Correlation of Car S<sub>1</sub> → Chl with Chl → Car S<sub>1</sub> Energy Transfer Supports the Excitonic Model in Quenched Light Harvesting Complex II

Liao, Pen-Nan; Holleboom, Christoph-Peter; Wilk, Laura; Kühlbrandt, Werner; Walla, Peter Jomo

doi:10.1021/jp1034163

Cited by 55 publications

(69 citation statements)

References 32 publications

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“…Even though discrepancies exist in the literature, in almost all cases, there is the common conclusion that there is increased Chl/Pc ? Car S 1 energy transfer whenever the Pc or Chl fluorescence is quenched (Berera et al 2009;Kloz et al 2011;Liao et al 2010b;Ma et al 2003;Ruban et al 2007). Also, in all these quenched samples, increased Car S 1 ?…”

Section: Resultsmentioning

confidence: 79%

On the role of excitonic interactions in carotenoid–phthalocyanine dyads and implications for photosynthetic regulation

et al. 2011

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In two recent studies, energy transfer was reported in certain phthalocyanine-carotenoid dyads between the optically forbidden first excited state of carotenoids (Car S(1)) and phthalocyanines (Pcs) in the direction Pc → Car S(1) (Kloz et al., J Am Chem Soc 133:7007-7015, 2011) as well as in the direction Car S(1) → Pc (Liao et al., J Phys Chem A 115:4082-4091, 2011). In this article, we show that the extent of this energy transfer in both directions is closely correlated in these dyads. This correlation and the additional observation that Car S(1) is instantaneously populated after Pc excitation provides evidence that in these compounds excitonic interactions can occur. Besides pure energy transfer and electron transfer, this is the third type of tetrapyrrole-carotenoid interaction that has been shown to occur in these model compounds and that has previously been proposed as a photosynthetic regulation mechanism. We discuss the implications of these models for photosynthetic regulation. The findings are also discussed in the context of a model in which both electronic states are disordered and in which the strength of the electronic coupling determines whether energy transfer, excitonic coupling, or electron transfer occurs.

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Section: Resultsmentioning

confidence: 79%

On the role of excitonic interactions in carotenoid–phthalocyanine dyads and implications for photosynthetic regulation

et al. 2011

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“…6), is stabilized by the interaction of LHCI with PSI-core/gap pigments and is responsible for the zeaxanthin-dependent, 30%reduction of the functional antenna size in vivo. We cannot exclude the occurrence of other kind of zeaxanthin-dependent quenching mechanisms (67)(68)(69). The zeaxanthin-dependent reduction of functional PSI-LHCI antenna size is associated with improved photoprotection of PSI-LHCI both in vitro and in vivo.…”

Section: Discussionmentioning

confidence: 92%

Regulation of photosystem I light harvesting by zeaxanthin

Ballottari

Alcocer

D’Andrea

et al. 2014

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

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In oxygenic photosynthetic eukaryotes, the hydroxylated carotenoid zeaxanthin is produced from preexisting violaxanthin upon exposure to excess light conditions. Zeaxanthin binding to components of the photosystem II (PSII) antenna system has been investigated thoroughly and shown to help in the dissipation of excess chlorophyll-excited states and scavenging of oxygen radicals. However, the functional consequences of the accumulation of the light-harvesting complex I (LHCI) proteins in the photosystem I (PSI) antenna have remained unclarified so far. In this work we investigated the effect of zeaxanthin binding on photoprotection of PSI-LHCI by comparing preparations isolated from wild-type Arabidopsis thaliana (i.e., with violaxanthin) and those isolated from the A. thaliana nonphotochemical quenching 2 mutant, in which violaxanthin is replaced by zeaxanthin. Time-resolved fluorescence measurements showed that zeaxanthin binding leads to a previously unrecognized quenching effect on PSI-LHCI fluorescence. The efficiency of energy transfer from the LHCI moiety of the complex to the PSI reaction center was down-regulated, and an enhanced PSI resistance to photoinhibition was observed both in vitro and in vivo. Thus, zeaxanthin was shown to be effective in inducing dissipative states in PSI, similar to its well-known effect on PSII. We propose that, upon acclimation to high light, PSI-LHCI changes its light-harvesting efficiency by a zeaxanthin-dependent quenching of the absorbed excitation energy, whereas in PSII the stoichiometry of LHC antenna proteins per reaction center is reduced directly.photosynthesis | xanthophylls | violaxanthin de-epoxidase | photobleaching

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“…Such an effect could be produced by one of the following mechanisms; (i) the conformational change induced by Zea binding causes excitons in Chls bound to such a domain to be diverted from the sites where 3 Chl* are formed with higher yield (i.e. the red-most sites such as Chl A2, A4), possibly due to changes in the energy level of the former Chls (69), or (ii) alternatively, Chls generating triplet states with higher yield might become more readily quenched when still at their 1 Chl* state via thermal relaxation (70,71). In such case, the singlet quenching would be limited to a subset of Chls of limited amplitude when refereed to the whole complex (52,68,72), whereas the effect on triplet state would be stronger.…”

Section: Discussionmentioning

confidence: 99%

Zeaxanthin Protects Plant Photosynthesis by Modulating Chlorophyll Triplet Yield in Specific Light-harvesting Antenna Subunits

Dall’Osto

Holt

Kaligotla

et al. 2012

Journal of Biological Chemistry

126

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Background:The plant carotenoid zeaxanthin is accumulated under excess light. Results: Zeaxanthin induces a red shift in the carotenoid triplet excited state spectrum and reveals a higher efficiency in controlling chlorophyll triplet formation. Conclusion: Binding of zeaxanthin to specific proteins modulates the yield of dangerous chlorophyll excited states and protects photosynthesis from over-excitation. Significance: Functional dissection of zeaxanthin-dependent photoprotective mechanisms is crucial for understanding how plants avoid photoinhibition.

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Correlation of Car S₁ → Chl with Chl → Car S₁ Energy Transfer Supports the Excitonic Model in Quenched Light Harvesting Complex II

Cited by 55 publications

References 32 publications

On the role of excitonic interactions in carotenoid–phthalocyanine dyads and implications for photosynthetic regulation

On the role of excitonic interactions in carotenoid–phthalocyanine dyads and implications for photosynthetic regulation

Regulation of photosystem I light harvesting by zeaxanthin

Zeaxanthin Protects Plant Photosynthesis by Modulating Chlorophyll Triplet Yield in Specific Light-harvesting Antenna Subunits

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Correlation of Car S1 → Chl with Chl → Car S1 Energy Transfer Supports the Excitonic Model in Quenched Light Harvesting Complex II

Cited by 55 publications

References 32 publications

On the role of excitonic interactions in carotenoid–phthalocyanine dyads and implications for photosynthetic regulation

On the role of excitonic interactions in carotenoid–phthalocyanine dyads and implications for photosynthetic regulation

Regulation of photosystem I light harvesting by zeaxanthin

Zeaxanthin Protects Plant Photosynthesis by Modulating Chlorophyll Triplet Yield in Specific Light-harvesting Antenna Subunits

Contact Info

Product

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Correlation of Car S₁ → Chl with Chl → Car S₁ Energy Transfer Supports the Excitonic Model in Quenched Light Harvesting Complex II