scholarly journals The Binding of Xanthophylls to the Bulk Light-harvesting Complex of Photosystem II of Higher Plants

2002 ◽  
Vol 277 (28) ◽  
pp. 25160-25169 ◽  
Author(s):  
Denise Phillip ◽  
Stephan Hobe ◽  
Harald Paulsen ◽  
Peter Molnar ◽  
Hideki Hashimoto ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Light Harvesting ◽  
Higher Plants ◽  
Light Harvesting Complex

scholarly journals Exciton equilibration in the light-harvesting complex of Photosystem II of higher plants

1995 ◽  
Vol 1231 (2) ◽  
pp. 147-156 ◽  
Author(s):  
Gerhard Kehrberg ◽  
Joachim Voigt ◽  
Thorsten Schrötter ◽  
Gernot Renger
Keyword(s):  
Photosystem Ii ◽  
Light Harvesting ◽  
Higher Plants ◽  
Light Harvesting Complex

scholarly journals Multiscale QM/MM Molecular Dynamics Simulations of the Trimeric Major Light-Harvesting Complex II

2021 ◽  
Author(s):  
Sayan Maity ◽  
Vangelis Daskalakis ◽  
Marcus Elstner ◽  
Ulrich Kleinekathöfer
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Chlorophyll A ◽  
Density Functional ◽  
Light Harvesting ◽  
Higher Plants ◽  
Tight Binding ◽  
Spectral Densities ◽  
Light Harvesting Complex ◽  
Dynamics Simulations

Photosynthetic processes are driven by sunlight. Too little of it and the photosynthetic machinery cannot produce the reductive power to drive the anabolic pathways. Too much sunlight and the machinery can get damaged. In higher plants, the major Light Harvesting Complex (LHCII) efficiently absorbs the light energy, but can also dissipate it when in excess (quenching). In order to study the dynamics related to the quenching process but also the exciton dynamics in general, one needs to accurately determine the so-called spectral density which describes the coupling between the relevant pigment modes and the environmental degrees of freedom. To this end, Born–Oppenheimer molecular dynamics simulations in a quantum mechanics/molecular mechanics (QM/MM) fashion utilizing the density functional based tight binding (DFTB) method have been performed for the ground state dynamics. Subsequently, the time-dependent extension of the long-range-corrected DFTB scheme has been employed for the excited state calculations of the individual chlorophyll-a molecules in the LHCII complex. The analysis of this data resulted in spectral densities showing an astonishing agreement with the experimental counterpart in this rather large system. This consistency with an experimental observable also supports the accuracy, robustness, and reliability of the present multi-scale scheme. In addition, the resulting spectral densities and site energies were used to determine the exciton transfer rate within a special pigment pair consisting of a chlorophyll-a and a carotenoid molecule which is assumed to play a role in the balance between the light harvesting and quenching modes.

Photosensitization of triplet carotenoid in photosynthetic light-harvesting complex of photosystem II

1988 ◽  
Vol 92 (5) ◽  
pp. 1165-1168 ◽  
Author(s):  
R. Nechushtai ◽  
J. P. Thornber ◽  
L. K. Patterson ◽  
R. W. Fessenden ◽  
H. Levanon
Keyword(s):  
Photosystem Ii ◽  
Light Harvesting ◽  
Light Harvesting Complex

scholarly journals Spatial relationship of photosystem I, photosystem II, and the light-harvesting complex in chloroplast membranes.

1977 ◽  
Vol 73 (2) ◽  
pp. 400-418 ◽  
Author(s):  
P A Armond ◽  
L A Staehelin ◽  
C J Arntzen
Keyword(s):  
Particle Size ◽  
Photosystem Ii ◽  
Photosystem I ◽  
Light Harvesting ◽  
Particle Density ◽  
Unit Size ◽  
Fracture Face ◽  
Photosynthetic Unit ◽  
Light Harvesting Complex ◽  
Chloroplast Membrane

We have previously demonstrated (Armond, P. A., C. J. Arntzen, J.-M. Briantais, and C. Vernotte. 1976. Arch. Biochem. Biophys. 175:54-63; and Davis, D. J., P. A. Armond, E. L. Gross, and C. J. Arntzen. 1976. Arch. Biochem. Biophys. 175:64-70) that pea seedlings which were exposed to intermittent illumination contained incompletely developed chloroplasts. These plastids were photosynthetically competent, but did not contain grana. We now demonstrate that the incompletely developed plastids have a smaller photosynthetic unit size; this is primarily due to the absence of a major light-harvesting pigment-protein complex which is present in the mature membranes. Upon exposure of intermittent-light seedlings to continuous white light for periods up to 48 h, a ligh-harvesting chlorophyll-protein complex was inserted into the chloroplast membrane with a concomitant appearance of grana stacks and an increase in photosynthetic unit size. Plastid membranes from plants grown under intermediate light were examined by freeze-fracture electron microscopy. The membrane particles on both the outer (PF) and inner (EF) leaflets of the thylakoid membrane were found to be randomly distributed. The particle density of the PF fracture face was approx. four times that of the EF fracture face. While only small changes in particle density were observed during the greening process under continuous light, major changes in particle size were noted, particularly in the EF particles of stacked regions (EFs) of the chloroplast membrane. Both the changes in particle size and an observed aggregation of the EF particles into the newly stacked regions of the membrane were correlated with the insertion of light-harvesting pigment-protein into the membrane. Evidence is presented for identification of the EF particles as the morphological equivalent of a "complete" photosystem II complex, consisting of a phosochemically active "core" complex surrounded by discrete aggregates of the light-harvesting pigment protein. A model demonstrating the spatial relationships of photosystem I, photosystem II, and the light-harvesting complex in the chloroplast membrane is presented.

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