scholarly journals Multiscale modeling of molecular structure and optical properties of complex supramolecular aggregates

2020 ◽  
Vol 11 (42) ◽  
pp. 11514-11524 ◽  
Author(s):  
Anna S. Bondarenko ◽  
Ilias Patmanidis ◽  
Riccardo Alessandri ◽  
Paulo C. T. Souza ◽  
Thomas L. C. Jansen ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Optical Properties ◽  
Multiscale Modeling ◽  
Light Harvesting ◽  
Photophysical Properties ◽  
Light Harvesting Complex ◽  
Supramolecular Aggregates ◽  
Microscopic Origin

Multiscale modeling resolves the molecular structure of a synthetic light-harvesting complex, unraveling the microscopic origin of its photophysical properties.

scholarly journals Variable optical properties of light-harvesting complex II revisited

2020 ◽  
Author(s):  
Masakazu Iwai ◽  
Jie-Jie Chen ◽  
Soomin Park ◽  
Yusuke Yoneda ◽  
Eva M. Schmid ◽  
...  
Keyword(s):  
Optical Properties ◽  
Protein Interactions ◽  
Physical Environment ◽  
Molecular Mechanisms ◽  
Light Harvesting ◽  
Light Exposure ◽  
Protein Protein Interactions ◽  
Light Harvesting Complex ◽  
Complex Ii ◽  
Light Harvesting Complex Ii

AbstractUnderstanding photosynthetic light harvesting requires knowledge of the molecular mechanisms that dissipate excess energy in thylakoids. However, it remains unclear how the physical environment of light-harvesting complex II (LHCII) influences the process of chlorophyll de-excitation. Here, we demonstrate that protein-protein interactions between LHCIIs affect the optical properties of LHCII and thus influence the total energy budget. Aggregation of LHCII in the dark altered its absorption properties, independent of the amount of prior light exposure. We also revisited the triplet excited state involved in light-induced fluorescence quenching and found another relaxation pathway involving emission in the green region, which might be related to triplet excited energy transfer to neighboring carotenoids and annihilation processes that result in photoluminescence. LHCII- containing liposomes with different protein densities exhibited altered fluorescence and scattering properties. Our results suggest that macromolecular reorganization affects overall optical properties, which need to be addressed to compare the level of energy dissipation.

Macroorganisation and flexibility of thylakoid membranes

2019 ◽  
Vol 476 (20) ◽  
pp. 2981-3018 ◽  
Author(s):  
Petar H. Lambrev ◽  
Parveen Akhtar
Keyword(s):  
Light Harvesting ◽  
Current Knowledge ◽  
Three Dimensional ◽  
Photosynthetic Apparatus ◽  
Dynamic Responses ◽  
State Transitions ◽  
Photochemical Quenching ◽  
Light Harvesting Complex ◽  
Complex Ii ◽  
Light Harvesting Complex Ii

Abstract The light reactions of photosynthesis are hosted and regulated by the chloroplast thylakoid membrane (TM) — the central structural component of the photosynthetic apparatus of plants and algae. The two-dimensional and three-dimensional arrangement of the lipid–protein assemblies, aka macroorganisation, and its dynamic responses to the fluctuating physiological environment, aka flexibility, are the subject of this review. An emphasis is given on the information obtainable by spectroscopic approaches, especially circular dichroism (CD). We briefly summarise the current knowledge of the composition and three-dimensional architecture of the granal TMs in plants and the supramolecular organisation of Photosystem II and light-harvesting complex II therein. We next acquaint the non-specialist reader with the fundamentals of CD spectroscopy, recent advances such as anisotropic CD, and applications for studying the structure and macroorganisation of photosynthetic complexes and membranes. Special attention is given to the structural and functional flexibility of light-harvesting complex II in vitro as revealed by CD and fluorescence spectroscopy. We give an account of the dynamic changes in membrane macroorganisation associated with the light-adaptation of the photosynthetic apparatus and the regulation of the excitation energy flow by state transitions and non-photochemical quenching.

Theoretical Framework of 1,3-Thiazolium-5-Thiolates Mesoionic Compounds: Exploring the Nature of Photophysical Properties and Molecular Nonlinearity

2020 ◽  
Author(s):  
Zeyu Liu ◽  
Shugui Hua ◽  
Tian Lu ◽  
Ziqi Tian
Keyword(s):  
Optical Properties ◽  
Rational Design ◽  
Rayleigh Scattering ◽  
Function Analysis ◽  
Theoretical Calculations ◽  
Photophysical Properties ◽  
Optical Nonlinearity ◽  
Nonlinear Properties ◽  
Photoelectric Performance ◽  
Wave Function Analysis

Inspired by a previous experimental study on the first-order hyperpolarizabilities of 1,3-thiazolium-5-thiolates mesoionic compounds using Hyper-Rayleigh scattering technique, we theoretically investigated the UV-Vis absorption spectra and every order polarizabilities of these mesoionic molecules. Based on the fact that the photophysical and nonlinear properties observed in the experiment can be perfectly replicated, our theoretical calculations explored the essential characteristics of the optical properties of the mesoionic compounds with different electron-donating groups at the level of electronic structures through various wave function analysis methods. The influence of the electron-donating ability of the donor on the optical properties of the molecules and the contribution of the mesoionic ring moiety to their optical nonlinearity are clarified, which have not been reported by any research so far. This work will help people understand the nature of optical properties of mesoionic-based molecules and provide guidance for the rational design of molecules with excellent photoelectric performance in the future.

scholarly journals Synthesis and Photophysical Properties of Light‐Harvesting Gold Nanoclusters Fully Functionalized with Antenna Chromophores

Small ◽  
2021 ◽  
pp. 2004836
Author(s):  
Kyunglim Pyo ◽  
Hongmei Xu ◽  
Sang Myeong Han ◽  
Shivi Saxena ◽  
Sook Young Yoon ◽  
...  
Keyword(s):  
Light Harvesting ◽  
Photophysical Properties ◽  
Gold Nanoclusters

scholarly journals Plant Physiology, 2021 Functional redox links between lumen thiol oxidoreductase1 and serine/threonine-protein kinase STN7

2021 ◽  
Author(s):  
Jianghao Wu ◽  
Liwei Rong ◽  
Weijun Lin ◽  
Lingxi Kong ◽  
Dengjie Wei ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Disulfide Bonds ◽  
Kinase Activity ◽  
Light Harvesting ◽  
Photosynthetic Electron Transport ◽  
State Transitions ◽  
Light Harvesting Complex ◽  
Light Harvesting Complex Ii

Abstract In response to changing light quantity and quality, photosynthetic organisms perform state transitions, a process which optimizes photosynthetic yield and mitigates photo-damage. The serine/threonine-protein kinase STN7 phosphorylates the light-harvesting complex of photosystem II (PSII; light-harvesting complex II), which then migrates from PSII to photosystem I (PSI), thereby rebalancing the light excitation energy between the photosystems and restoring the redox poise of the photosynthetic electron transport chain. Two conserved cysteines forming intra- or intermolecular disulfide bonds in the lumenal domain (LD) of STN7 are essential for the kinase activity although it is still unknown how activation of the kinase is regulated. In this study, we show lumen thiol oxidoreductase 1 (LTO1) is co-expressed with STN7 in Arabidopsis (Arabidopsis thaliana) and interacts with the LD of STN7 in vitro and in vivo. LTO1 contains thioredoxin (TRX)-like and vitamin K epoxide reductase domains which are related to the disulfide-bond formation system in bacteria. We further show that the TRX-like domain of LTO1 is able to oxidize the conserved lumenal cysteines of STN7 in vitro. In addition, loss of LTO1 affects the kinase activity of STN7 in Arabidopsis. Based on these results, we propose that LTO1 helps to maintain STN7 in an oxidized active state in state 2 through redox interactions between the lumenal cysteines of STN7 and LTO1.

Structure of plant photosystem I‐light harvesting complex I supercomplex at 2.4 Å resolution

2021 ◽  
Author(s):  
Jie Wang ◽  
Long‐Jiang Yu ◽  
Wenda Wang ◽  
Qiujing Yan ◽  
Tingyun Kuang ◽  
...  
Keyword(s):  
Photosystem I ◽  
Complex I ◽  
Light Harvesting ◽  
Light Harvesting Complex
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