Search results for "Chlorophyll"
showing 10 items of 453 documents
Methodical Studies in the Separation of Chlorophyll-Protein Complexes by Polyacrylamide Gel Electrophoresis
1980
Summary Chlorophyll-protein complexes from thylakoids of Sinapis alba plants were separated, using Tris-HCl and Tris-borate buffer in the sodium dodecyl sulphate acrylamide gel electrophoresis. In the electrophoretogram with Tris-borate buffer, 6 bands could be characterized in the gel pattern. In addition to the three major green zones (P-700-chlorophyll a-protein, light-harvesting chlorophyll a/b-protein, free pigment zone), which were also observed in experiments with the Tris-HC1 buffer, three further bands (LHCP 1 , LHCP 2 , CPa) were electrophoretically separated. An elongation of the electrophoretical period resulted especially in a decrease of the proportion of the light-harvesting …
The Effect of Different Light Intensities on the Frequency and Size of Stomata, the Size of Cells, the Number, Size and Chlorophyll Content of Chloro…
1980
Summary Plants of Sinapis alba were cultivated under high light (60 W m -2 PhAR) and low light (6 W m -2 PhAR) conditions. High light intensity during growth increased the stomatal frequency but there were only small changes in the length of the stomatal pore. High-light leaves had more than twice as many stomata per unit area as low-light leaves. The decrease of stomatal diffusive resistance in high-light leaves is primarily caused by the increase in stomatal density. There were striking changes in stomatal frequency during the ontogeny of primary leaves. High light caused a stronger development of the assimilating mesophyll. The volume of the palisade cells increased to a much higher exte…
Hubungan Aktivitas Nitrat Reduktase dan Kadar Klorofil Kultivar Kedelai Tahan Kekeringan
2018
<em>Plants suffering from drought stress can be indicated by the changing of character on the morphology, anatomy and physiology, characterized by inhibition of leaf growth, accelerated root growth, stomata closure and leaf curly. Cultivars that are tolerance to drought can physiologically adapted by increasing prolin level reduce the osmotic potential in order to maintain turgor in the condition of low tissue water potential. The research was aimed to study the physiological characters of drought tolerant soybean cultivar of determine the relationship of nitrate reductase activity and chlorophyll content of drought-tolerance cultivars and susceptible to drought stress conditions. The…
Synthesis and Functional Reconstitution of Light-Harvesting Complex II into Polymeric Membrane Architectures.
2015
One of most important processes in nature is the harvesting and dissipation of solar energy with the help of light-harvesting complex II (LHCII). This protein, along with its associated pigments, is the main solar-energy collector in higher plants. We aimed to generate stable, highly controllable, and sustainable polymer-based membrane systems containing LHCII-pigment complexes ready for light harvesting. LHCII was produced by cell-free protein synthesis based on wheat-germ extract, and the successful integration of LHCII and its pigments into different membrane architectures was monitored. The unidirectionality of LHCII insertion was investigated by protease digestion assays. Fluorescence …
Light-harvesting chlorophyll a/b-binding protein stably inserts into etioplast membranes supplemented with Zn-pheophytin a/b.
1997
Light-harvesting chlorophyll a/b-binding protein, LHCP, or its precursor, pLHCP, cannot be stably inserted into barley etioplast membranes in vitro. However, when these etioplast membranes are supplemented with the chlorophyll analogs Zn-pheophytin a/b, synthesized in situ from Zn-pheophorbide a/b and digeranyl pyrophosphate, pLHCP is inserted into a protease-resistant state. This proves that chlorophyll is the only component lacking in etioplast membranes that is necessary for stable LHCP insertion. Synthesis of Zn-pheophytin b alone promotes insertion of LHCP in vitro into a protease-resistant state, whereas synthesis of Zn-pheophytin a alone does not. Insertion of pLHCP into etioplast me…
Determination of relative chlorophyll binding affinities in the major light-harvesting chlorophyll a/b complex.
2002
The major light-harvesting complex (LHCIIb) of photosystem II can be reconstituted in vitro from its recombinant apoprotein in the presence of a mixture of carotenoids and chlorophylls a and b. By varying the chlorophyll a/b ratio in the reconstitution mixture, the relative amounts of chlorophyll a and chlorophyll b bound to LHCIIb can be changed. We have analyzed the chlorophyll stoichiometry in recombinant wild type and mutant LHCIIb reconstituted at different chlorophyll a/b ratios in order to assess relative affinities of the chlorophyll-binding sites. This approach reveals five sites that exclusively bind chlorophyll b. Another site exhibits a slight preference of chlorophyll b over ch…
Consecutive binding of chlorophylls a and b during the assembly in vitro of light-harvesting chlorophyll-a/b protein (LHCIIb).
2006
The apoprotein of the major light-harvesting chlorophyll a/b complex (LHCIIb) is post-translationally imported into the chloroplast, where membrane insertion, protein folding, and pigment binding take place. The sequence and molecular mechanism of the latter steps is largely unknown. The complex spontaneously self-organises in vitro to form structurally authentic LHCIIb upon reconstituting the unfolded recombinant protein with the pigments chlorophyll a, b, and carotenoids in detergent micelles. Former measurements of LHCIIb assembly had revealed two apparent kinetic phases, a faster one (tau1) in the range of 10 s to 1 min, and a slower one (tau2) in the range of several min. To unravel th…
Refinement of a structural model of a pigment-protein complex by accurate optical line shape theory and experiments.
2007
Time-local and time-nonlocal theories are used in combination with optical spectroscopy to characterize the water-soluble chlorophyll binding protein complex (WSCP) from cauliflower. The recombinant cauliflower WSCP complexes reconstituted with either chlorophyll b (Chl b) or Chl a/Chl b mixtures are characterized by absorption spectroscopy at 77 and 298 K and circular dichroism at 298 K. On the basis of the analysis of these spectra and spectra reported for recombinant WSCP reconstituted with Chl a only (Hughes, J. L.; Razeghifard, R.; Logue, M.; Oakley, A.; Wydrzynski, T.; Krausz, E. J. Am. Chem. Soc. U.S.A. 2006, 128, 3649), the "open-sandwich" model proposed for the structure of the pig…
Chlorophyll b is involved in long-wavelength spectral properties of light-harvesting complexes LHC I and LHC II.
2001
AbstractChlorophyll (Chl) molecules attached to plant light-harvesting complexes (LHC) differ in their spectral behavior. While most Chl a and Chl b molecules give rise to absorption bands between 645 nm and 670 nm, some special Chls absorb at wavelengths longer than 700 nm. Among the Chl a/b-antennae of higher plants these are found exclusively in LHC I. In order to assign this special spectral property to one chlorophyll species we reconstituted LHC of both photosystem I (Lhca4) and photosystem II (Lhcb1) with carotenoids and only Chl a or Chl b and analyzed the effect on pigment binding, absorption and fluorescence properties. In both LHCs the Chl-binding sites of the omitted Chl species…
Random mutations directed to transmembrane and loop domains of the light-harvesting chlorophyll a/b protein: impact on pigment binding.
1999
The major light-harvesting complex of photosystem II (LHCII) can be reconstituted in vitro by folding its bacterially expressed apoprotein, Lhcb, in detergent solution in the presence of chlorophylls and carotenoids. To compare the impact of alpha-helical transmembrane domains and hydrophilic loop domains of the apoprotein on complex formation and stability, we introduced random mutations into a segment of the protein comprising the stromal loop, the third (C-proximal) transmembrane helix, and part of the amphipathic helix in the C-terminal domain. The mutant versions of Lhcb were screened for the loss of their ability to form stable LHCII upon reconstitution in vitro. Most steps during the…