Thermal stability of trimeric light-harvesting chlorophyll a/b complex (LHCIIb) in liposomes of thylakoid lipids

Yang, Chuanyan; Boggasch, Stephanie; Haase, Winfried; Paulsen, Harald

doi:10.1016/j.bbabio.2006.08.010

Cited by 57 publications

(57 citation statements)

References 39 publications

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“…In general, no large differences were observed between the spectra, indicating that the incorporation into liposomes does not lead to loss of pigments. These features are in agreement with previously published works on LHCII incorporated into liposomes (21,25,27).…”

Section: Incorporation Of Chlamydomonas Reinhardtii Lhcii Intosupporting

confidence: 83%

“…Proteoliposomes, where light-harvesting complexes are embedded in a lipid bilayer that contains the lipids of the thylakoid membrane, are becoming a popular system to study antenna complexes in vitro (20,21,24,25,27,32,33). With the aim to mimic the thylakoid membrane, highly concentrated proteoliposomes with a lipid/protein molar ratio between ϳ30 -600:1 are used.…”

Section: Discussionmentioning

confidence: 99%

“…2 To whom correspondence should be addressed. The advantage provided by liposomes in the study of lightharvesting is their flexibility; they permit the analysis of the characteristic of the antennas by varying lipid composition (21) and protein/lipid ratio (20). They make it possible to change in the composition of the membrane in a controlled way and to study the effect of the presence of different pigments or proteins on the properties of the complexes (23,24).…”

mentioning

confidence: 99%

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Light-harvesting Complexes (LHCs) Cluster Spontaneously in Membrane Environment Leading to Shortening of Their Excited State Lifetimes

Natali

Gruber

Dietzel

et al. 2016

Journal of Biological Chemistry

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The light reactions of photosynthesis, which include lightharvesting and charge separation, take place in the amphiphilic environment of the thylakoid membrane. The light-harvesting complex II (LHCII) is the main responsible for light absorption in plants and green algae and is involved in photoprotective mechanisms that regulate the amount of excited states in the membrane. The dual function of LHCII has been extensively studied in detergent micelles, but recent results have indicated that the properties of this complex differ in a lipid environment. In this work we checked these suggestions by studying LHCII in liposomes. By combining bulk and single molecule measurements, we monitored the fluorescence characteristics of liposomes containing single complexes up to densely packed proteoliposomes. We show that the natural lipid environment per se does not alter the properties of LHCII, which for single complexes remain very similar to that in detergent. However, we show that LHCII has the strong tendency to cluster in the membrane and that protein interactions and the extent of crowding modulate the lifetimes of the excited state in the membrane. Finally, the presence of LHCII monomers at low concentrations of complexes per liposome is discussed.Photosynthetic organisms evolved the capacity to harvest the energy of solar radiation and store it into chemical compounds. In vascular plants and green algae, sunlight is absorbed by a series of membrane proteins called light-harvesting complexes (LHC).3 The most abundant of these pigment-protein complexes is LHCII. The LHCs have a dual function; in low light conditions they absorb solar energy and efficiently transfer the excitation energy to the reaction center, and in high light they additionally play a role in photoprotection by dissipating the energy absorbed in excess as heat (1, 2). This last process called non-photochemical quenching (NPQ) leads to a decrease of the excited state lifetime of chlorophyll a (Chl a), limiting the possibility of Chl triplet formation and thus the production of singlet oxygen (3). The fast, on the timescale of seconds, and fully reversible part of NPQ is called qE. This mechanism is triggered by the acidification of the lumenal space of the thylakoids, which activates PsbS (4) and LhcSR (5), the proteins responsible for NPQ in plants and green algae, respectively, and the violaxanthin de-epoxidase, which converts violaxanthin into zeaxanthin (for reviews, see Refs. 6 and 7). Although the precise molecular mechanism of quenching has not been fully elucidated yet, a prominent idea discussed in literature is that NPQ is regulated via conformational changes of LHCII. Those changes could be correlated to, or even caused by, LHCII aggregation (8, 9). It was observed that low pH and zeaxanthin, both occurring in high light, enhance LHCII aggregation (10). Aggregation of LHCII in vitro is accompanied by a decrease of the Chl a fluorescence yield, indicating an increased rate of energy dissipation (9, 11). The generation of new quenching sit...

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Section: Incorporation Of Chlamydomonas Reinhardtii Lhcii Intosupporting

confidence: 83%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Light-harvesting Complexes (LHCs) Cluster Spontaneously in Membrane Environment Leading to Shortening of Their Excited State Lifetimes

Natali

Gruber

Dietzel

et al. 2016

Journal of Biological Chemistry

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“…S1), and proceeded to reconstitute the protein into liposomes. To approximate the thylakoid membrane environment, we used thylakoid lipids in proportions close to those in vivo (28). Reconstitution of pigment-free PsbS into thylakoid-like liposomes was achieved by dialysis.…”

Section: Resultsmentioning

confidence: 99%

Direct interaction of the major light-harvesting complex II and PsbS in nonphotochemical quenching

Wilk

Grunwald

Liao

et al. 2013

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

101

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The photosystem II (PSII) subunit S (PsbS) plays a key role in nonphotochemical quenching, a photoprotective mechanism for dissipation of excess excitation energy in plants. The precise function of PsbS in nonphotochemical quenching is unknown. By reconstituting PsbS together with the major light-harvesting complex of PSII (LHC-II) and the xanthophyll zeaxanthin (Zea) into proteoliposomes, we have tested the individual contributions of PSII complexes and Zea to chlorophyll (Chl) fluorescence quenching in a membrane environment. We demonstrate that PsbS is stable in the absence of pigments in vitro. Significant Chl fluorescence quenching of reconstituted LHC-II was observed in the presence of PsbS and Zea, although neither Zea nor PsbS alone was sufficient to induce the same quenching. Coreconstitution with PsbS resulted in the formation of LHC-II/PsbS heterodimers, indicating their direct interaction in the lipid bilayer. Two-photon excitation measurements on liposomes containing LHC-II, PsbS, and Zea showed an increase of electronic interactions between carotenoid S 1 and Chl states, Φ CarS1−ChlCoupling , that correlated directly with Chl fluorescence quenching. These findings are in agreement with a carotenoid-dependent Chl fluorescence quenching by direct interactions of LHCs of PSII with PsbS monomers.

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“…It can be supposed that two high temperature transitions originate from components situated in the membrane regions readily accessible for both sterols. The effect of sterol incorporation on the T m of the transition of the most abundant pigmentprotein complex in thylakoid membranes -LHCII, could be regarded in the light of the recently published data about the effect of lipid classes and lipid/protein ratio on the dissociation temperature of trimeric LHCII incorporated into liposomes of thylakoid lipids (Yang et al 2006). …”

Section: Controlmentioning

confidence: 99%

Response of isolated thylakoid membranes with altered fluidity to short term heat stress

Velitchkova

Lazarova

Popova

2009

Physiol Mol Biol Plants

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The effect of alterations of lipid phase order of thylakoid membranes on the thermosensitivity of photosystem I (PS I) and photosystem II (PS II) was studied. Plant sterols stigmasterol and cholesterol were applied to decrease the fluidity in isolated membranes. After sterol treatment, a decrease of the temperature of 50 % inhibition of PSII activity was observed. Heat stressinduced stimulation of PSI-mediated electron transport rate was registered for control, but not for sterol-treated membranes. Effect of altered lipid order on oxygen evolving complex was evaluated by means of flash oxygen yields revealing changes in the stoichiometry of PSII α and PSII β centers. The effect of sterol incorporation on the changes in the thermotropic behavior of the main pigment-protein complexes was studied by differential scanning calorimetry (DSC). DSC traces of control thylakoids in the temperature range 20-98 o C exhibited several irreversible endothermic transitions. Incorporation of cholesterol and stigmasterol results in superimposition of the transitions and only two main bands could be resolved. While high temperature band peaks at the same temperature after treatment with both sterols, the band that combines low temperature transitions shows different melting temperature (T m ) : 70 o C for stigmasterol-and 65 0 C for cholesterol-treated membranes. The data presented here emphasise the crucial role of lipid order for the response of thylakoids to high temperatures, mediated not only by changes in the fluidity of bulk lipid phase as result of sterol incorporation but also by changes in the thermotropic properties of pigment-protein complexes.

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Thermal stability of trimeric light-harvesting chlorophyll a/b complex (LHCIIb) in liposomes of thylakoid lipids

Cited by 57 publications

References 39 publications

Light-harvesting Complexes (LHCs) Cluster Spontaneously in Membrane Environment Leading to Shortening of Their Excited State Lifetimes

Light-harvesting Complexes (LHCs) Cluster Spontaneously in Membrane Environment Leading to Shortening of Their Excited State Lifetimes

Direct interaction of the major light-harvesting complex II and PsbS in nonphotochemical quenching

Response of isolated thylakoid membranes with altered fluidity to short term heat stress

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