Supramolecular organization of photosystem I and light‐harvesting complex I in <i>Chlamydomonas reinhardtii</i>

Germano, M.; Yakushevska, Alevtyna; Keegstra, Wilko; Gorkom, Hans J. van; Dekker, Jan; Boekema, Egbert J.

doi:10.1016/s0014-5793(02)03100-9

Cited by 104 publications

(131 citation statements)

References 29 publications

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“…The alignment with D. salina complexes revealed that the PS-I antenna in iron-sufficient cells is significantly larger than that of pea. These results are in agreement with the comparison of PS-I-LHC-I complexes from C. reinhardtii and from spinach by single particle analysis (34,36). The antenna of iron-deficient PS-I is even larger and further extends on the opposite side of the RC.…”

Section: Imaging Of the Ps-i-lhc-i By Single Particle Electronsupporting

confidence: 90%

See 1 more Smart Citation

A Chlorophyll a/b-binding Protein Homolog That Is Induced by Iron Deficiency Is Associated with Enlarged Photosystem I Units in the Eucaryotic Alga Dunaliella salina

Varsano

Wolf

Pick

2006

Journal of Biological Chemistry

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Section: Imaging Of the Ps-i-lhc-i By Single Particle Electronsupporting

confidence: 90%

“…The diameter of the complexes was estimated to be 22, 31, and 37 nm for complex 3, ⑀, and ␣, respectively. The shape and dimensions of complex 3 from control D. salina cell are similar to reported dimensions for PS-I-LHC-I complexes from C. reinhardtii (21.3 ϫ 18.2 nm) (34).…”

Section: Imaging Of the Ps-i-lhc-i By Single Particle Electronsupporting

confidence: 78%

A Chlorophyll a/b-binding Protein Homolog That Is Induced by Iron Deficiency Is Associated with Enlarged Photosystem I Units in the Eucaryotic Alga Dunaliella salina

Varsano

Wolf

Pick

2006

Journal of Biological Chemistry

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“…PSI-LHCI complexes were obtained from C. reinhardtii strain CC-2137 by -DM solubilization and sucrose gradient centrifugation as described in Germano et al 33 with an additional FPLC run through a Superdex 200 column after the ultracentrifugation. This preparation was characterized before by electron microscopy 33 and consists of two slightly different types of particles which however contain the same number of LHCI subunits. 34 These types of complexes bind most likely 9 LHCI subunits per PSI core complex 35 and contain about 230 Chls (M. Hippler, personal communication; ref 26).…”

Section: Methodsmentioning

confidence: 99%

Characterization of Low-Energy Chlorophylls in the PSI-LHCI Supercomplex from Chlamydomonas reinhardtii. A Site-Selective Fluorescence Study

et al. 2005

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Almost all photosystem I (PSI) complexes from oxygenic photosynthetic organisms contain chlorophylls that absorb at longer wavelength than that of the primary electron donor P700. We demonstrate here that the low-energy pool of chlorophylls in the PSI-LHCI complex from the green alga Chlamydomonas reinhardtii, containing five to six pigments, is significantly blue-shifted (A max at 700 nm at 4 K) compared to that in the PSI core preparations from several species of cyanobacteria and in PSI-LHCI particles from higher plants. This makes them almost isoenergetic with the primary donor. However, they keep the other characteristic features of "red" chlorophylls: clear spectral separation from the bulk chlorophylls, big Stokes shift revealing pronounced electron-phonon coupling, and large homogeneous and inhomogeneous broadening of ∼170 and ∼310 cm -1 , respectively.

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“…Thus, when the three mobile LHCII proteins are bound to PSI, the possible binding site could be modeled near the PsaH subunit. Germano et al (34) postulated that a mass of 40 nm 2 near this region in one of their single-particle images of PSI-LHCI supercomplex from C. reinhardtii corresponds to three LHCI monomers. It is possible that the three monomeric LHCII proteins identified in this study occupy the same region.…”

Section: Figmentioning

confidence: 99%

“…It is possible that the three monomeric LHCII proteins identified in this study occupy the same region. The PSI-LHCI supercomplex is much larger in C. reinhardtii than in higher plants (34,35) perhaps because the alga has nine Lhca genes (Fig. 5), whereas higher plants have only four or five.…”

Section: Figmentioning

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.

226

195

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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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Supramolecular organization of photosystem I and light‐harvesting complex I in Chlamydomonas reinhardtii

Cited by 104 publications

References 29 publications

A Chlorophyll a/b-binding Protein Homolog That Is Induced by Iron Deficiency Is Associated with Enlarged Photosystem I Units in the Eucaryotic Alga Dunaliella salina

A Chlorophyll a/b-binding Protein Homolog That Is Induced by Iron Deficiency Is Associated with Enlarged Photosystem I Units in the Eucaryotic Alga Dunaliella salina

Characterization of Low-Energy Chlorophylls in the PSI-LHCI Supercomplex from Chlamydomonas reinhardtii. A Site-Selective Fluorescence Study

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

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