Photosynthesis, Pigment–Protein Complexes and Electronic Energy Transport: Simple Models for Complicated Processes

2017 ◽  
Vol 100 (3) ◽  
pp. 313-330
Author(s):  
Lewis A. Baker ◽  
Scott Habershon
Keyword(s):  
Energy Transport ◽  
Environmental Changes ◽  
Protein Complexes ◽  
Electronic Energy ◽  
Quantum Dynamic ◽  
Transport Networks ◽  
Light Harvesting Complex ◽  
Light Harvesting Complex Ii ◽  
Pigment Protein Complexes ◽  
Qualitative Picture

In this review, we discuss our recent work on modelling biological pigment–protein complexes, such as the Fenna–Matthews–Olson complex and light-harvesting complex-II, to explain their electronic energy transport properties. In particular, we highlight how a network-based analysis approach, where the light-absorbing pigments are treated as a network of interconnected nodes, can provide a qualitative picture of quantum dynamic energy transport. With this in mind, we demonstrate how other properties such as robustness to environmental changes can be assessed in a simple and computationally tractable manner. Such analyses could prove useful for the design of artificial energy transport networks such as those which might find application in solar cells.

Research on Entanglement and Coherence in Light Harvesting Complex during Photosynthesis

2013 ◽  
Vol 641-642 ◽  
pp. 927-930
Author(s):  
Xing Yu Guan ◽  
J. Chee
Keyword(s):  
Energy Transport ◽  
Light Harvesting ◽  
Protein Complexes ◽  
Green Plant ◽  
Light Harvesting Complex ◽  
Transport Efficiency ◽  
The Past ◽  
Pigment Protein Complexes

Photosynthesis is a wonderful phenomenon which is present in green plant. In recent years, it has been discovered that there is entanglement in the biological pigment protein complexes, and that may be the reason of high transport efficiency. And coherence also plays an important role during the process of this efficiency energy transport. However, some scientists consider that it is not at all clear entanglement exists in the FMO complex, or unlike coherence, its role for the transport efficiency seems to be irrelevant. This paper mainly introduces what progress have scientists made during the past few years.

scholarly journals Structure of the stress-related LHCSR1 complex determined by an integrated computational strategy

2021 ◽  
Author(s):  
Ingrid Guarnetti Prandi ◽  
Vladislav Sláma ◽  
Cristina Pecorilla ◽  
Lorenzo Cupellini ◽  
Benedetta Mennucci
Keyword(s):  
Structural Model ◽  
Light Harvesting ◽  
Structural Information ◽  
Protein Complexes ◽  
Complex Stress ◽  
Main Function ◽  
Light Harvesting Complexes ◽  
Light Harvesting Complex ◽  
Pigment Protein Complexes ◽  
Computational Strategy

Light-harvesting complexes (LHCs) are pigment-protein complexes whose main function is to capture sunlight and transfer the energy to reaction centers of photosystems. In response to varying light conditions, LH complexes also play photoregulation and photoprotection roles. In algae and mosses, a sub-family of LHCs, Light-Harvesting complex stress related (LHCSR), is responsible for photoprotective quenching. Despite their functional and evolutionary importance, no direct structural information on LHCSRs is available that can explain their unique properties. In this work we propose a structural model of LHCSR1 from the moss P. Patens, obtained through an integrated computational strategy that combines homology modeling, molecular dynamics, and multiscale quantum chemical calculations. The model is validated by reproducing the spectral properties of LHCSR1. Our model reveals the structural specificity of LHCSR1, as compared with the CP29 LH complex, and poses the basis for understanding photoprotective quenching in mosses.

scholarly journals Electronic coherence lifetimes of the Fenna–Matthews–Olson complex and light harvesting complex II

2019 ◽  
Vol 10 (45) ◽  
pp. 10503-10509 ◽  
Author(s):  
Shawn Irgen-Gioro ◽  
Karthik Gururangan ◽  
Rafael G. Saer ◽  
Robert E. Blankenship ◽  
Elad Harel
Keyword(s):  
Energy Transport ◽  
Light Harvesting ◽  
Light Harvesting Complex ◽  
Complex Ii ◽  
Efficient Energy ◽  
Naturally Occurring ◽  
Light Harvesting Complex Ii ◽  
Electronic Coherence ◽  
Excitonic States

The study of coherence between excitonic states in naturally occurring photosynthetic systems offers tantalizing prospects for uncovering mechanisms of efficient energy transport.

Significance of protein crowding, order and mobility for photosynthetic membrane functions

2008 ◽  
Vol 36 (5) ◽  
pp. 967-970 ◽  
Author(s):  
Helmut Kirchhoff
Keyword(s):  
Large Scale ◽  
Protein Complexes ◽  
Photosynthetic Apparatus ◽  
Lateral Diffusion ◽  
Functional Communication ◽  
Protein Diffusion ◽  
Higher Plant ◽  
Photosynthetic Membrane ◽  
Light Harvesting Complex ◽  
Light Harvesting Complex Ii

Natural photosynthesis requires diffusion-based processes either for the functional communication of protein complexes or for the adaptation, maintenance and biogenesis of the photosynthetic apparatus. A conceptual problem with lateral diffusion in photosynthetic membranes arises from the fact that these membranes are densely packed with membrane integral protein complexes (molecular crowding). Theoretical analysis of PQ (plastoquinone) and protein diffusion in higher plant grana thylakoids reveal very inefficient lateral diffusion. In contrast, measurement of protein mobility in grana membranes shows that a fraction of protein complexes can move surprisingly fast. It is postulated that organization of protein complexes in supercomplexes and large-scale ordering of Photosystem II and light-harvesting complex II could be strategies for the optimization of diffusion in crowded thylakoid membranes.

Composition and regulation of thylakoid membrane of Antarctic ice microalgae Chlamydomonas sp. ICE-L in response to low-temperature environment stress

2016 ◽  
Vol 97 (6) ◽  
pp. 1241-1249 ◽  
Author(s):  
Wang Yi-Bin ◽  
Liu Fang-Ming ◽  
Zhang Xiu-Fang ◽  
Zhang Ai-Jun ◽  
Wang Bin ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Low Temperature ◽  
Protein Complexes ◽  
Thylakoid Membranes ◽  
Ice Algae ◽  
Stress Concentrations ◽  
Light Harvesting Complex ◽  
Pigment Protein Complexes ◽  
Environment Stress ◽  
The Antarctic

Ice algae have successfully adapted to the extreme environmental conditions in the Antarctic, however the underlying mechanisms involved in the regulation and response of thylakoid membranes and chloroplast to low-temperature stress are still not well understood. In this study, changes in pigment concentrations, lipids, fatty acids and pigment protein complexes in thylakoid membranes and chloroplast after exposure to low temperature conditions were investigated using the Antarctic ice algae Chlamydomonas sp. ICE-L. Results showed that the chloroplasts of Chlamydomonas sp. ICE-L are distributed throughout the cell except in the nuclear region in the form of thylakoid lamellas which exists in the gap between organelles and the starch granules. Also, the structure of mitochondria has no obvious change after cold stress. Concentrations of Chl a, Chl b, monogalactosyl diacylglycerol, digalactosyl diacylglycerol and fatty acids were also observed to exhibit changes with temperature, suggesting possible adaptations to cold environments. The light harvesting complex, lutein and β-carotene played an important role for adaptation of ICE-L, and increasing of monogalactosyl diacylglycerol and digalactosyl diacylglycerol improved the overall degree of unsaturation of thylakoid membranes, thereby maintaining liquidity of thylakoid membranes. The pigments, lipids, fatty acids and pigment-protein complexes maintained the stability of the thylakoid membranes and the normal physiological function of Chlamydomonas sp. ICE-L.

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.

scholarly journals Photosynthetic pigment-protein complexes as highly connected networks: implications for robust energy transport

2017 ◽  
Vol 473 (2201) ◽  
pp. 20170112 ◽  
Author(s):  
Lewis A. Baker ◽  
Scott Habershon
Keyword(s):  
Energy Transport ◽  
Light Harvesting ◽  
Higher Plants ◽  
Protein Complexes ◽  
Photosynthetic Pigment ◽  
Excitation Energy Transfer ◽  
Reaction Centre ◽  
Lhc Ii ◽  
Pigment Protein Complexes

Photosynthetic pigment-protein complexes (PPCs) are a vital component of the light-harvesting machinery of all plants and photosynthesizing bacteria, enabling efficient transport of the energy of absorbed light towards the reaction centre, where chemical energy storage is initiated. PPCs comprise a set of chromophore molecules, typically bacteriochlorophyll species, held in a well-defined arrangement by a protein scaffold; this relatively rigid distribution leads to a viewpoint in which the chromophore subsystem is treated as a network, where chromophores represent vertices and inter-chromophore electronic couplings represent edges. This graph-based view can then be used as a framework within which to interrogate the role of structural and electronic organization in PPCs. Here, we use this network-based viewpoint to compare excitation energy transfer (EET) dynamics in the light-harvesting complex II (LHC-II) system commonly found in higher plants and the Fenna-Matthews-Olson (FMO) complex found in green sulfur bacteria. The results of our simple network-based investigations clearly demonstrate the role of network connectivity and multiple EET pathways on the efficient and robust EET dynamics in these PPCs, and highlight a role for such considerations in the development of new artificial light-harvesting systems.

scholarly journals Absorption Properties of the Carotenoids after Alkaline Denaturation of the Light-Harvesting Complex II from Ectothiorhodospira sp.

2000 ◽  
Vol 55 (7-8) ◽  
pp. 576-581
Author(s):  
Andre Buche ◽  
Rafael Picorel
Keyword(s):  
Environmental Changes ◽  
Light Harvesting ◽  
Visible Region ◽  
Soret Band ◽  
Alkaline Treatment ◽  
Absorption Bands ◽  
Absorption Properties ◽  
Light Harvesting Complex ◽  
Light Harvesting Complex Ii ◽  
Carotenoid Absorption

Abstract Alkaline treatment of the Ectothiorhodospira sp. light harvesting system II induces monomerisation of the bacteriochlorophylls and a bleaching of the carotenoid absorption bands in the visible region. Concomitantly, the maximum of absorption observed around 373 nm shifts towards 354 nm. This shift does not result from the Soret band but from a change of the absorption properties of the carotenoids. Furthermore, these pigments are not modified chemically but the spectral conversion results from environmental changes. It is assumed that the dissociation of the bacteriochlorophylls in alkaline medium is accompanied by a structural reorganisation of the complex which reinforces the interactions between the polypeptides and the carotenoids.

Seasonal variations of leaf chlorophyll–protein complexes in the wintergreen herbaceous plant Ajuga reptans L.

2018 ◽  
Vol 45 (5) ◽  
pp. 519 ◽  
Author(s):  
Olga Dymova ◽  
Mikhail Khristin ◽  
Zbigniew Miszalski ◽  
Andrzej Kornas ◽  
Kazimierz Strzalka ◽  
...  
Keyword(s):  
Protein Complexes ◽  
Carotenoid Content ◽  
Protective Mechanism ◽  
Herbaceous Plant ◽  
Light Harvesting Complex ◽  
Chl A ◽  
Ajuga Reptans ◽  
Light Harvesting Complex Ii ◽  
Different Seasons ◽  
Chlorophyll Protein Complexes

The chlorophyll and carotenoid content, and the spectra of low-temperature fluorescence of the leaves, chloroplasts and isolated pigment–protein complexes in the perennial herbaceous wintergreen plant Ajuga reptans L. (bugle) in different seasons of the year were studied. During winter, these plants downregulate photosynthesis and the PSA is reorganised, including the loss of chlorophyll, possible reductions in the number of functional reaction centres of PSII, and changes in aggregation of the thylakoid protein complexes. We also observed a restructuring of the PSI–PSII megacomplex and the PSII–light-harvesting complex II supercomplex in leaves covered by snow. After snowmelt, the monomeric form of the chl a/b pigment–protein complex associated with PSII (LHCII) and the free pigments were also detected. We expect that snow cover provides favourable conditions for keeping photosynthetic machinery ready for photosynthesis in spring just after snowmelt. During winter, the role of the zeaxanthin-dependent protective mechanism, which is responsible for the dissipation of excess absorbed light energy, is likely to increase.

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