Cloning of a pea cDNA encoding a polypeptide of the light-harvesting complex associated with photosystem I using a monoclonal antibody

The outer antenna of higher-plant PSI (Photosystem I) is composed of four complexes [Lhc (light-harvesting complex) a1–Lhca4] belonging to the light-harvesting protein family. Difficulties in their purification have so far prevented the determination of their properties and most of the knowledge about Lhcas has been obtained from the study of the in vitro reconstituted antennas. In the present study we were able to purify the native complexes, showing that Lhca2/3 and Lhca1/4 form two functional heterodimers. Both dimers show red-fluorescence emission with maxima around 730 nm, as in the intact PSI complex. This indicates that the dimers are in their native state and that LHCI-680, which was previously assumed to be part of the PSI antenna, does not represent the native state of the system. The data show that the light-harvesting properties of the two dimers are functionally identical, concerning absorption, long-wavelength emission and fluorescence quantum yield, whereas they differ in their high-light response. Implications of the present study for the understanding of the energy transfer process in PSI are discussed. Finally, the comparison of the properties of the native dimers with those of the reconstituted complexes demonstrates that all of the major properties of the Lhcas are reproduced in the in vitro systems.

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

The Journal of Cell Biology ◽

10.1083/jcb.73.2.400 ◽

1977 ◽

Vol 73 (2) ◽

pp. 400-418 ◽

Cited By ~ 138

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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Isolation and characterization of a large photosystem I–light‐harvesting complex II supercomplex with an additional Lhca1–a4 dimer in Arabidopsis

The Plant Journal ◽

10.1111/tpj.14634 ◽

2020 ◽

Vol 102 (2) ◽

pp. 398-409 ◽

Cited By ~ 2

Author(s):

Aurélie Crepin ◽

Zuzana Kučerová ◽

Artemis Kosta ◽

Eric Durand ◽

Stefano Caffarri

Keyword(s):

Photosystem I ◽

Light Harvesting ◽

Light Harvesting Complex ◽

Complex Ii ◽

Isolation And Characterization ◽

Light Harvesting Complex Ii

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Isolation and characterization of three membranebound chlorophyll-protein complexes from four dinoflagellate species

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.1993.0080 ◽

1993 ◽

Vol 340 (1294) ◽

pp. 381-392 ◽

Cited By ~ 31

Keyword(s):

Energy Transfer ◽

Photosystem I ◽

Light Harvesting ◽

Protein Complexes ◽

Gradient Centrifugation ◽

Water Soluble ◽

Molar Ratio ◽

Light Harvesting Complexes ◽

Light Harvesting Complex ◽

Isolation And Characterization

Employing discontinuous sucrose density gradient centrifugation of n -dodecyl β-d-maltoside-solubilized thylakoid membranes, three chlorophyll (Chl)-protein complexes containing Chl a , Chl c 2 and peridinin in different proportions, were isolated from the dinoflagellates Symbiodinium microadriaticum, S. kawagutii, S. pilosum and Heterocapsa pygmaea . In S. microadriaticum , the first complex, containing 13% of the total cellular Chl a , and minor quantities of Chl c 2 and peridinin, is associated with polypeptides with apparent molecular mass ( M r ) of 8-9 kDa, and demonstrated inefficient energy transfer from the accessory pigments to Chl a . The second complex contains Chl a , Chl c 2 and peridinin in a molar ratio of 1:1:2, associated with two apoproteins of M r 19-20 kDa, and comprises 45%, 75% and 70%, respectively, of the cellular Chl a , Chl c 2 and peridinin. The efficient energy transfer from Chl c 2 and peridinin to Chl a in this complex is supportive of a light-harvesting function. This Chl a - c 2 - peridin-protein complex represents the major light-harvesting complex in dinoflagellates. The third complex obtained contains 12% of the cellular Chl a , and appears to be the core of photosystem I, associated with a light-harvesting complex. This complex is spectroscopically similar to analogous preparations from different taxonomic groups, but demonstrates a unique apoprotein composition. Antibodies against the water-soluble peridinin-Chl a -protein (sPCP) light-harvesting complexes failed to cross-react with any of the thylakoid-associated complexes, as did antibodies against Chl a - c -fucoxanthin apoprotein (from diatoms). Antibodies against the P 700 apoprotein of plants did not cross-react with the photosystem I complex. Similar results were observed in the other dinoflagellates.

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