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Rankelytė G, Gelzinis A, Robert B, Valkunas L, Chmeliov J. Environment-dependent chlorophyll-chlorophyll charge transfer states in Lhca4 pigment-protein complex. FRONTIERS IN PLANT SCIENCE 2024; 15:1412750. [PMID: 39170787 PMCID: PMC11335733 DOI: 10.3389/fpls.2024.1412750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Accepted: 07/02/2024] [Indexed: 08/23/2024]
Abstract
Photosystem I (PSI) light-harvesting antenna complexes LHCI contain spectral forms that absorb and emit photons of lower energy than that of its primary electron donor, P700. The most red-shifted fluorescence is associated with the Lhca4 complex. It has been suggested that this red emission is related to the inter-chlorophyll charge transfer (CT) states. In this work we present a systematic quantum-chemical study of the CT states in Lhca4, accounting for the influence of the protein environment by estimating the electrostatic interactions. We show that significant energy shifts result from these interactions and propose that the emission of the Lhca4 complex is related not only to the previously proposed a603+-a608- state, but also to the a602+-a603- state. We also investigate how different protonation patterns of protein amino acids affect the energetics of the CT states.
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Affiliation(s)
- Gabrielė Rankelytė
- Institute of Chemical Physics, Faculty of Physics, Vilnius University, Vilnius, Lithuania
- Department of Molecular Compound Physics, Center for Physical Sciences and Technology, Vilnius, Lithuania
| | - Andrius Gelzinis
- Institute of Chemical Physics, Faculty of Physics, Vilnius University, Vilnius, Lithuania
- Department of Molecular Compound Physics, Center for Physical Sciences and Technology, Vilnius, Lithuania
| | - Bruno Robert
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell, Gif-sur-Yvette, France
| | - Leonas Valkunas
- Department of Molecular Compound Physics, Center for Physical Sciences and Technology, Vilnius, Lithuania
| | - Jevgenij Chmeliov
- Institute of Chemical Physics, Faculty of Physics, Vilnius University, Vilnius, Lithuania
- Department of Molecular Compound Physics, Center for Physical Sciences and Technology, Vilnius, Lithuania
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Li X, Huang G, Zhu L, Hao C, Sui SF, Qin X. Structure of the red-shifted Fittonia albivenis photosystem I. Nat Commun 2024; 15:6325. [PMID: 39060282 PMCID: PMC11282222 DOI: 10.1038/s41467-024-50655-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Accepted: 07/11/2024] [Indexed: 07/28/2024] Open
Abstract
Photosystem I (PSI) from Fittonia albivenis, an Acanthaceae ornamental plant, is notable among green plants for its red-shifted emission spectrum. Here, we solved the structure of a PSI-light harvesting complex I (LHCI) supercomplex from F. albivenis at 2.46-Å resolution using cryo-electron microscopy. The supercomplex contains a core complex of 14 subunits and an LHCI belt with four antenna subunits (Lhca1-4) similar to previously reported angiosperm PSI-LHCI structures; however, Lhca3 differs in three regions surrounding a dimer of low-energy chlorophylls (Chls) termed red Chls, which absorb far-red beyond visible light. The unique amino acid sequences within these regions are exclusively shared by plants with strongly red-shifted fluorescence emission, suggesting candidate structural elements for regulating the energy state of red Chls. These results provide a structural basis for unraveling the mechanisms of light harvest and transfer in PSI-LHCI of under canopy plants and for designing Lhc to harness longer-wavelength light in the far-red spectral range.
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Affiliation(s)
- Xiuxiu Li
- School of Chemistry and Chemical Engineering, School of Biological Science and Technology, University of Jinan, Jinan, China
| | - Guoqiang Huang
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
- Multiscale Research Institute of Complex Systems, Fudan University, Shanghai, China
| | - Lixia Zhu
- School of Chemistry and Chemical Engineering, School of Biological Science and Technology, University of Jinan, Jinan, China
| | - Chenyang Hao
- School of Chemistry and Chemical Engineering, School of Biological Science and Technology, University of Jinan, Jinan, China
| | - Sen-Fang Sui
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China.
- School of Life Sciences, Southern University of Science and Technology, Shenzhen, China.
| | - Xiaochun Qin
- School of Chemistry and Chemical Engineering, School of Biological Science and Technology, University of Jinan, Jinan, China.
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3
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Li X, Yang G, Yuan X, Wu F, Wang W, Shen JR, Kuang T, Qin X. Structural elucidation of vascular plant photosystem I and its functional implications. FUNCTIONAL PLANT BIOLOGY : FPB 2022; 49:432-443. [PMID: 34637699 DOI: 10.1071/fp21077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 09/13/2021] [Indexed: 06/13/2023]
Abstract
In vascular plants, bryophytes and algae, the photosynthetic light reaction takes place in the thylakoid membrane where two transmembrane supercomplexes PSII and PSI work together with cytochrome b 6 f and ATP synthase to harvest the light energy and produce ATP and NADPH. Vascular plant PSI is a 600-kDa protein-pigment supercomplex, the core complex of which is partly surrounded by peripheral light-harvesting complex I (LHCI) that captures sunlight and transfers the excitation energy to the core to be used for charge separation. PSI is unique mainly in absorption of longer-wavelengths than PSII, fast excitation energy transfer including uphill energy transfer, and an extremely high quantum efficiency. From the early 1980s, a lot of effort has been dedicated to structural and functional studies of PSI-LHCI, leading to the current understanding of how more than 200 cofactors are kept at the correct distance and geometry to facilitate fast energy transfer in this supercomplex at an atomic level. In this review, we review the history of studies on vascular plant PSI-LHCI, summarise the present research progress on its structure, and present some new and further questions to be answered in future studies.
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Affiliation(s)
- Xiuxiu Li
- School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, China; and School of Biological Science and Technology, University of Jinan, Jinan 250022, China
| | - Gongxian Yang
- School of Biological Science and Technology, University of Jinan, Jinan 250022, China
| | - Xinyi Yuan
- School of Biological Science and Technology, University of Jinan, Jinan 250022, China
| | - Fenghua Wu
- School of Biological Science and Technology, University of Jinan, Jinan 250022, China
| | - Wenda Wang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Jian-Ren Shen
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Tingyun Kuang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Xiaochun Qin
- School of Biological Science and Technology, University of Jinan, Jinan 250022, China
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Wu F, Li X, Yang G, Song J, Zhao X, Zhu L, Qin X. Assembly of LHCA5 into PSI blue shifts the far-red fluorescence emission in higher plants. Biochem Biophys Res Commun 2022; 612:77-83. [PMID: 35512460 DOI: 10.1016/j.bbrc.2022.04.102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 04/21/2022] [Indexed: 11/02/2022]
Abstract
In higher plants, the PSI core complex is associated with light-harvesting complex I (LHCI), forming the PSI-LHCI super-complex. In vascular plants, four major antenna proteins (LHCA1-4) are assembled in the order of LHCA1, LHCA4, LHCA2, and LHCA3 into a crescent-shaped LHCI, while LHCA5 and LHCA6 are minor antenna proteins. By contrast, in moss and green algae, LHCA5 or LHCA5-like protein functions as one of the major antenna proteins by residing at the second site of LHCI. In order to learn the effect of binding different LHCA proteins, i.e. LHCA4 or LHCA5, within the PSI-LHCI super-complex on photosynthetic properties of plants, we constructed LHCA5 overexpression plants with a wild type (WT) background and an lhca4 mutant background in Arabidopsis thaliana. The results showed that: (i) there are little difference in phenotype, pigment composition and chlorophyll fluorescence parameters between the transgenic Arabidopsis and their corresponding background materials; (ii) in spite of a small amount of LHCA5, the LHCA5-included PSI-LHCI super-complex can be obtained by extracting samples incubated with anti-FLAG M2 Affinity Gel, in which LHCA5 is found to substitute for LHCA4 as analyzed by immunoblotting analysis; (iii) the replacement of LHCA4 with LHCA5 within PSI-LHCI super-complex leads to a blue shift in low temperature fluorescence emission, suggesting a decrease in far-red absorbance. These results provide new clues for understanding the position and function of LHCA4 and LHCA5 during the evolution of green plants from aquatic to terrestrial lifestyles.
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Affiliation(s)
- Fenghua Wu
- School of Biological Science and Technology, University of Jinan, Jinan, China
| | - Xiuxiu Li
- School of Chemistry and Chemical Engineering, University of Jinan, Jinan, China
| | - Gongxian Yang
- School of Chemistry and Chemical Engineering, University of Jinan, Jinan, China
| | - Jince Song
- School of Biological Science and Technology, University of Jinan, Jinan, China
| | - Xiaoyu Zhao
- School of Biological Science and Technology, University of Jinan, Jinan, China
| | - Lixia Zhu
- School of Biological Science and Technology, University of Jinan, Jinan, China.
| | - Xiaochun Qin
- School of Biological Science and Technology, University of Jinan, Jinan, China.
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Schiphorst C, Achterberg L, Gómez R, Koehorst R, Bassi R, van Amerongen H, Dall’Osto L, Wientjes E. The role of light-harvesting complex I in excitation energy transfer from LHCII to photosystem I in Arabidopsis. PLANT PHYSIOLOGY 2022; 188:2241-2252. [PMID: 34893885 PMCID: PMC8968287 DOI: 10.1093/plphys/kiab579] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 11/13/2021] [Indexed: 05/26/2023]
Abstract
Photosynthesis powers nearly all life on Earth. Light absorbed by photosystems drives the conversion of water and carbon dioxide into sugars. In plants, photosystem I (PSI) and photosystem II (PSII) work in series to drive the electron transport from water to NADP+. As both photosystems largely work in series, a balanced excitation pressure is required for optimal photosynthetic performance. Both photosystems are composed of a core and light-harvesting complexes (LHCI) for PSI and LHCII for PSII. When the light conditions favor the excitation of one photosystem over the other, a mobile pool of trimeric LHCII moves between both photosystems thus tuning their antenna cross-section in a process called state transitions. When PSII is overexcited multiple LHCIIs can associate with PSI. A trimeric LHCII binds to PSI at the PsaH/L/O site to form a well-characterized PSI-LHCI-LHCII supercomplex. The binding site(s) of the "additional" LHCII is still unclear, although a mediating role for LHCI has been proposed. In this work, we measured the PSI antenna size and trapping kinetics of photosynthetic membranes from Arabidopsis (Arabidopsis thaliana) plants. Membranes from wild-type (WT) plants were compared to those of the ΔLhca mutant that completely lacks the LHCI antenna. The results showed that "additional" LHCII complexes can transfer energy directly to the PSI core in the absence of LHCI. However, the transfer is about two times faster and therefore more efficient, when LHCI is present. This suggests LHCI mediates excitation energy transfer from loosely bound LHCII to PSI in WT plants.
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Affiliation(s)
- Christo Schiphorst
- Dipartimento di Biotecnologie, Università di Verona, 37134 Verona, Italy
- Laboratory of Biophysics, Wageningen University, 6700 ET Wageningen, The Netherlands
| | - Luuk Achterberg
- Laboratory of Biophysics, Wageningen University, 6700 ET Wageningen, The Netherlands
| | - Rodrigo Gómez
- Dipartimento di Biotecnologie, Università di Verona, 37134 Verona, Italy
| | - Rob Koehorst
- Laboratory of Biophysics, Wageningen University, 6700 ET Wageningen, The Netherlands
- MicroSpectroscopy Research Facility, Wageningen University, 6700 ET Wageningen, The Netherlands
| | - Roberto Bassi
- Dipartimento di Biotecnologie, Università di Verona, 37134 Verona, Italy
| | - Herbert van Amerongen
- Laboratory of Biophysics, Wageningen University, 6700 ET Wageningen, The Netherlands
- MicroSpectroscopy Research Facility, Wageningen University, 6700 ET Wageningen, The Netherlands
| | - Luca Dall’Osto
- Dipartimento di Biotecnologie, Università di Verona, 37134 Verona, Italy
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A megacomplex composed of both photosystem reaction centres in higher plants. Nat Commun 2015; 6:6675. [PMID: 25809225 DOI: 10.1038/ncomms7675] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 02/19/2015] [Indexed: 11/08/2022] Open
Abstract
Throughout the history of oxygen evolution, two types of photosystem reaction centres (PSI and PSII) have worked in a coordinated manner. The oxygen evolving centre is an integral part of PSII, and extracts an electron from water. PSI accepts the electron, and accumulates reducing power. Traditionally, PSI and PSII are thought to be spatially dispersed. Here, we show that about half of PSIIs are physically connected to PSIs in Arabidopsis thaliana. In the PSI-PSII complex, excitation energy is transferred efficiently between the two closely interacting reaction centres. PSII diverts excitation energy to PSI when PSII becomes closed-state in the PSI-PSII complex. The formation of PSI-PSII complexes is regulated by light conditions. Quenching of excess energy by PSI might be one of the physiological functions of PSI-PSII complexes.
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Nellaepalli S, Zsiros O, Tóth T, Yadavalli V, Garab G, Subramanyam R, Kovács L. Heat- and light-induced detachment of the light harvesting complex from isolated photosystem I supercomplexes. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2014; 137:13-20. [PMID: 24874922 DOI: 10.1016/j.jphotobiol.2014.04.026] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 04/23/2014] [Accepted: 04/25/2014] [Indexed: 11/26/2022]
Abstract
In a previous study, using photosystem I enriched stroma thylakoid membrane vesicles, we have shown that the light harvesting complexes of this photosystem are prone to heat- and light-induced, thermo-optically driven detachment from the supercomplex [43]. We have also shown that the splitting of the supercomplex occurs in a gradual and specific manner, selectively affecting the different constituents of the antenna complexes. Here we further analyse these heat- and light-induced processes in isolated Photosystem I supercomplex using circular dichroism and 77K fluorescence emission spectroscopy and immuno blotting, and obtain further details on the sequence of events of the dissociation process as well as on the thermal stability of the different components. Our absorption and circular dichroism spectroscopy and immuno blotting data show that the dissociation of LHCI from PSI-LHCI supercomplex starts above 50°C. Also, the low temperature fluorescence emission spectra depicts decrease of maximum fluorescence emission at 730nm and an increase of the intensity at 685nm, and about 10nm blue-shifts, from 730 to 720nm and from 685 to 676nm, respectively, indicating the heat (50°C) induced detachment of LHCI from PSI core complexes. The reaction centre proteins are highly stable even at high temperatures. Lhca2 is more heat stable than the other light harvesting protein complexes of PSI, whereas Lhca4 and Lhca3 are rather labile. Combined heat and light treatments significantly enhances the disorganization of PSI-LHCI supercomplexes, indicating a thermo-optic mechanism, which might have significant role under combined heat and light stress conditions.
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Affiliation(s)
- Sreedhar Nellaepalli
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India
| | - Ottó Zsiros
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, Hungary
| | - Tünde Tóth
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, Hungary
| | - Venkateswarlu Yadavalli
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India
| | - Győző Garab
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, Hungary
| | - Rajagopal Subramanyam
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India; Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India
| | - László Kovács
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, Hungary.
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8
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Croce R, van Amerongen H. Light-harvesting in photosystem I. PHOTOSYNTHESIS RESEARCH 2013; 116:153-66. [PMID: 23645376 PMCID: PMC3825136 DOI: 10.1007/s11120-013-9838-x] [Citation(s) in RCA: 169] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 04/23/2013] [Indexed: 05/18/2023]
Abstract
This review focuses on the light-harvesting properties of photosystem I (PSI) and its LHCI outer antenna. LHCI consists of different chlorophyll a/b binding proteins called Lhca's, surrounding the core of PSI. In total, the PSI-LHCI complex of higher plants contains 173 chlorophyll molecules, most of which are there to harvest sunlight energy and to transfer the created excitation energy to the reaction center (RC) where it is used for charge separation. The efficiency of the complex is based on the capacity to deliver this energy to the RC as fast as possible, to minimize energy losses. The performance of PSI in this respect is remarkable: on average it takes around 50 ps for the excitation to reach the RC in plants, without being quenched in the meantime. This means that the internal quantum efficiency is close to 100% which makes PSI the most efficient energy converter in nature. In this review, we describe the light-harvesting properties of the complex in relation to protein and pigment organization/composition, and we discuss the important parameters that assure its very high quantum efficiency. Excitation energy transfer and trapping in the core and/or Lhcas, as well as in the supercomplexes PSI-LHCI and PSI-LHCI-LHCII are described in detail with the aim of giving an overview of the functional behavior of these complexes.
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Affiliation(s)
- Roberta Croce
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands,
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Oey M, Ross IL, Stephens E, Steinbeck J, Wolf J, Radzun KA, Kügler J, Ringsmuth AK, Kruse O, Hankamer B. RNAi knock-down of LHCBM1, 2 and 3 increases photosynthetic H2 production efficiency of the green alga Chlamydomonas reinhardtii. PLoS One 2013; 8:e61375. [PMID: 23613840 PMCID: PMC3628864 DOI: 10.1371/journal.pone.0061375] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 03/10/2013] [Indexed: 11/18/2022] Open
Abstract
Single cell green algae (microalgae) are rapidly emerging as a platform for the production of sustainable fuels. Solar-driven H2 production from H2O theoretically provides the highest-efficiency route to fuel production in microalgae. This is because the H2-producing hydrogenase (HYDA) is directly coupled to the photosynthetic electron transport chain, thereby eliminating downstream energetic losses associated with the synthesis of carbohydrate and oils (feedstocks for methane, ethanol and oil-based fuels). Here we report the simultaneous knock-down of three light-harvesting complex proteins (LHCMB1, 2 and 3) in the high H2-producing Chlamydomonas reinhardtii mutant Stm6Glc4 using an RNAi triple knock-down strategy. The resultant Stm6Glc4L01 mutant exhibited a light green phenotype, reduced expression of LHCBM1 (20.6% ±0.27%), LHCBM2 (81.2% ±0.037%) and LHCBM3 (41.4% ±0.05%) compared to 100% control levels, and improved light to H2 (180%) and biomass (165%) conversion efficiencies. The improved H2 production efficiency was achieved at increased solar flux densities (450 instead of ∼100 µE m−2 s−1) and high cell densities which are best suited for microalgae production as light is ideally the limiting factor. Our data suggests that the overall improved photon-to-H2 conversion efficiency is due to: 1) reduced loss of absorbed energy by non-photochemical quenching (fluorescence and heat losses) near the photobioreactor surface; 2) improved light distribution in the reactor; 3) reduced photoinhibition; 4) early onset of HYDA expression and 5) reduction of O2-induced inhibition of HYDA. The Stm6Glc4L01 phenotype therefore provides important insights for the development of high-efficiency photobiological H2 production systems.
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Affiliation(s)
- Melanie Oey
- The University of Queensland, Institute for Molecular Bioscience, Brisbane, Queensland, Australia
| | - Ian L. Ross
- The University of Queensland, Institute for Molecular Bioscience, Brisbane, Queensland, Australia
| | - Evan Stephens
- The University of Queensland, Institute for Molecular Bioscience, Brisbane, Queensland, Australia
| | - Janina Steinbeck
- Institute of Plant Biology and Biotechnology, The University of Münster, Münster, Germany
| | - Juliane Wolf
- The University of Queensland, Institute for Molecular Bioscience, Brisbane, Queensland, Australia
| | - Khairul Adzfa Radzun
- The University of Queensland, Institute for Molecular Bioscience, Brisbane, Queensland, Australia
- Faculty of Applied Sciences, MARA University of Technology, Shah Alam, Selangor, Malaysia
| | - Johannes Kügler
- Institute of Process Engineering in Life Sciences, Section II: Technical Biology, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Andrew K. Ringsmuth
- The University of Queensland, Institute for Molecular Bioscience, Brisbane, Queensland, Australia
- ARC Centre for Engineered Quantum Systems, The University of Queensland, Brisbane, Queensland, Australia
| | - Olaf Kruse
- Center for Biotechnology (CeBiTec), Department of Algae Biotechnology & Bioenergy, Bielefeld University, Bielefeld, Germany
| | - Ben Hankamer
- The University of Queensland, Institute for Molecular Bioscience, Brisbane, Queensland, Australia
- * E-mail:
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From red to blue to far-red in Lhca4: How does the protein modulate the spectral properties of the pigments? BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:711-7. [DOI: 10.1016/j.bbabio.2012.02.030] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Revised: 02/22/2012] [Accepted: 02/23/2012] [Indexed: 10/28/2022]
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Ze Y, Liu C, Wang L, Hong M, Hong F. The regulation of TiO2 nanoparticles on the expression of light-harvesting complex II and photosynthesis of chloroplasts of Arabidopsis thaliana. Biol Trace Elem Res 2011; 143:1131-41. [PMID: 21104338 DOI: 10.1007/s12011-010-8901-0] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Accepted: 11/07/2010] [Indexed: 10/18/2022]
Abstract
Recent studies demonstrated that titanium dioxide nanoparticles (TiO2 NPs) could significantly promote photosynthesis and plant growth, but its mechanism is still unclear. In this article, we studied the mechanism of light absorption and transfer of chloroplasts of Arabidopsis thaliana caused by TiO2 NPs treated. The results showed that TiO2 NPs could induce significant increases of light-harvesting complex II (LHCII) b gene expression and LHCII II content on the thylakoid membrane in A. thaliana, and the increases in LHCII were higher than the non-nano TiO2 (bulk-TiO2) treatment. Meanwhile, spectroscopy assays indicated that TiO2 NPs obviously increased the absorption peak intensity of the chloroplast in red and blue region, the fluorescence quantum yield near 680 nm, the excitation peak intensity near 440 and 480 nm and/or near 650 and 680 nm of the chloroplast. TiO2 NPs treatment could reduce F480/F440 ratio and increase F650/F680 ratio and accelerate the rate of whole chain electron transport and oxygen evolution of the chloroplast. However, the photosynthesis improvement of the non-nanoTiO2 treatment was far less effective than TiO2 NPs treatment. Taken together, TiO2 NPs could promote the light absorption of chloroplast, regulate the distribution of light energy from PS I to PS II by increasing LHCII and accelerate the transformation from light energy to electronic energy, water photolysis, and oxygen evolution.
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Affiliation(s)
- Yuguan Ze
- Medical College of Suzhou University, Suzhou, 215123, People's Republic of China
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12
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Wientjes E, van Stokkum IHM, van Amerongen H, Croce R. Excitation-energy transfer dynamics of higher plant photosystem I light-harvesting complexes. Biophys J 2011; 100:1372-80. [PMID: 21354411 DOI: 10.1016/j.bpj.2011.01.030] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Accepted: 01/19/2011] [Indexed: 11/15/2022] Open
Abstract
Photosystem I (PSI) plays a major role in the light reactions of photosynthesis. In higher plants, PSI is composed of a core complex and four outer antennas that are assembled as two dimers, Lhca1/4 and Lhca2/3. Time-resolved fluorescence measurements on the isolated dimers show very similar kinetics. The intermonomer transfer processes are resolved using target analysis. They occur at rates similar to those observed in transfer to the PSI core, suggesting competition between the two transfer pathways. It appears that each dimer is adopting various conformations that correspond to different lifetimes and emission spectra. A special feature of the Lhca complexes is the presence of an absorption band at low energy, originating from an excitonic state of a chlorophyll dimer, mixed with a charge-transfer state. These low-energy bands have high oscillator strengths and they are superradiant in both Lhca1/4 and Lhca2/3. This challenges the view that the low-energy charge-transfer state always functions as a quencher in plant Lhc's and it also challenges previous interpretations of PSI kinetics. The very similar properties of the low-energy states of both dimers indicate that the organization of the involved chlorophylls should also be similar, in disagreement with the available structural data.
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Affiliation(s)
- Emilie Wientjes
- Department of Biophysical Chemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands
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13
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The light-harvesting complexes of higher-plant Photosystem I: Lhca1/4 and Lhca2/3 form two red-emitting heterodimers. Biochem J 2011; 433:477-85. [PMID: 21083539 DOI: 10.1042/bj20101538] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The outer antenna of higher-plant PSI (Photosystem I) is composed of four complexes [Lhc (light-harvesting complex) a1-Lhca4] belonging to the light-harvesting protein family. Difficulties in their purification have so far prevented the determination of their properties and most of the knowledge about Lhcas has been obtained from the study of the in vitro reconstituted antennas. In the present study we were able to purify the native complexes, showing that Lhca2/3 and Lhca1/4 form two functional heterodimers. Both dimers show red-fluorescence emission with maxima around 730 nm, as in the intact PSI complex. This indicates that the dimers are in their native state and that LHCI-680, which was previously assumed to be part of the PSI antenna, does not represent the native state of the system. The data show that the light-harvesting properties of the two dimers are functionally identical, concerning absorption, long-wavelength emission and fluorescence quantum yield, whereas they differ in their high-light response. Implications of the present study for the understanding of the energy transfer process in PSI are discussed. Finally, the comparison of the properties of the native dimers with those of the reconstituted complexes demonstrates that all of the major properties of the Lhcas are reproduced in the in vitro systems.
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Busch A, Hippler M. The structure and function of eukaryotic photosystem I. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1807:864-77. [PMID: 20920463 DOI: 10.1016/j.bbabio.2010.09.009] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Revised: 09/20/2010] [Accepted: 09/28/2010] [Indexed: 12/27/2022]
Abstract
Eukaryotic photosystem I consists of two functional moieties: the photosystem I core, harboring the components for the light-driven charge separation and the subsequent electron transfer, and the peripheral light-harvesting complex (LHCI). While the photosystem I-core remained highly conserved throughout the evolution, with the exception of the oxidizing side of photosystem I, the LHCI complex shows a high degree of variability in size, subunits composition and bound pigments, which is due to the large variety of different habitats photosynthetic organisms dwell in. Besides summarizing the most current knowledge on the photosystem I-core structure, we will discuss the composition and structure of the LHCI complex from different eukaryotic organisms, both from the red and the green clade. Furthermore, mechanistic insights into electron transfer between the donor and acceptor side of photosystem I and its soluble electron transfer carrier proteins will be given. This article is part of a Special Issue entitled: Regulation of Electron Transport in Chloroplasts.
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Affiliation(s)
- Andreas Busch
- Department of Plant Biology and Biotechnology, Faculty of Life Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark.
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15
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Wientjes E, Oostergetel GT, Jansson S, Boekema EJ, Croce R. The role of Lhca complexes in the supramolecular organization of higher plant photosystem I. J Biol Chem 2009; 284:7803-10. [PMID: 19139095 DOI: 10.1074/jbc.m808395200] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In this work, Photosystem I supercomplexes have been purified from Lhca-deficient lines of Arabidopsis thaliana using a mild detergent treatment that does not induce loss of outer antennas. The complexes have been studied by integrating biochemical analysis with electron microscopy. This allows the direct correlation of changes in protein content with changes in supramolecular structure of Photosystem I to get information about the position of the individual Lhca subunits, the association of the antenna to the core, and the influence of the individual subunits on the stability of the system. Photosystem I complexes with only two or three antenna complexes were purified, showing that the binding of Lhca1/4 and Lhca2/3 dimers to the core is not interdependent, although weak binding of Lhca2/3 to the core is stabilized by the presence of Lhca4. Moreover, Lhca2 and Lhca4 can be associated with the core in the absence of their "dimeric partners." The structure of Photosystem I is very rigid, and the absence of one antenna complex leaves a "hole" in the structure that cannot be filled by other Lhcas, clearly indicating that the docking sites for the individual subunits are highly specific. There is, however, an exception to the rule: Lhca5 can substitute for Lhca4, yielding highly stable PSI supercomplexes with a supramolecular organization identical to the WT.
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Affiliation(s)
- Emilie Wientjes
- Department of Biophysical Chemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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16
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Seelert H, Krause F. Preparative isolation of protein complexes and other bioparticles by elution from polyacrylamide gels. Electrophoresis 2008; 29:2617-36. [PMID: 18494038 DOI: 10.1002/elps.200800061] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Due to its unmatched resolution, gel electrophoresis is an indispensable tool for the analysis of diverse biomolecules. By adaptation of the electrophoretic conditions, even fragile protein complexes as parts of intracellular networks migrate through the gel matrix under sustainment of their integrity. If the thickness of such native gels is significantly increased compared to the analytical version, also high sample loads can be processed. However, the cage-like network obstructs an in-depth analysis for deciphering structure and function of protein complexes and other species. Consequently, the biomolecules have to be removed from the gel matrix into solution. Several approaches summarized in this review tackle this problem. While passive elution relies on diffusion processes, electroelution employs an electric field to force biomolecules out of the gel. An alternative procedure requires a special electrophoresis setup, the continuous elution device. In this apparatus, molecules migrate in the electric field until they leave the gel and were collected in a buffer stream. Successful isolation of diverse protein complexes like photosystems, ATP-dependent enzymes or active respiratory supercomplexes and some other bioparticles demonstrates the versatility of preparative electrophoresis. After liberating particles out of the gel cage, numerous applications are feasible. They include elucidation of the individual components up to high resolution structures of protein complexes. Therefore, preparative electrophoresis can complement standard purification methods and is in some cases superior to them.
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Affiliation(s)
- Holger Seelert
- Department of Chemistry, Physical Biochemistry, Technische Universität Darmstadt, Darmstadt, Germany.
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17
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Pedrós R, Moya I, Goulas Y, Jacquemoud S. Chlorophyll fluorescence emission spectrum inside a leaf. Photochem Photobiol Sci 2008; 7:498-502. [PMID: 18385895 DOI: 10.1039/b719506k] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Chlorophyll a fluorescence can be used as an early stress indicator. Fluorescence is also connected to photosynthesis so it can be proposed for global monitoring of vegetation status from a satellite platform. Nevertheless, the correct interpretation of fluorescence requires accurate physical models. The spectral shape of the leaf fluorescence free of any re-absorption effect plays a key role in the models and is difficult to measure. We present a vegetation fluorescence emission spectrum free of re-absorption based on a combination of measurements and modelling. The suggested spectrum takes into account the photosystem I and II spectra and their relative contribution to fluorescence. This emission spectrum is applicable to describe vegetation fluorescence in biospectroscopy and remote sensing.
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Affiliation(s)
- Roberto Pedrós
- Solar Radiation Group, Department of Earth Physics and Thermodynamics, University of Valencia, Spain
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18
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Jensen PE, Bassi R, Boekema EJ, Dekker JP, Jansson S, Leister D, Robinson C, Scheller HV. Structure, function and regulation of plant photosystem I. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2007; 1767:335-52. [PMID: 17442259 DOI: 10.1016/j.bbabio.2007.03.004] [Citation(s) in RCA: 151] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2007] [Revised: 03/03/2007] [Accepted: 03/06/2007] [Indexed: 12/20/2022]
Abstract
Photosystem I (PSI) is a multisubunit protein complex located in the thylakoid membranes of green plants and algae, where it initiates one of the first steps of solar energy conversion by light-driven electron transport. In this review, we discuss recent progress on several topics related to the functioning of the PSI complex, like the protein composition of the complex in the plant Arabidopsis thaliana, the function of these subunits and the mechanism by which nuclear-encoded subunits can be inserted into or transported through the thylakoid membrane. Furthermore, the structure of the native PSI complex in several oxygenic photosynthetic organisms and the role of the chlorophylls and carotenoids in the antenna complexes in light harvesting and photoprotection are reviewed. The special role of the 'red' chlorophylls (chlorophyll molecules that absorb at longer wavelength than the primary electron donor P700) is assessed. The physiology and mechanism of the association of the major light-harvesting complex of photosystem II (LHCII) with PSI during short term adaptation to changes in light quality and quantity is discussed in functional and structural terms. The mechanism of excitation energy transfer between the chlorophylls and the mechanism of primary charge separation is outlined and discussed. Finally, a number of regulatory processes like acclimatory responses and retrograde signalling is reviewed with respect to function of the thylakoid membrane. We finish this review by shortly discussing the perspectives for future research on PSI.
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Affiliation(s)
- Poul Erik Jensen
- Plant Biochemistry Laboratory, Department of Plant Biology, Faculty of Life Science, University of Copenhagen, DK-1871 Frederiksberg C, Denmark.
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19
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Tzvetkova-Chevolleau T, Hutin C, Noël LD, Goforth R, Carde JP, Caffarri S, Sinning I, Groves M, Teulon JM, Hoffman NE, Henry R, Havaux M, Nussaume L. Canonical signal recognition particle components can be bypassed for posttranslational protein targeting in chloroplasts. THE PLANT CELL 2007; 19:1635-48. [PMID: 17513500 PMCID: PMC1913721 DOI: 10.1105/tpc.106.048959] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The chloroplast signal recognition particle (cpSRP) and its receptor (cpFtsY) target proteins both cotranslationally and posttranslationally to the thylakoids. This dual function enables cpSRP to utilize its posttranslational activities for targeting a family of nucleus-encoded light-harvesting chlorophyll binding proteins (LHCPs), the most abundant membrane proteins in plants. Previous in vitro experiments indicated an absolute requirement for all cpSRP pathway soluble components. In agreement, a cpFtsY mutant in Arabidopsis thaliana exhibits a severe chlorotic phenotype resulting from a massive loss of LHCPs. Surprisingly, a double mutant, cpftsy cpsrp54, recovers to a great extent from the chlorotic cpftsy phenotype. This establishes that in plants, a new alternative pathway exists that can bypass cpSRP posttranslational targeting activities. Using a mutant form of cpSRP43 that is unable to assemble with cpSRP54, we complemented the cpSRP43-deficient mutant and found that this subunit is required for the alternative pathway. Along with the ability of cpSRP43 alone to bind the ALBINO3 translocase required for LHCP integration, our results indicate that cpSRP43 has developed features to function independently of cpSRP54/cpFtsY in targeting LHCPs to the thylakoid membranes.
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Affiliation(s)
- Tzvetelina Tzvetkova-Chevolleau
- Direction des Sciences du Vivant, Institut de Biologie Environementale et de Biotechnologie, Service de Biologie Végétale et de Microbiologie Environementale, Commissariat à l'Energie Atomique Cadarache, F-13108 Saint-Paul-lez-Durance Cedex, France
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20
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21
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Zheng L, Su M, Wu X, Liu C, Qu C, Chen L, Huang H, Liu X, Hong F. Effects of nano-anatase on spectral characteristics and distribution of LHCII on the thylakoid membranes of spinach. Biol Trace Elem Res 2007; 120:273-83. [PMID: 17916980 DOI: 10.1007/s12011-007-8025-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2007] [Revised: 11/30/1999] [Accepted: 07/09/2007] [Indexed: 10/23/2022]
Abstract
In the article, we report that effects of nano-anatase on the spectral characteristics and content of light-harvesting complex II (LHCII) on the thylakoid membranes of spinach were investigated. The results showed that nano-anatase treatment could increase LHCII content on the thylakoid membranes of spinach and the trimer of LHCII; nano-anatase could enter the spinach chloroplasts and bind to PSII. Meanwhile, spectroscopy assays indicated that the absorption intensity of LHCII from nano-anatase-treated spinach was obviously increased in the red and the blue region, fluorescence quantum yield near 685 nm of LHCII was enhanced, the fluorescence excitation intensity near 440 and 480 nm of LHCII significantly rose and F 480/F 440 ratio was reduced. Oxygen evolution rate of PSII was greatly improved. Together, nano-anatase promoted energy transferring from chlorophyll (chl) b and carotenoid to chl a, and nano-anatase TiO2 was photosensitized by chl of LHCII, which led to enhance the efficiency of absorbing, transferring, and converting light energy.
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Affiliation(s)
- Lei Zheng
- College of Life Sciences, Suzhou University, Suzhou 215123, People's Republic of China
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22
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Qin X, Wang K, Chen X, Qu Y, Li L, Kuang T. Rapid purification of photosystem I chlorophyll-binding proteins by differential centrifugation and vertical rotor. PHOTOSYNTHESIS RESEARCH 2006; 90:195-204. [PMID: 17235493 DOI: 10.1007/s11120-006-9104-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2006] [Accepted: 08/30/2006] [Indexed: 05/13/2023]
Abstract
Photosystem I (PSI), which consists of a core complex and light-harvesting complex I (LHCI), is an important multisubunit pigment-protein complex located in the photosynthetic membranes of cyanobacteria, algae and plants. In the present study, we described a rapid method for isolation and purification of PSI and its subfractions. For purification of PSI, crude PSI was first prepared by differential centrifugation, which was applicable on a large scale at low cost. Then PSI was purified by sucrose gradient ultracentrifugation in a vertical rotor to reduce the centrifugation time from more than 20 h when using a swinging bucket rotor to only 3 h. Similarly, for subfractionation of PSI into the core complex and light-harvesting complex I, sucrose gradient ultracentrifugation in a vertical rotor was also used and it took only 4 h to obtain the PSI core, LHCI-680, and LHCI-730 at the same time. The resulting preparations were characterized by sodium dodecyl-sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), absorption spectroscopy, and 77 K fluorescence spectroscopy. In addition, their pigment composition was analyzed by high-performance liquid chromatography and the results showed that each Lhca could bind 1.5-1.6 luteins, 1.0 Violaxanthins, and 0.8-1.1 beta-carotenes on average, demonstrating that fewer carotenoids were released than with the slower traditional centrifugation. These results showed that the rapid isolation procedure, based on differential centrifugation and sucrose gradient ultracentrifugation in a vertical rotor, was efficient, and it should significantly facilitate preparation and studies of plant PSI. Moreover, the vertical rotor, rather than the swinging bucket rotor, may be a good choice for isolation of some other proteins.
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Affiliation(s)
- Xiaochun Qin
- Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing , 100093, P.R. China
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23
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Lucinski R, Schmid VHR, Jansson S, Klimmek F. Lhca5 interaction with plant photosystem I. FEBS Lett 2006; 580:6485-8. [PMID: 17107674 DOI: 10.1016/j.febslet.2006.10.063] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2006] [Revised: 10/30/2006] [Accepted: 10/30/2006] [Indexed: 11/22/2022]
Abstract
In the outer antenna (LHCI) of higher plant photosystem I (PSI) four abundantly expressed light-harvesting protein of photosystem I (Lhca)-type proteins are organized in two heterodimeric domains (Lhca1/Lhca4 and Lhca2/Lhca3). Our cross-linking studies on PSI-LHCI preparations from wildtype Arabidopsis and pea plants indicate an exclusive interaction of the rarely expressed Lhca5 light-harvesting protein with LHCI in the Lhca2/Lhca3-site. In PSI particles with an altered LHCI composition Lhca5 assembles in the Lhca1/Lhca4 site, partly as a homodimer. This flexibility indicates a binding-competitive model for the LHCI assembly in plants regulated by molecular interactions of the Lhca proteins with the PSI core.
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Affiliation(s)
- Robert Lucinski
- Adam Mickiewicz University, Department of Plant Physiology, Institute of Experimental Biology, Al. Niepodleglosci 14, 61-713, Poznan, Poland
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24
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Nield J, Redding K, Hippler M. Remodeling of light-harvesting protein complexes in chlamydomonas in response to environmental changes. EUKARYOTIC CELL 2005; 3:1370-80. [PMID: 15590812 PMCID: PMC539040 DOI: 10.1128/ec.3.6.1370-1380.2004] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Jon Nield
- Department of Biological Sciences, Imperial College London, London, UK
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25
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Klimmek F, Ganeteg U, Ihalainen JA, van Roon H, Jensen PE, Scheller HV, Dekker JP, Jansson S. Structure of the Higher Plant Light Harvesting Complex I: In Vivo Characterization and Structural Interdependence of the Lhca Proteins. Biochemistry 2005; 44:3065-73. [PMID: 15723551 DOI: 10.1021/bi047873g] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have investigated the structure of the higher plant light harvesting complex of photosystem I (LHCI) by analyzing PSI-LHCI particles isolated from a set of Arabidopsis plant lines, each lacking a specific Lhca (Lhca1-4) polypeptide. Functional antenna size measurements support the recent finding that there are four Lhca proteins per PSI in the crystal structure [Ben-Shem, A., Frolow, F., and Nelson, N. (2003) Nature 426, 630-635]. According to HPLC analyses the number of pigment molecules bound within the LHCI is higher than expected from reconstitution studies or analyses of isolated native LHCI. Comparison of the spectra of the particles from the different lines reveals chlorophyll absorption bands peaking at 696, 688, 665, and 655 nm that are not present in isolated PSI or LHCI. These bands presumably originate from "gap" or "linker" pigments that are cooperatively coordinated by the Lhca and/or PSI proteins, which we have tentatively localized in the PSI-LHCI complex.
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Affiliation(s)
- Frank Klimmek
- Department of Plant Physiology, Umeå Plant Science Centre, SE 90189 Umeå, Sweden.
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26
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Storf S, Jansson S, Schmid VHR. Pigment Binding, Fluorescence Properties, and Oligomerization Behavior of Lhca5, a Novel Light-harvesting Protein. J Biol Chem 2005; 280:5163-8. [PMID: 15563470 DOI: 10.1074/jbc.m411248200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A new potential light-harvesting protein, named Lhca5, was recently detected in higher plants. Because of the low amount of Lhca5 in thylakoid membranes, the isolation of a native Lhca5 pigment-protein complex has not been achieved to date. Therefore, we used in vitro reconstitution to analyze whether Lhca5 binds pigments and is actually an additional light-harvesting protein. By this approach we could demonstrate that Lhca5 binds pigments in a unique stoichiometry. Analyses of pigment requirements for light-harvesting complex formation by Lhca5 revealed that chlorophyll b is the only indispensable pigment. Fluorescence measurements showed that ligated chlorophylls and carotenoids are arranged in a way that allows directed energy transfer within the light-harvesting complex. Reconstitutions of Lhca5 together with other Lhca proteins resulted in the formation of heterodimers with Lhca1. This result demonstrates that Lhca5 is indeed a protein belonging to the light-harvesting antenna of photosystem I. The properties of Lhca5 are compared with those of previously characterized Lhca proteins, and the consequences of an additional Lhca protein for the composition of the light-harvesting antenna of photosystem I are discussed in view of the recently published photosystem I structure of the pea.
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Affiliation(s)
- Stefanie Storf
- Institut für Allgemeine Botanik, Johannes Gutenberg-Universität Mainz, Müllerweg 6, 55099 Mainz, Germany
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27
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A sugar beet chlorophyll a/b binding protein promoter void of G-box like elements confers strong and leaf specific reporter gene expression in transgenic sugar beet. BMC Biotechnol 2004; 4:31. [PMID: 15579211 PMCID: PMC539256 DOI: 10.1186/1472-6750-4-31] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2004] [Accepted: 12/05/2004] [Indexed: 12/03/2022] Open
Abstract
Background Modification of leaf traits in sugar beet requires a strong leaf specific promoter. With such a promoter, expression in taproots can be avoided which may otherwise take away available energy resources for sugar accumulation. Results Suppression Subtractive Hybridization (SSH) was utilized to generate an enriched and equalized cDNA library for leaf expressed genes from sugar beet. Fourteen cDNA fragments corresponding to thirteen different genes were isolated. Northern blot analysis indicates the desired tissue specificity of these genes. The promoters for two chlorophyll a/b binding protein genes (Bvcab11 and Bvcab12) were isolated, linked to reporter genes, and transformed into sugar beet using promoter reporter gene fusions. Transient and transgenic analysis indicate that both promoters direct leaf specific gene expression. A bioinformatic analysis revealed that the Bvcab11 promoter is void of G-box like regulatory elements with a palindromic ACGT core sequence. The data indicate that the presence of a G-box element is not a prerequisite for leaf specific and light induced gene expression in sugar beet. Conclusions This work shows that SSH can be successfully employed for the identification and subsequent isolation of tissue specific sugar beet promoters. These promoters are shown to drive strong leaf specific gene expression in transgenic sugar beet. The application of these promoters for expressing resistance improving genes against foliar diseases is discussed.
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28
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Storf S, Stauber EJ, Hippler M, Schmid VHR. Proteomic analysis of the photosystem I light-harvesting antenna in tomato (Lycopersicon esculentum). Biochemistry 2004; 43:9214-24. [PMID: 15248779 DOI: 10.1021/bi0498196] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Until now, more genes of the light-harvesting antenna of higher-plant photosystem I (PSI) than proteins have been described. To improve our understanding of the composition of light-harvesting complex I (LHCI) of tomato (Lycopersicon esculentum), we combined one- and two-dimensional (1-D and 2-D, respectively) gel electrophoresis with immunoblotting and tandem mass spectrometry (MS/MS). Separation of PSI with high-resolution 1-D gels allowed separation of five bands attributed to proteins of LHCI. Immunoblotting with monospecific antibodies and MS/MS analysis enabled the correct assignment of the four prominent bands to light-harvesting proteins Lhca1-4. The fifth band was recognized by only the Lhca1 antibody. Immunodetection as well as mass spectrometric analysis revealed that these protein bands contain not only the eponymous protein but also other Lhca proteins, indicating a heterogeneous protein composition of Lhca bands. Additionally, highly sensitive MS/MS allowed detection of a second Lhca4 isoform and of Lhca5. These proteins had not been described before on the protein level in higher plants. Two-dimensional gel electrophoresis revealed an even more diverse composition of individual Lhca proteins than was apparent from 1-D gels. For each of the four prominent Lhca proteins, four to five isoforms with different isoelectric points could be identified. In the case of Lhca1, Lhca4, and Lhca3, additional isoforms with slightly differing molecular masses were identified. Thus, we were able to detect four to ten isoforms of each individual Lhca protein in PSI. Reasons for the origin of Lhca heterogeneity are discussed. The observed variety of Lhca proteins and their isoforms is of particular interest in the context of the recently published crystal structure of photosystem I from pea, which showed the presence of only four Lhca proteins per photosystem I. These findings indicate that several populations of photosystem I that differ in their Lhca composition may exist.
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Affiliation(s)
- Stefanie Storf
- Institut für Allgemeine Botanik, Johannes Gutenberg-Universität Mainz, Müllerweg 6, 55099 Mainz, Germany
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29
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Wehner A, Storf S, Jahns P, Schmid VHR. De-epoxidation of violaxanthin in light-harvesting complex I proteins. J Biol Chem 2004; 279:26823-9. [PMID: 15070896 DOI: 10.1074/jbc.m402399200] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The conversion of violaxanthin (Vx) to zeaxanthin (Zx) in the de-epoxidation reaction of the xanthophyll cycle plays an important role in the protection of chloroplasts against photooxidative damage. Vx is bound to the antenna proteins of both photosystems. In photosystem II, the formation of Zx is essential for the pH-dependent dissipation of excess light energy as heat. The function of Zx in photosystem I is still unclear. In this work we investigated the de-epoxidation characteristics of light-harvesting complex proteins of photosystem I (LHCI) under in vivo and in vitro conditions. Recombinant LHCI (Lhcal-4) proteins were reconstituted with Vx and lutein, and the convertibility of Vx was studied in an in vitro assay using partially purified Vx de-epoxidase isolated from spinach thylakoids. All four LHCI proteins exhibited unique de-epoxidation characteristics. An almost complete Vx conversion to Zx was observed only in Lhca3, whereas Zx formation in the other LHCI proteins decreased in the order Lhca4 > Lhca1 > Lhca2. Most likely, these differences in Vx de-epoxidation were related to the different accessibility of the respective carotenoid binding sites in the distinct antenna proteins. The results indicate that Vx bound to site V1 and N1 is easily accessible for de-epoxidation, whereas Vx bound to L2 is only partially and/or with the slower kinetics convertible to Zx. The de-epoxidation properties determined for the monomeric recombinant proteins were consistent with those obtained for isolated native LHCI-730 and LHCI-680 in the same in vitro assay and the de-epoxidation state found under in vivo conditions in native LHCIs.
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Affiliation(s)
- Antje Wehner
- Institut für Biochemie der Pflanzen, Heinrich Heine-Universität Düsseldorf, Germany
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30
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Castelletti S, Morosinotto T, Robert B, Caffarri S, Bassi R, Croce R. Recombinant Lhca2 and Lhca3 subunits of the photosystem I antenna system. Biochemistry 2003; 42:4226-34. [PMID: 12680777 DOI: 10.1021/bi027398r] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this study, two gene products (Lhca2 and Lhca3), encoding higher plants (Arabidopsis thaliana) Photosystem I antenna complexes, were overexpressed in bacteria and reconstituted in vitro with purified chloroplast pigments. The chlorophyll-xanthophyll proteins thus obtained were characterized by biochemical and spectroscopic methods. Both complexes were shown to bind 10 chlorophyll (a and b) molecules per polypeptide, Lhca2 having higher chlorophyll b content as compared to Lhca3. The two proteins differed for the number of carotenoid binding sites: two and three for Lhca2 and Lhca3, respectively. beta-carotene was specifically bound to Lhca3 in addition to the xanthophylls violaxanthin and lutein, indicating a peculiar structure of carotenoid binding sites in this protein since it is the only one so far identified with the ability of binding beta-carotene. Analysis of the spectroscopic properties of the two pigment proteins showed the presence of low energy absorption forms (red forms) in both complexes, albeit with different energies and amplitudes. The fluorescence emission maximum at 77 K of Lhca2 was found at 701 nm, while in Lhca3 the major emission was at 725 nm. Reconstitution of Lhca3 without Chl b reveals that Chl b is not involved in originating the low energy absorption forms of this complex. The present data are discussed in comparison to the properties of the recombinant Lhca1 and Lhca4 complexes and of the native LHCI preparation, previously analyzed, thus showing a comprehensive description of the gene products composing the Photosystem I light harvesting system of A. thaliana.
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Affiliation(s)
- Simona Castelletti
- Dipartimento Scientifico e Tecnologico, Università di Verona, Strada Le Grazie, 15- 37234 Verona, Italy
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Zolla L, Rinalducci S, Timperio AM, Huber CG. Proteomics of light-harvesting proteins in different plant species. Analysis and comparison by liquid chromatography-electrospray ionization mass spectrometry. Photosystem I. PLANT PHYSIOLOGY 2002; 130:1938-50. [PMID: 12481076 PMCID: PMC166704 DOI: 10.1104/pp.009803] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2002] [Revised: 07/29/2002] [Accepted: 07/30/2002] [Indexed: 05/21/2023]
Abstract
The light-harvesting proteins (Lhca) of photosystem I (PSI) from four monocot and five dicot species were extracted from plant material, separated by reversed-phase high-performance liquid chromatography (HPLC) and subsequently identified on the basis of their intact molecular masses upon on-line hyphenation with electrospray ionization mass spectrometry. Although their migration behavior in gel electrophoresis was very similar, the elution times among the four antenna types in reversed-phase-HPLC differed significantly, even more than those observed for the light-harvesting proteins of photosystem II. Identification of proteins is based on the good agreement between the measured intact molecular masses and the values calculated on the basis of their nucleotide-derived amino acid sequences, which makes the intact molecular masses applicable as intact mass tags. These values match excellently for Arabidopsis, most probably because of the availability of high-quality DNA sequence data. In all species examined, the four antennae eluted in the same order, namely Lhca1 > Lhca3 > Lhca4 > Lhca2. These characteristic patterns enabled an unequivocal assignment of the proteins in preparations from different species. Interestingly, in all species examined, Lhca1 and Lhca2 were present in two or three isoforms. A fifth antenna protein, corresponding to the Lhca6 gene, was found in tomato (Lycopersicon esculentum). However PSI showed a lower heterogeneity than photosystem II. In most plant species, Lhca2 and Lhca4 proteins are the most abundant PSI antenna proteins. The HPLC method used in this study was found to be highly reproducible, and the chromatograms may serve as a highly confident fingerprint for comparison within a single and among different species for future studies of the PSI antenna.
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Affiliation(s)
- Lello Zolla
- Department of Environmental Sciences, University of Tuscia, Viterbo, Italy.
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32
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Schmid VHR, Potthast S, Wiener M, Bergauer V, Paulsen H, Storf S. Pigment binding of photosystem I light-harvesting proteins. J Biol Chem 2002; 277:37307-14. [PMID: 12095996 DOI: 10.1074/jbc.m205889200] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Light-harvesting complexes (LHC) of higher plants are composed of at least 10 different proteins. Despite their pronounced amino acid sequence homology, the LHC of photosystem II show differences in pigment binding that are interpreted in terms of partly different functions. By contrast, there is only scarce knowledge about the pigment composition of LHC of photosystem I, and consequently no concept of potentially different functions of the various LHCI exists. For better insight into this issue, we isolated native LHCI-730 and LHCI-680. Pigment analyses revealed that LHCI-730 binds more chlorophyll and violaxanthin than LHCI-680. For the first time all LHCI complexes are now available in their recombinant form; their analysis allowed further dissection of pigment binding by individual LHCI proteins and analysis of pigment requirements for LHCI formation. By these different approaches a correlation between the requirement of a single chlorophyll species for LHC formation and the chlorophyll a/b ratio of LHCs could be detected, and indications regarding occupation of carotenoid-binding sites were obtained. Additionally the reconstitution approach allowed assignment of spectral features observed in native LHCI-680 to its components Lhca2 and Lhca3. It is suggested that excitation energy migrates from chlorophyll(s) fluorescing at 680 (Lhca3) via those fluorescing at 686/702 nm (Lhca2) or 720 nm (Lhca3) to the photosystem I core chlorophylls.
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Affiliation(s)
- Volkmar H R Schmid
- Institut für Allgemeine Botanik, Johannes Gutenberg-Universität, Müllerweg 6, 55099 Mainz, Germany.
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33
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Croce R, Morosinotto T, Castelletti S, Breton J, Bassi R. The Lhca antenna complexes of higher plants photosystem I. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1556:29-40. [PMID: 12351216 DOI: 10.1016/s0005-2728(02)00304-3] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The Lhca antenna complexes of photosystem I (PSI) have been characterized by comparison of native and recombinant preparations. Eight Lhca polypeptides have been found to be all organized as dimers in the PSI-LHCI complex. The red emission fluorescence is associated not only with Lhca1-4 heterodimer, but also with dimers containing Lhca2 and/or Lhca3 complexes. Reconstitution of Lhca1 and Lhca4 monomers as well as of the Lhca1-4 dimer in vitro was obtained. The biochemical and spectroscopic features of these three complexes are reported. The monomers Lhca1 and Lhca4 bind 10 Chls each, while the Chl a/b ratio is lower in Lhca4 as compared to Lhca1. Three carotenoid binding sites have been found in Lhca1, while only two are present in Lhca4. Both complexes contain lutein and violaxanthin while beta-carotene is selectively bound to the Lhca1-4 dimer in substoichiometric amounts upon dimerization. Spectral analysis revealed the presence of low energy absorption forms in Lhca1 previously thought to be exclusively associated with Lhca4. It is shown that the process of dimerization changes the spectroscopic properties of some chromophores and increases the amplitude of the red absorption tail of the complexes. The origin of these spectroscopic features is discussed.
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Affiliation(s)
- Roberta Croce
- Dipartimento Scientifico e Tecnologico, Università di Verona, Strada Le Grazie, 15-37234, Verona, Italy
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34
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Jensen PE, Rosgaard L, Knoetzel J, Scheller HV. Photosystem I activity is increased in the absence of the PSI-G subunit. J Biol Chem 2002; 277:2798-803. [PMID: 11707465 DOI: 10.1074/jbc.m110448200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
PSI-G is a subunit of photosystem I in eukaryotes. The function of PSI-G was characterized in Arabidopsis plants transformed with a psaG cDNA in antisense orientation. Several plants with significantly decreased PSI-G protein content were identified. Plants with reduced PSI-G content were indistinguishable from wild type when grown under optimal conditions, despite a 40% reduction of photosystem I. This decrease of photosystem I was correlated with a similar reduction in state transitions. Surprisingly, the reduced photosystem I content was compensated for by a more effective photosystem I because the light-dependent reduction of NADP(+) in vitro was 48% higher. Photosystem I antenna size determined from flash-induced P700 absorption changes did not reveal any significant effect on the size of the photosystem I antenna in the absence of PSI-G, whereas a 17% reduction was seen in the absence of PSI-K. However, nondenaturing green gels revealed that the interaction between photosystem I and the light-harvesting complex I was less stable in the absence of PSI-G. Thus, PSI-G plays a role in stabilizing the binding of the peripheral antenna. The increased activity in the absence of PSI-G suggests that PSI-G could have an important role in regulation of photosystem I.
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Affiliation(s)
- Poul Erik Jensen
- Plant Biochemistry Laboratory, Department of Plant Biology, The Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark.
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35
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Knoetzel J, Mant A, Haldrup A, Jensen PE, Scheller HV. PSI-O, a new 10-kDa subunit of eukaryotic photosystem I. FEBS Lett 2002; 510:145-8. [PMID: 11801243 DOI: 10.1016/s0014-5793(01)03253-7] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A novel polypeptide with an apparent molecular mass of 9 kDa was detected after sodium dodecyl sulphate-polyacrylamide gel electrophoresis of Arabidopsis photosystem I (PSI) and was N-terminally sequenced. Corresponding cDNA clones encode a precursor protein of 140 amino acid residues which was imported into isolated intact chloroplasts and processed to the mature protein, designated PSI-O. The mature protein has two transmembrane helices and a calculated mass of 10104 Da. The PSI-O protein was also shown to be present in PSI isolated from barley and spinach, and was essentially absent in chloroplast grana. Expressed sequences encoding similar proteins are available from many species of plants and green algae.
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Affiliation(s)
- Jürgen Knoetzel
- Plant Biochemistry Laboratory, Department of Plant Biology, The Royal Veterinary and Agricultural University, 40 Thorvaldsensvej, DK-1871 Frederiksberg C, Copenhagen, Denmark
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36
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Hippler M, Klein J, Fink A, Allinger T, Hoerth P. Towards functional proteomics of membrane protein complexes: analysis of thylakoid membranes from Chlamydomonas reinhardtii. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2001; 28:595-606. [PMID: 11849598 DOI: 10.1046/j.1365-313x.2001.01175.x] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Functional proteomics of membrane proteins is an important tool for the understanding of protein networks in biological membranes but structural studies on this part of the proteome are limited. In this study we undertook such an approach to analyse photosynthetic thylakoid membranes isolated from wild-type and mutant strains of Chlamydomonas reinhardtii. Thylakoid membrane proteins were separated by high-resolution two-dimensional gel electrophoresis (2-DE) and analysed by immuno-blotting and mass spectrometry for the presence of membrane-spanning proteins. Our data show that light-harvesting complex proteins (LHCP), that cross the membrane with three transmembrane domains, can be separated using this method. We have identified more than 30 different LHCP spots on our gels. Mass spectrometric analysis of 2-DE separated Lhcb1 indicates that this major LHCII protein can associate with the thylakoid membrane with part of its putative transit sequence. Separation of isolated photosystem I (PSI) complexes by 2-DE revealed the presence of 18 LHCI protein spots. The use of two peptide-specific antibodies directed against LHCI subunits supports the interpretation that some of these spots represent products arising from differential processing and post-translational modifications. In addition our data indicate that the reaction centre subunit of PSI, PsaA, that possesses 11 transmembrane domains, can be separated by 2-DE. Comparison between 2-DE maps from thylakoid membrane proteins isolated from a PSI-deficient (Deltaycf4) and a crd1 mutant, which is conditionally reduced in PSI and LHCI under copper-deficiency, showed the presence of most of the LHCI spots in the former but their absence in the latter. Our data demonstrate that (i) hydrophobic membrane proteins like the LHCPs can be faithfully separated by 2-DE, and (ii) that high-resolution 2-DE facilitates the comparative analysis of membrane protein complexes in wild-type and mutants cells.
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Affiliation(s)
- M Hippler
- Lehrstuhl für Biochemie der Pflanzen, Institut für Biologie II, Universität Freiburg, Schänzlestr. 1, 79104 Freiburg, Germany.
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37
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The photodamage process of pigments and proteins of PSI complexes fromSpinacia Oleracea L. ACTA ACUST UNITED AC 2001. [DOI: 10.1007/bf02900557] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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38
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Scheller HV, Jensen PE, Haldrup A, Lunde C, Knoetzel J. Role of subunits in eukaryotic Photosystem I. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1507:41-60. [PMID: 11687207 DOI: 10.1016/s0005-2728(01)00196-7] [Citation(s) in RCA: 144] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Photosystem I (PSI) of eukaryotes has a number of features that distinguishes it from PSI of cyanobacteria. In plants, the PSI core has three subunits that are not found in cyanobacterial PSI. The remaining 11 subunits of the core are conserved but several of the subunits have a different role in eukaryotic PSI. A distinguishing feature of eukaryotic PSI is the membrane-imbedded peripheral antenna. Light-harvesting complex I is composed of four different subunits and is specific for PSI. Light-harvesting complex II can be associated with both PSI and PSII. Several of the core subunits interact with the peripheral antenna proteins and are important for proper function of the peripheral antenna. The review describes the role of the different subunits in eukaryotic PSI. The emphasis is on features that are different from cyanobacterial PSI.
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Affiliation(s)
- H V Scheller
- Plant Biochemistry Laboratory, Department of Plant Biology, The Royal Veterinary and Agricultural University, 40 Thorvaldsensvej, DK-1871 Frederiksberg C, Copenhagen, Denmark.
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39
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Ganeteg U, Gustafsson P, Jansson S. The properties of the chlorophyll a/b-binding proteins Lhca2 and Lhca3 studied in vivo using antisense inhibition. PLANT PHYSIOLOGY 2001; 127:150-8. [PMID: 11553743 PMCID: PMC117971 DOI: 10.1104/pp.127.1.150] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2001] [Revised: 03/29/2001] [Accepted: 06/06/2001] [Indexed: 05/19/2023]
Abstract
The specific functions of the light-harvesting proteins Lhca2 and Lhca3 were studied in Arabidopsis ecotype Colombia antisense plants in which the proteins were individually repressed. The antisense effect was specific in each plant, but levels of Lhca proteins other than the targeted products were also affected. The contents of Lhca1 and Lhca4 were unaffected, but Lhca3 (in Lhca2-repressed plants) was almost completely depleted, and Lhca2 decreased to about 30% of wild-type levels in Lhca3-repressed plants. This suggests that the Lhca2 and Lhca3 proteins are in physical contact with each other and that they require each other for stability. Photosystem I fluorescence at 730 nm is thought to emanate from pigments bound to Lhca1 and Lhca4. However, fluorescence emission and excitation spectra suggest that Lhca2 and Lhca3, which fluoresce in vitro at 680 nm, also could contribute to far-red fluorescence in vivo. Spectral forms with absorption maxima at 695 and 715 nm, apparently with emission maxima at 702 and 735 nm, respectively, might be associated with Lhca2 and Lhca3.
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Affiliation(s)
- U Ganeteg
- Umeå Plant Science Center, Department of Plant Physiology, Umeå University, S-901 87 Umeå, Sweden.
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40
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Boekema EJ, Jensen PE, Schlodder E, van Breemen JF, van Roon H, Scheller HV, Dekker JP. Green plant photosystem I binds light-harvesting complex I on one side of the complex. Biochemistry 2001; 40:1029-36. [PMID: 11170425 DOI: 10.1021/bi0015358] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report a structural characterization by electron microscopy of green plant photosystem I solubilized by the mild detergent n-dodecyl-alpha-D-maltoside. It is shown by immunoblotting that the isolated complexes contain all photosystem I core proteins and all peripheral light-harvesting proteins. The electron microscopic analysis is based on a large data set of 14 000 negatively stained single-particle projections and reveals that most of the complexes are oval-shaped monomers. The monomers have a tendency to associate into artificial dimers, trimers, and tetramers in which the monomers are oppositely oriented. Classification of the dimeric complexes suggests that some of the monomers lack a part of the peripheral antenna. On the basis of a comparison with projections from trimeric photosystem I complexes from cyanobacteria, we conclude that light-harvesting complex I only binds to the core complex at the side of the photosystem I F/J subunits and does not cause structural hindrances for the type of trimerization observed in cyanobacterial photosystem I.
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Affiliation(s)
- E J Boekema
- Groningen Biotechnology and Biomolecular Sciences Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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41
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Haldrup A, Simpson DJ, Scheller HV. Down-regulation of the PSI-F subunit of photosystem I (PSI) in Arabidopsis thaliana. The PSI-F subunit is essential for photoautotrophic growth and contributes to antenna function. J Biol Chem 2000; 275:31211-8. [PMID: 10900198 DOI: 10.1074/jbc.m002933200] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The PSI-F subunit of photosystem I is a transmembrane protein with a large lumenal domain. The role of PSI-F was investigated in Arabidopsis plants transformed with an antisense construct of the psaF cDNA. Several plant lines with reduced amounts of the PSI-F subunit were generated. Many of the transgenic plants died, apparently because they were unable to survive without the PSI-F subunit. Plants with 5% of PSI-F were capable of photoautotrophic growth but were much smaller than wild-type plants. The plants suffered severely under normal growth conditions but recovered somewhat in the dark indicating chronic photoinhibition. Photosystem I lacking PSI-F was less stable, and the stromal subunits PSI-C, PSI-D, and PSI-E were present in lower amounts than in wild type. The lack of PSI-F resulted in an inability of light-harvesting complex I-730 to transfer energy to the P700 reaction center. In thylakoids deficient in PSI-F, the steady state NADP(+) reduction rate was only 10% of the wild-type levels indicating a lower efficiency in oxidation of plastocyanin. Surprisingly, the lack of PSI-F also gave rise to disorganization of the thylakoids. The strict arrangement in grana and stroma lamellae was lost, and instead a network of elongated and distorted grana was observed.
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Affiliation(s)
- A Haldrup
- Plant Biochemistry Laboratory, Department of Plant Biology, the Royal Veterinary and Agricultural University, 40 Thorvaldsensvej, DK-1871 Frederiksberg C, Denmark
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42
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Abstract
Exposure of isolated photosystem I (PSI) complexes to illumination (2300 microE m(-2) s(-1)) for various periods of time resulted in striking changes in their absorption spectra. A 6 nm blueshift of the absorption maximum in the red was detected after 100 min illumination. The fourth derivative of the absorption spectra verifies that the main change of the red peak was attributed to the 682 nm absorption band. Further, it was also shown that a shoulder in the absorption spectra located around 470 nm decreased after the first 5 min of illumination and almost disappeared after 40 min illumination, suggesting that chlorophyll b bound to light-harvesting complex I (LHCI) is also sensitive to excess light. A maximum inhibitory effect on the oxygen uptake rates and a strong stimulation were observed when the PSI complexes were exposed to illumination for about 20 and 40 min, respectively. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis shows that LHCI-680 started to degrade during the first 5 min of illumination and almost completely disappeared after 40 min of illumination. These observations demonstrated that LHCI was more sensitive to illumination than the PsaA/B subunits which also presented some degradation signs after 40 min illumination. In addition, insoluble-cohesive-denatured proteins also appeared between the stacking and resolving gel after prolonged illumination (100 min). A photoprotective function of LHCI for the PSI reaction center is proposed.
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Affiliation(s)
- Y Hui
- Groupe de Recherche en Energie et Information Biomoléculaires, Université du Québec à Trois-Rivières, Canada
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43
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Jensen PE, Gilpin M, Knoetzel J, Scheller HV. The PSI-K subunit of photosystem I is involved in the interaction between light-harvesting complex I and the photosystem I reaction center core. J Biol Chem 2000; 275:24701-8. [PMID: 10818090 DOI: 10.1074/jbc.m000550200] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
PSI-K is a subunit of photosystem I. The function of PSI-K was characterized in Arabidopsis plants transformed with a psaK cDNA in antisense orientation, and several lines without detectable PSI-K protein were identified. Plants without PSI-K have a 19% higher chlorophyll a/b ratio and 19% more P700 than wild-type plants. Thus, plants without PSI-K compensate by making more photosystem I. The photosystem I electron transport in vitro is unaffected in the absence of PSI-K. Light response curves for oxygen evolution indicated that the photosynthetic machinery of PSI-K-deficient plants have less capacity to utilize light energy. Plants without PSI-K have less state 1-state 2 transition. Thus, the redistribution of absorbed excitation energy between the two photosystems is reduced. Low temperature fluorescence emission spectra revealed a 2-nm blue shift in the long wavelength emission in plants lacking PSI-K. Furthermore, thylakoids and isolated PSI without PSI-K had 20-30% less Lhca2 and 30-40% less Lhca3, whereas Lhca1 and Lhca4 were unaffected. During electrophoresis under mildly denaturing conditions, all four Lhca subunits were partially dissociated from photosystem I lacking PSI-K. The observed effects demonstrate that PSI-K has a role in organizing the peripheral light-harvesting complexes on the core antenna of photosystem I.
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Affiliation(s)
- P E Jensen
- Plant Biochemistry Laboratory, Department of Plant Biology, The Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark.
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44
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Ihalainen JA, Gobets B, Sznee K, Brazzoli M, Croce R, Bassi R, van Grondelle R, Korppi-Tommola JE, Dekker JP. Evidence for two spectroscopically different dimers of light-harvesting complex I from green plants. Biochemistry 2000; 39:8625-31. [PMID: 10913270 DOI: 10.1021/bi0007369] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A preparation consisting of isolated dimeric peripheral antenna complexes from green plant photosystem I (light-harvesting complex I or LHCI) has been characterized by means of (polarized) steady-state absorption and fluorescence spectroscopy at low temperatures. We show that this preparation can be described reasonably well by a mixture of two types of dimers. In the first dimer about 10% of all Q(y)() absorption of the chlorophylls arises from two chlorophylls with absorption and emission maxima at about 711 and 733 nm, respectively, whereas in the second about 10% of the absorption arises from two chlorophylls with absorption and emission maxima at about 693 and 702 nm, respectively. The remaining chlorophylls show spectroscopic properties comparable to those of the related peripheral antenna complexes of photosystem II. We attribute the first dimer to a heterodimer of the Lhca1 and Lhca4 proteins and the second to a hetero- or homodimer of the Lhca2 and/or Lhca3 proteins. We suggest that the chlorophylls responsible for the 733 nm emission (F-730) and 702 nm emission (F-702) are excitonically coupled dimers and that F-730 originates from one of the strongest coupled pair of chlorophylls observed in nature.
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Affiliation(s)
- J A Ihalainen
- Department of Chemistry, University of Jyväskylä, Finland.
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45
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Koehne B, Elli G, Jennings RC, Wilhelm C, Trissl H. Spectroscopic and molecular characterization of a long wavelength absorbing antenna of Ostreobium sp. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1412:94-107. [PMID: 10393253 DOI: 10.1016/s0005-2728(99)00061-4] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
One of the strains of the marine green alga Ostreobium sp. possesses an exceptionally large number of long wavelength absorbing chlorophylls (P. Haldall, Biol. Bull. 134, 1968, 411-424) as evident from a distinct shoulder in the absorption spectrum at around 710 nm while in the other strain this shoulder is absent. Therefore, Ostreobium offers a unique possibility to explore the origin of these red-shifted chlorophylls, because strains with and without these spectral forms can be compared. Here, we characterize these red forms spectroscopically by absorption, fluorescence and CD spectroscopy. In the CD spectra at least three spectroscopic red forms are identified which lead to an unusual room temperature fluorescence spectrum that peaks at 715 nm. The gel electrophoretic pattern from thylakoids of Ostreobium sp. shows an intense band at 22 kDa which correlates with the presence or absence of long wavelength absorbing pigments. By protein sequencing of the N-terminus of the 22-kDa polypeptide and sequence alignments, this was identified as an Lhca1-type light-harvesting complex. The abundance of this polypeptide - and a possibly co-migrating one - in Ostreobium sp. indicates an antenna size of approximately 340 chlorophyll molecules (Chl a and Chl b) per PS IIalpha reaction center, which is significantly larger than in higher plants ( approximately 240). The red forms are more abundant in the interior of the thalli where a 'shade-light' light field is expected than in the white-light exposed surface. This demonstrates that algae exist which may be able to up-regulate the synthesis of large amounts of LHCI and associated red forms under appropriate illumination conditions.
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Affiliation(s)
- B Koehne
- Abteilung Biophysik, Fachbereich Biologie/Chemie, Universität Osnabrück, Barbarastrasse 11, D-49069, Osnabrück, Germany
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46
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Knoetzel J, Bossmann B, Grimme LH. Chlorina and viridis mutants of barley (Hordeum vulgare L.) allow assignment of long-wavelength chlorophyll forms to individual Lhca proteins of photosystem I in vivo. FEBS Lett 1998; 436:339-42. [PMID: 9801144 DOI: 10.1016/s0014-5793(98)01158-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The isolated subcomplex LHCI-730 of plant photosystem I (PSI) chlorophyll (Chl) alb binding antenna is a heterodimer of Lhca1 and Lhca4 and has a 77 K fluorescence emission peak at 730 nm (F730). Recently, three Chl spectral forms with 77 K fluorescence emission peaks at 720 nm, 730 nm and 742 nm were identified in native PSI. In an attempt to assign the two longest wavelength emission maxima to peripheral PSI antenna proteins, we performed 77 K fluorescence emission spectroscopy on intact leaves of chlorina and viridis mutants from barley which lack individual LHCI-730 proteins. This approach indicates that F732 is found only in Lhca1 and F742 only in Lhca4, when these proteins are associated with the PSI reaction centre.
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Affiliation(s)
- J Knoetzel
- Institute of Cell Biology, Biochemistry and Biotechnology, University of Bremen, Germany.
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47
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Melkozernov AN, Schmid VHR, Schmidt GW, Blankenship RE. Energy Redistribution in Heterodimeric Light-Harvesting Complex LHCI-730 of Photosystem I. J Phys Chem B 1998. [DOI: 10.1021/jp9810466] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Alexander N. Melkozernov
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604; Center for the Study of Early Events in Photosynthesis, Arizona State University, Tempe, Arizona 85287-1604; and Department of Botany, University of Georgia, Athens, Georgia 30602-7271
| | - Volkmar H. R. Schmid
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604; Center for the Study of Early Events in Photosynthesis, Arizona State University, Tempe, Arizona 85287-1604; and Department of Botany, University of Georgia, Athens, Georgia 30602-7271
| | - Gregory W. Schmidt
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604; Center for the Study of Early Events in Photosynthesis, Arizona State University, Tempe, Arizona 85287-1604; and Department of Botany, University of Georgia, Athens, Georgia 30602-7271
| | - Robert E. Blankenship
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604; Center for the Study of Early Events in Photosynthesis, Arizona State University, Tempe, Arizona 85287-1604; and Department of Botany, University of Georgia, Athens, Georgia 30602-7271
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Schubert WD, Klukas O, Krauss N, Saenger W, Fromme P, Witt HT. Photosystem I of Synechococcus elongatus at 4 A resolution: comprehensive structure analysis. J Mol Biol 1997; 272:741-69. [PMID: 9368655 DOI: 10.1006/jmbi.1997.1269] [Citation(s) in RCA: 224] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
An improved structural model of the photosystem I complex from the thermophilic cyanobacterium Synechococcus elongatus is described at 4 A resolution. This represents the most complete model of a photosystem presently available, uniting both a photosynthetic reaction centre domain and a core antenna system. Most constituent elements of the electron transfer system have been located and their relative centre-to-centre distances determined at an accuracy of approximately 1 A. These include three pseudosymmetric pairs of Chla and three iron-sulphur centres, FX, FA and FB. The first pair, a Chla dimer, has been assigned to the primary electron donor P700. One or both Chla of the second pair, eC2 and eC'2, presumably functionally link P700 to the corresponding Chla of the third pair, eC3 and eC'3, which is assumed to constitute the spectroscopically-identified primary electron acceptor(s), A0, of PSI. A likely location of the subsequent phylloquinone electron acceptor, QK, in relation to the properties of the spectroscopically identified electron acceptor A1 is discussed. The positions of a total of 89 Chla, 83 of which constitute the core antenna system, are presented. The maximal centre-to-centre distance between antenna Chla is < or = 16 A; 81 Chla are grouped into four clusters comprising 21, 23, 17 and 20 Chla, respectively. Two "connecting" Chla are positioned to structurally (and possibly functionally) link the Chla of the core antenna to those of the electron transfer system. Thus the second and third Chla pairs of the electron transfer system may have a dual function both in energy transfer and electron transport. A total of 34 transmembrane and nine surface alpha-helices have been identified and assigned to the 11 subunits of the PSI complex. The connectivity of the nine C-terminal (seven transmembrane, two "surface") alpha-helices of each of the large core subunits PsaA and PsaB is described. The assignment of the amino acid sequence to the transmembrane alpha-helices is proposed and likely residues involved in co-ordinating the Chla of the electron transfer system discussed.
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Affiliation(s)
- W D Schubert
- Institut für Kristallographie, Freie Universität Berlin, Germany
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Schmid VH, Cammarata KV, Bruns BU, Schmidt GW. In vitro reconstitution of the photosystem I light-harvesting complex LHCI-730: heterodimerization is required for antenna pigment organization. Proc Natl Acad Sci U S A 1997; 94:7667-72. [PMID: 11038558 PMCID: PMC23880 DOI: 10.1073/pnas.94.14.7667] [Citation(s) in RCA: 119] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Here we describe the in vitro reconstitution of photosystem I light-harvesting complexes with pigments and proteins (Lhca1 and Lhca4) obtained by overexpression of tomato Lhca genes in Escherichia coli. Using Lhca1 and Lhca4 individually for reconstitution results in monomeric pigment-proteins, whereas a combination thereof yields a dimeric complex. Interactions of the apoproteins is highly specific, as reconstitution of either of the two constituent proteins in combination with a light-harvesting protein of photosystem II does not result in dimerization. The reconstituted Lhca1/4, but not complexes obtained with either Lhca1 or Lhca4 alone, closely resembles the native LHCI-730 dimer from tomato leaves with regard to spectroscopic properties, pigment composition, and stoichiometry. Monomeric complexes of Lhca1 or Lhca4 possess lower pigment/protein ratios, indicating that interactions of the two subunits not only facilitates pigment reorganization but also recruitment of additional pigments. In addition to higher averages of chlorophyll a/b ratios in monomeric complexes than in LHCI-730, comparative fluorescence and CD spectra demonstrate that heterodimerization involves preferential ligation of more chlorophyll b.
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Affiliation(s)
- V H Schmid
- Department of Botany, University of Georgia, Athens, GA 30602-7271, USA
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Antenna protein composition of PS I and PS II in thylakoid sub-domains. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1997. [DOI: 10.1016/s0005-2728(97)00033-9] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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