Single-molecule exploration of photoprotective mechanisms in light-harvesting complexes

2015 ◽  
Author(s):  
Hsiang-Yu Yang ◽  
Gabriela S. Schlau-Cohen ◽  
Michal Gwizdala ◽  
Tjaart Krüger ◽  
Pengqi Xu ◽  
...  
Keyword(s):  
Single Molecule ◽  
Light Harvesting ◽  
Light Harvesting Complexes

scholarly journals From isolated light-harvesting complexes to the thylakoid membrane: a single-molecule perspective

Nanophotonics ◽  
2018 ◽  
Vol 7 (1) ◽  
pp. 81-92 ◽  
Author(s):  
J. Michael Gruber ◽  
Pavel Malý ◽  
Tjaart P.J. Krüger ◽  
Rienk van Grondelle
Keyword(s):  
Single Molecule ◽  
Thylakoid Membrane ◽  
Light Harvesting ◽  
Protein Complexes ◽  
Conformational Dynamics ◽  
Physical Models ◽  
Photochemical Quenching ◽  
Light Harvesting Complexes ◽  
Fluorescence Measurements

AbstractThe conversion of solar radiation to chemical energy in plants and green algae takes place in the thylakoid membrane. This amphiphilic environment hosts a complex arrangement of light-harvesting pigment-protein complexes that absorb light and transfer the excitation energy to photochemically active reaction centers. This efficient light-harvesting capacity is moreover tightly regulated by a photoprotective mechanism called non-photochemical quenching to avoid the stress-induced destruction of the catalytic reaction center. In this review we provide an overview of single-molecule fluorescence measurements on plant light-harvesting complexes (LHCs) of varying sizes with the aim of bridging the gap between the smallest isolated complexes, which have been well-characterized, and the native photosystem. The smallest complexes contain only a small number (10–20) of interacting chlorophylls, while the native photosystem contains dozens of protein subunits and many hundreds of connected pigments. We discuss the functional significance of conformational dynamics, the lipid environment, and the structural arrangement of this fascinating nano-machinery. The described experimental results can be utilized to build mathematical-physical models in a bottom-up approach, which can then be tested on larger in vivo systems. The results also clearly showcase the general property of biological systems to utilize the same system properties for different purposes. In this case it is the regulated conformational flexibility that allows LHCs to switch between efficient light-harvesting and a photoprotective function.

Single Molecule Spectroscopy of Oriented Recombinant Trimeric Light Harvesting Complexes of Higher Plants

2002 ◽  
Vol 3 (4) ◽  
pp. 183-188 ◽  
Author(s):  
Uwe Gerken ◽  
Henriette Wolf-Klein ◽  
Christine Huschenbett ◽  
Britta Götze ◽  
Sebastian Schuler ◽  
...  
Keyword(s):  
Single Molecule ◽  
Light Harvesting ◽  
Higher Plants ◽  
Single Molecule Spectroscopy ◽  
Light Harvesting Complexes

Individual LH3 (B800-820) Light-Harvesting Complexes Studied by Optical Single-Molecule Spectroscopy

2002 ◽  
Vol 3 (5-6) ◽  
pp. 319-320 ◽  
Author(s):  
S. Oellerich ◽  
M. Ketelaars ◽  
J.-M. Segura ◽  
G. Margis ◽  
W. de Ruijter ◽  
...  
Keyword(s):  
Single Molecule ◽  
Light Harvesting ◽  
Single Molecule Spectroscopy ◽  
Light Harvesting Complexes

scholarly journals Metal-Enhanced Fluorescence of Chlorophylls in Single Light-Harvesting Complexes

2009 ◽  
Vol 1208 ◽  
Author(s):  
Sebastian Mackowski ◽  
Dawid Piatkowski ◽  
Stephan Wörmke ◽  
Achim Hartschuh ◽  
Christoph Bräeuchle ◽  
...  
Keyword(s):  
Single Molecule ◽  
Light Harvesting ◽  
Protein Complexes ◽  
Fluorescence Emission ◽  
Fold Increase ◽  
Metal Nanoparticle ◽  
Metal Nanostructures ◽  
Enhanced Fluorescence ◽  
Light Harvesting Complexes ◽  
Light Harvesting Complex

AbstractWe show that the fluorescence of peridinin-chlorophyll a-protein complexes can be strongly enhanced via coupling with plasmon excitations localized in metal nanostructures. The results of ensemble and single-molecule spectroscopy experiments at room temperature demonstrate six-fold increase of the emission intensity of the light-harvesting complex when it is placed in the vicinity of chemically prepared silver islands. Irrespective of the enhancement, we observe no effect of the metal nanoparticle on the fluorescence emission energy of the complex. This observation implies that plasmon excitations may be applied for controlling the optical properties of complex biomolecules.

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

2017 ◽  
Vol 114 (52) ◽  
pp. E11063-E11071 ◽  
Author(s):  
Tjaart P. J. Krüger ◽  
Pavel Malý ◽  
Maxime T. A. Alexandre ◽  
Tomáš Mančal ◽  
Claudia Büchel ◽  
...  
Keyword(s):  
Excitation Energy ◽  
Single Molecule ◽  
Light Harvesting ◽  
Excitation Energy Transfer ◽  
Direct Result ◽  
Light Harvesting Complexes ◽  
Light Harvesting Complex ◽  
Enhanced Sensitivity ◽  
Excitonic Interactions ◽  
Excitonic Coupling

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) a’s, despite a high pigment density. Here, we show, using single-molecule spectroscopy, that the FCP complexes of Cyclotella meneghiniana 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 a 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.

scholarly journals Noise-Assisted Discord-Like Correlations in Light-Harvesting Photosynthetic Complexes

2021 ◽  
Vol 3 (2) ◽  
pp. 262-271
Author(s):  
Pablo Reséndiz-Vázquez ◽  
Ricardo Román-Ancheyta ◽  
Roberto León-Montiel
Keyword(s):  
Potential Role ◽  
Energy Transport ◽  
Light Harvesting ◽  
Quantum Correlations ◽  
Transport Processes ◽  
Quantum Evolution ◽  
Light Harvesting Complexes ◽  
Transport Efficiency ◽  
Photovoltaic Materials ◽  
Photosynthetic Complexes

Transport phenomena in photosynthetic systems have attracted a great deal of attention due to their potential role in devising novel photovoltaic materials. In particular, energy transport in light-harvesting complexes is considered quite efficient due to the balance between coherent quantum evolution and decoherence, a phenomenon coined Environment-Assisted Quantum Transport (ENAQT). Although this effect has been extensively studied, its behavior is typically described in terms of the decoherence’s strength, namely weak, moderate or strong. Here, we study the ENAQT in terms of quantum correlations that go beyond entanglement. Using a subsystem of the Fenna–Matthews–Olson complex, we find that discord-like correlations maximize when the subsystem’s transport efficiency increases, while the entanglement between sites vanishes. Our results suggest that quantum discord is a manifestation of the ENAQT and highlight the importance of beyond-entanglement correlations in photosynthetic energy transport processes.

scholarly journals Fast Diffusion of the Unassembled PetC1-GFP Protein in the Cyanobacterial Thylakoid Membrane

Life ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 15
Author(s):  
Radek Kaňa ◽  
Gábor Steinbach ◽  
Roman Sobotka ◽  
György Vámosi ◽  
Josef Komenda
Keyword(s):  
Membrane Proteins ◽  
Single Molecule ◽  
Protein Interactions ◽  
Thylakoid Membrane ◽  
Protein Complexes ◽  
Correlation Spectroscopy ◽  
Membrane Microdomains ◽  
Fast Diffusion ◽  
Light Harvesting Complexes ◽  
Term Survival

Biological membranes were originally described as a fluid mosaic with uniform distribution of proteins and lipids. Later, heterogeneous membrane areas were found in many membrane systems including cyanobacterial thylakoids. In fact, cyanobacterial pigment–protein complexes (photosystems, phycobilisomes) form a heterogeneous mosaic of thylakoid membrane microdomains (MDs) restricting protein mobility. The trafficking of membrane proteins is one of the key factors for long-term survival under stress conditions, for instance during exposure to photoinhibitory light conditions. However, the mobility of unbound ‘free’ proteins in thylakoid membrane is poorly characterized. In this work, we assessed the maximal diffusional ability of a small, unbound thylakoid membrane protein by semi-single molecule FCS (fluorescence correlation spectroscopy) method in the cyanobacterium Synechocystis sp. PCC6803. We utilized a GFP-tagged variant of the cytochrome b6f subunit PetC1 (PetC1-GFP), which was not assembled in the b6f complex due to the presence of the tag. Subsequent FCS measurements have identified a very fast diffusion of the PetC1-GFP protein in the thylakoid membrane (D = 0.14 − 2.95 µm2s−1). This means that the mobility of PetC1-GFP was comparable with that of free lipids and was 50–500 times higher in comparison to the mobility of proteins (e.g., IsiA, LHCII—light-harvesting complexes of PSII) naturally associated with larger thylakoid membrane complexes like photosystems. Our results thus demonstrate the ability of free thylakoid-membrane proteins to move very fast, revealing the crucial role of protein–protein interactions in the mobility restrictions for large thylakoid protein complexes.

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