| 1. |
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| 2. |
- Carlberg, Inger, et al.
(författare)
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A novel plant protein undergoing light-induced phosphorylation and release from the photosynthetic thylakoid membranes
- 2003
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 100:2, s. 757-62
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Tidskriftsartikel (refereegranskat)abstract
- The characteristics of a phosphoprotein with a relative electrophoretic mobility of 12 kDa have been unknown during two decades of studies on redox-dependent protein phosphorylation in plant photosynthetic membranes. Digestion of this protein from spinach thylakoid membranes with trypsin and subsequent tandem nanospray-quadrupole-time-of-flight mass spectrometry of the peptides revealed a protein sequence that did not correspond to any previously known protein. Sequencing of the corresponding cDNA uncovered a gene for a precursor protein with a transit peptide followed by a strongly basic mature protein with a molecular mass of 8,640 Da. Genes encoding homologous proteins were found on chromosome 3 of Arabidopsis and rice as well as in ESTs from 20 different plant species, but not from any other organisms. The protein can be released from the membrane with high salt and is also partially released in response to light-induced phosphorylation of thylakoids, in contrast to all other known thylakoid phosphoproteins, which are integral to the membrane. On the basis of its properties, this plant-specific protein is named thylakoid soluble phosphoprotein of 9 kDa (TSP9). Mass spectrometric analyses revealed the existence of non-, mono-, di-, and triphosphorylated forms of TSP9 and phosphorylation of three distinct threonine residues in the central part of the protein. The phosphorylation and release of TSP9 from the photosynthetic membrane on illumination favor participation of this basic protein in cell signaling and regulation of plant gene expression in response to changing light conditions.
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| 3. |
- Funk, Christiane, et al.
(författare)
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D1' centers are less efficient than normal photosystem II centers
- 2001
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Ingår i: FEBS Letters. - 0014-5793 .- 1873-3468. ; 505:1, s. 113-117
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Tidskriftsartikel (refereegranskat)abstract
- One prominent difference between the photosystem II (PSII) reaction center protein D1 ' in Synechocystis 6803 and normal D1 is the replacement of Phe-186 in D1 with leucine in D1 '. Mutants of Synechocystis 6803 producing only D1 ', or containing engineered D1 proteins with Phe-186 substitutions, were analyzed by 77 K fluorescence emission spectra, chlorophyll a fluorescence induction yield and decay kinetics, and flash-induced oxygen evolution. Compared to D1-containing PSII centers, D1 ' centers exhibited a 50% reduction in variable chlorophyll a fluorescence yield, while the flash-induced O-2 evolution pattern was unaffected. In the F186 mutants, both the P680(+)/Q(A)(-) recombination and O-2 oscillation pattern were noticeably perturbed.
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| 4. |
- Huang, Fang, et al.
(författare)
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Isolation of Outer Membrane of Synechocystis sp. PCC 6803 and Its Proteomic Characterization
- 2004
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Ingår i: Molecular & Cellular Proteomics. - : American Society for Biochemistry and Molecular Biology. - 1535-9476 .- 1535-9484. ; 3:6, s. 586-595
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Tidskriftsartikel (refereegranskat)abstract
- In this report, we describe a newly developed method for isolating outer membranes from Synechocystis sp. PCC 6803 cells. The purity of the outer membrane fraction was verified by immunoblot analysis using antibodies against membrane-specific marker proteins. We investigated the protein composition of the outer membrane using two-dimensional gel electrophoresis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry followed by database identification. Forty-nine proteins were identified corresponding to 29 different gene products. All of the identified proteins have a putative N-terminal signal peptide. About 40% of the proteins identified represent hypothetical proteins with unknown function. Among the proteins identified are a Toc75 homologue, a protein that was initially found in the outer envelope of chloroplasts in pea, as well as TolC, putative porins, and a pilus protein. Other proteins identified include ABC transporters and GumB, which has a suggested function in carbohydrate export. A number of proteases such as HtrA were also found in the outer membrane of Synechocystis sp. PCC 6803.
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| 5. |
- Kieselbach, T, et al.
(författare)
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A peroxidase homologue and novel plastocyanin located by proteomics to the Arabidopsis chloroplast thylakoid lumen
- 2000
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Ingår i: FEBS Letters. - 0014-5793 .- 1873-3468. ; 480:2-3, s. 271-276
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Tidskriftsartikel (refereegranskat)abstract
- A study by two-dimensional electrophoresis showed that the soluble, lumenal fraction of Arabidopsis thaliana thylakoids can be resolved into 300 protein spots. After subtraction of low-intensity spots and accounting for low-level stromal contamination, the number of more abundant, lumenal proteins was estimated to be between 30 and 60. Two of these proteins have been identified: a novel plastocyanin that also was the predominant component of the total plastocyanin pool, and a putative ascorbate peroxidase. Import studies shamed that these proteins are routed to the thylakoid lumen by the Sec- and delta pH-dependent translocation pathways, respectively, In addition, novel isoforms of PsbO and PsbQ were identified.
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| 6. |
- Kieselbach, Thomas, et al.
(författare)
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The proteome of the chloroplast lumen of higher plants
- 2003
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Ingår i: Photosynthesis Research. - 1573-5079. ; 78:3, s. 249-64
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Tidskriftsartikel (refereegranskat)abstract
- Recent research in proteomics of the higher plant chloroplast has achieved considerable progress and added to our knowledge of lumenal chloroplast proteins. This work shows that chloroplast lumen has its own specific proteome and may comprise as many as 80 proteins. Although the new map of the lumenal proteome provides a great deal of information, it also raises numerous questions because the physiological functions of most of the novel lumenal proteins are unknown. In this Minireview, we summarize the latest discoveries regarding lumenal proteins and present the currently known facts about the lumenal chloroplast proteome of higher plants.
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| 7. |
- Schröder, Wolfgang, et al.
(författare)
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Update on chloroplast proteomics
- 2003
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Ingår i: Photosynthesis Research. - 0166-8595 .- 1573-5079. ; 78:3, s. 181-93
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Tidskriftsartikel (refereegranskat)abstract
- Currently, relatively few proteomics studies of chloroplast have been published, but the field has just started emerging and is likely to develop more rapidly in the future. While the complex membrane structure of the chloroplast makes it difficult to study its entire proteome by global approaches, proteomics has considerably increased our knowledge of the proteins of single compartments such as, for instance, the envelope and the thylakoid lumen. Proteomics has also succeeded in the subunit characterisation of select protein complexes such as the ribosomes and the cytochrome b 6f complex. In addition, proteomics was successfully applied to find new potential target pathways for thioredoxin-mediated signal transduction. In this review, we present an overview of the latest developments in the field of chloroplast proteomics and discuss their impact on photosynthesis research. In addition, we summarise the current state of research in proteomics of the photosynthetic cyanobactrium Synechocystis sp. PCC 6803.
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| 8. |
- Schubert, Maria, et al.
(författare)
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Proteome Map of the Chloroplast Lumen of Arabidopsis thaliana
- 2002
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Ingår i: Journal of Biological Chemistry. - : American Society for Biochemistry and Molecular Biology. - 0021-9258 .- 1083-351X. ; 277:10, s. 8354-8365
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Tidskriftsartikel (refereegranskat)abstract
- The thylakoid membrane of the chloroplast is the center of oxygenic photosynthesis. To better understand the function of the luminal compartment within the thylakoid network, we have carried out a systematic characterization of the luminal thylakoid proteins from the model organism Arabidopsis thaliana. Our data show that the thylakoid lumen has its own specific proteome, of which 36 proteins were identified. Besides a large group of peptidyl-prolyl cis-trans isomerases and proteases, a family of novel PsbP domain proteins was found. An analysis of the luminal signal peptides showed that 19 of 36 luminal precursors were marked by a twin-arginine motif for import via the Tat pathway. To compare the model organism Arabidopsis with another typical higher plant, we investigated the proteome from the thylakoid lumen of spinach and found that the luminal proteins from both plants corresponded well. As a complement to our experimental investigation, we made a theoretical prediction of the luminal proteins from the whole Arabidopsis genome and estimated that the thylakoid lumen of the chloroplast contains ~80 proteins.
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| 9. |
- Shi, L X, et al.
(författare)
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The low molecular mass PsbW protein is involved in the stabilization of the dimeric photosystem II complex in Arabidopsis thaliana
- 2000
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 275:48, s. 37945-37950
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Tidskriftsartikel (refereegranskat)abstract
- Arabidopsis thaliana plants have been transformed with an antisense gene to the psbW of photosystem II (PSII). Eight transgenic lines containing low levels of psbW mRNA have been obtained. Transgenic seedlings with low contents of PsbW protein (more than 96% reduced) were selected by Western blotting and used for photosynthetic functional studies. There were no distinct differences in phenotype between the antisense and wild type plants during vegetative period under normal growth light intensities. However, a sucrose gradient separation of briefly solubilized thylakoid membranes revealed that no dimeric PSII supracomplex could be detected in the transgenic plants lacking the PsbW protein. Furthermore, analysis of isolated thylakoids demonstrated that the oxygen-evolving rate in antisense plants decreased by 50% compared with the wild type, This was found to be due to up to 40% of D1 and D2 reaction center proteins of PSII disappearing in the transgenic plants. The absence of the PsbW protein also altered the contents of other PSII proteins to differing extents. These results show that in the absence of the PsbW protein, the stability of the dimeric PSII is diminished and consequently the total number of PSII complexes is greatly reduced. Thus the nuclear encoded PsbW protein may play a crucial role in the biogenesis and regulation of the photosynthetic apparatus.
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| 10. |
- Shi, Lan-Xin, et al.
(författare)
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The low molecular mass subunits of the photosynthetic supracomplex, photosystem II
- 2004
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Ingår i: Biochimica et Biophysica Acta - Bioenergetics. - : Elsevier BV. - 0005-2728 .- 1879-2650. ; 1608:2-3, s. 75-96
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Tidskriftsartikel (refereegranskat)abstract
- The photosystem II (PSII) complex is located in the thylakoid membrane of higher plants, algae and cyanobacteria and drives the water oxidation process of photosynthesis, which splits water into reducing equivalents and molecular oxygen by solar energy. Electron and X-ray crystallography analyses have revealed that the PSII core complex contains between 34 and 36 transmembrane α-helices, depending on the organism. Of these helices at least 12-14 are attributed to low molecular mass proteins. However, to date, at least 18 low molecular mass (<10 kDa) subunits are putatively associated with the PSII complex. Most of them contain a single transmembrane span and their protein sequences are conserved among photosynthetic organisms. In addition, these proteins do not have any similarity to any known functional proteins in any type of organism, and only two of them bind a cofactor. These findings raise intriguing questions about why there are so many small protein subunits with single-transmembrane spans in the PSII complex, and their possible functions. This article reviews our current knowledge of this group of proteins. Deletion mutations of the low molecular mass subunits from both prokaryotic and eukaryotic model systems are compared in an attempt to understand the function of these proteins. From these comparisons it seems that the majority of them are involved in stabilization, assembly or dimerization of the PSII complex. The small proteins may facilitate fast dynamic conformational changes that the PSII complex needs to perform an optimal photosynthetic activity.
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