Interactions Determining the Structural Integrity of the Trimer of Plant Light Harvesting Complex in Lipid Membranes

AbstractBiology provides a suite of optically-active nanomaterials in the form of “light harvesting” protein-chlorophyll complexes, however, these have drawbacks including their limited spectral range. We report the generation of model lipid membranes (proteoliposomes) incorporating the photosynthetic protein Light-Harvesting Complex II (LHCII) and lipid-tethered Texas Red (TR) chromophores that act as a “bio-hybrid” energy transferring nanomaterial. The effective spectral range of the protein is enhanced due to highly efficient energy transfer from the TR chromophores (up to 94%), producing a marked increase in LHCII fluorescence (up to 3x). Our self-assembly procedure offers excellent modularity allowing the incorporation of a range of concentrations of energy donors (TR) and acceptors (LHCII), allowing the energy transfer efficiency (ETE) and LHCII fluorescence to be tuned as desired. Fluorescence Lifetime Imaging Microscopy (FLIM) provides single-proteoliposome-level quantification of ETE, revealing distributions within the population and proving that functionality is maintained on a surface. Our membrane-based system acts as a controllable light harvesting nanomaterial with potential applications as thin films in photo-active devices.Table of Contents Figure

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High-Resolution electron crystallography of the light-harvesting chlorophyll-a/b protein complex from chloroplast membranes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100181816 ◽

1990 ◽

Vol 48 (1) ◽

pp. 610-610

Author(s):

Werner Kühlbrandt ◽

Da Neng Wang ◽

K.H. Downing

Keyword(s):

High Resolution ◽

Electron Diffraction ◽

Chlorophyll A ◽

Protein Complex ◽

Structural Integrity ◽

Light Harvesting ◽

Lhc Ii ◽

Diffraction Patterns ◽

Difference Fourier ◽

2D Crystals

The light-harvesting chlorophyll-a/b protein complex (LHC-II) is the most abundant membrane protein in the chloroplasts of green plants where it functions as a molecular antenna of solar energy for photosynthesis. We have grown two-dimensional (2d) crystals of the purified, detergent-solubilized LHC-II . The crystals which measured 5 to 10 μm in diameter were stabilized for electron microscopy by washing with a 0.5% solution of tannin. Electron diffraction patterns of untilted 2d crystals cooled to 130 K showed sharp spots to 3.1 Å resolution. Spot-scan images of 2d crystals were recorded at 160 K with the Berkeley microscope . Images of untilted crystals were processed, using the unbending procedure by Henderson et al . A projection map of the complex at 3.7Å resolution was generated from electron diffraction amplitudes and high-resolution phases obtained by image processing .A difference Fourier analysis with the same image phases and electron diffraction amplitudes recorded of frozen, hydrated specimens showed no significant differences in the 3.7Å projection map. Our tannin treatment therefore does not affect the structural integrity of the complex.

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Macroorganisation and flexibility of thylakoid membranes

Biochemical Journal ◽

10.1042/bcj20190080 ◽

2019 ◽

Vol 476 (20) ◽

pp. 2981-3018 ◽

Cited By ~ 8

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.

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Thylakoid-associated Polyamines Adjust the UV-B Sensitivity of the Photosynthetic Apparatus by Means of Light-harvesting Complex II Changes¶

Photochemistry and Photobiology ◽

10.1562/2004-04-01-ra-130.1 ◽

2004 ◽

Vol 80 (3) ◽

pp. 499 ◽

Cited By ~ 29

Author(s):

Liliana Sfichi ◽

Nikolaos Ioannidis ◽

Kiriakos Kotzabasis

Keyword(s):

Light Harvesting ◽

Photosynthetic Apparatus ◽

Light Harvesting Complex ◽

Complex Ii ◽

Light Harvesting Complex Ii

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Direct Evidence for Excitation Energy Transfer Limitations Imposed by Low-Energy Chlorophylls in Photosystem I–Light Harvesting Complex I of Land Plants

The Journal of Physical Chemistry B ◽

10.1021/acs.jpcb.1c01498 ◽

2021 ◽

Author(s):

Mattia Russo ◽

Anna Paola Casazza ◽

Giulio Cerullo ◽

Stefano Santabarbara ◽

Margherita Maiuri

Keyword(s):

Energy Transfer ◽

Excitation Energy ◽

Photosystem I ◽

Complex I ◽

Direct Evidence ◽

Light Harvesting ◽

Excitation Energy Transfer ◽

Low Energy ◽

Land Plants ◽

Light Harvesting Complex

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

Plant Physiology ◽

10.1093/plphys/kiab091 ◽

2021 ◽

Cited By ~ 1

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.

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