1. Functional Analyses of the Plant Photosystem I–Light-Harvesting Complex II Supercomplex Reveal That Light-Harvesting Complex II Loosely Bound to Photosystem II Is a Very Efficient Antenna for Photosystem I in State II
- Author
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Robert C. Jennings, Stefano Caffarri, Hervé Degand, Pierre Morsomme, Egbert J. Boekema, Thi Thu Khuong Khuong, Stefano Santabarbara, Pierre Galka, Luminy Génétique et Biophysique des Plantes (LGBP), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Electron Microscopy, and Groningen Biomolecular Sciences and Biotechnology
- Subjects
0106 biological sciences ,Circular dichroism ,PHOTOCHEMICAL TRAPPING RATE ,Photosystem II ,FLUCTUATING LIGHT ,ANGSTROM RESOLUTION ,Chlamydomonas reinhardtii ,Plant Science ,Photosystem I ,Photosynthesis ,01 natural sciences ,CHLAMYDOMONAS-REINHARDTII ,03 medical and health sciences ,chemistry.chemical_compound ,Botany ,[SDV.BV]Life Sciences [q-bio]/Vegetal Biology ,EXCITATION-ENERGY TRANSFER ,[SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology ,ComputingMilieux_MISCELLANEOUS ,030304 developmental biology ,Photosystem ,0303 health sciences ,biology ,PLASTOQUINONE REDOX STATE ,FLUORESCENCE DECAY ,Cell Biology ,biology.organism_classification ,chemistry ,Chlorophyll ,Excited state ,ARABIDOPSIS-THALIANA ,Biophysics ,SUPRAMOLECULAR ORGANIZATION ,High Energy Physics::Experiment ,PROTEIN-PHOSPHORYLATION ,010606 plant biology & botany - Abstract
State transitions are an important photosynthetic short-term response that allows energy distribution balancing between photosystems I (PSI) and II (PSII). In plants when PSII is preferentially excited compared with PSI (State II), part of the major light-harvesting complex LHCII migrates to PSI to form a PSI-LHCII supercomplex. So far, little is known about this complex, mainly due to purification problems. Here, a stable PSI-LHCII supercomplex is purified from Arabidopsis thaliana and maize (Zea mays) plants. It is demonstrated that LHCIIs loosely bound to PSII in State I are the trimers mainly involved in state transitions and become strongly bound to PSI in State II. Specific Lhcb1-3 isoforms are differently represented in the mobile LHCII compared with S and M trimers. Fluorescence analyses indicate that excitation energy migration from mobile LHCII to PSI is rapid and efficient, and the quantum yield of photochemical conversion of PSI-LHCII is substantially unaffected with respect to PSI, despite a sizable increase of the antenna size. An updated PSI-LHCII structural model suggests that the lowenergy chlorophylls 611 and 612 in LHCII interact with the chlorophyll 11145 at the interface of PSI. In contrast with the common opinion, we suggest that the mobile pool of LHCII may be considered an intimate part of the PSI antenna system that is displaced to PSII in State I.
- Published
- 2012