Light Adaptation in Phycobilisome Antennas: Influence on the Rod Length and Structural Arrangement

Chenu, Aurélia; Keren, Nir; Paltiel, Yossi; Nevo, Reinat; Reich, Ziv; Cao, Jianshu

doi:10.1021/acs.jpcb.7b07781

Cited by 18 publications

(20 citation statements)

References 65 publications

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“…Average thylakoid repeat distance of 600–700 Å, number of layers in a thylakoid stack is 3.5–4.5, average lumen thickness is 60–85 Å and average thylakoid membrane thickness is 33.8–42 Å. Inter-thylakoid space height d IT = D-d L -4 · d T = 430–555 Å, is in very close agreement with values obtained from (cryo-)TEM studies 1,3,34–36 . From cryoEM measurements, which exclude fixation-induced sample shrinkage, inter-thylakoid space height of 6803 is 580 ± 130 Å, and of 7942–450 ± 30 Å 36 .…”

Section: Resultssupporting

confidence: 84%

Ultrastructural modeling of small angle scattering from photosynthetic membranes

Jakubauskas

Kowalewska

Соколова

et al. 2019

Sci Rep

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The last decade has seen a range of studies using non-invasive neutron and X-ray techniques to probe the ultrastructure of a variety of photosynthetic membrane systems. A common denominator in this work is the lack of an explicitly formulated underlying structural model, ultimately leading to ambiguity in the data interpretation. Here we formulate and implement a full mathematical model of the scattering from a stacked double bilayer membrane system taking instrumental resolution and polydispersity into account. We validate our model by direct simulation of scattering patterns from 3D structural models. Most importantly, we demonstrate that the full scattering curves from three structurally typical cyanobacterial thylakoid membrane systems measured in vivo can all be described within this framework. The model provides realistic estimates of key structural parameters in the thylakoid membrane, in particular the overall stacking distance and how this is divided between membranes, lumen and cytoplasmic liquid. Finally, from fitted scattering length densities it becomes clear that the protein content in the inner lumen has to be lower than in the outer cytoplasmic liquid and we extract the first quantitative measure of the luminal protein content in a living cyanobacteria.

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Section: Resultssupporting

confidence: 84%

Ultrastructural modeling of small angle scattering from photosynthetic membranes

Jakubauskas

Kowalewska

Соколова

et al. 2019

Sci Rep

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“…In subsection 5.2 we show that the coupling between SRSs in each ring displays a super-transfer effect, , as given by equation (12), as a function of the cylindrical length L at a fixed temperature T=300 K. All models have a total number of dipoles ranging from 120 to 9600. Note that since energy is measured in -( ) cm 1 , the mean energy density in the thermal energy width k T B is measured in (cm), see equation (12).…”

Section: Relationship Between Structure and Macroscopic Coherencementioning

confidence: 99%

“…Molecular nanotubes are among the most interesting and most investigated structures. They are present in several natural photosynthetic complexes, for instance in the Green Sulphur Bacteria [4][5][6][7][8][9][10][11] or in Phycobilisome Antennas [12][13][14][15]. They are also present in other biomolecular systems, for instance in Microtubules, which are fundamental biological structures, showing interesting similarities with photosynthetic Antenna complexes [16,17].…”

Section: Introductionmentioning

confidence: 99%

“…Green Sulphur bacteria are photosynthetic organisms which live in deep water where the sunlight flux is very low [5] and they are among the most efficient photosynthetic systems [6][7][8]. Similarly to other antenna complexes present in nature [12][13][14][15], they present a high degree of symmetry being arranged in nontrivial cylindrical structures with an ordered orientation of the molecule dipoles. We analyse both the wild type (WT) and the triple mutant type (MT), which have been recently investigated in [53,54].…”

Section: Introductionmentioning

confidence: 99%

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Macroscopic coherence as an emergent property in molecular nanotubes

et al. 2019

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Nanotubular molecular self-aggregates are characterized by a high degree of symmetry and they are fundamental systems for light-harvesting and energy transport. While coherent effects are thought to be at the basis of their high efficiency, the relationship between structure, coherence and functionality is still an open problem. We analyse natural nanotubes present in Green Sulphur Bacteria. We show that they have the ability to support macroscopic coherent states, i.e. delocalized excitonic states coherently spread over many molecules, even at room temperature. Specifically, assuming a canonical thermal state we find, in natural structures, a large thermal coherence length, of the order of 1000 molecules. By comparing natural structures with other mathematical models, we show that this macroscopic coherence cannot be explained either by the magnitude of the nearest-neighbour coupling between the molecules, which would induce a thermal coherence length of the order of 10 molecules, nor by the presence of long-range interactions between the molecules. Indeed we prove that the existence of macroscopic coherent states is an emergent property of such structures due to the interplay between geometry and cooperativity (superradiance and super-transfer). In order to prove that, we give evidence that the lowest part of the spectrum of natural systems is determined by a cooperatively enhanced coupling (super-transfer) between the eigenstates of modular sub-units of the whole structure. Due to this enhanced coupling strength, the density of states is lowered close to the ground state, thus boosting the thermal coherence length. As a striking consequence of the lower density of states, an energy gap between the excitonic ground state and the first excited state emerges. Such energy gap increases with the length of the nanotube (instead of decreasing as one would expect), up to a critical system size which is close to the length of the natural complexes considered.

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“…The PCB/APCB ratio is a good indicator of the rod lengths of phycobilisomes (Chenu et al, 2017). Synechocystis may change the PCB/APCB ratio as an adaption response to different light intensities (Chenu et al, 2017). Therefore, we calculated the PCB/APCB ratio for Synechocystis cultures grown at different light intensities ( Table 1 ).…”

Section: Resultsmentioning

confidence: 99%

Introducing an Arabidopsis thaliana Thylakoid Thiol/Disulfide-Modulating Protein Into Synechocystis Increases the Efficiency of Photosystem II Photochemistry

Wessendorf

2019

Front. Plant Sci.

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Photosynthetic species are subjected to a variety of environmental stresses, including suboptimal irradiance. In oxygenic photosynthetic organisms, a major effect of high light exposure is damage to the Photosystem II (PSII) reaction-center protein D1. This process even happens under low or moderate light. To cope with photodamage to D1, photosynthetic organisms evolved an intricate PSII repair and reassembly cycle, which requires the participation of different auxiliary proteins, including thiol/disulfide-modulating proteins. Most of these auxiliary proteins exist ubiquitously in oxygenic photosynthetic organisms. Due to differences in mobility and environmental conditions, land plants are subject to more extensive high light stress than algae and cyanobacteria. Therefore, land plants evolved additional thiol/disulfide-modulating proteins, such as Low Quantum Yield of PSII 1 (LQY1), to aid in the repair and reassembly cycle of PSII. In this study, we introduced an Arabidopsis thaliana homolog of LQY1 (AtLQY1) into the cyanobacterium Synechocystis sp. PCC6803 and performed a series of biochemical and physiological assays on AtLQY1-expressing Synechocystis. At a moderate growth light intensity (50 µmol photons m-2 s-1), AtLQY1-expressing Synechocystis was found to have significantly higher F v /F m, and lower nonphotochemical quenching and reactive oxygen species levels than the empty-vector control, which is opposite from the loss-of-function Atlqy1 mutant phenotype. Light response curve analysis of PSII operating efficiency and electron transport rate showed that AtLQY1-expressing Synechocystis also outperform the empty-vector control under higher light intensities. The increases in F v /F m, PSII operating efficiency, and PSII electron transport rate in AtLQY1-expressing Synechocystis under such growth conditions most likely come from an increased amount of PSII, because the level of D1 protein was found to be higher in AtLQY1-expressing Synechocystis. These results suggest that introducing AtLQY1 is beneficial to Synechocystis.

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Light Adaptation in Phycobilisome Antennas: Influence on the Rod Length and Structural Arrangement

Cited by 18 publications

References 65 publications

Ultrastructural modeling of small angle scattering from photosynthetic membranes

Ultrastructural modeling of small angle scattering from photosynthetic membranes

Macroscopic coherence as an emergent property in molecular nanotubes

Introducing an Arabidopsis thaliana Thylakoid Thiol/Disulfide-Modulating Protein Into Synechocystis Increases the Efficiency of Photosystem II Photochemistry

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