragón (UZ-CSIC), Zaragoza, Spain
| | - Rosa Garriga
- Departamento de Química Física, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain
| | - Javier Galbán
- Departamento de Química Analítica, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain
| | - Vicente L. Cebolla
- Instituto de Carboquímica, ICB-CSIC, C/Miguel Luesma, 4, 50018 Zaragoza, Spain
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Polidori A, Raynal S, Barret LA, Dahani M, Barrot-Ivolot C, Jungas C, Frotscher E, Keller S, Ebel C, Breyton C, Bonneté F. Sparingly fluorinated maltoside-based surfactants for membrane-protein stabilization. NEW J CHEM 2016. [DOI: 10.1039/c5nj03502c] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Dahani M, Barret LA, Raynal S, Jungas C, Pernot P, Polidori A, Bonneté F. Use of dynamic light scattering and small-angle X-ray scattering to characterize new surfactants in solution conditions for membrane-protein crystallization. Acta Crystallogr F Struct Biol Commun 2015; 71:838-46. [PMID: 26144228 PMCID: PMC4498704 DOI: 10.1107/s2053230x15009516] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 05/18/2015] [Indexed: 11/11/2022] Open
Abstract
The structural and interactive properties of two novel hemifluorinated surfactants, F2H9-β-M and F4H5-β-M, the syntheses of which were based on the structure and hydrophobicity of the well known dodecyl-β-maltoside (DD-β-M), are described. The shape of their micellar assemblies was characterized by small-angle X-ray scattering and their intermicellar interactions in crystallizing conditions were measured by dynamic light scattering. Such information is essential for surfactant phase-diagram determination and membrane-protein crystallization.
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Affiliation(s)
- Mohamed Dahani
- Institut des Biomolécules Max Mousseron/CBSA, UMR 5247, Avignon University, 33 Rue Louis Pasteur, 84000 Avignon,France
| | - Laurie-Anne Barret
- Institut des Biomolécules Max Mousseron/CBSA, UMR 5247, Avignon University, 33 Rue Louis Pasteur, 84000 Avignon,France
- Laboratoire de Bioénergétique Cellulaire/Biologie Végétale et Microbiologie Environnementales, UMR 7265, 13108 Saint-Paul-lez-Durance, France
| | - Simon Raynal
- Institut des Biomolécules Max Mousseron/CBSA, UMR 5247, Avignon University, 33 Rue Louis Pasteur, 84000 Avignon,France
| | - Colette Jungas
- Laboratoire de Bioénergétique Cellulaire/Biologie Végétale et Microbiologie Environnementales, UMR 7265, 13108 Saint-Paul-lez-Durance, France
| | - Pétra Pernot
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Ange Polidori
- Institut des Biomolécules Max Mousseron/CBSA, UMR 5247, Avignon University, 33 Rue Louis Pasteur, 84000 Avignon,France
| | - Françoise Bonneté
- Institut des Biomolécules Max Mousseron/CBSA, UMR 5247, Avignon University, 33 Rue Louis Pasteur, 84000 Avignon,France
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Barret LA, Barrot-Ivolot C, Raynal S, Jungas C, Polidori A, Bonneté F. Influence of Hydrophobic Micelle Structure on Crystallization of the Photosynthetic RC-LH1-PufX Complex from Rhodobacter blasticus. J Phys Chem B 2013; 117:8770-81. [DOI: 10.1021/jp403483q] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Laurie-Anne Barret
- Institut des Biomolécules
Max Mousseron (IBMM) UMR 5247 CNRS-Universités Montpellier
1 et 2, Chimie Bioorganique et Systèmes Amphiphiles, Université d’Avignon et des Pays de Vaucluse, 33 rue Louis Pasteur, F-84000 Avignon, France
- CEA DSV IBEB Lab Bioenerget Cellulaire, CNRS UMR Biol Veget & Microbiol Environ, Aix-Marseille Université, Saint-Paul-lez-Durance, F-13108, France
| | - Cherone Barrot-Ivolot
- Institut des Biomolécules
Max Mousseron (IBMM) UMR 5247 CNRS-Universités Montpellier
1 et 2, Chimie Bioorganique et Systèmes Amphiphiles, Université d’Avignon et des Pays de Vaucluse, 33 rue Louis Pasteur, F-84000 Avignon, France
| | - Simon Raynal
- Institut des Biomolécules
Max Mousseron (IBMM) UMR 5247 CNRS-Universités Montpellier
1 et 2, Chimie Bioorganique et Systèmes Amphiphiles, Université d’Avignon et des Pays de Vaucluse, 33 rue Louis Pasteur, F-84000 Avignon, France
| | - Colette Jungas
- CEA DSV IBEB Lab Bioenerget Cellulaire, CNRS UMR Biol Veget & Microbiol Environ, Aix-Marseille Université, Saint-Paul-lez-Durance, F-13108, France
| | - Ange Polidori
- Institut des Biomolécules
Max Mousseron (IBMM) UMR 5247 CNRS-Universités Montpellier
1 et 2, Chimie Bioorganique et Systèmes Amphiphiles, Université d’Avignon et des Pays de Vaucluse, 33 rue Louis Pasteur, F-84000 Avignon, France
| | - Françoise Bonneté
- Institut des Biomolécules
Max Mousseron (IBMM) UMR 5247 CNRS-Universités Montpellier
1 et 2, Chimie Bioorganique et Systèmes Amphiphiles, Université d’Avignon et des Pays de Vaucluse, 33 rue Louis Pasteur, F-84000 Avignon, France
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Semchonok DA, Chauvin JP, Frese RN, Jungas C, Boekema EJ. Structure of the dimeric RC-LH1-PufX complex from Rhodobaca bogoriensis investigated by electron microscopy. Philos Trans R Soc Lond B Biol Sci 2013; 367:3412-9. [PMID: 23148268 DOI: 10.1098/rstb.2012.0063] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Electron microscopy and single-particle averaging were performed on isolated reaction centre (RC)-antenna complexes (RC-LH1-PufX complexes) of Rhodobaca bogoriensis strain LBB1, with the aim of establishing the LH1 antenna conformation, and, in particular, the structural role of the PufX protein. Projection maps of dimeric complexes were obtained at 13 Å resolution and show the positions of the 2 × 14 LH1 α- and β-subunits. This new dimeric complex displays two open, C-shaped LH1 aggregates of 13 αβ polypeptides partially surrounding the RCs plus two LH1 units forming the dimer interface in the centre. Between the interface and the two half rings are two openings on each side. Next to the openings, there are four additional densities present per dimer, considered to be occupied by four copies of PufX. The position of the RC in our model was verified by comparison with RC-LH1-PufX complexes in membranes. Our model differs from previously proposed configurations for Rhodobacter species in which the LH1 ribbon is continuous in the shape of an S, and the stoichiometry is of one PufX per RC.
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Affiliation(s)
- Dmitry A Semchonok
- Electron Microscopy Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, Groningen, The Netherlands
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Barret LA, Polidori A, Bonneté F, Bernard-Savary P, Jungas C. A new high-performance thin layer chromatography-based assay of detergents and surfactants commonly used in membrane protein studies. J Chromatogr A 2013; 1281:135-41. [PMID: 23398993 DOI: 10.1016/j.chroma.2013.01.061] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 01/09/2013] [Accepted: 01/11/2013] [Indexed: 10/27/2022]
Abstract
The hydrophobic nature of membrane proteins (MPs) necessitates the use of detergents for their extraction, solubilization and purification. Because the concentration of amphiphiles is crucial in the crystallization process, detergent quantification is essential to routine analysis. Here we describe a quantitative high-performance thin-layer chromatography (HPTLC) method we developed for the detection of small quantities of detergent bound to solubilized MPs. After optimization of aqueous deposit conditions, we show that most detergents widely used in membrane protein crystallography display distinctive mobilities in a mixture of dichloromethane, methanol and acetic acid 32:7.6:0.4 (v/v/v). Migration and derivatization conditions were optimized with n-dodecyl-β-D-maltoside (DDM), the most popular detergent for membrane protein crystallization. A linear calibration curve very well fits our data from 0.1 to 1.6 μg of DDM in water with a limit of detection of 0.05 μg. This limit of detection is the best achieved to date for a routine detergent assay, being not modified by the addition of NaCl, commonly used in protein buffers. With these chromatographic conditions, no prior treatment is required to assess the quantities of detergent bound to purified MPs, thus enabling the quantification of close structure detergents via a single procedure. This HPTLC method, which is fast and requires low sample volume, is fully suitable for routine measurements.
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Affiliation(s)
- Laurie-Anne Barret
- CEA, IBEB, Lab Bioenerget Cellulaire, Saint-Paul-lez-Durance, F-13108, France
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M'rah S, Ouerghi Z, Berthomieu C, Havaux M, Jungas C, Hajji M, Grignon C, Lachaâl M. Effects of NaCl on the growth, ion accumulation and photosynthetic parameters of Thellungiella halophila. J Plant Physiol 2006; 163:1022-31. [PMID: 16971214 DOI: 10.1016/j.jplph.2005.07.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2005] [Accepted: 07/18/2005] [Indexed: 05/11/2023]
Abstract
Thellungiella halophila seedlings grown on a solid substrate for 25 days on standard medium were challenged with NaCl. Growth, tissue hydration, ion accumulation, photosynthesis, lipid peroxidation and antioxidant enzymatic activities were studied on rosette leaves. Three accessions of Arabidopsis thaliana were cultivated under the same conditions. During the first two weeks of salt treatment, the growth of T. halophila leaves was restricted by NaCl. No significant difference appeared between T. halophila and A. thaliana concerning biomass deposition, or hydric and ionic parameters. However, all A. thaliana plants displayed foliar damage, and died during the third week of salt (50mM NaCl) treatment. Almost all (94%) T. halophila plants remained alive, but did not display any sign of altered physiological condition. Tissue hydration, chlorophyll content, stomatal conductance, photosynthetic quantum yield, and photosynthetic rate were very similar to those of control plants. Lipid peroxidation, estimated from thermoluminescence, was very low and insensitive to salt treatment. Only slight changes occurred in antioxidant enzymatic activities (SOD, several peroxidases, and catalase). From the absence of physiological disorder symptoms, we infer that salt was efficiently compartmentalized in leaf vacuoles. In salt-treated A. thaliana, the photosynthetic quantum yield was diminished, and lipid peroxidation was augmented. These observations reinforce the conclusion that T. halophila could accumulate salt in its leaves without damage, in contrast to A. thaliana.
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Affiliation(s)
- Sabah M'rah
- Physiologie et Biochimie de la Tolérance au Sel des Plantes, Faculté des Sciences de Tunis, Campus Universitaire, 1060 Tunis, Tunisia
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Abstract
In the bacterium R. sphaeroides, the polypeptide PufX is indispensable for photosynthetic growth. Its deletion is known to have important consequences on the organization of the photosynthetic apparatus. In the wild-type strain, complexes between the reaction center (RC) and the antenna (light-harvesting complex 1 (LH1)) are associated in dimers, and LH1 does not fully encircle the RC. In the absence of PufX, the complexes become monomeric, and the LH1 ring closes around the RC. We analyzed the functional consequences of PufX deletion. Some effects can be ascribed to the monomerization of the RC.LH1 complexes: the number of RCs that share a common antenna for excitation transfer or a common quinone pool become smaller. We examined the kinetic effects of the closed LH1 ring on quinone turnover: diffusion across LH1 entails a delay of approximately 1 ms, and the barrier appears to be located directly against the quinone-binding (secondary quinone acceptor (Q(B))) pocket. The diffusion of ubiquinol from the RC to the cytochrome bc1 complex is approximately 2-fold slower in the mutant, suggesting an increased distance between the two complexes. The properties of the Q(B) pocket (binding of inhibitors, stabilization of Q(B-), and rate of Q(B)-H2 formation) appear to be modified in the mutant. Another specificity of PufX- is the accumulation of closed centers in the Q(A-) (where Q(A) is the primary quinone acceptor) state as the secondary acceptor pool becomes reduced, which is probably the origin of photosynthetic incompetence. We suggest that this is related to the Q(B) pocket alterations. The malfunction of the reaction center is probably due to a faulty association with LH1 that is prevented in the PufX-containing structure.
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Affiliation(s)
- Frédéric Comayras
- Unité Mixte de Recherche 6191 CNRS-Commissariat à l'Energie Atomique-Aix Marseille II, Département d'Ecophysiologie Végétale et de Microbiologie, Commissariat à l'Energie Atomique Cadarache, 13108 Saint Paul-lez-Durance, France
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Comayras F, Jungas C, Lavergne J. Functional consequences of the organization of the photosynthetic apparatus in Rhodobacter sphaeroides. I. Quinone domains and excitation transfer in chromatophores and reaction center.antenna complexes. J Biol Chem 2005; 280:11203-13. [PMID: 15632164 DOI: 10.1074/jbc.m412088200] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The purpose of this study was to gain information on the functional consequences of the supramolecular organization of the photosynthetic apparatus in the bacterium Rhodobacter sphaeroides. Isolated complexes of the reaction center (RC) with its core antenna ring (light-harvesting complex 1 (LH1)) were studied in their dimeric (native) form or as monomers with respect to excitation transfer and distribution of the quinone pool. Similar issues were examined in chromatophore membranes. The relationship between the fluorescence yield and the amount of closed centers is indicative of a very efficient excitation transfer between the two monomers in isolated dimeric complexes. A similar dependence was observed in chromatophores, suggesting that excitation transfer in vivo from a closed RC.LH1 unit is also essentially directed to its partner in the dimer. The isolated complexes were found to retain 25-30% of the endogenous quinone acceptor pool, and the distribution of this pool among the complexes suggests a cooperative character for the association of quinones with the protein complexes. In chromatophores, the decrease in the amount of photoreducible quinones when inhibiting a fraction of the centers implies a confinement of the quinone pool over small domains, including one to six reaction centers. We suggest that the crowding of membrane proteins may not be the sole reason for quinone confinement and that a quinone-rich region is formed around the RC.LH1 complexes.
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Affiliation(s)
- Frédéric Comayras
- Unité Mixte de Recherche 6191 CNRS-Commissariat à l'Energie Atomique-Aix Marseille II, Département d'Ecophysiologie Végétale et de Microbiologie, Commissariat à l'Energie Atomique Cadarache, 13108 Saint Paul-lez-Durance Cedex, France
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Abstract
Native tubular membranes were purified from the purple non-sulfur bacterium Rhodobacter sphaeroides. These tubular structures contain all the membrane components of the photosynthetic apparatus, in the relative ratio of one cytochrome bc1 complex to two reaction centers, and approximately 24 bacteriochlorophyll molecules per reaction center. Electron micrographs of negative-stained membranes diffract up to 25 A and allow the calculation of a projection map at 20 A. The unit cell (a = 198 A, b = 120 A and gamma = 103 degrees) contains an elongated S-shaped supercomplex presenting a pseudo-2-fold symmetry. Comparison with density maps of isolated reaction center and light-harvesting complexes allowed interpretation of the projection map. Each supercomplex is composed of light-harvesting 1 complexes that take the form of two C-shaped structures of approximately 112 A in external diameter, facing each other on the open side and enclosing the two reaction centers. The remaining positive density is tentatively attributed to one cytochrome bc1 complex. These features shed new light on the association of the reaction center and the light-harvesting complexes. In particular, the organization of the light-harvesting complexes in C-shaped structures ensures an efficient exchange of ubihydroquinone/ubiquinone between the reaction center and the cytochrome bc1 complex.
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Affiliation(s)
- C Jungas
- CEA/Cadarache-DSV-DEVM Laboratoire de Bioenergetique Cellulaire, 13108 St Paul-lez-Durance Cedex
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