A5052403328- Photosynthetic Processes and Mechanisms
- Mitochondrial Function and Pathology
- ATP Synthase and ATPases Research
- Plant biochemistry and biosynthesis
- Genomics and Phylogenetic Studies
- Algal biology and biofuel production
- Antioxidant Activity and Oxidative Stress
- Enzyme Structure and Function
- Postharvest Quality and Shelf Life Management
- Plant Gene Expression Analysis
- Legume Nitrogen Fixing Symbiosis
- Plant Stress Responses and Tolerance
- Photoreceptor and optogenetics research
- Microbial Community Ecology and Physiology
- Light effects on plants
- Mass Spectrometry Techniques and Applications
- Plant Micronutrient Interactions and Effects
- Plant Reproductive Biology
- Ubiquitin and proteasome pathways
- Biochemical and biochemical processes
- Plant Molecular Biology Research
- Plant and animal studies
- Metal-Catalyzed Oxygenation Mechanisms
- Enzyme Catalysis and Immobilization
- Plant Physiology and Cultivation Studies
Hebrew University of Jerusalem
2011-2025
Institut des Sciences du Végétal
2011
Biologie du Chloroplaste et Perception de la Lumière chez les Microalgues
2011
Sorbonne Université
2011
Centre National de la Recherche Scientifique
2011
Institut de Biologie Physico-Chimique
2011
Centre de Génétique Moléculaire
2011
Hebrew College
2007
Weizmann Institute of Science
2004
Christ University
1996
The photosystem II reaction center D1 protein is known to turn over frequently. This prone irreversible damage caused by reactive oxygen species that are formed in the light; damaged, nonfunctional degraded and replaced a new copy. However, proteases responsible for degradation remain unknown. In this study, we investigate possible role of FtsH protease, an ATP-dependent zinc metalloprotease, during process. primary light-induced cleavage product protein, 23-kD fragment, was found be...
Abstract For centuries, rose has been the most important crop in floriculture industry; its economic importance also lies use of petals as a source natural fragrances. Here, we used genomics approaches to identify novel scent-related genes, using flowers from tetraploid scented and nonscented cultivars. An annotated petal EST database ∼2100 unique genes both cultivars was created, DNA chips were prepared for expression analyses selected clones. Detailed chemical analysis volatile composition...
Arabidopsis YELLOW VARIEGATED1 (VAR1) and VAR2 are separate loci that encode similar chloroplast FtsH proteases. To date, is the best-characterized protease in thylakoid membranes involved turnover of photosynthetic protein complexes. It comprises a family encoded by 12 different nuclear genes Arabidopsis. We show here nine proteins located chloroplasts. Mutations either VAR1 or cause typical leaf variegation sensitivity to photoinhibition. By contrast, none these phenotypes was observed...
Abstract The aroma of roses (Rosa hybrida) is due to more than 400 volatile compounds including terpenes, esters, and phenolic derivatives. 2-Phenylethyl acetate, cis-3-hexenyl geranyl citronellyl acetate were identified as the main esters emitted by flowers scented rose var. “Fragrant Cloud.” Cell-free extracts petals acetylated several alcohols, utilizing acetyl-coenzyme A, produce corresponding esters. Screening for genes similar known plant alcohol acetyltransferases in a expressed...
Abstract Deg1 is a Ser protease peripherally attached to the lumenal side of thylakoid membrane. Its physiological function unknown, but its localization makes it suitable candidate for participation in photoinhibition repair by degradation photosystem II reaction center protein D1. We transformed Arabidopsis thaliana with an RNA interference construct and obtained plants reduced levels Deg1. These were smaller than wild-type plants, flowered earlier, more sensitive photoinhibition,...
Abstract The identity and scope of chloroplast mitochondrial proteases in higher plants has only started to become apparent recent years. Biochemical molecular studies suggested the existence Clp, FtsH, DegP chloroplasts, a Lon protease mitochondria, although currently full extent their role organellar biogenesis function remains poorly understood. Rapidly accumulating DNA sequence data, especially from Arabidopsis, revealed that these proteolytic enzymes are found plant cells multiple...
In an attempt to identify and characterize chloroplast proteases, we performed immunological analysis of chloroplasts using antibody against Escherichia coli FtsH protease, which is ATP-dependent metalloprotease bound the cytoplasmic membrane. A cross-reacting protein 78 kDa was found in thylakoid membrane spinach, but not soluble stromal fraction. Alkali high salt washes, as well trypsin treatment membranes, suggest that chloroplastic integral membrane, with its hydrophilic portion exposed...
FtsH protease is important in chloroplast biogenesis and thylakoid maintenance. Although bacteria contain only one essential FTSH gene, multiple genes exist cyanobacteria higher plants. However, the functional significance of multiplication plants unclear. We hypothesized that some may be redundant. To test this hypothesis, we generated double mutant combinations among different Arabidopsis thaliana. A ftsh1 ftsh8 showed no obvious phenotypic alterations, disruption either FTSH1 or FTSH5...
The earliest visual changes of leaf senescence occur in the chloroplast as chlorophyll is degraded and photosynthesis declines. Yet, a comprehensive understanding sequence catabolic events occurring chloroplasts during natural still missing. Here, we combined confocal electron microscopy together with proteomics biochemistry to follow structural molecular Arabidopsis senescence. We observed that initiation catabolism precedes other breakdown processes. Chloroplast size, stacking thylakoids,...
Abstract Rose (Rosa hybrida) flowers produce and emit a diverse array of volatiles, characteristic to their unique scent. One the most prominent compounds in floral volatiles many rose varieties is methoxylated phenolic derivative 3,5-dimethoxytoluene (orcinol dimethyl ether). Cell-free extracts derived from developing petals displayedO-methyltransferase (OMT) activities toward several substrates, including 3,5-dihydroxytoluene (orcinol), 3-methoxy,5-hydroxytoluene monomethyl ether),...
The proteases involved in proteolytic degradation the thylakoid lumen are largely unknown. Western analysis with an antibody against Escherichia coli periplasmic serine protease DegP suggested that pea chloroplasts contain a homologue of this protease. This was peripherally bound to luminal side membrane and could only be removed by combination high salt non-ionic detergent. Its level increased almost 2-fold seedlings exposed elevated temperature for 4 h, suggesting protease's role...
Abstract The proteolytic machinery of chloroplasts and mitochondria in Arabidopsis consists primarily three families ATP-dependent proteases, Clp, Lon, FtsH, one family ATP-independent DegP. However, the functional significance multiplicity their genes is not clear. To test whether expression specific isomers could be differently affected by growth conditions, we analyzed transcript abundance following short-term exposure to different environmental stimuli, using 70-mer oligonucleotide...
DegP proteases have been shown to possess both chaperone and protease activities. The proteolytic activities of chloroplast DegP-like well documented. However, whether Deg also has remained unknown. Here we show that Deg1 activities, like its Escherichia coli ortholog DegP. Transgenic plants with reduced levels accumulated normal different subunits the major photosynthetic protein complexes, but their photosystem-II (PSII) dimers supercomplexes were reduced. In vivo pulse-chase labeling...
Chloroplasts of higher plants develop from proplastids, which are undifferentiated plastids that lack photosynthetic (thylakoid) membranes. In flowering plants, the proplastid-chloroplast transition takes place at shoot apex, consists apical meristem (SAM) and flanking leaf primordia. It has been believed SAM contains only proplastids these become chloroplasts in primordial leaves. Here, we show neither homogeneous nor necessarily null. Rather, their developmental state varies with specific...
Most plants have the ability to respond fluctuations in light minimize damage photosynthetic apparatus. A proteolytic activity has been discovered that is involved degradation of major light-harvesting chlorophyll a/b-binding protein photosystem II (LHCII) when antenna size reduced upon acclimation from low high intensities. This ATP-dependent serine or cysteine type and associated with outer membrane surface stroma-exposed thylakoid regions. The identity protease not known, but it does...
The ATP-dependent Clp protease is one of the newly identified proteolytic systems in plant organelles that incorporate activity molecular chaperones to target specific polypeptide substrates and avoid inadvertent degradation others. We describe new nuclear-encoded ClpC (ClpC1) ClpP (ClpP3-5) isomers Arabidopsis thaliana raise total number proteins 19. extra are localized within stroma chloroplasts along with ClpD, -P1 -P6 proteins. Potential differential regulation among these was analysed...
Summary The Arabidopsis E3 ligase AtCHIP was found to interact with FtsH1, a subunit of the chloroplast FtsH protease complex. FtsH1 can be ubiquitylated by in vitro , and steady‐state level is reduced ‐over‐expressing plants under high‐intensity light conditions, suggesting that ubiquitylation might lead degradation vivo . Furthermore, another complex, FtsH2, also FtsH2 interacts physically possibility substrate protein for plant cells. A photosystem II reaction center D1, not efficiently...
Abstract During desiccation, homoiochlorophyllous resurrection plants retain most of their photosynthetic apparatus, allowing them to resume activity quickly upon water availability. These rely on various mechanisms prevent the formation reactive oxygen species and/or protect tissues from damage they inflict. In this work, we addressed issue how deal with problem excessive excitation/electron pressures during dehydration using Craterostigma pumilum as a model plant. To investigate...