The Light-Harvesting Complex of Photosystem I in Chlamydomonas reinhardtii: Protein Composition, Gene Structures and Phylogenic Implications

Tokutsu, Ryutaro; Teramoto, Haruhiko; Takahashi, Yuichiro; Ono, T.; Minagawa, Jun

doi:10.1093/pcp/pch013

Cited by 50 publications

(56 citation statements)

References 39 publications

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“…5), whereas higher plants have only four or five. At least seven LHCI proteins are involved in the PSI-LHCI complex (23,36) and may form a second row of the LHCI belt, as has previously been suggested in ref. 35 (Fig.…”

Section: Figmentioning

confidence: 64%

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Identification of the mobile light-harvesting complex II polypeptides for state transitions in Chlamydomonas reinhardtii

Takahashi

Iwai

Takahashi³

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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220

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State transition in photosynthesis is a short-term balancing mechanism of energy distribution between photosystem I (PSI) and photosystem II (PSII). When PSII is preferentially excited (state 2), a pool of mobile light-harvesting complex II (LHCII) antenna proteins is thought to migrate from PSII to PSI, but biochemical evidence for a physical association between LHCII proteins and PSI in state 2 is weak. Here, using the green alga Chlamydomonas reinhardtii, which has a high capacity for state transitions, we report the isolation of PSI-light-harvesting complex I (LHCI) supercomplexes from cells locked into state 1 and state 2. We solubilized the thylakoid membranes with a mild detergent, separated the proteins by sucrose density gradient centrifugation, and subjected gradient fractions to gel-filtration chromatography. Three LHCII polypeptides were associated with a PSI-LHCI supercomplex only in state 2; we identified them as two minor monomeric LHCII proteins (CP26 and CP29) and one previously unreported major LHCII protein type II, or LhcbM5. These three LHCII proteins, in addition to the major trimeric LHCII proteins, were phosphorylated upon transition to state 2. The corresponding phylogenetic tree indicates that among the LHCII proteins associated with PSII, these three LHCII proteins are the most similar to the LHC proteins for PSI (LHCI). Our results are important because CP26, CP29, and LhcbM5, which have been viewed as belonging solely to the PSII complex, are now postulated to shuttle between PSI and PSII during state transitions, thereby acting as docking sites for the trimeric LHCII proteins in both PSI and PSII.photoacclimation ͉ photosynthesis ͉ photosystem I n oxygen-evolving photosynthetic organisms, two types of photosystems, photosystem I (PSI) and photosystem II (PSII), operate in series in the transfer of electrons from water to NADP ϩ . The two photosystems contain their own reaction centers and light-harvesting antenna systems. The PSI lightharvesting antenna system contains light-harvesting complex I (LHCI) proteins as peripheral monomeric antennas, whereas the PSII light-harvesting antenna system contains major and minor light-harvesting complex II (LHCII) proteins as peripheral trimeric and inner monomeric antennas, respectively (see review in ref. 1). The distribution of absorbed light energy between the two photosystems is dynamically balanced, ensuring maximum efficiency for photosynthetic electron transport in changing light environments (2, 3). That balance is regulated by a process termed ''state transitions'': state 1 is induced by preferential excitation of PSI, and state 2 is induced by preferential excitation of PSII (see recent reviews in refs. 4-6). This short-term adaptation process involves thylakoid-bound protein kinase(s) that is responsible for the phosphorylation of LHCII (7,8). The activation of the kinase(s) is regulated by the redox state of the intersystem pool of plastoquinone (9) through cytochrome b 6 f complexes (10). The phospho-LHCII proteins in the PSIIenri...

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Section: Figmentioning

confidence: 64%

“…We performed sequence alignment and phylogenetic analysis as previously described in ref. 36, displaying bootstrap values (% of 1,000 replicates) at the appropriate nodes. LHCI and LHCII protein names are after Stauber et al (17) and Minagawa and Takahashi (19), respectively.…”

Section: Methodsmentioning

confidence: 99%

Identification of the mobile light-harvesting complex II polypeptides for state transitions in Chlamydomonas reinhardtii

Takahashi

Iwai

Takahashi³

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

220

195

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“…Mass spectrometric analysis of the 2-DGEseparated Lhca protein spots confirmed this large variability and identified nine different Lhca proteins from C. reinhardtii (113). Of these nine, Lhca2 and Lhca9 were not found by N-terminal Edman amino acid sequencing (122). For the naming of the Lhca proteins we follow the nomenclature of Stauber et al (113) (Table 1).…”

Section: Composition Of Light-harvesting Systems Inmentioning

confidence: 76%

“…In C. reinhardtii at least seven distinct LHCI subunits have been identified (11,120). From seven Lhca proteins, N-terminal amino acid sequences have been obtained by Edman amino acid sequencing (120,122). Separation of isolated PSI complexes from C. reinhardtii by 2-DGE revealed the presence of about 18 LHCI protein spots, suggesting an even higher variability of Lhca proteins (56).…”

Section: Composition Of Light-harvesting Systems Inmentioning

confidence: 99%

Remodeling of Light-Harvesting Protein Complexes in Chlamydomonas in Response to Environmental Changes

2004

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3Photosynthesis is dependent on light. Photosynthetic organisms struggle their entire lives to optimize photosynthetic function and minimize photooxidative damage in response to light quantity and quality. When the absorbed light energy exceeds the capacity of photosynthetic energy consumption, overreduction of electron transport carriers and accumulation of excitation energy in the light-harvesting-antennae may occur. The latter favors the production of excited triplet-state chlorophyll molecules ( 3 Chl) that can interact with O 2 to cause the formation of reactive singlet oxygen ( 1 O 2 ). The former favors the direct reduction of O 2 by photosystem I (PSI) and the subsequent generation of reactive oxygen species, such as superoxide (O 2 Ϫ ), hydrogen peroxide (H 2 O 2 ), and the hydroxyl radical (⅐OH) (5,6,75). These reactive oxygen species are able to cause photo-oxidative damage to photosystem II (PSII), a primary target for photoinhibition (2, 4, 9), but also to PSI (59, 60), in particular under weak light at chilled temperatures (111, 121). Thus, adaptation mechanisms that balance the energy input, through photochemistry via the photosynthetic machinery, with the energy output through CO 2 assimilation and other metabolic pathways, are essential for plant survival.The function of the light-harvesting complexes (LHCs) is, as the name implies, to increase the effective absorption crosssection of the photosystems and to supply them with excitation energy. The LHCs bind chlorophyll a and b but lack any photochemical activity of their own. Both PSI and PSII have their own core antenna pigments, but the addition of the LHCs increases the number of antenna pigments connected to each reaction center by a factor of 2 to 4, depending upon the conditions (47). Energy transfer operates in a time scale of femtoseconds to picoseconds. The transfer time of excitation energy between neighboring Chl molecules in the antenna has been estimated to be 100 to 300 fs (45). It had long been known that the pigment molecules must be closely packed to allow such fast and efficient transfer, a supposition beautifully confirmed by the emergence of the X-ray crystal structures of PSI (65), PSII (42,66,135), and LHCI-PSI (12) in the last several years (see discussion below). On average, excitation energy makes 100 to 1,000 such hops between antenna chlorophylls before it is trapped at a reaction center. Depending upon the arrangement of pigment molecules within LHCs and of LHCs vis-à-vis the photosystems, excitation energy can be directed to specific photosystems, temporarily trapped on low-energy chlorophylls, or even converted to heat by "nonphotochemical quenching." It does not require a great stretch of imagination to see how evolution might have taken advantage of such possibilities for the development of regulatory mechanisms to deal with variable illumination.The regulation of light energy input and distribution, by the dynamic regulation of the light-harvesting system, probably plays the most important role in balancing the l...

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“…In C. reinhardtii thylakoids, Stt7 has been found associated with Cytb 6 f, LHCII and PSI, but not with PSII (Lemeille et al 2009). Phosphorylation and migration of the PSII linker protein CP29 have also been reported to be vital for docking of P*LHCII proteins to PSI in C. reinhardtii, but the extent to which CP29 moves between the photosystems seems to depend on the experimental conditions used (Tokutsu et al 2004;Lemeille et al 2010). In higher plants, CP29 phosphorylation regulates disassembly of PSII supercomplexes under high light (Fristedt and Vener 2011).…”

Section: Specific Properties Of Lhcs In Diatomsmentioning

confidence: 99%

Phylogenetic viewpoints on regulation of light harvesting and electron transport in eukaryotic photosynthetic organisms

Grouneva

Gollan

Kangasjärvi

et al. 2012

Planta

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The comparative study of photosynthetic regulation in the thylakoid membrane of different phylogenetic groups can yield valuable insights into mechanisms, genetic requirements and redundancy of regulatory processes. This review offers a brief summary on the current understanding of light harvesting and photosynthetic electron transport regulation in different photosynthetic eukaryotes, with a special focus on the comparison between higher plants and unicellular algae of secondary endosymbiotic origin. The foundations of thylakoid structure, light harvesting, reversible protein phosphorylation and PSI-mediated cyclic electron transport are traced not only from green algae to vascular plants but also at the branching point between the ''green'' and the ''red'' lineage of photosynthetic organisms. This approach was particularly valuable in revealing processes that (1) are highly conserved between phylogenetic groups, (2) serve a common physiological role but nevertheless originate in divergent genetic backgrounds or (3) are missing in one phylogenetic branch despite their unequivocal importance in another, necessitating a search for alternative regulatory mechanisms and interactions.Keywords Cyclic/linear electron flow Á Diatoms Á Light-harvesting proteins Á Red lineage Á Reversible phosphorylation of thylakoid proteins Á PGR5 Á STN7

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The Light-Harvesting Complex of Photosystem I in Chlamydomonas reinhardtii: Protein Composition, Gene Structures and Phylogenic Implications

Cited by 50 publications

References 39 publications

Identification of the mobile light-harvesting complex II polypeptides for state transitions in Chlamydomonas reinhardtii

Identification of the mobile light-harvesting complex II polypeptides for state transitions in Chlamydomonas reinhardtii

Remodeling of Light-Harvesting Protein Complexes in Chlamydomonas in Response to Environmental Changes

Phylogenetic viewpoints on regulation of light harvesting and electron transport in eukaryotic photosynthetic organisms

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