151
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Bonente G, Pippa S, Castellano S, Bassi R, Ballottari M. Acclimation of Chlamydomonas reinhardtii to different growth irradiances. J Biol Chem 2011; 287:5833-47. [PMID: 22205699 DOI: 10.1074/jbc.m111.304279] [Citation(s) in RCA: 142] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
We report on the changes the photosynthetic apparatus of Chlamydomonas reinhardtii undergoes upon acclimation to different light intensity. When grown in high light, cells had a faster growth rate and higher biomass production compared with low and control light conditions. However, cells acclimated to low light intensity are indeed able to produce more biomass per photon available as compared with high light-acclimated cells, which dissipate as heat a large part of light absorbed, thus reducing their photosynthetic efficiency. This dissipative state is strictly dependent on the accumulation of LhcSR3, a protein related to light-harvesting complexes, responsible for nonphotochemical quenching in microalgae. Other changes induced in the composition of the photosynthetic apparatus upon high light acclimation consist of an increase of carotenoid content on a chlorophyll basis, particularly zeaxanthin, and a major down-regulation of light absorption capacity by decreasing the chlorophyll content per cell. Surprisingly, the antenna size of both photosystem I and II is not modulated by acclimation; rather, the regulation affects the PSI/PSII ratio. Major effects of the acclimation to low light consist of increased activity of state 1 and 2 transitions and increased contributions of cyclic electron flow.
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Affiliation(s)
- Giulia Bonente
- Dipartimento di Biotecnologie, Università di Verona, Ca'Vignal 1, Strada le Grazie 15, I-37134 Verona, Italy
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152
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Roose JL, Frankel LK, Bricker TM. Developmental defects in mutants of the PsbP domain protein 5 in Arabidopsis thaliana. PLoS One 2011; 6:e28624. [PMID: 22174848 PMCID: PMC3235149 DOI: 10.1371/journal.pone.0028624] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Accepted: 11/11/2011] [Indexed: 11/25/2022] Open
Abstract
Plants contain an extensive family of PsbP-related proteins termed PsbP-like (PPL) and PsbP domain (PPD) proteins, which are localized to the thylakoid lumen. The founding member of this family, PsbP, is an established component of the Photosystem II (PS II) enzyme, and the PPL proteins have also been functionally linked to other photosynthetic processes. However, the functions of the remaining seven PPD proteins are unknown. To elucidate the function of the PPD5 protein (At5g11450) in Arabidopsis, we have characterized a mutant T-DNA insertion line (SALK_061118) as well as several RNAi lines designed to suppress the expression of this gene. The functions of the photosynthetic electron transfer reactions are largely unaltered in the ppd5 mutants, except for a modest though significant decrease in NADPH dehydrogenase (NDH) activity. Interestingly, these mutants show striking plant developmental and morphological defects. Relative to the wild-type Col-0 plants, the ppd5 mutants exhibit both increased lateral root branching and defects associated with axillary bud formation. These defects include the formation of additional rosettes originating from axils at the base of the plant as well as aerial rosettes formed at the axils of the first few nodes of the shoot. The root-branching phenotype is chemically complemented by treatment with the synthetic strigolactone, GR24. We propose that the developmental defects observed in the ppd5 mutants are related to a deficiency in strigolactone biosynthesis.
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Affiliation(s)
- Johnna L Roose
- Department of Biological Sciences, Biochemistry and Molecular Biology Section, Louisiana State University, Baton Rouge, Louisiana, United States of America.
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153
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Takabayashi A, Kurihara K, Kuwano M, Kasahara Y, Tanaka R, Tanaka A. The oligomeric states of the photosystems and the light-harvesting complexes in the Chl b-less mutant. PLANT & CELL PHYSIOLOGY 2011; 52:2103-14. [PMID: 22006940 DOI: 10.1093/pcp/pcr138] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The reversible associations between the light-harvesting complexes (LHCs) and the core complexes of PSI and PSII are essential for the photoacclimation mechanisms in higher plants. Two types of Chls, Chl a and Chl b, both function in light harvesting and are required for the biogenesis of the photosystems. Chl b-less plants have been studied to determine the function of the LHCs because the Chl b deficiency has severe effects specific to the LHCs. Previous studies have shown that the amounts of the LHCs, especially the LHCII trimer, were decreased in the mutants; however, it is still unclear whether Chl b is required for the assembly of the LHCs and for the association of the LHCs with PSI and PSII. Here, to reveal the function of Chl b in the LHCs, we investigated the oligomeric states of the LHCs, PSI and PSII in the Arabidopsis Chl b-less mutant. A two-dimensional blue native-PAGE/SDS-PAGE demonstrated that the PSI-LHCI supercomplex was fully assembled in the absence of Chl b, whereas the trimeric LHCII and PSII-LHCII supercomplexes were not detected. The PSI-NAD(P)H dehydrogenase (NDH) supercomplexes were also assembled in the mutant. Furthermore, we detected two forms of monomeric LHC proteins. The faster migrating forms, which were detected primarily in the mutant, were probably apo-LHC proteins, whereas the slower migrating forms were probably the LHC proteins that contained Chl a. These findings increase our understanding of the Chl b function in the assembly of LHCs and the association of the LHCs with PSI, PSII and NDH.
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Affiliation(s)
- Atsushi Takabayashi
- Institute of Low Temperature Science, Hokkaido University, N19 W8 Kita-Ku, Sapporo, 060-0819 Japan.
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154
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Gollan PJ, Ziemann M, Bhave M. PPIase activities and interaction partners of FK506-binding proteins in the wheat thylakoid. PHYSIOLOGIA PLANTARUM 2011; 143:385-395. [PMID: 21848652 DOI: 10.1111/j.1399-3054.2011.01503.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
FK506-binding proteins (FKBPs) and cyclophilins, collectively called immunophilins, conserve peptidyl-prolyl cis/trans isomerase (PPIase) active sites, although many lack PPIase activity. The chloroplast thylakoid contains a large proportion of the plant immunophilin family, but their functions within this compartment are unclear. Some lumenal immunophilins are important for assembly of photosynthetic complexes, implicating them in the maintenance and turnover of the photosynthetic apparatus during acclimation processes. In this investigation into the functions of three FKBPs localized to the thylakoid of Triticum aestivum (wheat), we present the first evidence of PPIase activity in the thylakoid of a cereal plant, and also show that PPIase activity is not conserved in all lumenal FKBPs. Using yeast two-hybrid analysis we found that the PPIase-active FKBP13 interacts with the globular domain of the wheat Rieske protein, with potential impact on photosynthetic electron transfer. Specific interaction partners for PPIase-deficient FKBP16-1 and FKBP16-3 link these isoforms to photosystem assembly.
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Affiliation(s)
- Peter J Gollan
- Environment and Biotechnology Centre, Faculty of Life and Social Sciences, Swinburne University of Technology, PO Box 218, Hawthorn, VIC 3122, Australia
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155
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Redestig H, Costa IG. Detection and interpretation of metabolite-transcript coresponses using combined profiling data. ACTA ACUST UNITED AC 2011; 27:i357-65. [PMID: 21685093 PMCID: PMC3117345 DOI: 10.1093/bioinformatics/btr231] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Motivation: Studying the interplay between gene expression and metabolite levels can yield important information on the physiology of stress responses and adaptation strategies. Performing transcriptomics and metabolomics in parallel during time-series experiments represents a systematic way to gain such information. Several combined profiling datasets have been added to the public domain and they form a valuable resource for hypothesis generating studies. Unfortunately, detecting coresponses between transcript levels and metabolite abundances is non-trivial: they cannot be assumed to overlap directly with underlying biochemical pathways and they may be subject to time delays and obscured by considerable noise. Results: Our aim was to predict pathway comemberships between metabolites and genes based on their coresponses to applied stress. We found that in the presence of strong noise and time-shifted responses, a hidden Markov model-based similarity outperforms the simpler Pearson correlation but performs comparably or worse in their absence. Therefore, we propose a supervised method that applies pathway information to summarize similarity statistics to a consensus statistic that is more informative than any of the single measures. Using four combined profiling datasets, we show that comembership between metabolites and genes can be predicted for numerous KEGG pathways; this opens opportunities for the detection of transcriptionally regulated pathways and novel metabolically related genes. Availability: A command-line software tool is available at http://www.cin.ufpe.br/~igcf/Metabolites. Contact:henning@psc.riken.jp; igcf@cin.ufpe.br Supplementary information:Supplementary data are available at Bioinformatics online.
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156
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Battchikova N, Wei L, Du L, Bersanini L, Aro EM, Ma W. Identification of novel Ssl0352 protein (NdhS), essential for efficient operation of cyclic electron transport around photosystem I, in NADPH:plastoquinone oxidoreductase (NDH-1) complexes of Synechocystis sp. PCC 6803. J Biol Chem 2011; 286:36992-7001. [PMID: 21880717 PMCID: PMC3196108 DOI: 10.1074/jbc.m111.263780] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Revised: 08/25/2011] [Indexed: 11/06/2022] Open
Abstract
Cyanobacterial NADPH:plastoquinone oxidoreductase, or type I NAD(P)H dehydrogenase, or the NDH-1 complex is involved in plastoquinone reduction and cyclic electron transfer (CET) around photosystem I. CET, in turn, produces extra ATP for cell metabolism particularly under stressful conditions. Despite significant achievements in the study of cyanobacterial NDH-1 complexes during the past few years, the entire subunit composition still remains elusive. To identify missing subunits, we screened a transposon-tagged library of Synechocystis 6803 cells grown under high light. Two NDH-1-mediated CET (NDH-CET)-defective mutants were tagged in the same ssl0352 gene encoding a short unknown protein. To clarify the function of Ssl0352, the ssl0352 deletion mutant and another mutant with Ssl0352 fused to yellow fluorescent protein (YFP) and the His(6) tag were constructed. Immunoblotting, mass spectrometry, and confocal microscopy analyses revealed that the Ssl0352 protein resides in the thylakoid membrane and associates with the NDH-1L and NDH-1M complexes. We conclude that Ssl0352 is a novel subunit of cyanobacterial NDH-1 complexes and designate it NdhS. Deletion of the ssl0352 gene considerably impaired the NDH-CET activity and also retarded cell growth under high light conditions, indicating that NdhS is essential for efficient operation of NDH-CET. However, the assembly of the NDH-1L and NDH-1M complexes and their content in the cells were not affected in the mutant. NdhS contains a Src homology 3-like domain and might be involved in interaction of the NDH-1 complex with an electron donor.
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Affiliation(s)
- Natalia Battchikova
- Department of Biochemistry and Food Chemistry, Molecular Plant Biology, University of Turku, FI-20520 Turku, Finland
| | - Lanzhen Wei
- From the College of Life and Environment Sciences, Shanghai Normal University, Guilin Road 100, Shanghai 200234, China and
| | - Lingyu Du
- From the College of Life and Environment Sciences, Shanghai Normal University, Guilin Road 100, Shanghai 200234, China and
| | - Luca Bersanini
- Department of Biochemistry and Food Chemistry, Molecular Plant Biology, University of Turku, FI-20520 Turku, Finland
| | - Eva-Mari Aro
- Department of Biochemistry and Food Chemistry, Molecular Plant Biology, University of Turku, FI-20520 Turku, Finland
| | - Weimin Ma
- From the College of Life and Environment Sciences, Shanghai Normal University, Guilin Road 100, Shanghai 200234, China and
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157
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Wu Y, Zheng F, Ma W, Han Z, Gu Q, Shen Y, Mi H. Regulation of NAD(P)H dehydrogenase-dependent cyclic electron transport around PSI by NaHSO₃ at low concentrations in tobacco chloroplasts. PLANT & CELL PHYSIOLOGY 2011; 52:1734-43. [PMID: 21828103 DOI: 10.1093/pcp/pcr109] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Although bisulfite at low concentrations (L-NaHSO₃) has been found to increase the cyclic electron transport around PSI (CET), its regulative mechanism remains unknown. In this work, the role of L-NaHSO₃ (0.1-500 μM) in NAD(P)H dehydrogenase-dependent CET (the NDH pathway) was investigated. After treatment of tobacco leaves with L-NaHSO₃, the NDH pathway, as reflected by a transient post-illumination increase in Chl fluorescence, the dark reduction of P700+ after far-red light and the amount of NDH, was increased after the light-dark-light transition, but was slightly lowered under continuous light. Meanwhile, the linear electron transport (LET) was accelerated by L-NaHSO₃ under both the light regimes. Experiments in thylakoids further demonstrated that both LET, monitored by light-dependent oxygen uptake, and CET, as determined from the NADPH-dependent oxygen uptake and dark reduction of P700+, were enhanced by L-NaHSO₃ and the enhancements were abolished by superoxide dismutase. Furthermore, L-NaHSO₃-induced CET was partially impaired in thylakoids of the ΔndhCKJ mutant, while L-NaHSO₃-induced LET was not affected. Based on these results, we propose that the photooxidation of L-NaHSO₃ initiated by superoxide anions in PSI regulates NDH pathway to maintain efficient photosynthesis.
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Affiliation(s)
- Yanxia Wu
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, PR China
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158
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Ifuku K, Endo T, Shikanai T, Aro EM. Structure of the chloroplast NADH dehydrogenase-like complex: nomenclature for nuclear-encoded subunits. PLANT & CELL PHYSIOLOGY 2011; 52:1560-8. [PMID: 21785130 DOI: 10.1093/pcp/pcr098] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The chloroplast NADH dehydrogenase-like complex (NDH) was first discovered based on its similarity to complex I in respiratory electron transport, and is involved in electron transport from photoproduced stromal reductants such as NADPH and ferredoxin to the intersystem plastoqunone pool. However, a recent study suggested that it is a ferredoxin-dependent plastoquinone reductase rather than an NAD(P)H dehydrogenase. Furthermore, recent advances in subunit analysis of NDH have revealed the presence of a novel hydrophilic subcomplex on the stromal side of the thylakoid membrane, as well as an unexpected lumenal subcomplex. This review discusses these new studies on the structure of NDH, and proposes a unified nomenclature for newly discovered NDH subunits.
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Affiliation(s)
- Kentaro Ifuku
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Sakyo, Kyoto, 606-8502 Japan
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159
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Schöttler MA, Albus CA, Bock R. Photosystem I: its biogenesis and function in higher plants. JOURNAL OF PLANT PHYSIOLOGY 2011; 168:1452-61. [PMID: 21255865 DOI: 10.1016/j.jplph.2010.12.009] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Revised: 12/21/2010] [Accepted: 12/21/2010] [Indexed: 05/06/2023]
Abstract
Photosystem I (PSI), the plastocyanin-ferredoxin oxidoreductase of the photosynthetic electron transport chain, is one of the largest bioenergetic complexes known. It is composed of subunits encoded in both the chloroplast genome and the nuclear genome and thus, its assembly requires an intricate coordination of gene expression and intensive communication between the two compartments. In this review, we first briefly describe PSI structure and then focus on recent findings on the role of the two small chloroplast genome-encoded subunits PsaI and PsaJ in the stability and function of PSI in higher plants. We then address the sequence of PSI biogenesis, discuss the role of auxiliary proteins involved in cofactor insertion into the PSI apoproteins and in the establishment of protein-protein interactions during subunit assembly. Finally, we consider potential limiting steps of PSI biogenesis, and how they may contribute to the control of PSI accumulation.
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Affiliation(s)
- Mark Aurel Schöttler
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, Potsdam-Golm, Germany.
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160
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Cai W, Okuda K, Peng L, Shikanai T. PROTON GRADIENT REGULATION 3 recognizes multiple targets with limited similarity and mediates translation and RNA stabilization in plastids. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2011; 67:318-27. [PMID: 21457370 DOI: 10.1111/j.1365-313x.2011.04593.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
PROTON GRADIENT REGULATION 3 (PGR3) contains 27 pentatricopeptide repeat (PPR) motifs and belongs to the P-subfamily. Previous studies have suggested that PGR3 functions in the stabilization of petL operon RNA and also in the translation of petL and one, or some, of the 11 plastid ndh genes encoding subunits of chloroplast NADH dehydrogenase-like complex (NDH). The pgr3-3 allele has been suggested to be specifically defective in the putative PGR3 function of translation. Herein, we show that the polysome association of the monocistronic petL transcript is impaired in pgr3-3. We detected sequences weakly conserved in the 5' untranslated regions (UTRs) of petL and ndhA, and these putative elements were recognized by recombinant PGR3 in vitro. Previously, pgr3-2 was shown to be specifically defective in stabilizing petL operon RNA and to accumulate NDH at wild-type levels. Consistent with this pgr3-2 phenotype, we show here that a recombinant protein carrying the pgr3-2 mutation in the 12th PPR motif bound to the 5' UTR of ndhA but not of petL. This indicates that a single amino acid alteration changes the binding specificity of PGR3. In contrast, the recombinant protein carrying the pgr3-3 mutation in the final, 27th, incomplete PPR motif can bind to both petL and ndhA 5' UTRs, suggesting that the C-terminal end of PGR3 is not required for binding to targets but is essential for translation of petL and probably also ndhA. Our results fully support the model in which PGR3 recognizes two target sequences and is involved in multiple functions, i.e. stabilizing RNA and activating translation.
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Affiliation(s)
- Wenhe Cai
- Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, Japan
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161
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Sanda S, Yoshida K, Kuwano M, Kawamura T, Munekage YN, Akashi K, Yokota A. Responses of the photosynthetic electron transport system to excess light energy caused by water deficit in wild watermelon. PHYSIOLOGIA PLANTARUM 2011; 142:247-64. [PMID: 21438881 DOI: 10.1111/j.1399-3054.2011.01473.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
In plants, drought stress coupled with high levels of illumination causes not only dehydration of tissues, but also oxidative damage resulting from excess absorbed light energy. In this study, we analyzed the regulation of electron transport under drought/high-light stress conditions in wild watermelon, a xerophyte that shows strong resistance to this type of stress. Under drought/high-light conditions that completely suppressed CO(2) fixation, the linear electron flow was diminished between photosystem (PS) II and PS I, there was no photoinhibitory damage to PS II and PS I and no decrease in the abundance of the two PSs. Proteome analyses revealed changes in the abundance of protein spots representing the Rieske-type iron-sulfur protein (ISP) and I and K subunits of NAD(P)H dehydrogenase in response to drought stress. Two-dimensional electrophoresis and immunoblot analyses revealed new ISP protein spots with more acidic isoelectric points in plants under drought stress. Our findings suggest that the modified ISPs depress the linear electron transport activity under stress conditions to protect PS I from photoinhibition. The qualitative changes in photosynthetic proteins may switch the photosynthetic electron transport from normal photosynthesis mode to stress-tolerance mode.
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Affiliation(s)
- Satoko Sanda
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Takayama, Ikoma, Nara, Japan
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162
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Johnson GN. Reprint of: physiology of PSI cyclic electron transport in higher plants. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1807:906-11. [PMID: 21620796 DOI: 10.1016/j.bbabio.2011.05.008] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Revised: 11/12/2010] [Accepted: 11/13/2010] [Indexed: 11/17/2022]
Abstract
Having long been debated, it is only in the last few years that a concensus has emerged that the cyclic flow of electrons around Photosystem I plays an important and general role in the photosynthesis of higher plants. Two major pathways of cyclic flow have been identified, involving either a complex termed NDH or mediated via a pathway involving a protein PGR5 and two functions have been described-to generate ATP and to provide a pH gradient inducing non-photochemical quenching. The best evidence for the occurrence of the two pathways comes from measurements under stress conditions-high light, drought and extreme temperatures. In this review, the possible relative functions and importance of the two pathways is discussed as well as evidence as to how the flow through these pathways is regulated. Our growing knowledge of the proteins involved in cyclic electron flow will, in the future, enable us to understand better the occurrence and diversity of cyclic electron transport pathways. This article is part of a Special Issue entitled: Regulation of Electron Transport in Chloroplasts.
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163
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Terashima M, Specht M, Hippler M. The chloroplast proteome: a survey from the Chlamydomonas reinhardtii perspective with a focus on distinctive features. Curr Genet 2011; 57:151-68. [PMID: 21533645 DOI: 10.1007/s00294-011-0339-1] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Revised: 04/05/2011] [Accepted: 04/07/2011] [Indexed: 01/12/2023]
Abstract
The unicellular green alga Chlamydomonas reinhardtii has emerged to be an important model organism for the study of oxygenic eukaryotic photosynthesis as well as other processes occurring in the chloroplast. However, the chloroplast proteome in C. reinhardtii has only recently been comprehensively characterized, made possible by proteomics emerging as an accessible and powerful tool over the last decade. In this review, we introduce a compiled list of 996 experimentally chloroplast-localized proteins for C. reinhardtii, stemming largely from our previous proteomic dataset comparing chloroplasts and mitochondria samples to localize proteins. In order to get a taste of some cellular functions taking place in the C. reinhardtii chloroplast, we will focus this review particularly on metabolic differences between chloroplasts of C. reinhardtii and higher plants. Areas that will be covered are photosynthesis, chlorophyll biosynthesis, carbon metabolism, fermentative metabolism, ferredoxins and ferredoxin-interacting proteins.
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Affiliation(s)
- Mia Terashima
- Department of Biology, Institute of Plant Biology and Biotechnology, University of Münster, Hindenburgplatz 55, 48143, Münster, Germany
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164
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A chaperonin subunit with unique structures is essential for folding of a specific substrate. PLoS Biol 2011; 9:e1001040. [PMID: 21483722 PMCID: PMC3071376 DOI: 10.1371/journal.pbio.1001040] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 02/23/2011] [Indexed: 01/01/2023] Open
Abstract
Type I chaperonins are large, double-ring complexes present in bacteria (GroEL),
mitochondria (Hsp60), and chloroplasts (Cpn60), which are involved in mediating
the folding of newly synthesized, translocated, or stress-denatured proteins. In
Escherichia coli, GroEL comprises 14 identical subunits and
has been exquisitely optimized to fold its broad range of substrates. However,
multiple Cpn60 subunits with different expression profiles have evolved in
chloroplasts. Here, we show that, in Arabidopsis thaliana, the
minor subunit Cpn60β4 forms a heterooligomeric Cpn60 complex with
Cpn60α1 and Cpn60β1–β3 and is specifically required for the
folding of NdhH, a subunit of the chloroplast NADH dehydrogenase-like complex
(NDH). Other Cpn60β subunits cannot complement the function of Cpn60β4.
Furthermore, the unique C-terminus of Cpn60β4 is required for the full
activity of the unique Cpn60 complex containing Cpn60β4 for folding of NdhH.
Our findings suggest that this unusual kind of subunit enables the Cpn60 complex
to assist the folding of some particular substrates, whereas other dominant
Cpn60 subunits maintain a housekeeping chaperonin function by facilitating the
folding of other obligate substrates. Chaperonins assist the folding of some nascent and denatured proteins to their
native, functional forms. Each chaperonin consists of a pair of protein
complexes resembling two stacked toroids; folding occurs inside the toroid
cavity. Chaperonins are ubiquitous in both bacteria and more complex nucleated
cells, as well as in the intracellular organelles that have evolved from
bacteria by endosymbiosis: mitochondria and, in plants, chloroplasts. They are
indispensable for cellular function. Many different chaperonin subunits have
evolved in various species of bacteria as well as in most mitochondria and
chloroplasts. The physiological and functional relevance of these multiple
chaperonin subunits is poorly understood, however. In this study, we have
characterized the minor chaperonin subunit Cpn60β4 from
Arabidopsis chloroplasts, which differs in structure from
other chloroplast chaperonins. When the Cpn60β4 gene is
defective, the plants fail to accumulate one protein complex in particular: the
chloroplast NADH dehydrogenase-like complex (NDH). We discovered that
Cpn60β4 forms a complex with other Cpn60 α and β
subunits and that this complex is essential for the folding of the NDH subunit
NdhH. Cpn60β4 has a unique protein “tail” that is required for
the efficient folding of NdhH. Our findings suggest that Cpn60β4 has evolved
with distinctive structural features that facilitate the folding of one specific
substrate and that this strategy is used by plants to satisfy their conflicting
requirements for chaperonins with both specialized and general functions.
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165
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Yamamoto H, Peng L, Fukao Y, Shikanai T. An Src homology 3 domain-like fold protein forms a ferredoxin binding site for the chloroplast NADH dehydrogenase-like complex in Arabidopsis. THE PLANT CELL 2011; 23:1480-93. [PMID: 21505067 PMCID: PMC3101538 DOI: 10.1105/tpc.110.080291] [Citation(s) in RCA: 167] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Revised: 03/07/2011] [Accepted: 04/05/2011] [Indexed: 05/18/2023]
Abstract
Some subunits of chloroplast NAD(P)H dehydrogenase (NDH) are related to those of the respiratory complex I, and NDH mediates photosystem I (PSI) cyclic electron flow. Despite extensive surveys, the electron donor and its binding subunits have not been identified. Here, we identified three novel components required for NDH activity. CRRJ and CRRL are J- and J-like proteins, respectively, and are components of NDH subcomplex A. CRR31 is an Src homology 3 domain-like fold protein, and its C-terminal region may form a tertiary structure similar to that of PsaE, a ferredoxin (Fd) binding subunit of PSI, although the sequences are not conserved between CRR31 and PsaE. Although CRR31 can accumulate in thylakoids independently of NDH, its accumulation requires CRRJ, and CRRL accumulation depends on CRRJ and NDH. CRR31 was essential for the efficient operation of Fd-dependent plastoquinone reduction in vitro. The phenotype of crr31 pgr5 suggested that CRR31 is required for NDH activity in vivo. We propose that NDH functions as a PGR5-PGRL1 complex-independent Fd:plastoquinone oxidoreductase in chloroplasts and rename it the NADH dehydrogenase-like complex.
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Affiliation(s)
- Hiroshi Yamamoto
- Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Lianwei Peng
- Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Yoichiro Fukao
- Plant Global Educational Project, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma 630-0101, Japan
| | - Toshiharu Shikanai
- Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
- Address correspondence to
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166
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Plöscher M, Reisinger V, Eichacker LA. Proteomic comparison of etioplast and chloroplast protein complexes. J Proteomics 2011; 74:1256-65. [PMID: 21440687 DOI: 10.1016/j.jprot.2011.03.020] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Revised: 03/01/2011] [Accepted: 03/16/2011] [Indexed: 11/16/2022]
Abstract
Angiosperms grown in darkness develop etioplasts during skotomorphogenesis. It is well known that etioplasts accumulate large quantities of protochlorophyllideoxidoreductase, are devoid of chlorophyll and are the site to assemble the photosynthetic machinery during photomorphogenesis. Proteomic investigation of the membrane protein complexes by Native PAGE, in combination with CyDye labelling and mass spectrometric analysis revealed that etioplasts and chloroplasts share a number of membrane protein complexes characteristic for electron transport, chlorophyll and protein synthesis as well as fatty acid biosynthesis. The complex regulatory function in both developmental states is discussed.
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167
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Peng L, Shikanai T. Supercomplex formation with photosystem I is required for the stabilization of the chloroplast NADH dehydrogenase-like complex in Arabidopsis. PLANT PHYSIOLOGY 2011; 155:1629-39. [PMID: 21278308 PMCID: PMC3091109 DOI: 10.1104/pp.110.171264] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Accepted: 01/23/2011] [Indexed: 05/18/2023]
Abstract
In higher plants, the chloroplast NADH dehydrogenase-like complex (NDH) interacts with photosystem I (PSI) to form the NDH-PSI supercomplex via two minor light-harvesting complex I (LHCI) proteins, Lhca5 and Lhca6. Previously, we showed that in lhca5 and lhca6, NDH still associates with PSI to form smaller versions of the NDH-PSI supercomplex, although their molecular masses are far smaller than that of the full-size NDH-PSI supercomplex. In this study, we show that the NDH complex is present in the monomeric form in Arabidopsis (Arabidopsis thaliana) lhca5 lhca6, implying that NDH interacts with multiple copies of PSI. NDH subunit levels were slightly reduced in immature leaves and more drastically (approximately 50%) in mature leaves of the lhca5 lhca6 double mutant compared with the wild type. Chlorophyll fluorescence analyses detected NDH activity of lhca5 lhca6, suggesting that the supercomplex formation is not essential for NDH activity. However, the severe phenotypes of the lhca5 lhca6 proton gradient regulation5 triple mutant in both plant growth rate and photosynthesis suggest that the function of NDH was impaired in this mutant in vivo. Accumulation of NDH subunits was drastically reduced in lhca5 lhca6 when the light intensity was shifted from 50 to 500 μmol photons m(-2) s(-1). Furthermore, the half-life of NDH subunits, especially that of NDH18, was shorter in monomeric NDH than in the NDH-PSI supercomplex under the high-light conditions. We propose that NDH-PSI supercomplex formation stabilizes NDH and that the process is especially required under stress conditions.
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168
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Watkins KP, Rojas M, Friso G, van Wijk KJ, Meurer J, Barkan A. APO1 promotes the splicing of chloroplast group II introns and harbors a plant-specific zinc-dependent RNA binding domain. THE PLANT CELL 2011; 23:1082-92. [PMID: 21421812 PMCID: PMC3082255 DOI: 10.1105/tpc.111.084335] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Revised: 02/14/2011] [Accepted: 03/05/2011] [Indexed: 05/18/2023]
Abstract
Arabidopsis thaliana APO1 is required for the accumulation of the chloroplast photosystem I and NADH dehydrogenase complexes and had been proposed to facilitate the incorporation of [4Fe-4S] clusters into these complexes. The identification of maize (Zea mays) APO1 in coimmunoprecipitates with a protein involved in chloroplast RNA splicing prompted us to investigate a role for APO1 in splicing. We show here that APO1 promotes the splicing of several chloroplast group II introns: in Arabidopsis apo1 mutants, ycf3-intron 2 remains completely unspliced, petD intron splicing is strongly reduced, and the splicing of several other introns is compromised. These splicing defects can account for the loss of photosynthetic complexes in apo1 mutants. Recombinant APO1 from both maize and Arabidopsis binds RNA with high affinity in vitro, demonstrating that DUF794, the domain of unknown function that makes up almost the entirety of APO1, is an RNA binding domain. We provide evidence that DUF794 harbors two motifs that resemble zinc fingers, that these bind zinc, and that they are essential for APO1 function. DUF794 is found in a plant-specific protein family whose members are all predicted to localize to mitochondria or chloroplasts. Thus, DUF794 adds a new example to the repertoire of plant-specific RNA binding domains that emerged as a product of nuclear-organellar coevolution.
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Affiliation(s)
- Kenneth P. Watkins
- Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403
| | - Margarita Rojas
- Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403
| | - Giulia Friso
- Department of Plant Biology, Cornell University, Ithaca, New York 14853
| | - Klaas J. van Wijk
- Department of Plant Biology, Cornell University, Ithaca, New York 14853
| | - Jörg Meurer
- Department Biology I, Ludwig-Maximilians University, D-82152 Munich, Germany
| | - Alice Barkan
- Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403
- Address correspondence to
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169
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Chen G, Allahverdiyeva Y, Aro EM, Styring S, Mamedov F. Electron paramagnetic resonance study of the electron transfer reactions in photosystem II membrane preparations from Arabidopsis thaliana. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1807:205-15. [DOI: 10.1016/j.bbabio.2010.10.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2010] [Revised: 10/06/2010] [Accepted: 10/08/2010] [Indexed: 10/18/2022]
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170
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Armbruster U, Pesaresi P, Pribil M, Hertle A, Leister D. Update on chloroplast research: new tools, new topics, and new trends. MOLECULAR PLANT 2011; 4:1-16. [PMID: 20924030 DOI: 10.1093/mp/ssq060] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Chloroplasts, the green differentiation form of plastids, are the sites of photosynthesis and other important plant functions. Genetic and genomic technologies have greatly boosted the rate of discovery and functional characterization of chloroplast proteins during the past decade. Indeed, data obtained using high-throughput methodologies, in particular proteomics and transcriptomics, are now routinely used to assign functions to chloroplast proteins. Our knowledge of many chloroplast processes, notably photosynthesis and photorespiration, has reached such an advanced state that biotechnological approaches to crop improvement now seem feasible. Meanwhile, efforts to identify the entire complement of chloroplast proteins and their interactions are progressing rapidly, making the organelle a prime target for systems biology research in plants.
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Affiliation(s)
- Ute Armbruster
- Lehrstuhl für Molekularbiologie der Pflanzen (Botanik), Department Biologie I, Ludwig-Maximilians-Universität München, Großhaderner Str. 2, D-82152 Planegg-Martinsried, Germany
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171
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Physiology of PSI cyclic electron transport in higher plants. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1807:384-9. [PMID: 21118673 DOI: 10.1016/j.bbabio.2010.11.009] [Citation(s) in RCA: 155] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Revised: 11/12/2010] [Accepted: 11/13/2010] [Indexed: 11/21/2022]
Abstract
Having long been debated, it is only in the last few years that a concensus has emerged that the cyclic flow of electrons around Photosystem I plays an important and general role in the photosynthesis of higher plants. Two major pathways of cyclic flow have been identified, involving either a complex termed NDH or mediated via a pathway involving a protein PGR5 and two functions have been described-to generate ATP and to provide a pH gradient inducing non-photochemical quenching. The best evidence for the occurrence of the two pathways comes from measurements under stress conditions-high light, drought and extreme temperatures. In this review, the possible relative functions and importance of the two pathways is discussed as well as evidence as to how the flow through these pathways is regulated. Our growing knowledge of the proteins involved in cyclic electron flow will, in the future, enable us to understand better the occurrence and diversity of cyclic electron transport pathways. This article is part of a Special Issue entitled: Regulation of Electron Transport in Chloroplasts.
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172
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Neilson JAD, Durnford DG. Structural and functional diversification of the light-harvesting complexes in photosynthetic eukaryotes. PHOTOSYNTHESIS RESEARCH 2010; 106:57-71. [PMID: 20596891 DOI: 10.1007/s11120-010-9576-2] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2010] [Accepted: 06/16/2010] [Indexed: 05/25/2023]
Abstract
Eukaryotes acquired photosynthetic metabolism over a billion years ago, and during that time the light-harvesting antennae have undergone significant structural and functional divergence. The antenna systems are generally used to harvest and transfer excitation energy into the reaction centers to drive photosynthesis, but also have the dual role of energy dissipation. Phycobilisomes formed the first antenna system in oxygenic photoautotrophs, and this soluble protein complex continues to be the dominant antenna in extant cyanobacteria, glaucophytes, and red algae. However, phycobilisomes were lost multiple times during eukaryotic evolution in favor of a thylakoid membrane-integral light-harvesting complex (LHC) antenna system found in the majority of eukaryotic taxa. While photosynthesis spread across different eukaryotic kingdoms via endosymbiosis, the antenna systems underwent extensive modification as photosynthetic groups optimized their light-harvesting capacity and ability to acclimate to changing environmental conditions. This review discusses the different classes of LHCs within photosynthetic eukaryotes and examines LHC diversification in different groups in a structural and functional context.
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Affiliation(s)
- Jonathan A D Neilson
- Department of Biology, University of New Brunswick, Fredericton, NB E3B 5A3, Canada
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173
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Peng L, Yamamoto H, Shikanai T. Structure and biogenesis of the chloroplast NAD(P)H dehydrogenase complex. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1807:945-53. [PMID: 21029720 DOI: 10.1016/j.bbabio.2010.10.015] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Revised: 10/15/2010] [Accepted: 10/17/2010] [Indexed: 11/19/2022]
Abstract
Eleven genes (ndhA-ndhK) encoding proteins homologous to the subunits of bacterial and mitochondrial NADH dehydrogenase (complex I) were found in the plastid genome of most land plants. These genes encode subunits of the chloroplast NAD(P)H dehydrogenase (NDH) complex involved in photosystem I (PSI) cyclic electron transport and chlororespiration. Although the chloroplast NDH is believed to be closely and functionally related to the cyanobacterial NDH-1L complex, extensive proteomic, genetic and bioinformatic studies have discovered many novel subunits that are specific to higher plants. On the basis of extensive mutant characterization, the chloroplast NDH complex is divided into four parts, the A, B, membrane and lumen subcomplexes, of which subunits in the B and lumen subcomplexes are specific to higher plants. These results suggest that the structure of NDH has been drastically altered during the evolution of land plants. Furthermore, chloroplast NDH interacts with multiple copies of PSI to form the unique NDH-PSI supercomplex. Two minor light-harvesting-complex I (LHCI) proteins, Lhca5 and Lhca6, are required for the specific interaction between NDH and PSI. The evolution of chloroplast NDH in land plants may be required for development of the function of NDH to alleviate oxidative stress in chloroplasts. In this review, we summarize recent progress on the subunit composition and structure of the chloroplast NDH complex, as well as the information on some factors involved in its assembly. This article is part of a Special Issue entitled: Regulation of Electron Transport in Chloroplasts.
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Affiliation(s)
- Lianwei Peng
- Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.
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174
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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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175
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Chloroplast-targeted ferredoxin-NADP(+) oxidoreductase (FNR): structure, function and location. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1807:927-34. [PMID: 20934402 DOI: 10.1016/j.bbabio.2010.10.001] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Revised: 10/01/2010] [Accepted: 10/02/2010] [Indexed: 11/20/2022]
Abstract
Ferredoxin-NADP(+) oxidoreductase (FNR) is a ubiquitous flavin adenine dinucleotide (FAD)-binding enzyme encoded by a small nuclear gene family in higher plants. The chloroplast targeted FNR isoforms are known to be responsible for the final step of linear electron flow transferring electrons from ferredoxin to NADP(+), while the putative role of FNR in cyclic electron transfer has been under discussion for decades. FNR has been found from three distinct chloroplast compartments (i) at the thylakoid membrane, (ii) in the soluble stroma, and (iii) at chloroplast inner envelope. Recent in vivo studies have indicated that besides the membrane-bound FNR, also the soluble FNR is photosynthetically active. Two chloroplast proteins, Tic62 and TROL, were recently identified and shown to form high molecular weight protein complexes with FNR at the thylakoid membrane, and thus seem to act as the long-sought molecular anchors of FNR to the thylakoid membrane. Tic62-FNR complexes are not directly involved in photosynthetic reactions, but Tic62 protects FNR from inactivation during the dark periods. TROL-FNR complexes, however, have an impact on the photosynthetic performance of the plants. This article is part of a Special Issue entitled: Regulation of Electron Transport in Chloroplasts.
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176
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LIL3, a light-harvesting-like protein, plays an essential role in chlorophyll and tocopherol biosynthesis. Proc Natl Acad Sci U S A 2010; 107:16721-5. [PMID: 20823244 DOI: 10.1073/pnas.1004699107] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The light-harvesting chlorophyll-binding (LHC) proteins are major constituents of eukaryotic photosynthetic machinery. In plants, six different groups of proteins, LHC-like proteins, share a conserved motif with LHC. Although the evolution of LHC and LHC-like proteins is proposed to be a key for the diversification of modern photosynthetic eukaryotes, our knowledge of the evolution and functions of LHC-like proteins is still limited. In this study, we aimed to understand specifically the function of one type of LHC-like proteins, LIL3 proteins, by analyzing Arabidopsis mutants lacking them. The Arabidopsis genome contains two gene copies for LIL3, LIL3:1 and LIL3:2. In the lil3:1/lil3:2 double mutant, the majority of chlorophyll molecules are conjugated with an unsaturated geranylgeraniol side chain. This mutant is also deficient in α-tocopherol. These results indicate that reduction of both the geranylgeraniol side chain of chlorophyll and geranylgeranyl pyrophosphate, which is also an essential intermediate of tocopherol biosynthesis, is compromised in the lil3 mutants. We found that the content of geranylgeranyl reductase responsible for these reactions was severely reduced in the lil3 double mutant, whereas the mRNA level for this enzyme was not significantly changed. We demonstrated an interaction of geranylgeranyl reductase with both LIL3 isoforms by using a split ubiquitin assay, bimolecular fluorescence complementation, and combined blue-native and SDS polyacrylamide gel electrophoresis. We propose that LIL3 is functionally involved in chlorophyll and tocopherol biosynthesis by stabilizing geranylgeranyl reductase.
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177
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Okegawa Y, Kobayashi Y, Shikanai T. Physiological links among alternative electron transport pathways that reduce and oxidize plastoquinone in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 63:458-68. [PMID: 20497376 DOI: 10.1111/j.1365-313x.2010.04252.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
In addition to linear electron transport from water to NADP(+) , alternative electron transport pathways are believed to regulate photosynthesis. In the two routes of photosystem I (PSI) cyclic electron transport, electrons are recycled from the stromal reducing pool to plastoquinone (PQ), generating additional ΔpH (proton gradient across thylakoid membranes). Plastid terminal oxidase (PTOX) accepts electrons from PQ and transfers them to oxygen to produce water. Although both electron transport pathways share the PQ pool, it is unclear whether they interact in vivo. To investigate the physiological link between PSI cyclic electron transport-dependent PQ reduction and PTOX-dependent PQ oxidation, we characterized mutants defective in both functions. Impairment of PSI cyclic electron transport suppressed leaf variegation in the Arabidopsis immutans (im) mutant, which is defective in PTOX. The im variegation was more effectively suppressed in the pgr5 mutant, which is defective in the main pathway of PSI cyclic electron transport, than in the crr2-2 mutant, which is defective in the minor pathway. In contrast to this chloroplast development phenotype, the im defect alleviated the growth phenotype of the crr2-2 pgr5 double mutant. This was accompanied by partial suppression of stromal over-reduction and restricted linear electron transport. We discuss the function of the alternative electron transport pathways in both chloroplast development and photosynthesis in mature leaves.
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Affiliation(s)
- Yuki Okegawa
- Graduate School of Agriculture, Kyushu University, Fukuoka 812-8581, JapanDepartment of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
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178
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Ifuku K, Ishihara S, Sato F. Molecular functions of oxygen-evolving complex family proteins in photosynthetic electron flow. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2010; 52:723-34. [PMID: 20666928 DOI: 10.1111/j.1744-7909.2010.00976.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Oxygen-evolving complex (OEC) protein is the original name for membrane-peripheral subunits of photosystem (PS) II. Recently, multiple isoforms and homologs for OEC proteins have been identified in the chloroplast thylakoid lumen, indicating that functional diversification has occurred in the OEC family. Gene expression profiles suggest that the Arabidopsis OEC proteins are roughly categorized into three groups: the authentic OEC group, the stress-responsive group, and the group including proteins related to the chloroplast NAD(P)H dehydrogenase (NDH) complex involved in cyclic electron transport around PSI. Based on the above gene expression profiles, molecular functions of the OEC family proteins are discussed together with our current knowledge about their functions.
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Affiliation(s)
- Kentaro Ifuku
- Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto, Japan.
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179
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Gollan PJ, Bhave M. A thylakoid-localised FK506-binding protein in wheat may be linked to chloroplast biogenesis. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2010; 48:655-662. [PMID: 20570161 DOI: 10.1016/j.plaphy.2010.05.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2009] [Revised: 04/21/2010] [Accepted: 05/03/2010] [Indexed: 05/29/2023]
Abstract
Plant chloroplasts contain a large proportion of immunophilins, comprising the FK506-binding proteins (FKBPs) and cyclophilins (CYPs), which are members of the peptidyl-prolyl cis/trans isomerase (PPIase) family of proline-folding enzymes. Some of the chloroplastic immunophilins are known to chaperone certain photosynthetic proteins, however the functions of a majority of these proteins are unknown. This work focussed on characterisation of genes encoding the chloroplast-localised FKBP16-1 from wheat and its progenitor species, and identification of its putative promoters, as well as investigations into the effects of light regulation and plant development on its expression. The work identified several alternatively spliced FKBP16-1 transcripts, indicating expression of FKBP16-1 may be post-transcriptionally regulated. FKBP16-1 was expressed in both green and etiolated tissues, and highest levels were detected in developing tissues, indicating a role in chloroplast biogenesis. We also report a novel transcription module, designated 'chloroplast biogenesis module' (CBM) in the FKBP16-1 promoter of cereals that also appears to be involved in the regulation of additional genes involved in chloroplast biogenesis or other aspects of plant development. The results point to considerable potential for a role for FKBP16-1 in early chloroplast development, architecture of photosynthetic apparatus and plant development.
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Affiliation(s)
- Peter J Gollan
- Environment and Biotechnology Centre, Faculty of Life and Social Sciences, Swinburne University of Technology, P O Box 218, Hawthorn, Victoria 3122, Australia
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180
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Peng L, Cai W, Shikanai T. Chloroplast stromal proteins, CRR6 and CRR7, are required for assembly of the NAD(P)H dehydrogenase subcomplex A in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 63:203-211. [PMID: 20444231 DOI: 10.1111/j.1365-313x.2010.04240.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
In higher plants, the chloroplast NAD(P)H dehydrogenase (NDH) complex mediates chlororespiration and photosystem I (PSI) cyclic electron transport in thylakoid membranes. Because of its low abundance and fragility, our knowledge on the assembly of chloroplast NDH is very limited, and some nuclear-encoded factors may be involved in this process. We show here that two Arabidopsis proteins, CHLORORESPIRATORY REDUCTION 6 (CRR6) and CRR7, which were previously identified in mutants specifically defective in NDH accumulation, are present in the stroma, and their stability is independent of the NDH complex, suggesting that they are unlikely to be NDH subunits. Blue native PAGE analysis showed that the accumulation of NDH subcomplex A, which is a core part of NDH that is conserved in divergent species, was specifically impaired in the crr6 and crr7-1 mutants. However, the expression of plastid-encoded genes encoding the subcomplex A subunits was not affected, suggesting that CRR6 and CRR7 are involved in post-translational steps during the biogenesis of subcomplex A. We also discovered that a substantial quantity of NdhH is present in several protein complexes in the chloroplast stroma, possibly as early assembly intermediates of subcomplex A. Although the accumulation of these stromal complexes was not affected in crr6 or crr7-1, CRR6 was co-purified with NdhH, implying that CRR6 functions in the later step of subcomplex-A biogenesis. Accumulation of CRR7 was independent of that of CRR6; we propose that CRR7 functions in a different step in subcomplex-A biogenesis from CRR6.
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Affiliation(s)
- Lianwei Peng
- Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Wenhe Cai
- Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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181
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Yabuta S, Ifuku K, Takabayashi A, Ishihara S, Ido K, Ishikawa N, Endo T, Sato F. Three PsbQ-like proteins are required for the function of the chloroplast NAD(P)H dehydrogenase complex in Arabidopsis. PLANT & CELL PHYSIOLOGY 2010; 51:866-76. [PMID: 20430763 DOI: 10.1093/pcp/pcq060] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Arabidopsis has three PsbQ-like (PQL) proteins in addition to the PsbQ subunit of the oxygen-evolving complex of PSII. Recent bioinformatic and proteomic studies suggested that the two PQL proteins, PQL1 (At1g14150) and PQL2 (At3g01440), might function in the chloroplast NAD(P)H dehydrogenase (NDH) complex; however, their molecular function has not been characterized. In this study, we examined the function of the chloroplast NDH in the Arabidopsis pql1 and pql2 mutants. Post-illumination increases in Chl fluorescence, which are caused by an NDH-dependent cyclic electron flow, were absent in both mutants, indicating that PQL1 and PQL2 are required for NDH activity. In the thylakoid membranes of wild-type plants, PQL1 and PQL2 were tightly associated with the NDH-PSI supercomplex and protected from protease treatments, while unassembled PQLs were not stably accumulated in mutants lacking known NDH subunits. Subunit stability of the NDH complex was affected differently in the thylakoid membranes of the pql1 and pql2 mutants. These data indicate that PQL1 and PQL2 are novel NDH subunits and differ in their functional roles and in their binding sites in the NDH complex. Furthermore, functional analysis on PQL3 (At2g01918) using the pql3 mutant suggests that PQL3 is also required for NDH activity. Proteins homologous to each PQL protein are found in various plant species, but not in cyanobacteria, algae, mosses or ferns. These results suggest that seed plants that have NDH activity in chloroplasts specifically developed three PQL proteins for the function of the chloroplast NDH complex.
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Affiliation(s)
- Shinya Yabuta
- Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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182
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Nashilevitz S, Melamed-Bessudo C, Izkovich Y, Rogachev I, Osorio S, Itkin M, Adato A, Pankratov I, Hirschberg J, Fernie AR, Wolf S, Usadel B, Levy AA, Rumeau D, Aharoni A. An orange ripening mutant links plastid NAD(P)H dehydrogenase complex activity to central and specialized metabolism during tomato fruit maturation. THE PLANT CELL 2010; 22:1977-97. [PMID: 20571113 PMCID: PMC2910969 DOI: 10.1105/tpc.110.074716] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2010] [Revised: 05/14/2010] [Accepted: 06/07/2010] [Indexed: 05/18/2023]
Abstract
In higher plants, the plastidial NADH dehydrogenase (Ndh) complex supports nonphotochemical electron fluxes from stromal electron donors to plastoquinones. Ndh functions in chloroplasts are not clearly established; however, its activity was linked to the prevention of the overreduction of stroma, especially under stress conditions. Here, we show by the characterization of Orr(Ds), a dominant transposon-tagged tomato (Solanum lycopersicum) mutant deficient in the NDH-M subunit, that this complex is also essential for the fruit ripening process. Alteration to the NDH complex in fruit changed the climacteric, ripening-associated metabolites and transcripts as well as fruit shelf life. Metabolic processes in chromoplasts of ripening tomato fruit were affected in Orr(Ds), as mutant fruit were yellow-orange and accumulated substantially less total carotenoids, mainly beta-carotene and lutein. The changes in carotenoids were largely influenced by environmental conditions and accompanied by modifications in levels of other fruit antioxidants, namely, flavonoids and tocopherols. In contrast with the pigmentation phenotype in mature mutant fruit, Orr(Ds) leaves and green fruits did not display a visible phenotype but exhibited reduced Ndh complex quantity and activity. This study therefore paves the way for further studies on the role of electron transport and redox reactions in the regulation of fruit ripening and its associated metabolism.
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Affiliation(s)
- Shai Nashilevitz
- Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
- Faculty of Agricultural, Food, and Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot 76100, Israel
| | | | - Yinon Izkovich
- Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ilana Rogachev
- Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Sonia Osorio
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Maxim Itkin
- Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Avital Adato
- Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ilya Pankratov
- Department of Genetics, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Joseph Hirschberg
- Department of Genetics, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Alisdair R. Fernie
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Shmuel Wolf
- Faculty of Agricultural, Food, and Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - Björn Usadel
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Avraham A. Levy
- Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Dominique Rumeau
- Commissariat à l'Energie Atomique Cadarache, Direction des Sciences du Vivant, Institut de Biologie Environnementale et Biotechnologie, Service de Biologie Végétale et de Microbiologie Environnementale, Laboratoire d'Ecophysiologie Moléculaire des Plantes, Unité Mixte de Recherche 6191, Centre National de la Recherche Scientifique/Commissariat à l'Energie Atomique/Université de la Méditerranée, F-13108 Saint-Paul-lez-Durance, France
| | - Asaph Aharoni
- Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
- Address correspondence to
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183
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Suorsa M, Sirpiö S, Paakkarinen V, Kumari N, Holmström M, Aro EM. Two proteins homologous to PsbQ are novel subunits of the chloroplast NAD(P)H dehydrogenase. PLANT & CELL PHYSIOLOGY 2010; 51:877-83. [PMID: 20460499 DOI: 10.1093/pcp/pcq070] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The PsbQ-like (PQL) proteins 1 and 2, previously shown to be located in the thylakoid lumen of Arabidopsis thaliana, are homologous to PSII oxygen-evolving complex protein PsbQ. Nevertheless, pql mutants showed no defects in PSII but instead the activity of the chloroplast NAD(P)H dehydrogenease (NDH) complex was severely impaired. In line with this observation, the NDH subunits were low in abundance in pql mutants, and, conversely, ndh mutants strongly down-regulated the accumulation of the PQL proteins. In addition, the PQL2 protein was up-regulated in mutant plants deficient in the PSI complex or the thylakoid membrane-bound ferredoxin-NADP(+) oxidoreductase, whereas in pql mutants the PSI complex was slightly up-regulated. Taken together, the two PQL proteins are shown to be novel subunits of the lumenal protuberance of the NDH complex.
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Affiliation(s)
- Marjaana Suorsa
- Department of Biochemistry and Food Chemistry, Molecular Plant Biology, FI-20014 University of Turku, Finland
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184
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Friso G, Majeran W, Huang M, Sun Q, van Wijk KJ. Reconstruction of metabolic pathways, protein expression, and homeostasis machineries across maize bundle sheath and mesophyll chloroplasts: large-scale quantitative proteomics using the first maize genome assembly. PLANT PHYSIOLOGY 2010; 152:1219-50. [PMID: 20089766 PMCID: PMC2832236 DOI: 10.1104/pp.109.152694] [Citation(s) in RCA: 155] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Accepted: 01/17/2010] [Indexed: 05/17/2023]
Abstract
Chloroplasts in differentiated bundle sheath (BS) and mesophyll (M) cells of maize (Zea mays) leaves are specialized to accommodate C(4) photosynthesis. This study provides a reconstruction of how metabolic pathways, protein expression, and homeostasis functions are quantitatively distributed across BS and M chloroplasts. This yielded new insights into cellular specialization. The experimental analysis was based on high-accuracy mass spectrometry, protein quantification by spectral counting, and the first maize genome assembly. A bioinformatics workflow was developed to deal with gene models, protein families, and gene duplications related to the polyploidy of maize; this avoided overidentification of proteins and resulted in more accurate protein quantification. A total of 1,105 proteins were assigned as potential chloroplast proteins, annotated for function, and quantified. Nearly complete coverage of primary carbon, starch, and tetrapyrole metabolism, as well as excellent coverage for fatty acid synthesis, isoprenoid, sulfur, nitrogen, and amino acid metabolism, was obtained. This showed, for example, quantitative and qualitative cell type-specific specialization in starch biosynthesis, arginine synthesis, nitrogen assimilation, and initial steps in sulfur assimilation. An extensive overview of BS and M chloroplast protein expression and homeostasis machineries (more than 200 proteins) demonstrated qualitative and quantitative differences between M and BS chloroplasts and BS-enhanced levels of the specialized chaperones ClpB3 and HSP90 that suggest active remodeling of the BS proteome. The reconstructed pathways are presented as detailed flow diagrams including annotation, relative protein abundance, and cell-specific expression pattern. Protein annotation and identification data, and projection of matched peptides on the protein models, are available online through the Plant Proteome Database.
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185
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Okuda K, Hammani K, Tanz SK, Peng L, Fukao Y, Myouga F, Motohashi R, Shinozaki K, Small I, Shikanai T. The pentatricopeptide repeat protein OTP82 is required for RNA editing of plastid ndhB and ndhG transcripts. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 61:339-49. [PMID: 19845878 DOI: 10.1111/j.1365-313x.2009.04059.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Several hundred nucleus-encoded factors are required for regulating gene expression in plant organelles. Among them, the most numerous are the members of the pentatricopeptide repeat (PPR) protein family. We found that PPR protein OTP82 is essential for RNA editing of the ndhB-9 and ndhG-1 sites within transcripts encoding subunits of chloroplast NAD(P)H dehydrogenase. Despite the defects in RNA editing, otp82 did not show any phenotypes in NDH activity, stability or interaction with photosystem I, suggesting that the RNA editing events mediated by OTP82 are functionally silent even though they induce amino acid alterations. In agreement with this result, both sites are partially edited even in the wild type, implying the possibility that a single gene produces heterogeneous proteins that are functionally equivalent. Although only five nucleotides separate the ndhB-8 and ndhB-9 sites, the ndhB-8 site is normally edited in otp82 mutants, suggesting that both sites are recognized by different PPR proteins. OTP82 falls into the DYW subclass containing conserved C-terminal E and DYW motifs. As in CRR22 and CRR28, the DYW motif present in OTP82 is not essential for RNA editing in vivo.
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Affiliation(s)
- Kenji Okuda
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
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