Identification of two emitting sites in the dissipative state of the major light harvesting antenna

Wahadoszamen, Md.; Berera, Rudi; Ara, Anjue Mane; Romero, Elisabet; Grondelle, Rienk van

doi:10.1039/c1cp23059j

Cited by 82 publications

(82 citation statements)

References 71 publications

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“…In this work, blinking was shown to correlate with these conditions, leading to the hypothesis that blinking underlies qE [48]. Additionally, experiments suggest the underlying mechanism may be dissipation on the carotenoids by increased coupling between the Chl and the carotenoids [49,50] or charge transfer [51,52].…”

Section: Environmentally Controlled Functionalitymentioning

confidence: 90%

Principles of light harvesting from single photosynthetic complexes

Schlau‐Cohen

2015

Interface Focus.

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Photosynthetic systems harness sunlight to power most life on Earth. In the initial steps of photosynthetic light harvesting, absorbed energy is converted to chemical energy with near-unity quantum efficiency. This is achieved by an efficient, directional and regulated flow of energy through a network of proteins. Here, we discuss the following three key principles of this flow and of photosynthetic light harvesting: thermal fluctuations of the protein structure; intrinsic conformational switches with defined functional consequences; and environmentally triggered conformational switches. Through these principles, photosynthetic systems balance two types of operational costs: metabolic costs, or the cost of maintaining and running the molecular machinery, and opportunity costs, or the cost of losing any operational time. Understanding how the molecular machinery and dynamics are designed to balance these costs may provide a blueprint for improved artificial light-harvesting devices. With a multi-disciplinary approach combining knowledge of biology, this blueprint could lead to low-cost and more effective solar energy conversion. Photosynthetic systems achieve widespread light harvesting across the Earth's surface; in the face of our growing energy needs, this is functionality we need to replicate, and perhaps emulate.

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Section: Environmentally Controlled Functionalitymentioning

confidence: 90%

Principles of light harvesting from single photosynthetic complexes

Schlau‐Cohen

2015

Interface Focus.

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“…21 Recent transient absorption measurements on LHCII also showed no significant changes on the spectra and dynamics of excitation energy transfer from carotenoid upon protein aggregation of LHCII complexes. 16 On the other hand, the presence of Chl-Chl and possibly Chl-Car charge-transfer states has been recently confirmed by Stark spectroscopy 25 and spectral holeburning. 26 Regardless of the mechanism of dissipation, there is ample evidence that structural changes within the LHCII Chl energy transfer pathways and dynamics in the unquenched trimeric LHCII have been extensively studied using pump-probe spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

Energy transfer dynamics in trimers and aggregates of light-harvesting complex II probed by 2D electronic spectroscopy

Enriquez

Akhtar

Zhang

et al. 2015

The Journal of Chemical Physics

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The pathways and dynamics of excitation energy transfer between the chlorophyll (Chl) domains in solubilized trimeric and aggregated light-harvesting complex II (LHCII) are examined using two-dimensional electronic spectroscopy (2DES). The LHCII trimers and aggregates exhibit the unquenched and quenched excitonic states of Chl a, respectively. 2DES allows direct correlation of excitation and emission energies of coupled states over population time delays, hence enabling mapping of the energy flow between Chls. By the excitation of the entire Chl b Q y band, energy transfer from Chl b to Chl a states is monitored in the LHCII trimers and aggregates. Global analysis of the two-dimensional (2D) spectra reveals that energy transfer from Chl b to Chl a occurs on fast and slow time scales of 240-270 fs and 2.8 ps for both forms of LHCII. 2D decay-associated spectra resulting from the global analysis identify the correlation between Chl states involved in the energy transfer and decay at a given lifetime. The contribution of singlet-singlet annihilation on the kinetics of Chl energy transfer and decay is also modelled and discussed. The results show a marked change in the energy transfer kinetics in the time range of a few picoseconds. Owing to slow energy equilibration processes, long-lived intermediate Chl a states are present in solubilized trimers, while in aggregates, the population decay of these excited states is significantly accelerated, suggesting that, overall, the energy transfer within the LHCII complexes is faster in the aggregated state. C 2015 AIP Publishing LLC. [http://dx

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“…A very recent SMS study revealed the presence of an additional energy dissipative state in LHC2, which was found to be accessed more frequently in an acidic environment and for a zeaxanthin-enriched mutant, both of which are NPQ-related conditions [36]. Furthermore, Stark fluorescence experiments have indicated that excitation-dissipating charge-transfer states appear when LHC2 forms aggregates, another state representing NPQ [37]. Recently, a multiphoton experimental study has disclosed yet another dark state in LHC2, which was suggested to be related to fluorescence blinking and which may also explain the strong quenching observed from LHC2 aggregates [38].…”

Section: Photoactive Control Over the Intrinsic Protein Disordermentioning

confidence: 99%

Design principles of natural light-harvesting as revealed by single molecule spectroscopy

Krüger

Grondelle

2016

Physica B: Condensed Matter

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Biology offers a boundless source of adaptation, innovation, and inspiration. A wide range of photosynthetic organisms exist that are capable of harvesting solar light in an exceptionally efficient way, using abundant and low-cost materials. These natural light-harvesting complexes consist of proteins that strongly bind a high density of chromophores to capture solar photons and rapidly transfer the excitation energy to the photochemical reaction centre. The amount of harvested light is also delicately tuned to the level of solar radiation to maintain a constant energy throughput at the reaction centre and avoid the accumulation of the products of charge separation. In this Review, recent developments in the understanding of light harvesting by plants will be discussed, based on results obtained from single molecule spectroscopy studies. Three design principles of the main light-harvesting antenna of plants will be highlighted: (a) fine, photoactive control over the intrinsic protein disorder to efficiently use intrinsically available thermal energy dissipation mechanisms; (b) the design of the protein microenvironment of a low-energy chromophore dimer to control the amount of shade absorption; (c) the design of the exciton manifold to ensure efficient funneling of the harvested light to the terminal emitter cluster.

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Identification of two emitting sites in the dissipative state of the major light harvesting antenna

Cited by 82 publications

References 71 publications

Principles of light harvesting from single photosynthetic complexes

Principles of light harvesting from single photosynthetic complexes

Energy transfer dynamics in trimers and aggregates of light-harvesting complex II probed by 2D electronic spectroscopy

Design principles of natural light-harvesting as revealed by single molecule spectroscopy

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