scholarly journals Dissecting pigment architecture of individual photosynthetic antenna complexes in solution

2015 ◽  
Vol 112 (45) ◽  
pp. 13880-13885 ◽  
Author(s):  
Quan Wang ◽  
W. E. Moerner
Keyword(s):  
Single Molecule ◽  
Light Harvesting ◽  
Fluorescent Proteins ◽  
Protein Complexes ◽  
Photophysical Properties ◽  
Critical Role ◽  
Photosynthetic Pigment ◽  
Emergent Properties ◽  
Aqueous Environment ◽  
Harvesting Systems

Oligomerization plays a critical role in shaping the light-harvesting properties of many photosynthetic pigment−protein complexes, but a detailed understanding of this process at the level of individual pigments is still lacking. To study the effects of oligomerization, we designed a single-molecule approach to probe the photophysical properties of individual pigment sites as a function of protein assembly state. Our method, based on the principles of anti-Brownian electrokinetic trapping of single fluorescent proteins, step-wise photobleaching, and multiparameter spectroscopy, allows pigment-specific spectroscopic information on single multipigment antennae to be recorded in a nonperturbative aqueous environment with unprecedented detail. We focus on the monomer-to-trimer transformation of allophycocyanin (APC), an important antenna protein in cyanobacteria. Our data reveal that the two chemically identical pigments in APC have different roles. One (α) is the functional pigment that red-shifts its spectral properties upon trimer formation, whereas the other (β) is a “protective” pigment that persistently quenches the excited state of α in the prefunctional, monomer state of the protein. These results show how subtleties in pigment organization give rise to functionally important aspects of energy transfer and photoprotection in antenna complexes. The method developed here should find immediate application in understanding the emergent properties of other natural and artificial light-harvesting systems.

scholarly journals Structure, Dynamics, and Function in the Major Light-Harvesting Complex of Photosystem II

2012 ◽  
Vol 65 (6) ◽  
pp. 583 ◽  
Author(s):  
Gabriela S. Schlau-Cohen ◽  
Graham R. Fleming
Keyword(s):  
Excited State ◽  
Photosystem Ii ◽  
Light Harvesting ◽  
Protein Complexes ◽  
Electronic Spectroscopy ◽  
Emergent Properties ◽  
Light Harvesting Complex ◽  
Natural Systems ◽  
Harvesting Systems ◽  
And Function

In natural light-harvesting systems, pigment-protein complexes (PPC) convert sunlight to chemical energy with near unity quantum efficiency. PPCs exhibit emergent properties that cannot be simply extrapolated from knowledge of their component parts. In this Perspective, we examine the design principles of PPCs, focussing on the major light-harvesting complex of Photosystem II (LHCII), the most abundant PPC in green plants. Studies using two-dimensional electronic spectroscopy (2DES) provide an incisive tool to probe the electronic, energetic, and spatial landscapes that enable the efficiency observed in photosynthetic light-harvesting. Using the information about energy transfer pathways, quantum effects, and excited state geometry contained within 2D spectra, the excited state properties can be linked back to the molecular structure. This understanding of the structure-function relationships of natural systems constitutes a step towards a blueprint for the construction of artificial light-harvesting devices that can reproduce the efficacy of natural systems.

Variabilität des "light-harvesting-systems" im Zellzyklus von Chlorella fusca / Variability of the Light-Harvesting-System during the Cell Cycle of Chlorella fusca

1985 ◽  
Vol 40 (1-2) ◽  
pp. 115-121 ◽  
Author(s):  
Peter Brandt ◽  
Helene Gleibs ◽  
Andrea Kohne ◽  
Wolfgang Wiessner
Keyword(s):  
Cell Cycle ◽  
Light Harvesting ◽  
Higher Plants ◽  
Protein Complexes ◽  
Light Period ◽  
Chlorella Fusca ◽  
Chlorophyll Accumulation ◽  
Harvesting Systems ◽  
Chlorophyll Protein Complexes ◽  
Chlorophyll Protein

The seven chlorophyll-protein complexes CPIa, CPI, LHCP1, LHCP2, CPa, LHCP1 and LHCP11 known in part also from the chloroplasts of higher plants were isolated from Chlorella fusca. They were characterized by their molecular weight, their absorption maxima and their ratio of chlorophyll a/chlorophyll b. The composition of the chloropyhll-protein complexes changes during the cell cycle of Chlorella fusca. The ratio of LHCP/CPI decreases at the beginning of the light period and the ratio LHCP/CPa after the 2nd hour of the light period. Both quotients increase at the 5th hour of the light period, have a maximum at the 8th hour of the light period and decrease afterwards during the second part of the cell cycle. These altera­tions are no reflections of chlorophyll-accumulation, but cause modifications in the organization of the thylakoids and influence the photosynthetic efficiency of Chlorella fusca. The size of the PSI- and PSII-units during the cell cycle was estimated by these changes of the LHCP/CPI- and LHCP/CPa-ratios. In addition evidence is given that the assembly of LHCP1 and LHCP2 is no simple association of the monomeric forms of LHCPI or LHCPII.

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.

Exciton Self Trapping in Photosynthetic Pigment–Protein Complexes Studied by Single-Molecule Spectroscopy

2012 ◽  
Vol 116 (36) ◽  
pp. 11017-11023 ◽  
Author(s):  
Ralf Kunz ◽  
Kõu Timpmann ◽  
June Southall ◽  
Richard J. Cogdell ◽  
Arvi Freiberg ◽  
...  
Keyword(s):  
Single Molecule ◽  
Protein Complexes ◽  
Photosynthetic Pigment ◽  
Single Molecule Spectroscopy ◽  
Self Trapping ◽  
Pigment Protein Complexes

Hybrid Nanostructures for Enhanced Light-Harvesting: Plasmon Induced Increase in Fluorescence from Individual Photosynthetic Pigment–Protein Complexes

Nano Letters ◽  
2011 ◽  
Vol 11 (11) ◽  
pp. 4897-4901 ◽  
Author(s):  
Sebastian R. Beyer ◽  
Simon Ullrich ◽  
Stefan Kudera ◽  
Alastair T. Gardiner ◽  
Richard J. Cogdell ◽  
...  
Keyword(s):  
Light Harvesting ◽  
Protein Complexes ◽  
Photosynthetic Pigment ◽  
Hybrid Nanostructures ◽  
Pigment Protein Complexes

scholarly journals Silver Island Film for Enhancing Light Harvesting in Natural Photosynthetic Proteins

2020 ◽  
Vol 21 (7) ◽  
pp. 2451 ◽  
Author(s):  
Dorota Kowalska ◽  
Marcin Szalkowski ◽  
Karolina Sulowska ◽  
Dorota Buczynska ◽  
Joanna Niedziolka-Jonsson ◽  
...  
Keyword(s):  
Light Harvesting ◽  
Protein Complexes ◽  
Photosynthetic Pigment ◽  
Functional Materials ◽  
Photosynthetic Reaction Centers ◽  
Light Harvesting Complexes ◽  
Pigment Protein Complexes ◽  
Chlorophyll Protein ◽  
Silver Island ◽  
Photosynthetic Complexes

The effects of combining naturally evolved photosynthetic pigment–protein complexes with inorganic functional materials, especially plasmonically active metallic nanostructures, have been a widely studied topic in the last few decades. Besides other applications, it seems to be reasonable using such hybrid systems for designing future biomimetic solar cells. In this paper, we describe selected results that point out to various aspects of the interactions between photosynthetic complexes and plasmonic excitations in Silver Island Films (SIFs). In addition to simple light-harvesting complexes, like peridinin-chlorophyll-protein (PCP) or the Fenna–Matthews–Olson (FMO) complex, we also discuss the properties of large, photosynthetic reaction centers (RCs) and Photosystem I (PSI)—both prokaryotic PSI core complexes and eukaryotic PSI supercomplexes with attached antenna clusters (PSI-LHCI)—deposited on SIF substrates.

The lutein epoxide cycle in higher plants: its relationships to other xanthophyll cycles and possible functions

2007 ◽  
Vol 34 (9) ◽  
pp. 759 ◽  
Author(s):  
Jose I. García-Plazaola ◽  
Shizue Matsubara ◽  
C. Barry Osmond
Keyword(s):  
Light Harvesting ◽  
Higher Plants ◽  
Protein Complexes ◽  
Light Exposure ◽  
Photosynthetic Pigment ◽  
In Vivo Studies ◽  
Photochemical Quenching ◽  
Strong Light

Several xanthophyll cycles have been described in photosynthetic organisms. Among them, only two are present in higher plants: the ubiquitous violaxanthin (V) cycle, and the taxonomically restricted lutein epoxide (Lx) cycle, whereas four cycles seem to occur in algae. Although V is synthesised through the β-branch of the carotenoid biosynthetic pathway and Lx is the product of the α-branch; both are co-located in the same sites of the photosynthetic pigment-protein complexes isolated from thylakoids. Both xanthophylls are also de-epoxidised upon light exposure by the same enzyme, violaxanthin de-epoxidase (VDE) leading to the formation of zeaxanthin (Z) and lutein (L) at comparable rates. In contrast with VDE, the reverse reaction presumably catalysed by zeaxanthin epoxidase (ZE), is much slower (or even inactive) with L than with antheraxanthin (A) or Z. Consequently many species lack Lx altogether, and although the presence of Lx shows an irregular taxonomical distribution in unrelated taxa, it has a high fidelity at family level. In those plants which accumulate Lx, variations in ZE activity in vivo mean that a complete Lx-cycle occurs in some (with Lx pools being restored overnight), whereas in others a truncated cycle is observed in which VDE converts Lx into L, but regeneration of Lx by ZE is extremely slow. Accumulation of Lx to high concentrations is found most commonly in old leaves in deeply shaded canopies, and the Lx cycle in these leaves is usually truncated. This seemingly anomalous situation presumably arises because ZE has a low but finite affinity for L, and because deeply shaded leaves are not often exposed to light intensities strong enough to activate VDE. Notably, both in vitro and in vivo studies have recently shown that accumulation of Lx can increase the light harvesting efficiency in the antennae of PSII. We propose a model for the truncated Lx cycle in strong light in which VDE converts Lx to L which then occupies sites L2 and V1 in the light-harvesting antenna complex of PSII (Lhcb), displacing V and Z. There is correlative evidence that this photoconverted L facilitates energy dissipation via non-photochemical quenching and thereby converts a highly efficient light harvesting system to an energy dissipating system with improved capacity to engage photoprotection. Operation of the α- and β-xanthophyll cycles with different L and Z epoxidation kinetics thus allows a combination of rapidly and slowly reversible modulation of light harvesting and photoprotection, with each cycle having distinct effects. Based on the patchy taxonomical distribution of Lx, we propose that the presence of Lx (and the Lx cycle) could be the result of a recurrent mutation in the epoxidase gene that increases its affinity for L, which is conserved whenever it confers an evolutionary advantage.

The influence of bridging ligand electronic structure on the photophysical properties of noble metal diimine and triimine light harvesting systems

2006 ◽  
Vol 87 (1) ◽  
pp. 83-103 ◽  
Author(s):  
Xian-yong Wang ◽  
Andre Del Guerzo ◽  
Sujoy Baitalik ◽  
Gerald Simon ◽  
George B. Shaw ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Noble Metal ◽  
Light Harvesting ◽  
Photophysical Properties ◽  
Bridging Ligand ◽  
Harvesting Systems

scholarly journals The orf162b Sequence ofRhodobacter capsulatus Encodes a Protein Required for Optimal Levels of Photosynthetic Pigment-Protein Complexes

2000 ◽  
Vol 182 (19) ◽  
pp. 5440-5447 ◽  
Author(s):  
Muktak Aklujkar ◽  
Andrea L. Harmer ◽  
Roger C. Prince ◽  
J. Thomas Beatty
Keyword(s):  
Rhodobacter Capsulatus ◽  
Light Harvesting ◽  
Protein Complexes ◽  
Photosynthetic Pigment ◽  
Photosynthetic Apparatus ◽  
Coding Region ◽  
Reading Frame ◽  
Light Harvesting Complex ◽  
Pseudostationary Phase ◽  
Light Harvesting Complex Ii

ABSTRACT The orf162b sequence, the second open reading frame 3′ of the reaction center (RC) H protein gene puhA in theRhodobacter capsulatus photosynthesis gene cluster, is shown to be transcribed from a promoter located 5′ of puhA. A nonpolar mutation of orf162b was generated by replacing most of the coding region with an antibiotic resistance cartridge. Although the mutant strain initiated rapid photosynthetic growth, growth slowed progressively and cultures often entered a pseudostationary phase. The amounts of the RC and light harvesting complex I (LHI) in cells obtained from such photosynthetic cultures were abnormally low, but these deficiencies were less severe when the mutant was grown to a pseudostationary phase induced by low aeration in the absence of illumination. The orf162b mutation did not significantly affect the expression of apufB::lacZ translationally in-frame gene fusion under the control of the puf promoter, indicating normal transcription and translation of RC and LHI genes. Spontaneous secondary mutations in the strain with theorf162b disruption resulted in a bypass of the photosynthetic growth retardation and reduced the level of light harvesting complex II. These results and the presence of sequences similar to orf162b in other species indicate that the Orf162b protein is required for normal levels of the photosynthetic apparatus in purple photosynthetic bacteria.

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