Light-harvesting Complexes of Plants and Algae: Introduction, Survey and Nomenclature

Simpson, David J. W.; Knoetzel, Jürgen

doi:10.1007/0-306-48127-8_27

Cited by 20 publications

(19 citation statements)

References 67 publications

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“…Our results are in agreement with recently proposed models of the topology for the different Chl a/Chl b/carotenoid-binding subunits within LHC II [14,54]. The techniques described here represent a powerful approach to study the topography within the PS II antenna system that will complement other physical and biochemical approaches.…”

Section: Discussionsupporting

confidence: 90%

Close vicinity of Lhc b1 and Lhc b4 in Photosystem II

Miao

Irrgang

Salnikow

et al. 1998

European Journal of Biochemistry

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The nearest neighbourhood of pigment-protein complexes within Photosystem II (PSII) membrane fragments has been studied by means of chemical cross-linking with o-phthalaldehyde (OPA) in conjunction with protein-chemical techniques. By means of OPA-induced cross-linking a major conjugate of about 60 kDa has been identified. This conjugate was shown to consist of two pigment-protein complexes of light-harvesting complex II (LHC II), Lhc b1 (CP27) and Lhc b4 (CP29) by means of SDS/PAGE in combination with an immunological analysis using mAbs directed against Lhc b4 and by matrix-assistedlaser-desorptionϪionization mass spectrometry (MALDI-MS) and sequence analysis of peptides derived from a proteolytic digest of the conjugate. Domains of Lhc b1 and Lhc b4 have been localized to a distance of not more than 5 Å within LHC II. Our results are discussed in the light of recent models on the topography of the two subunits within the antenna system of Photosystem II.

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Section: Discussionsupporting

confidence: 90%

Close vicinity of Lhc b1 and Lhc b4 in Photosystem II

Miao

Irrgang

Salnikow

et al. 1998

European Journal of Biochemistry

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“…To confirm these results, photochemical reactions in PS II in the absence of detergent were also measured, which will exclude the possibility of plausible artifact(s) in the above results derived from the presence of detergents. In green plants, PS II core complexes are associated with 6 -12 copies of light-harvesting Chl-binding proteins (LHCII) (42) and are located in the grana region of the thylakoid (43). PS II reaction centers are connected directly or via surrounding LHCII (44).…”

Section: Form Of Ps II Assessed By Photochemical Reaction-mentioning

confidence: 99%

Photosystem II Complex in Vivo Is a Monomer

Takahashi

Inoue-Kashino

Ozawa

et al. 2009

Journal of Biological Chemistry

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Photosystem II (PS II) complexes are membrane protein complexes that are composed of >20 distinct subunit proteins. Similar to many other membrane protein complexes, two PS II complexes are believed to form a homo-dimer whose molecular mass is ϳ650 kDa. Contrary to this well known concept, we propose that the functional form of PS II in vivo is a monomer, based on the following observations. Deprivation of lipids caused the conversion of PS II from a monomeric form to a dimeric form. Only a monomeric PS II was detected in solubilized cyanobacterial and red algal thylakoids using blue-native polyacrylamide gel electrophoresis. Furthermore, energy transfer between PS II units, which was observed in the purified dimeric PS II, was not detected in vivo. Our proposal will lead to a re-evaluation of many crystallographic models of membrane protein complexes in terms of their oligomerization status. Photosystem II (PS II)3 complexes convert solar energy to biological redox energy. Through this reaction process, water molecules are oxidized and molecular oxygen is released as a byproduct (reviewed in Ref. 1), which is the only source of molecular oxygen upon which all aerobic organisms on earth rely. PS II core complexes are membrane protein complexes that are composed of Ͼ20 distinct subunit proteins and many functional cofactors, including chlorophylls (Chls), carotenoids, plastoquinone, and metal ions (2-5). Similar to many other membrane protein complexes (6 -10), two PS II core complexes are believed to associate together to form a homodimer with a molecular mass of ϳ650 kDa, as shown by crystallographic models (2, 3, 5).The PS II complex turns over dynamically, although it is quite an integrated complex; our current understanding is that the PS II complex that is damaged by high light is disintegrated into a monomeric form and is further dissociated to replace a degraded D1 protein with a de novo synthesized D1 (reviewed in Refs. 11 and 12). After the replacement, the PS II complex is integrated into a functional form as a dimer. It is supposed that PS II subunit proteins such as PsbI (13) or PsbTc (14) participate in the formation of the PS II dimer.Crystallographic models of PS II have enabled the determination of the accurate molecular architecture of PS II complexes, all of which are in a dimeric form. The most recent crystallographic model of the PS II dimer at 3.0-Å resolution revealed the presence of six detergent molecules located at the interface of the two monomers (5). Small structural fluctuations during the purification process might allow the invasion of those detergent molecules. However, it is also probable that the PS II complexes exist in the form of a monomer in vivo and the two distinct monomers become a dimer during the purification step incorporating detergents between their interfaces. This idea led us to investigate the actual form of PS II in vivo. Contrary to the above well known dimeric model of a functional PS II core complex, here we show that the PS II core complex functions and exist...

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“…Distinct pigment -protein complexes are contained within PSI and PSII and perform the functions of light absorption and excitation energy transfer to a photochemical reaction centre [2,3]. Up to 350 chlorophyll a (Chl a) and Chl b molecules can be found in association with PSII, whereas the Chl antenna of PSI may contain up to 300 mainly Chl a molecules [4 -6].…”

Section: Introductionmentioning

confidence: 99%

Modulation of the light-harvesting chlorophyll antenna size in Chlamydomonas reinhardtii by TLA1 gene over-expression and RNA interference

Mitra

Kirst

Dewez

et al. 2012

Phil. Trans. R. Soc. B

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Truncated light-harvesting antenna 1 (TLA1) is a nuclear gene proposed to regulate the chlorophyll (Chl) antenna size in Chlamydomonas reinhardtii. The Chl antenna size of the photosystems and the chloroplast ultrastructure were manipulated upon TLA1 gene over-expression and RNAi downregulation. The TLA1 over-expressing lines possessed a larger chlorophyll antenna size for both photosystems and contained greater levels of Chl b per cell relative to the wild type. Conversely, TLA1 RNAi transformants had a smaller Chl antenna size for both photosystems and lower levels of Chl b per cell. Western blot analyses of the TLA1 over-expressing and RNAi transformants showed that modulation of TLA1 gene expression was paralleled by modulation in the expression of light-harvesting protein, reaction centre D1 and D2, and VIPP1 genes. Transmission electron microscopy showed that modulation of TLA1 gene expression impacts the organization of thylakoid membranes in the chloroplast. Over-expressing lines showed well-defined grana, whereas RNAi transformants possessed loosely held together and more stroma-exposed thylakoids. Cell fractionation suggested localization of the TLA1 protein in the inner chloroplast envelope and potentially in association with nascent thylakoid membranes, indicating a role in Chl antenna assembly and thylakoid membrane biogenesis. The results provide a mechanistic understanding of the Chl antenna size regulation by the TLA1 gene.

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Light-harvesting Complexes of Plants and Algae: Introduction, Survey and Nomenclature

Cited by 20 publications

References 67 publications

Close vicinity of Lhc b1 and Lhc b4 in Photosystem II

Close vicinity of Lhc b1 and Lhc b4 in Photosystem II

Photosystem II Complex in Vivo Is a Monomer

Modulation of the light-harvesting chlorophyll antenna size in Chlamydomonas reinhardtii by TLA1 gene over-expression and RNA interference

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