The Experts below are selected from a list of 255 Experts worldwide ranked by ideXlab platform
Christiane Funk - One of the best experts on this subject based on the ideXlab platform.
-
Deletion of the gene family of small Chlorophyll-Binding Proteins (ScpABCDE) offsets C/N homeostasis in Synechocystis PCC 6803.
Biochimica et Biophysica Acta (BBA) - Bioenergetics, 2016Co-Authors: Tania Tibiletti, Miguel A. Hernández-prieto, Hans C. P. Matthijs, Krishna K. Niyogi, Christiane FunkAbstract:In the family of Chlorophyll Binding Proteins, single helix small CAB-like Proteins (SCPs) are found in all organisms performing oxygenic photosynthesis. Here, we investigated the function of these ...
-
The search for new Chlorophyll-Binding Proteins in the cyanobacterium Synechocystis sp. PCC 6803.
Journal of Biotechnology, 2012Co-Authors: Otilia Cheregi, Willem Vermaas, Christiane FunkAbstract:Light harvesting provides a major challenge in the production of biofuels from microorganisms; while sunlight provides the energy necessary for biomass/biofuel production, at the same time it damages the cells. The genome of Synechocystis sp. PCC 6803 was searched for open reading frames that might code for yet unidentified Chlorophyll-Binding Proteins with low molecular mass that could be involved in stress-adaptation. Amongst 9167 hypothetical ORFs corresponding to potential polypeptides of 100 amino acids or less, two were identified that had the potential to be pigment-Binding, because they (i) encoded a potential transmembrane region, (ii) showed sequence similarity with known Chlorophyll-Binding domains, (iii) were conserved in other cyanobacterial species, and (iv) their codon adaptation index indicated significant translation probability. The two ORFs were located complementary (antisense) and internal to the ferrochelatase (hemH) and the pyruvate dehydrogenase (pdh) genes and therefore were named a-fch and a-pdh, respectively. Transcription of both genes was confirmed; however, no translated Proteins could be detected immunologically. Whereas mutations within a-pdh or a-fch did not lead to any obvious phenotype, it is clear that transcripts and Proteins over and above the currently known set may play a role in defining the physiology of cyanobacteria and other organisms.
-
Small Chlorophyll Binding Proteins overexpressed in the cyanobacterium Synechocystis sp. PCC 6803
2007Co-Authors: Galyna I. Kufryk, Willem Vermaas, Christiane FunkAbstract:Small Chlorophyll Binding Proteins overexpressed in the cyanobacterium Synechocystis sp. PCC 6803
-
hole burning study of cyanobacterial photosystem ii complexes differing in the content of small putative Chlorophyll Binding Proteins
Journal of Luminescence, 2004Co-Authors: Roman Dědic, Kamoltip Promnares, Jakub Psencik, Antonin Svoboda, M Kořinek, Martin Tichý, Josef Komenda, Christiane FunkAbstract:This contribution presents low-temperature absorption, both broad-band and site-selective excited fluorescence, and persistent hole burning spectra of Photosystem II complexes from the Photosystem ...
Lixin Zhang - One of the best experts on this subject based on the ideXlab platform.
-
LTD is a protein required for sorting light-harvesting Chlorophyll-Binding Proteins to the chloroplast SRP pathway
Nature Communications, 2011Co-Authors: Min Ouyang, Wei Chi, Jianwei Xiao, Meijuan Zou, Fan Chen, Lixin ZhangAbstract:Higher plants require chloroplasts for essential functions in photosynthesis and other important physiological processes, such as sugar, lipid and amino-acid biosynthesis. Most chloroplast Proteins are nuclear-encoded Proteins that are synthesized in the cytosol as precursors, and imported into chloroplasts by protein translocases in the outer and inner chloroplast envelope. The imported chloroplast Proteins are then translocated into or across the thylakoid membrane by four distinct pathways. However, the mechanisms by which the imported nuclear-encoded Proteins are delivered to these pathways remain largely unknown. Here we show that an Arabidopsis ankyrin protein, LTD (mutation of which causes the light-harvesting Chlorophyll-Binding protein translocation defect), is localized in the chloroplast and using yeast two-hybrid screens demonstrate that LTD interacts with both Proteins from the signal recognition particle (SRP) pathway and the inner chloroplast envelope. Our study shows that LTD is essential for the import of light-harvesting Chlorophyll-Binding Proteins and subsequent routing of these Proteins to the chloroplast SRP-dependent pathway.
-
ltd is a protein required for sorting light harvesting Chlorophyll Binding Proteins to the chloroplast srp pathway
Nature Communications, 2011Co-Authors: Min Ouyang, Jianwei Xiao, Fan Chen, Xiaoyi Li, Congming Lu, Lixin ZhangAbstract:Chloroplast Proteins are synthesized in the cytosol and imported into the chloroplast before being delivered to the thylakoids. The authors report that an ankyrin-repeat protein, LTD, is essential for the routing of Chlorophyll-Binding Proteins to the signal recognition particle pathway.
Juan Jose Guiamet - One of the best experts on this subject based on the ideXlab platform.
-
effects of the stay green genotype ggd1d1d2d2 on leaf gas exchange dry matter accumulation and seed yield in soybean glycine max l merr
Annals of Botany, 2001Co-Authors: Virginia Martha Cristina Luquez, Juan Jose GuiametAbstract:Abstract The homozygous combination of the recessive mutations d1 and d2, i.e.d1d1d2d2 , causes retention of Chlorophyll, Chlorophyll-Binding Proteins and Rubisco in senescing leaves of soybean (Glycine max L. Merr.). Together with G(a gene that preserves only Chlorophyll in the mature seed coat), d1d1d2d2 prolonged photosynthetic activity and increased seed yield in growth chamber experiments. The objective of this work was to test the effects of GGd1d1d2d2(abbreviated to Gd1d2) on leaf gas exchange, growth and seed yield in soybean plants cultured outdoors during the normal growing season. Despite preservation of the photosynthetic machinery in Gd1d2, photosynthesis during the seed filling period was similar in Gd1d2 and its near-isogenic wild type line ‘Clark’. The main factor limiting photosynthesis in the mutant appeared to be stomatal conductance, which was substantially lower in Gd1d2 than in ‘Clark’. In Gd1d2 the rate of dry matter accumulation during the seed filling period was similar or lower than in the wild type. At maturity, Gd1d2 had fewer nodes, fruiting nodes, fruits and seeds per plant, and therefore its seed yield was reduced by 10–20% compared to ‘Clark’. Thus, pleiotropic effects of G, d1 and/or d2 affecting stomatal conductance and seed number appear to be major limitations to the yield potential of Gd1d2. These pleiotropic effects suggest thatG , d1 and/or d2 have regulatory functions in addition to the control of chloroplast disassembly during senescence.
Min Ouyang - One of the best experts on this subject based on the ideXlab platform.
-
LTD is a protein required for sorting light-harvesting Chlorophyll-Binding Proteins to the chloroplast SRP pathway
Nature Communications, 2011Co-Authors: Min Ouyang, Wei Chi, Jianwei Xiao, Meijuan Zou, Fan Chen, Lixin ZhangAbstract:Higher plants require chloroplasts for essential functions in photosynthesis and other important physiological processes, such as sugar, lipid and amino-acid biosynthesis. Most chloroplast Proteins are nuclear-encoded Proteins that are synthesized in the cytosol as precursors, and imported into chloroplasts by protein translocases in the outer and inner chloroplast envelope. The imported chloroplast Proteins are then translocated into or across the thylakoid membrane by four distinct pathways. However, the mechanisms by which the imported nuclear-encoded Proteins are delivered to these pathways remain largely unknown. Here we show that an Arabidopsis ankyrin protein, LTD (mutation of which causes the light-harvesting Chlorophyll-Binding protein translocation defect), is localized in the chloroplast and using yeast two-hybrid screens demonstrate that LTD interacts with both Proteins from the signal recognition particle (SRP) pathway and the inner chloroplast envelope. Our study shows that LTD is essential for the import of light-harvesting Chlorophyll-Binding Proteins and subsequent routing of these Proteins to the chloroplast SRP-dependent pathway.
-
ltd is a protein required for sorting light harvesting Chlorophyll Binding Proteins to the chloroplast srp pathway
Nature Communications, 2011Co-Authors: Min Ouyang, Jianwei Xiao, Fan Chen, Xiaoyi Li, Congming Lu, Lixin ZhangAbstract:Chloroplast Proteins are synthesized in the cytosol and imported into the chloroplast before being delivered to the thylakoids. The authors report that an ankyrin-repeat protein, LTD, is essential for the routing of Chlorophyll-Binding Proteins to the signal recognition particle pathway.
Adam M Gilmore - One of the best experts on this subject based on the ideXlab platform.
-
xanthophyll cycle dependent nonphotochemical quenching in photosystem ii mechanistic insights gained from arabidopsis thaliana l mutants that lack violaxanthin deepoxidase activity and or lutein
Photosynthesis Research, 2001Co-Authors: Adam M GilmoreAbstract:This study compares Photosystem II (PS II) Chlorophyll (Chl) a fluorescence yield changes of Arabidopsis thaliana L. nuclear gene mutants, thoughtfully provided by the authors of Pogson et al. (1998 Proc Natl Acad Sci USA 95: 13324–13329). One single mutant (npq1) inhibits the violaxanthin deepoxidase that converts violaxanthin to antheraxanthin and zeaxanthin. A second single mutant (lut2) inhibits the ∈-cyclization enzyme step between lycopene and β,∈-carotene causing accumulation of β,β-carotene derivatives, primarily the violaxanthin cycle pigments, at the expense of lutein. The double mutant (lut2-npq1) incorporates both lesions. PS II Chl a fluorescence was characterized in leaves and thylakoids using both steady state and time-resolved methods, the intrathylakoid pH was estimated by 9-aminoacridine fluorescence quenching and chloroplast pigments were determined by HPLC. Under maximal PS II Chl a fluorescence intensity conditions without intrathylakoid acidification, the main 2 nanosecond (ns) fluorescence lifetime distribution mode parameters were similar for the WT and mutants both before and after illumination. The light and ATPase mediated intrathylakoid pH levels were also similar and caused similar changes in the fluorescence lifetime distribution widths and centers for the WT and each mutant. The npq1 exhibited low antheraxanthin and zeaxanthin and high violaxanthin levels and the uncoupler-sensitive amplitudes of short (< 1 ns) PS II Chl a fluorescence distribution modes were strongly inhibited compared to the WT. Lutein deficiency coincided with pleiotropic effects on PS II energy dissipation and probably altered conformations of PS II carotenoid-Chlorophyll Binding Proteins. The lut2 exhibited separate active and inactive pools of antheraxanthin and zeaxanthin with respect to all deepoxidation, epoxidation and fluorescence quenching activities. The active xanthophyll cycle pool in lut2 exhibited a lower (≈35% of WT) concentration efficiency, for a given intrathylakoid pH, to increase the sub-nanosecond distribution amplitudes, which predicts and explains inhibited induction kinetics and fluorescence quenching. The lut2-npq1 mutant exhibited a constant pool of antheraxanthin and zeaxanthin, no deepoxidation and little or no pH-reversible fluorescence decrease. It is concluded that in addition to intrathylakoid acidification, a certain level of zeaxanthin and antheraxanthin (or lutein) is absolutely required for the major reversible component of PS II Chl a fluorescence quenching.
-
mechanistic aspects of xanthophyll cycle dependent photoprotection in higher plant chloroplasts and leaves
Physiologia Plantarum, 1997Co-Authors: Adam M GilmoreAbstract:Higher plants must dissipate absorbed light energy that exceeds the photosynthetic capacity to avoid molecular damage to the pigments and Proteins that comprise the photosynthetic apparatus. Described in this minireview is a current view of the biochemical, biophysical and bioenergetic aspects of the primary photoprotective mechanism responsible for dissipating excess excitation energy as heat from photosystem II (PSII). The photoprotective heat dissipation is measured as nonphotochemical quenching (NPQ) of the PSII Chlorophyll a (Chl a) fluorescence. The NPQ mechanism is controlled by the trans-thylakoid membrane pH gradient (ΔpH) and the special xanthophyll cycle pigments. In the NPQ mechanism, the de-epoxidized endgroup moieties and the trans-thylakoid membrane orientations of antheraxanthin (A) and zeaxanthin (Z) strongly affect their interactions with protonated Chlorophyll Binding Proteins (CPs) of the PSII inner antenna. The CP protonation sites and steps are influenced by proton domains sequestered within the proteo-lipid core of the thylakoid membrane. Xanthophyll cycle enrichment around the CPs may explain why changes in the peripheral PSII antenna size do not necessarily affect either the concentration of the xanthophyll cycle pigments on a per PSII unit basis or the NPQ mechanism. Recent time-resolved PSII Chi a fluorescence studies suggest the NPQ mechanism switches PSII units to an increased rate constant of heat dissipation in a series of steps that include xanthophyll de-epoxidation, CP-protonation and Binding of the xanthophylls to the protonated CPs; the concerted process can be described with a simple two-step, pH-activation model. The xanthophyll cycle-dependent NPQ mechanism is profoundly influenced by temperatures suboptimal for photosynthesis via their effects on the trans-thylakoid membrane energy coupling system. Further, low temperature effects can be grouped into either short term (minutes to hours) or long term (days to seasonal) series of changes in the content and composition of the PSII pigment-Proteins. This minireview concludes by briefly highlighting primary areas of future research interest regarding the NPQ mechanism.