Revisiting the Supramolecular Organization of Photosystem II in Chlamydomonas reinhardtii

Tokutsu, Ryutaro; Kato, Noriyoshi; Bui, Khanh Huy; Ishikawa, Takashi; Minagawa, Jun

doi:10.1074/jbc.m111.331991

Cited by 106 publications

(118 citation statements)

References 47 publications

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“…In particular, LHCII proteins in Chlamydomonas have biochemical/spectroscopic properties similar to those of plants (Natali and Croce, 2015), but they cannot be classified in the Lhcb1-3 isoforms as in plants (Jansson, 1999;Elrad and Grossman, 2004). In Chlamydomonas, the CP24 subunit, which is next to the LHCII-M trimer (Dekker and Boekema, 2005) and that has been suggested to detach from PSII during NPQ induction in a PsbS-dependent phenomenon (Betterle et al, 2009), is lacking and at its place a third LHCII trimer is bound to PSII (Tokutsu et al, 2012;Drop et al, 2014). Even if it is possible that PsbS in Chlamydomonas interacts somehow differently with PSII than in plants, we found that PsbS accumulation has a positive correlation with NPQ capacity as in plants (Li et al, 2002a(Li et al, , 2002b, further supporting a conserved PsbS-dependent NPQ mechanism.…”

Section: Psbs In Photoprotectionmentioning

confidence: 99%

Chlamydomonas reinhardtii PsbS Protein Is Functional and Accumulates Rapidly and Transiently under High Light

et al. 2016

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Photosynthetic organisms must respond to excess light in order to avoid photo-oxidative stress. In plants and green algae the fastest response to high light is non-photochemical quenching (NPQ), a process that allows the safe dissipation of the excess energy as heat. This phenomenon is triggered by the low luminal pH generated by photosynthetic electron transport. In vascular plants the main sensor of the low pH is the PsbS protein, while in the green alga Chlamydomonas reinhardtii LhcSR proteins appear to be exclusively responsible for this role. Interestingly, Chlamydomonas also possesses two PsbS genes, but so far the PsbS protein has not been detected and its biological function is unknown. Here, we reinvestigated the kinetics of gene expression and PsbS and LhcSR3 accumulation in Chlamydomonas during high light stress. We found that, unlike LhcSR3, PsbS accumulates very rapidly but only transiently. In order to determine the role of PsbS in NPQ and photoprotection in Chlamydomonas, we generated transplastomic strains expressing the algal or the Arabidopsis psbS gene optimized for plastid expression. Both PsbS proteins showed the ability to increase NPQ in Chlamydomonas wild-type and npq4 (lacking LhcSR3) backgrounds, but no clear photoprotection activity was observed. Quantification of PsbS and LhcSR3 in vivo indicates that PsbS is much less abundant than LhcSR3 during high light stress. Moreover, LhcSR3, unlike PsbS, also accumulates during other stress conditions. The possible role of PsbS in photoprotection is discussed.

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Section: Psbs In Photoprotectionmentioning

confidence: 99%

Chlamydomonas reinhardtii PsbS Protein Is Functional and Accumulates Rapidly and Transiently under High Light

et al. 2016

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“…Suc gradient centrifugation of isolated thylakoid membranes was performed as described in the literature (Tokutsu et al, 2012) but with some modifications. An amount of thylakoid membranes corresponding to 200 mg of chlorophyll was resuspended in 5 mM HEPES and 10 mM EDTA (pH 7.5) buffer and solubilized in 1% (w/v) a-DM on ice in the dark for 5 min.…”

Section: Sdg Ultracentrifugationmentioning

confidence: 99%

“…Isolated thylakoids from 14 N-labeled wild type and 15 N-labeled psbr knockdown strains and FUD39 cells were solubilized and separated by SDG centrifugation as described (Tokutsu et al, 2012). Separated LHCII, PSII, and PSI fractions from 14 N-labeled wild-type and 15 N-labeled psbr knockdown strains and FUD39 cells were mixed at equal volume and digested with trypsin according to the filter-aided sample preparation protocol (Wisniewski et al, 2009).…”

Section: Mass Spectrometrymentioning

confidence: 99%

“…Even larger complexes containing two additional LHCII trimers (L-trimer), bound via Lhcb6, are found and are known as C 2 S 2 M 2 L 1-2 (Boekema et al, 1999). A recent study in Chlamydomonas reinhardtii identified PSII-LHCII supercomplexes with three LHCII trimers attached to each side of the core (C 2 S 2 M 2 L 2 ; Tokutsu et al, 2012). Interestingly, such PSII-LHCII supercomplexes associate with LIGHT-HARVESTING COMPLEX STRESS-RELATED PROTEIN3 (LHCSR3; Tokutsu and Minagawa, 2013), an ancient light-harvesting protein required for efficient energy-dependent (qE) quenching in the alga (Peers et al, 2009).…”

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confidence: 99%

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PHOTOSYSTEM II SUBUNIT R Is Required for Efficient Binding of LIGHT-HARVESTING COMPLEX STRESS-RELATED PROTEIN3 to Photosystem II-Light-Harvesting Supercomplexes in Chlamydomonas reinhardtii

et al. 2015

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Okazaki 444-8585, Japan (R.T., J.M.)In Chlamydomonas reinhardtii, the LIGHT-HARVESTING COMPLEX STRESS-RELATED PROTEIN3 (LHCSR3) protein is crucial for efficient energy-dependent thermal dissipation of excess absorbed light energy and functionally associates with photosystem II-lightharvesting complex II (PSII-LHCII) supercomplexes. Currently, it is unknown how LHCSR3 binds to the PSII-LHCII supercomplex. In this study, we investigated the role of PHOTOSYSTEM II SUBUNIT R (PSBR) an intrinsic membrane-spanning PSII subunit, in the binding of LHCSR3 to PSII-LHCII supercomplexes. Down-regulation of PSBR expression diminished the efficiency of oxygen evolution and the extent of nonphotochemical quenching and had an impact on the stability of the oxygen-evolving complex as well as on PSII-LHCII-LHCSR3 supercomplex formation. Its down-regulation destabilized the PSII-LHCII supercomplex and strongly reduced the binding of LHCSR3 to PSII-LHCII supercomplexes, as revealed by quantitative proteomics. PHOTOSYSTEM II SUBUNIT P deletion, on the contrary, destabilized PHOTOSYSTEM II SUBUNIT Q binding but did not affect PSBR and LHCSR3 association with PSII-LHCII. In summary, these data provide clear evidence that PSBR is required for the stable binding of LHCSR3 to PSII-LHCII supercomplexes and is essential for efficient energy-dependent quenching and the integrity of the PSII-LHCII-LHCSR3 supercomplex under continuous high light.

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“…The authors suggested that these tubules may act as channels for the diffusion of small molecules between the stroma and pyrenoid, thereby connecting products from the light reactions and the CBB cycle. based on the single-particle image analysis by Tokutsu et al (2012) and Drop et al (2011) respectively.…”

Section: Structure Of the Photosynthetic Apparatusmentioning

confidence: 99%

Photosynthesis of microalgae in outdoor mass cultures and modelling its effects on biomass productivity for fuels, feeds and chemicals

Yarnold¹

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Practical applications of microalgae include uses as feedstocks for sustainable fuels, feeds, nutraceuticals, and chemicals; for the treatment of wastewater and industrial flue gas; and for use as recombinant protein expression systems. Improvements in biomass yields are required for commercially viable and sustainable algal technologies, particularly for low value commodities such as biofuels.Although several algae exhibit higher growth rates than terrestrial crops, with theoretical upper limits of 8-10% photon conversion efficiency (PCE), solar-illuminated outdoor microalgal production systems typically have a PCE far below this and even below those achieved under laboratory conditions. The most intractable limiting factor is poor light distribution through the mass culture, where photoinhibitory light at the surface and dark zones deeper in the culture reduce photosynthetic productivity. Moreover, microalgae have evolved a suite of photoacclimation and photoregulation mechanisms to cope with rapid (seconds to minutes) light fluxes in natural environments, yet these processes remain poorly understood in well-mixed photobioreactors.The aim of this thesis study was to combine an experimental and theoretical approach to: 1) investigate and understand the photosynthetic response of algae under mass culture conditions; 2) develop a mathematical model which could accurately predict light-tobiomass productivities under a broad range of design scenarios for outdoor production systems; and 3) identify key biological and design parameters to maximise biomass yields.In the first part of the study, a light-to-biomass model was developed that could be easily applied to rapidly assess biomass yields of different algal strains under a range of design scenarios. This model predicts temporal and spatial irradiance at the reactor surface and through the mass culture with inputs of local solar radiation data, local coordinates, system properties and the optical properties of the culture. Local growth rates are then coupled to local light intensities within the reactor based on a static Haldane growth model derived from empirical growth-irradiance curves. Growth rates are integrated over space and time to compute areal and volumetric productivities.Validation of the model was attempted by conducting batch harvest experiments in a laboratory scale photobioreactor matrix which simulated diurnal light cycles representative of three 'typical' days of solar radiation in Brisbane. The strains used were ii Chlamydomonas reinhardtii and its truncated light-harvesting antenna mutant, tla1, reported to possess improved optical properties. Initially, the model did not satisfactorily predict growth under batch cultivation for the three different incident light conditions, overestimating productivity under low light days and overestimating on high light days.Subsequent adjustment of the model to include photoacclimative changes in the optical properties of the cell and a re-fit of the growth parameter values provided a more accurate m...

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Revisiting the Supramolecular Organization of Photosystem II in Chlamydomonas reinhardtii

Cited by 106 publications

References 47 publications

Chlamydomonas reinhardtii PsbS Protein Is Functional and Accumulates Rapidly and Transiently under High Light

Chlamydomonas reinhardtii PsbS Protein Is Functional and Accumulates Rapidly and Transiently under High Light

PHOTOSYSTEM II SUBUNIT R Is Required for Efficient Binding of LIGHT-HARVESTING COMPLEX STRESS-RELATED PROTEIN3 to Photosystem II-Light-Harvesting Supercomplexes in Chlamydomonas reinhardtii

Photosynthesis of microalgae in outdoor mass cultures and modelling its effects on biomass productivity for fuels, feeds and chemicals

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