Stark fluorescence spectroscopy reveals two emitting sites in the dissipative state of FCP antennas

Wahadoszamen, Md.; Ghazaryan, Artur; Cingil, Hande E.; Ara, Anjue Mane; Büchel, Claudia; Grondelle, Rienk van; Berera, Rudi

doi:10.1016/j.bbabio.2013.09.001

Cited by 30 publications

(31 citation statements)

References 48 publications

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“…For example, formation of hydrogen bonds (39,40) and charge transfer states (41)(42)(43) are generally connected to spectral shifts of at least 10 nm, which are larger than the spectral changes considered in the present study. It is of note that, in a recent 77 K Stark fluorescence study on FCP aggregates, a band near 680 nm was identified, which contributed more strongly to the fluorescence and Stark fluorescence spectra of FCPb than to those of FCPa (43), in agreement with the relative abundance of 680-nm emission in the present study. In the same study, the identified ∼680-nm state exhibited no charge transfer character for the FCPa sample, while for FCPb a weak charge transfer character was attributed to this state, even though a similar 680-nm band resolved for a mixture of FCPa and FCPb complexes showed no evidence of charge transfer.…”

Section: Discussionmentioning

confidence: 51%

How reduced excitonic coupling enhances light harvesting in the main photosynthetic antennae of diatoms

Krüger

Malý

Alexandre

et al. 2017

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

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Strong excitonic interactions are a key design strategy in photosynthetic light harvesting, expanding the spectral cross-section for light absorption and creating considerably faster and more robust excitation energy transfer. These molecular excitons are a direct result of exceptionally densely packed pigments in photosynthetic proteins. The main light-harvesting complexes of diatoms, known as fucoxanthin-chlorophyll proteins (FCPs), are an exception, displaying surprisingly weak excitonic coupling between their chlorophyll (Chl) 's, despite a high pigment density. Here, we show, using single-molecule spectroscopy, that the FCP complexes of switch frequently into stable, strongly emissive states shifted 4-10 nm toward the red. A few percent of isolated FCPa complexes and ∼20% of isolated FCPb complexes, on average, were observed to populate these previously unobserved states, percentages that agree with the steady-state fluorescence spectra of FCP ensembles. Thus, the complexes use their enhanced sensitivity to static disorder to increase their light-harvesting capability in a number of ways. A disordered exciton model based on the structure of the main plant light-harvesting complex explains the red-shifted emission by strong localization of the excitation energy on a single Chl pigment in the terminal emitter domain due to very specific pigment orientations. We suggest that the specific construction of FCP gives the complex a unique strategy to ensure that its light-harvesting function remains robust in the fluctuating protein environment despite limited excitonic interactions.

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Section: Discussionmentioning

confidence: 51%

How reduced excitonic coupling enhances light harvesting in the main photosynthetic antennae of diatoms

Krüger

Malý

Alexandre

et al. 2017

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

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“…tricornutum only trimers of FCPs exist as basic antenna units. These FCPs have a high capacity for aggregation, bind Dtx and might provide the two different quenching sites, that is, the Q1 and Q2 site, of NPQ (Gundermann & Büchel, ; Miloslavina et al, ; Wahadoszamen et al, ). After the termination of the de‐epoxidation reaction, the aggregation of FCPs and the establishment of quenching sites Q1 and Q2 might be detected as a stable, new arrangement of the thylakoid membrane in the present experiments.…”

Section: Discussionmentioning

confidence: 99%

Diadinoxanthin de‐epoxidation as important factor in the short‐term stabilization of diatom photosynthetic membranes exposed to different temperatures

Bojko

Olchawa-Pajor

Goss

et al. 2018

Plant Cell & Environment

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The importance of diadinoxanthin (Ddx) de‐epoxidation in the short‐term modulation of the temperature effect on photosynthetic membranes of the diatom Phaeodactylum tricornutum was demonstrated by electron paramagnetic resonance (EPR), Laurdan fluorescence spectroscopy, and high‐performance liquid chromatography. The 5‐SASL spin probe employed for the EPR measurements and Laurdan provided information about the membrane area close to the polar head groups of the membrane lipids, whereas with the 16‐SASL spin probe, the hydrophobic core, where the fatty acid residues are located, was probed. The obtained results indicate that Ddx de‐epoxidation induces a two component mechanism in the short‐term regulation of the membrane fluidity of diatom thylakoids during changing temperatures. One component has been termed the “dynamic effect” and the second the “stable effect” of Ddx de‐epoxidation. The “dynamic effect” includes changes of the membrane during the time course of de‐epoxidation whereas the “stable effect” is based on the rigidifying properties of Dtx. The combination of both effects results in a temporary increase of the rigidity of both peripheral and internal parts of the membrane whereas the persistent increase of the rigidity of the hydrophobic core of the membrane is solely based on the “stable effect.”

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“…This quenching site would allow the fast dissipation of excess light through inter-complex pigment–pigment interactions, induced by conformational changes within the oligomerized antenna and acting independently from the xanthophyll cycle [ 6 , 105 ]. The quenching could either be determined by chlorophyll–chlorophyll interactions [ 106 ] or by chlorophyll-fucoxanthin interaction, attributing a new photoprotective role to the light-harvesting pigment fucoxanthin [ 6 , 107 ].…”

Section: All- Trans -Neoxanthin In Bryopsidalesmentioning

confidence: 99%

Photoprotective Role of Neoxanthin in Plants and Algae

2020

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Light is a paramount parameter driving photosynthesis. However, excessive irradiance leads to the formation of reactive oxygen species that cause cell damage and hamper the growth of photosynthetic organisms. Xanthophylls are key pigments involved in the photoprotective response of plants and algae to excessive light. Of particular relevance is the operation of xanthophyll cycles (XC) leading to the formation of de-epoxidized molecules with energy dissipating capacities. Neoxanthin, found in plants and algae in two different isomeric forms, is involved in the light stress response at different levels. This xanthophyll is not directly involved in XCs and the molecular mechanisms behind its photoprotective activity are yet to be fully resolved. This review comprehensively addresses the photoprotective role of 9′-cis-neoxanthin, the most abundant neoxanthin isomer, and one of the major xanthophyll components in plants’ photosystems. The light-dependent accumulation of all-trans-neoxanthin in photosynthetic cells was identified exclusively in algae of the order Bryopsidales (Chlorophyta), that lack a functional XC. A putative photoprotective model involving all-trans-neoxanthin is discussed.

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Stark fluorescence spectroscopy reveals two emitting sites in the dissipative state of FCP antennas

Cited by 30 publications

References 48 publications

How reduced excitonic coupling enhances light harvesting in the main photosynthetic antennae of diatoms

How reduced excitonic coupling enhances light harvesting in the main photosynthetic antennae of diatoms

Diadinoxanthin de‐epoxidation as important factor in the short‐term stabilization of diatom photosynthetic membranes exposed to different temperatures

Photoprotective Role of Neoxanthin in Plants and Algae

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