Journal articles: 'Pigment proteine complexe'

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Luciński, Robert, and Grzegorz Jackowski. "The structure, functions and degradation of pigment-binding proteins of photosystem II." Acta Biochimica Polonica 53, no. 4 (November 14, 2006): 693–708. http://dx.doi.org/10.18388/abp.2006_3297.

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Eleven proteins belonging to photosystem II (PSII) bind photosynthetic pigments in the form of thylakoid membrane-associated pigment-protein complexes. Five of them (PsbA, PsbB, PsbC, PsbD and PsbS) are assigned to PSII core complex while the remaining six (Lhcb1, Lhcb2, Lhcb3, Lhcb4, Lhcb5 and Lhcb6) constitute, along with their pigments, functional complexes situated more distantly with regard to P680 - the photochemical center of PSII. The main function of the pigment-binding proteins is to harvest solar energy and deliver it, in the form of excitation energy, ultimately to P680 although individual pigment-proteins may be engaged in other photosynthesis-related processes as well. The aim of this review is to present the current state of knowledge regarding the structure, functions and degradation of this family of proteins.

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Wang, Quan, and W. E. Moerner. "Dissecting pigment architecture of individual photosynthetic antenna complexes in solution." Proceedings of the National Academy of Sciences 112, no. 45 (October 5, 2015): 13880–85. http://dx.doi.org/10.1073/pnas.1514027112.

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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.

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Deravi, Leila F., Andrew P. Magyar, Sean P. Sheehy, George R. R. Bell, Lydia M. Mäthger, Stephen L. Senft, Trevor J. Wardill, et al. "The structure–function relationships of a natural nanoscale photonic device in cuttlefish chromatophores." Journal of The Royal Society Interface 11, no. 93 (April 6, 2014): 20130942. http://dx.doi.org/10.1098/rsif.2013.0942.

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Cuttlefish, Sepia officinalis , possess neurally controlled, pigmented chromatophore organs that allow rapid changes in skin patterning and coloration in response to visual cues. This process of adaptive coloration is enabled by the 500% change in chromatophore surface area during actuation. We report two adaptations that help to explain how colour intensity is maintained in a fully expanded chromatophore when the pigment granules are distributed maximally: (i) pigment layers as thin as three granules that maintain optical effectiveness and (ii) the presence of high-refractive-index proteins—reflectin and crystallin—in granules. The latter discovery, combined with our finding that isolated chromatophore pigment granules fluoresce between 650 and 720 nm, refutes the prevailing hypothesis that cephalopod chromatophores are exclusively pigmentary organs composed solely of ommochromes. Perturbations to granular architecture alter optical properties, illustrating a role for nanostructure in the agile, optical responses of chromatophores. Our results suggest that cephalopod chromatophore pigment granules are more complex than homogeneous clusters of chromogenic pigments. They are luminescent protein nanostructures that facilitate the rapid and sophisticated changes exhibited in dermal pigmentation.

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Takeuchi, TS, and JP Thornber. "Heat-Induced Alterations in Thylakoid Membrane Protein Composition in Barley." Functional Plant Biology 21, no. 6 (1994): 759. http://dx.doi.org/10.1071/pp9940759.

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Biochemical and spectroscopic studies on the effects of high temperatures (45-47� C) over a 1 h period on the protein composition, fluorescence and photochemical activities of the barley thylakoid membrane were made. Photosystem II (PS II) activity decreased as expected, and photosystem I (PS I) activity also unexpectedly decreased. Our data support previous conclusions that the decrease in PS I activity is largely due to inactivation (or loss) of a component between the two photosystems. A two-dimensional electrophoretic system permitted first the separation of the thylakoid pigment-protein complexes of unstressed and stressed plants, followed by a determination of their subunit composition. The changes in the protein composition of each pigment-protein complex in response to elevated temperatures were monitored. Heat changed the quaternary structure of PS II and resulted in removal of the oxygen-evolving enhancer proteins from the thylakoid, but did essentially no damage to the PS I complex. The PS II core complex dissociated from a dimeric form to a monomeric one, and the major LHC II component (LHC IIb) changed from a trimeric to a monomeric form. The pigments that are lost from thylakoids during heat stress are mainly removed from the PS II pigment-proteins.

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Carpentier, Robert, Roger M. Leblanc, and Guy Bellemare. "Chlorophyll Photobleaching in Pigment-Protein Complexes." Zeitschrift für Naturforschung C 41, no. 3 (March 1, 1986): 284–90. http://dx.doi.org/10.1515/znc-1986-0307.

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Pigment photobleaching was performed in thylakoid membranes of Hordeum vulgare (wild type, mutant Chlorina f2, Norfluranzon treated seedlings) and in pigment-protein complexes (CP-I and LHCP) isolated from H. vulgare and Chlamydomonas reinhardtii. Multiphasic kinetics were obtained in all of the above cases. Energy transfer towards pigments absorbing at longer wavelength is postulated as a general protection mechanism against photobleaching. This mechanism explains a substantial bleaching of carotenoids and a faster bleaching of chlorophyll aggregates, absorbing at long wavelength. These conclusions were valid for isolated complexes as well as for thylakoid membranes, although membranes were less sensitive to light.

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De Vico, Luca, André Anda, Vladimir Al Osipov, Anders Ø. Madsen, and Thorsten Hansen. "Macrocycle ring deformation as the secondary design principle for light-harvesting complexes." Proceedings of the National Academy of Sciences 115, no. 39 (September 7, 2018): E9051—E9057. http://dx.doi.org/10.1073/pnas.1719355115.

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Natural light-harvesting is performed by pigment–protein complexes, which collect and funnel the solar energy at the start of photosynthesis. The identity and arrangement of pigments largely define the absorption spectrum of the antenna complex, which is further regulated by a palette of structural factors. Small alterations are induced by pigment–protein interactions. In light-harvesting systems 2 and 3 from Rhodoblastus acidophilus, the pigments are arranged identically, yet the former has an absorption peak at 850 nm that is blue-shifted to 820 nm in the latter. While the shift has previously been attributed to the removal of hydrogen bonds, which brings changes in the acetyl moiety of the bacteriochlorophyll, recent work has shown that other mechanisms are also present. Using computational and modeling tools on the corresponding crystal structures, we reach a different conclusion: The most critical factor for the shift is the curvature of the macrocycle ring. The bending of the planar part of the pigment is identified as the second-most important design principle for the function of pigment–protein complexes—a finding that can inspire the design of novel artificial systems.

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Krüger, Tjaart P. J., Pavel Malý, Maxime T. A. Alexandre, Tomáš Mančal, Claudia Büchel, and Rienk van Grondelle. "How reduced excitonic coupling enhances light harvesting in the main photosynthetic antennae of diatoms." Proceedings of the National Academy of Sciences 114, no. 52 (December 11, 2017): E11063—E11071. http://dx.doi.org/10.1073/pnas.1714656115.

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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.

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Dymova, Olga, Mikhail Khristin, Zbigniew Miszalski, Andrzej Kornas, Kazimierz Strzalka, and Tamara Golovko. "Seasonal variations of leaf chlorophyll–protein complexes in the wintergreen herbaceous plant Ajuga reptans L." Functional Plant Biology 45, no. 5 (2018): 519. http://dx.doi.org/10.1071/fp17199.

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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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Lehto, Kirsi, Mikko Tikkanen, Jean-Baptiste Hiriart, Virpi Paakkarinen, and Eva-Mari Aro. "Depletion of the Photosystem II Core Complex in Mature Tobacco Leaves Infected by the Flavum Strain of Tobacco mosaic virus." Molecular Plant-Microbe Interactions® 16, no. 12 (December 2003): 1135–44. http://dx.doi.org/10.1094/mpmi.2003.16.12.1135.

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The flavum strain of Tobacco mosaic virus (TMV) differs from the wild-type (wt) virus by causing strong yellow and green mosaic in the systemically infected developing leaves, yellowing in the fully expanded leaves, and distinct malformations of chloroplasts in both types of infected tissues. Analysis of the thylakoid proteins of flavum strain-infected tobacco leaves indicated that the chlorosis in mature leaves was accompanied by depletion of the entire photosystem II (PSII) core complexes and the 33-kDa protein of the oxygen evolving complex. The only change observed in the thyla-koid proteins of the corresponding wt TMV-infected leaves was a slight reduction of the α and β subunits of the ATP synthase complex. The coat proteins of different yellowing strains of TMV are known to effectively accumulate inside chloroplasts, but in this work, the viral movement protein also was detected in association with the thylakoid membranes of flavum strain-infected leaves. The mRNAs of different enzymes involved in the chlorophyll biosynthesis pathway were not reduced in the mature chlorotic leaves. These results suggest that the chlorosis was not caused by reduction of pigment biosynthesis, but rather, by reduction of specific proteins of the PSII core complexes and by consequent break-down of the pigments.

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Milivojevic, D. B., D. D. Stojanovic, and S. D. Drinic. "Effects of Aluminium on Pigments and Pigment-Protein Complexes of Soybean." Biologia plantarum 43, no. 4 (December 1, 2000): 595–97. http://dx.doi.org/10.1023/a:1002899932075.

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11

Baker, Lewis A., and Scott Habershon. "Photosynthesis, Pigment–Protein Complexes and Electronic Energy Transport: Simple Models for Complicated Processes." Science Progress 100, no. 3 (September 2017): 313–30. http://dx.doi.org/10.3184/003685017x14967574639964.

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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.

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12

Huber, Robert. "Flexibility and Rigidity of Proteins and Protein–Pigment Complexes." Angewandte Chemie International Edition in English 27, no. 1 (January 1988): 79–88. http://dx.doi.org/10.1002/anie.198800791.

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Yi-Bin, Wang, Liu Fang-Ming, Zhang Xiu-Fang, Zhang Ai-Jun, Wang Bin, Zheng Zhou, Sun Cheng-Jun, and Miao Jin-Lai. "Composition and regulation of thylakoid membrane of Antarctic ice microalgae Chlamydomonas sp. ICE-L in response to low-temperature environment stress." Journal of the Marine Biological Association of the United Kingdom 97, no. 6 (May 6, 2016): 1241–49. http://dx.doi.org/10.1017/s0025315416000588.

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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.

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Köhler, J., A. M. van Oijen, M. Ketelaars, C. Hofmann, M. Matsushita, T. J. Aartsma, and J. Schmidt. "Optical Spectroscopy of Individual Photosynthetic Pigment Protein Complexes." International Journal of Modern Physics B 15, no. 28n30 (December 10, 2001): 3633–36. http://dx.doi.org/10.1142/s0217979201008317.

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Photosynthesis is the process by which plants, algae and photosynthetic bacteria convert solar energy into a form that can be used to sustain the life process. The light reactions occur in closely coupled pigment systems. The energy is absorbed by a network of antenna pigment proteins and efficiently transferred to the photochemical reaction centre where a charge separation takes place providing the free energy for subsequent chemical reactions. The total conversion process, starting with the absorption of a photon and ending with a stable charge separated state occurs within less than 50 ps and has an overall quantum yield of more than 90%. The success of this natural process is based on both the highly efficient absorption of photons by the light-harvesting antenna system and the rapid and efficient transfer of excitation energy to the reaction centre. It is known that most photosynthetic purple bacteria contain two types of antenna complexes, light-harvesting complex 1 (LH1) and light harvesting complex 2 (LH2) which both have a ring-like structure [1,2]. (Some bacterial species like Rhodopseudomonas acidophila contain a third light-harvesting complex termed B800-820.) The reaction centre (RC) presumably forms the core of the LH1 complex, while LH2 complexes are arranged around the perimeter of the LH1 ring in a two-dimensional structure. However the full three-dimensional structure of the whole photosynthetic unit is as yet unknown. The absorption of a photon (mainly) takes place in the LH2 pigments followed by a fast transfer of the excitation energy to the LH1 complex and subsequently to the reaction centre. It appears that the whole structure is highly optimized for capturing light energy and to funnel it to the reaction centre [3-7].

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Brotosudarmo, Tatas H. P., and Richard J. Cogdell. "STUDY ON THE STRUCTURAL BASIS OF PERIPHERAL LIGHT HARVESTING COMPLEXES (LH2) IN PURPLE NON-SULPHUR PHOTOSYNTHETIC BACTERIA." Indonesian Journal of Chemistry 10, no. 3 (December 14, 2010): 401–8. http://dx.doi.org/10.22146/ijc.21450.

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Photosynthesis provides an example of a natural process that has been optimized during evolution to harness solar energy efficiently and safely, and finally to use it to produce a carbon-based fuel. Initially, solar energy is captured by the light harvesting pigment-protein complexes. In purple bacteria these antenna complexes are constructed on a rather simple modular basis. Light absorbed by these antenna complexes is funnelled downhill to reaction centres, where light drives a trans-membrane redox reaction. The light harvesting proteins not only provide the scaffolding that correctly positions the bacteriochlorophyll a and carotenoid pigments for optimal energy transfer but also creates an environment that can modulate the wavelength at which different bacteriochlorophyll molecules absorb light thereby creating the energy funnel. How these proteins can modulate the absorption spectra of the bacteriochlorophylls will be discussed in this review.

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Nagarajan, Aparna, Mowei Zhou, Amelia Y. Nguyen, Michelle Liberton, Komal Kedia, Tujin Shi, Paul Piehowski, et al. "Proteomic Insights into Phycobilisome Degradation, A Selective and Tightly Controlled Process in The Fast-Growing Cyanobacterium Synechococcus elongatus UTEX 2973." Biomolecules 9, no. 8 (August 16, 2019): 374. http://dx.doi.org/10.3390/biom9080374.

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Phycobilisomes (PBSs) are large (3–5 megadalton) pigment-protein complexes in cyanobacteria that associate with thylakoid membranes and harvest light primarily for photosystem II. PBSs consist of highly ordered assemblies of pigmented phycobiliproteins (PBPs) and linker proteins that can account for up to half of the soluble protein in cells. Cyanobacteria adjust to changing environmental conditions by modulating PBS size and number. In response to nutrient depletion such as nitrogen (N) deprivation, PBSs are degraded in an extensive, tightly controlled, and reversible process. In Synechococcus elongatus UTEX 2973, a fast-growing cyanobacterium with a doubling time of two hours, the process of PBS degradation is very rapid, with 80% of PBSs per cell degraded in six hours under optimal light and CO2 conditions. Proteomic analysis during PBS degradation and re-synthesis revealed multiple proteoforms of PBPs with partially degraded phycocyanobilin (PCB) pigments. NblA, a small proteolysis adaptor essential for PBS degradation, was characterized and validated with targeted mass spectrometry. NblA levels rose from essentially 0 to 25,000 copies per cell within 30 min of N depletion, and correlated with the rate of decrease in phycocyanin (PC). Implications of this correlation on the overall mechanism of PBS degradation during N deprivation are discussed.

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Giuliani, Kurt T. K., Andrew J. Kassianos, Helen Healy, and Pedro H. F. Gois. "Pigment Nephropathy: Novel Insights into Inflammasome-Mediated Pathogenesis." International Journal of Molecular Sciences 20, no. 8 (April 23, 2019): 1997. http://dx.doi.org/10.3390/ijms20081997.

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Pigment nephropathy is an acute decline in renal function following the deposition of endogenous haem-containing proteins in the kidneys. Haem pigments such as myoglobin and haemoglobin are filtered by glomeruli and absorbed by the proximal tubules. They cause renal vasoconstriction, tubular obstruction, increased oxidative stress and inflammation. Haem is associated with inflammation in sterile and infectious conditions, contributing to the pathogenesis of many disorders such as rhabdomyolysis and haemolytic diseases. In fact, haem appears to be a signalling molecule that is able to activate the inflammasome pathway. Recent studies highlight a pathogenic function for haem in triggering inflammatory responses through the activation of the nucleotide-binding domain-like receptor protein 3 (NLRP3) inflammasome. Among the inflammasome multiprotein complexes, the NLRP3 inflammasome has been the most widely characterized as a trigger of inflammatory caspases and the maturation of interleukin-18 and -1β. In the present review, we discuss the latest evidence on the importance of inflammasome-mediated inflammation in pigment nephropathy. Finally, we highlight the potential role of inflammasome inhibitors in the prophylaxis and treatment of pigment nephropathy.

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Oba, Toru, and Hitoshi Tamiaki. "Asymmetry of chlorophylls in photosynthetic proteins: from the viewpoint of coordination chemistry." Journal of Porphyrins and Phthalocyanines 18, no. 10n11 (October 2014): 919–32. http://dx.doi.org/10.1142/s1088424614500710.

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We conducted a meta-analysis of (bacterio)chlorophyll [(B)Chl] molecules in photosynthetic pigment-protein complexes from the viewpoint of coordination chemistry. We surveyed the ligand species and site in the axial coordination of 146 Chl and 21 BChl molecules in 42 reported crystal structures of 12-type proteins. The imidazolyl moiety of histidine (His) is the most abundant ligand, and the second is water, a much weaker ligand. We focused on the positions, the circumstances, and the macrocycle sides for the coordination of the 31 hydrated (B)Chl molecules found in these proteins. A ligand water molecule of a hydrated (B)Chl is not necessarily hydrogen-bonded to the surrounding protein residues. A hydrated (B)Chl seems to occupy the redundant space where more strongly coupled His-Chl complexes cannot be formed. It is noted that 28 of 31 hydrated (B)Chl molecules (90) were coordinated from the α-side of the (bacterio)chlorin macrocycle, the opposite side from which the C 17-propionic ester protrudes. Among them, all five hydrated Chl molecules at the edges of the proteins were coordinated from the α-side, suggesting that (B)Chl molecules prefer this side for the coordination bondings to the β-side. The analysis also revealed that each (B)Chl binding site was composed of both the protein residues and the neighboring pigment molecules contributing roughly equally. It can be safely said that the cofactor pigments aggregated even in the proteins. Penta-coordination is advantageous to flexible adjustment of intermolecular orientations of (B)Chl molecules in the aggregates.

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Niedzwiedzki, Dariusz M., David J. K. Swainsbury, Daniel P. Canniffe, C. Neil Hunter, and Andrew Hitchcock. "A photosynthetic antenna complex foregoes unity carotenoid-to-bacteriochlorophyll energy transfer efficiency to ensure photoprotection." Proceedings of the National Academy of Sciences 117, no. 12 (March 5, 2020): 6502–8. http://dx.doi.org/10.1073/pnas.1920923117.

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Carotenoids play a number of important roles in photosynthesis, primarily providing light-harvesting and photoprotective energy dissipation functions within pigment–protein complexes. The carbon–carbon double bond (C=C) conjugation length of carotenoids (N), generally between 9 and 15, determines the carotenoid-to-(bacterio)chlorophyll [(B)Chl] energy transfer efficiency. Here we purified and spectroscopically characterized light-harvesting complex 2 (LH2) fromRhodobacter sphaeroidescontaining theN= 7 carotenoid zeta (ζ)-carotene, not previously incorporated within a natural antenna complex. Transient absorption and time-resolved fluorescence show that, relative to the lifetime of the S1state of ζ-carotene in solvent, the lifetime decreases ∼250-fold when ζ-carotene is incorporated within LH2, due to transfer of excitation energy to the B800 and B850 BChlsa. These measurements show that energy transfer proceeds with an efficiency of ∼100%, primarily via the S1→ Qxroute because the S1→ S0fluorescence emission of ζ-carotene overlaps almost perfectly with the Qxabsorption band of the BChls. However, transient absorption measurements performed on microsecond timescales reveal that, unlike the nativeN≥ 9 carotenoids normally utilized in light-harvesting complexes, ζ-carotene does not quench excited triplet states of BChla, likely due to elevation of the ζ-carotene triplet energy state above that of BChla. These findings provide insights into the coevolution of photosynthetic pigments and pigment–protein complexes. We propose that theN≥ 9 carotenoids found in light-harvesting antenna complexes represent a vital compromise that retains an acceptable level of energy transfer from carotenoids to (B)Chls while allowing acquisition of a new, essential function, namely, photoprotective quenching of harmful (B)Chl triplets.

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Knoetzel, Juergen, Thomas Braumann, and L. Horst Grimme. "Pigment—protein complexes of green algae: Improved methodological steps for the quantification of pigments in pigment—protein complexes derived from the green algae Chlorella and Chlamydomonas." Journal of Photochemistry and Photobiology B: Biology 1, no. 4 (May 1988): 475–91. http://dx.doi.org/10.1016/1011-1344(88)85009-7.

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Troschel, D., and M. Müller. "Development of a cell-free system to study the membrane assembly of photosynthetic proteins of Rhodobacter capsulatus." Journal of Cell Biology 111, no. 1 (July 1, 1990): 87–94. http://dx.doi.org/10.1083/jcb.111.1.87.

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A cell-free translation system from the facultatively photoheterotrophic bacterium Rhodobacter capsulatus is described. Synthesis of two proteins of the bacterium's photosynthetic apparatus (light-harvesting complex B870 alpha and beta) was performed by SP6 polymerase transcription of the subcloned genes, isolation of the mRNA and translation in vitro using a cell-free extract of R. capsulatus cells. The integration of these proteins in vitro into added intracytoplasmic membrane vesicles (ICM) is demonstrated. Without addition of ICM approximately 70% of the synthesized B870 proteins were soluble. If, however, ICM were present during synthesis, the majority of the soluble protein was found to associate with the membranes. The membrane-associated polypeptides could be solubilized only by detergent treatment but could not be extracted by treatment at alkaline pH (Na2CO3), suggesting that the proteins had been firmly inserted into the lipid bilayer. Moreover, the B870 alpha and beta proteins that integrated in vitro into ICM were also found to associate with pigment ligands and to assemble into a native reaction center/B870 complex. The native conformation of this complex isolated from ICM by Triton fractionation was demonstrated by microspectral analysis of the bound pigments.

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Timpmann, Kõu, Margus Rätsep, Liina Kangur, Alexandra Lehtmets, Zheng-Yu Wang-Otomo, and Arvi Freiberg. "Exciton Origin of Color-Tuning in Ca2+-Binding Photosynthetic Bacteria." International Journal of Molecular Sciences 22, no. 14 (July 8, 2021): 7338. http://dx.doi.org/10.3390/ijms22147338.

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Flexible color adaptation to available ecological niches is vital for the photosynthetic organisms to thrive. Hence, most purple bacteria living in the shade of green plants and algae apply bacteriochlorophyll a pigments to harvest near infra-red light around 850–875 nm. Exceptions are some Ca2+-containing species fit to utilize much redder quanta. The physical basis of such anomalous absorbance shift equivalent to ~5.5 kT at ambient temperature remains unsettled so far. Here, by applying several sophisticated spectroscopic techniques, we show that the Ca2+ ions bound to the structure of LH1 core light-harvesting pigment–protein complex significantly increase the couplings between the bacteriochlorophyll pigments. We thus establish the Ca-facilitated enhancement of exciton couplings as the main mechanism of the record spectral red-shift. The changes in specific interactions such as pigment–protein hydrogen bonding, although present, turned out to be secondary in this regard. Apart from solving the two-decade-old conundrum, these results complement the list of physical principles applicable for efficient spectral tuning of photo-sensitive molecular nano-systems, native or synthetic.

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Zeng, Xiaohua, Jung Hyeob Roh, Stephen J. Callister, Christine L. Tavano, Timothy J. Donohue, Mary S. Lipton, and Samuel Kaplan. "Proteomic Characterization of the Rhodobacter sphaeroides 2.4.1 Photosynthetic Membrane: Identification of New Proteins." Journal of Bacteriology 189, no. 20 (August 17, 2007): 7464–74. http://dx.doi.org/10.1128/jb.00946-07.

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ABSTRACT The Rhodobacter sphaeroides intracytoplasmic membrane (ICM) is an inducible membrane that is dedicated to the major events of bacterial photosynthesis, including harvesting light energy, separating primary charges, and transporting electrons. In this study, multichromatographic methods coupled with Fourier transform ion cyclotron resonance mass spectrometry, combined with subcellular fractionation, was used to test the hypothesis that the photosynthetic membrane of R. sphaeroides 2.4.1 contains a significant number of heretofore unidentified proteins in addition to the integral membrane pigment-protein complexes, including light-harvesting complexes 1 and 2, the photochemical reaction center, and the cytochrome bc 1 complex described previously. Purified ICM vesicles are shown to be enriched in several abundant, newly identified membrane proteins, including a protein of unknown function (AffyChip designation RSP1760) and a possible alkane hydroxylase (RSP1467). When the genes encoding these proteins are mutated, specific photosynthetic phenotypes are noted, illustrating the potential new insights into solar energy utilization to be gained by this proteomic blueprint of the ICM. In addition, proteins necessary for other cellular functions, such as ATP synthesis, respiration, solute transport, protein translocation, and other physiological processes, were also identified to be in association with the ICM. This study is the first to provide a more global view of the protein composition of a photosynthetic membrane from any source. This protein blueprint also provides insights into potential mechanisms for the assembly of the pigment-protein complexes of the photosynthetic apparatus, the formation of the lipid bilayer that houses these integral membrane proteins, and the possible functional interactions of ICM proteins with activities that reside in domains outside this specialized bioenergetic membrane.

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Allgood, Leonard, Robert D. Curtright, and John Markwell. "SOLUBILIZATION OF PHOTOSYNTHETIC PIGMENT-PROTEIN COMPLEXES." Photochemistry and Photobiology 54, no. 3 (September 1991): 459–63. http://dx.doi.org/10.1111/j.1751-1097.1991.tb02041.x.

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Goss, Reimund, Michael Richter, and Aloysius Wild. "Pigment composition of PS II pigment protein complexes purified by anion exchange chromatography. identification of xanthophyll cycle pigment binding proteins." Journal of Plant Physiology 151, no. 1 (January 1997): 115–19. http://dx.doi.org/10.1016/s0176-1617(97)80046-6.

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Reinbothe, C., K. Apel, and S. Reinbothe. "A light-induced protease from barley plastids degrades NADPH:protochlorophyllide oxidoreductase complexed with chlorophyllide." Molecular and Cellular Biology 15, no. 11 (November 1995): 6206–12. http://dx.doi.org/10.1128/mcb.15.11.6206.

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The NADPH:protochlorophyllide oxidoreductase precursor protein (pPorA) of barley (Hordeum vulgare L. cv. Carina), synthesized from a full-length cDNA clone by coupling in vitro transcription and translation, is a catalytically active protein. It converts protochlorophyllide to chlorophyllide in a light- and NADPH-dependent manner. At least the pigment product of catalysis remains tightly bound to the precursor protein. The chlorophyllide-pPorA complex differs markedly from the protochlorophyllide-pPorA complex with respect to sensitivity to attack by a light-induced, nucleus-encoded, and energy-dependent protease activity of barley plastids. The pPorA-chlorophyllide complex is rapidly degraded, in contrast to pPorA-protochlorophyllide complexes containing or lacking NADPH, which are both resistant to protease treatment. Unexpectedly, pPorA devoid of its substrates or products was less sensitive to proteolysis than the pPorA-chlorophyllide complex, suggesting that both substrate binding and product formation during catalysis had caused differential changes in protein conformation.

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Hsu, Ban-Dar, and Jee-Yau Lee. "Orientation of pigments and pigment-protein complexes in the diatom Cylindrotheca fusiformis. A linear-dichroism study." Biochimica et Biophysica Acta (BBA) - Bioenergetics 893, no. 3 (October 1987): 572–77. http://dx.doi.org/10.1016/0005-2728(87)90109-5.

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Milivojević, Dragica, and D. Stojanović. "Role of Calcium in Aluminum Toxicity on Content of Pigments and Pigment‐Protein Complexes of Soybean." Journal of Plant Nutrition 26, no. 2 (March 2003): 341–50. http://dx.doi.org/10.1081/pln-120017140.

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Vaswani, Harsha M., Nancy E. Holt, and Graham R. Fleming. "Carotenoid-chlorophyll complexes: Ready-to-harvest." Pure and Applied Chemistry 77, no. 6 (January 1, 2005): 925–45. http://dx.doi.org/10.1351/pac200577060925.

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The fundamental interactions between naturally occurring pigments in light-harvesting systems are responsible for the high efficiency of the photosynthetic apparatus. We describe the role of carotenoids (Cars) in light-harvesting systems, including our work elucidating the mechanism of energy transfer from the optically dark Car singlet excited state (S1) to chlorophyll (Chl) and calculations on the electronic structure of Cars by means of time-dependent density functional theory (TDDFT). We highlight new studies on the charge-transfer state of the Car, peridinin (Per), which enhances the light-harvesting efficiency of the Car by increasing the electronic coupling to Chl. The role of another Car, zeaxanthin (Zea), is discussed with respect to its role in the mechanism of the feedback deexcitation quenching in green plants, a vital regulation process under light conditions which exceed photosynthetic capacity. Lastly, we provide insight on how the 96 Chls in Photosystem I are optimized to generate a pigment-protein complex which utilizes solar energy with near unit efficiency.

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Fidder, Henk, Gregory J. S. Fowler, C. Neil Hunter, and Villy Sundström. "Optical dephasing in photosynthetic pigment–protein complexes." Chemical Physics 233, no. 2-3 (August 1998): 311–22. http://dx.doi.org/10.1016/s0301-0104(98)00100-1.

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Tietz, Carsten, Uwe Gerken, Fedor Jelezko, and Jörg Wrachtrup. "Polarization Measurements on Single Pigment-Protein Complexes." Single Molecules 1, no. 1 (April 2000): 67–72. http://dx.doi.org/10.1002/(sici)1438-5171(200004)1:1<67::aid-simo67>3.0.co;2-4.

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32

Singgih, Marlia, Benny Permana, Selvira Anandia Intan Maulidya, and Anna Yuliana. "Studi In Silico Metabolit Sekunder Kapang Monascus sp. sebagai Kandidat Obat Antikolesterol dan Antikanker." ALCHEMY Jurnal Penelitian Kimia 15, no. 1 (March 14, 2019): 104. http://dx.doi.org/10.20961/alchemy.15.1.25294.104-123.

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Kapang Monascus sp. secara tradisional telah digunakan dalam fermentasi beras merah (angkak) yang bermanfaat sebagai pewarna makanan, pengawet makanan maupun obat-obatan. Saat ini, beras angkak telah menjadi suplemen makanan yang terkenal karena banyaknya senyawa bioaktif yang terkandung seperti monakolin, pigmen, asam dimerumat dan lain-lain. Tujuan penelitian ini adalah untuk menemukan metabolit sekunder kapang Monascus sp. yang meliputi senyawa monakolin dengan efek antikolesterol, pigmen dengan efek antikanker pada kanker payudara serta memprediksi toksisitas senyawa melalui studi in silico. Senyawa uji terdiri dari 14 senyawa monakolin dan 33 pigmen Monascus sp. Protein HMG KoA (3-hidroksi-3-metilglutaril koenzim A) reduktase digunakan sebagai reseptor antikolesterol sementara estrogen alfa, estrogen beta, dan aromatase digunakan sebagai reseptor antikanker. Perangkat lunak AutoDock digunakan untuk menganalisis kompleks struktural reseptor dengan senyawa uji. Prediksi toksisitas dilakukan menggunakan perangkat lunak ADMET predictor dan QSAR Toolbox. Prediksi toksisitas dan hasil docking menunjukkan bahwa asam monakolin L menunjukkan aktivitas antikolesterol yang baik terhadap HMG KoA reduktase; pigmen monaskin menunjukkan aktivitas antikanker yang selektif terhadap reseptor estrogen beta; dan keduanya diprediksi aman. Prediksi toksisitas senyawa monakolin dan pigmen Monascus sp. menunjukkan terdapat 7 senyawa monakolin yaitu 3-hidroksi-3,5-dihidromonakolin L, asam dihidromonakolin L, monakolin L, asam monakolin J, monakolin J, asam monakolin L , monakolin M, dan 5 pigmen Monascus sp. yaitu ankaflavin, monaskin, monaskopiridin A, monaskopiridin B dan monascuspiloin yang dinyatakan tidak toksik. Tujuh pigmen Monascus sp. yang terdiri dari monankarin A, monankarin B, monankarin C, monankarin D, monankarin E, monankarin F, dan monasfluol A bersifat positif mutagen, karsinogen dan toksik terhadap reproduksi. Hasil penelitian ini berpotensi dapat diaplikasikan untuk desain dan pengembangan obat antikolesterol dan antikanker.In Silico Study of Secondary Metabolites of Monascus sp. as A Candidate for Anticholesterol and Anticancer Drugs. The fungus Monascus sp. has traditionally been used to prepare red fermented rice (angkak) as a natural food colorant, food preservative or medicinal agent. Recently, it has become a popular dietary supplement due to many of its bioactive constituents such as monacolin compounds, pigments, and dimerumic acid, etc. These functional constituents also had been deemed to be provided with various health benefits. This research aims to find secondary metabolites of monacolin compounds with antihypercholesterolemic effect, Monascus sp. pigment with anticancer effect on breast cancer, and predict their toxicity through in silico study. The studied compounds consist of 14 monacolin compounds and 33 Monascus sp. pigments. HMG CoA (3-hydroxy-3-methylglutaryl Coenzyme A) reductase protein was used as antihypercholesterolemic receptor in which estrogen alfa, estrogen beta, and aromatase were used as anticancer receptors. AutoDock docking software was used to analyze structural complexes of the receptors with studied compounds. Toxicity prediction was done using ADMET predictor and QSAR Toolbox softwares. Toxicity prediction and docking results revealed that monacolin L acid exhibits good anticholesterol activity towards HMG CoA reductase; monascin pigment exhibits selective anticancer activity towards estrogen beta receptor; and both of them were predicted to be safe. Toxicity prediction of studied compounds showed that 7 monacolin compounds which are 3-hydroxy-3,5-dihydromonakolin L, dihydromonacolin L acid, monacolin L, monacolin J acid, monacolin J, monacolin L acid, monacolin M and 5 Monascus sp. pigments which are ankaflavin, monascin, monascopyridine A, monascopyridine B dan monascuspiloin are not toxic. Seven Monascus sp. pigments which are monankarin A, monankarin B, monankarin C, monankarin D, monankarin E, monankarin F and monasfluol A are mutagenic, carcinogenic and also reprotoxic. The research results could be useful for the design and development of the anticholesterol and anticancer drugs.

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HUBER, ROBERT. "Flexibility and rigidity, requirements for the function of proteins and protein pigment complexes." Biochemical Society Transactions 15, no. 6 (December 1, 1987): 1009–20. http://dx.doi.org/10.1042/bst0151009.

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Hirota, Nozomu, and Akiko Kumagai. "Pigment composition of chlorophyll-protein complexes and seasonal variations of pigments in the brown algae Hizikia fusiformis." NIPPON SUISAN GAKKAISHI 56, no. 6 (1990): 991–98. http://dx.doi.org/10.2331/suisan.56.991.

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Lloyd, Vett K., D. A. Sinclair, R. Wennberg, T. S. Warner, B. M. Honda, and T. A. Grigliatti. "A genetic and molecular characterization of the garnet gene of Drosophila melanogaster." Genome 42, no. 6 (December 1, 1999): 1183–93. http://dx.doi.org/10.1139/g99-088.

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The garnet gene was one of the first genes to be identified in Drosophila melanogaster. Mutations in the garnet gene affect both of the biochemically distinct types of pigments in the eye and disrupt pigmentation of other organs. As an initial step in the analysis of this gene, we have analyzed the pigmentation defects in several of the garnet alleles. We have also cloned the gene and examined its expression in various tissues and at different stages of development. The garnet gene is expressed throughout development and in all tissues examined. Structurally related sequences can be detected in a variety of other eukaryotes. The predicted protein sequence of the garnet product resembles clathrin and nonclathrin adaptin proteins and is highly similar to the delta subunit of the newly isolated mammalian AP-3 adaptin complex, which is associated with the trans-Golgi network and endosomes. This suggests that garnet encodes a protein that acts in the intracellular sorting and trafficking of vesicles from the trans-Golgi network to endosomes, and related specialized organelles such as the pigment granule. This finding provides an explanation for the phenotype of garnet mutations and predicts that other Drosophila eye-colour genes will be a rich resource for the genetic dissection of intracellular vesicle transport.Key words: garnet, Drosophila melanogaster, AP-3, eye pigments.

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Riznichenk, Galina, Ilya Kovalenko, Vladimir Fedorov, Sergei Khruschev, and Andrey Rubin. "Photosynthetic Electron Transfer by Dint of Protein Mobile Carriers. Multi-particle Brownian and Molecular Modeling." EPJ Web of Conferences 224 (2019): 03008. http://dx.doi.org/10.1051/epjconf/201922403008.

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The paper presents the review of works on modeling the interaction of photosynthetic proteins using the multiparticle Brownian dynamics method developed at the Department of Biophysics, Biological Faculty, Lomonosov Moscow State University. The method describes the displacement of individual macromolecules – mobile electron carriers, and their electrostatic interactions between each other and with pigment-protein complexes embedded in photosynthetic membrane. Three-dimensional models of the protein molecules were constructed on the basis of the data from the Protein Data Bank. We applied the Brownian methods coupled to molecular dynamic simulations to reveal the role of electrostatic interactions and conformational motions in the transfer of an electron from the cytochrome complex Cyt b6f) membrane we developed the model which combines events of proteins Pc diffusion along the thylakoid membrane, electrostatic interactions of Pc with the membrane charges, formation of Pc super-complexes with multienzyme complexes of Photosystem I and to the molecule of the mobile carrier plastocyanin (Pc) in plants, green algae and cyanic bacteria. Taking into account the interior of photosynthetic membrane we developed the model which combines events of proteins Pc diffusion along the thylakoid membrane, electrostatic interactions of Pc with the membrane charges, formation of Pc super-complexes with multienzyme complexes of Photosystem I and Cyt b6f, embedded in photosynthetic membrane, electron transfer and complex dissociation. Multiparticle Brownian simulation method can be used to consider the processes of protein interactions in subcellular systems in order to clarify the role of individual stages and the biophysical mechanisms of these processes.

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Freeman, Thomas, Murray Duysen, Ken Eskins, and James Guikema. "Thylakoid membrane development in pigment-deficient wheat chloroplasts." Proceedings, annual meeting, Electron Microscopy Society of America 49 (August 1991): 214–15. http://dx.doi.org/10.1017/s042482010008537x.

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The thylakoid membranes of higher plant chloroplasts contain at least two major pigment protein complexes, photosystem I (PSI), and photosystem II (PSII). The mature apoprotein of these complexes (involved in the initial reactions of photosynthesis) bind specific chlorophylls (Chl) and specific carotenoids in an unknown manner. It has been suggested, however, that the synthesis of pigments is normally coordinated with that of apoproteins. We have examined the effect of gabaculine (3-amino-2, 3-dihydrobenzoic acid) on granal thylakoid stacking as well as pigment and apoprotein accumulations for PSI and PSII in wheat.Gabaculine (0.5mM) was applied with nutrient solution to 6.5 day-old wheat seedlings maintained in a growth chamber at 23C. One seedling lot grown under continuous light (400 μmol photons s-1 m-2) possessed green primary leaves at time of treatment whereas another seedling lot, dark grown, possessed only etiolated primary leaves. Twelve hours after treatment, the etiolated seedlings were transferred into continuous light. The primary and secondary leaves were subsequently harvested from 14 day-old seedlings of both lots.

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Ruf, Stephanie, Klaus Biehler, and Ralph Bock. "A Small Chloroplast-Encoded Protein as a Novel Architectural Component of the Light-Harvesting Antenna." Journal of Cell Biology 149, no. 2 (April 17, 2000): 369–78. http://dx.doi.org/10.1083/jcb.149.2.369.

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A small conserved open reading frame in the plastid genome, ycf9, encodes a putative membrane protein of 62 amino acids. To determine the function of this reading frame we have constructed a knockout allele for targeted disruption of ycf9. This allele was introduced into the tobacco plastid genome by biolistic transformation to replace the wild-type ycf9 allele. Homoplasmic ycf9 knockout plants displayed no phenotype under normal growth conditions. However, under low light conditions, their growth rate was significantly reduced as compared with the wild-type, due to a lowered efficiency of the light reaction of photosynthesis. We show that this phenotype is caused by the deficiency in a pigment–protein complex of the light-harvesting antenna of photosystem II and hence by a reduced efficiency of photon capture when light availability is limiting. Our results indicate that, in contrast to the current view, light-harvesting complexes do not only consist of the classical pigment-binding proteins, but may contain small structural subunits in addition. These subunits appear to be crucial architectural factors for the assembly and/or maintenance of stable light-harvesting complexes.

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Kaňa, Radek, Gábor Steinbach, Roman Sobotka, György Vámosi, and Josef Komenda. "Fast Diffusion of the Unassembled PetC1-GFP Protein in the Cyanobacterial Thylakoid Membrane." Life 11, no. 1 (December 29, 2020): 15. http://dx.doi.org/10.3390/life11010015.

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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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Higgins, Jacob S., Lawson T. Lloyd, Sara H. Sohail, Marco A. Allodi, John P. Otto, Rafael G. Saer, Ryan E. Wood, et al. "Photosynthesis tunes quantum-mechanical mixing of electronic and vibrational states to steer exciton energy transfer." Proceedings of the National Academy of Sciences 118, no. 11 (March 9, 2021): e2018240118. http://dx.doi.org/10.1073/pnas.2018240118.

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Photosynthetic species evolved to protect their light-harvesting apparatus from photoxidative damage driven by intracellular redox conditions or environmental conditions. The Fenna–Matthews–Olson (FMO) pigment–protein complex from green sulfur bacteria exhibits redox-dependent quenching behavior partially due to two internal cysteine residues. Here, we show evidence that a photosynthetic complex exploits the quantum mechanics of vibronic mixing to activate an oxidative photoprotective mechanism. We use two-dimensional electronic spectroscopy (2DES) to capture energy transfer dynamics in wild-type and cysteine-deficient FMO mutant proteins under both reducing and oxidizing conditions. Under reducing conditions, we find equal energy transfer through the exciton 4–1 and 4–2-1 pathways because the exciton 4–1 energy gap is vibronically coupled with a bacteriochlorophyll-a vibrational mode. Under oxidizing conditions, however, the resonance of the exciton 4–1 energy gap is detuned from the vibrational mode, causing excitons to preferentially steer through the indirect 4–2-1 pathway to increase the likelihood of exciton quenching. We use a Redfield model to show that the complex achieves this effect by tuning the site III energy via the redox state of its internal cysteine residues. This result shows how pigment–protein complexes exploit the quantum mechanics of vibronic coupling to steer energy transfer.

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van Gurp, M., G. van Ginkel, and Y. K. Levine. "Orientational properties of biological pigments in ordered systems studied with polarized light: Photosynthetic pigment-protein complexes in membranes." Journal of Theoretical Biology 131, no. 3 (April 1988): 333–49. http://dx.doi.org/10.1016/s0022-5193(88)80229-7.

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Jelezko, F., C. Tietz, U. Gerken, E. Thews, S. Schuler, A. Wechsler, and J. Wrachtrup. "Single molecule spectroscopy on photosynthetic pigment-protein complexes." Optics and Spectroscopy 91, no. 3 (September 2001): 457–60. http://dx.doi.org/10.1134/1.1405228.

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Opačić, Milena, Grégory Durand, Michael Bosco, Ange Polidori, and Jean-Luc Popot. "Amphipols and Photosynthetic Light-Harvesting Pigment-Protein Complexes." Journal of Membrane Biology 247, no. 9-10 (October 2014): 1031–41. http://dx.doi.org/10.1007/s00232-014-9712-6.

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Zhang, Hao, Weidong Cui, Michael L. Gross, and Robert E. Blankenship. "Native mass spectrometry of photosynthetic pigment-protein complexes." FEBS Letters 587, no. 8 (January 18, 2013): 1012–20. http://dx.doi.org/10.1016/j.febslet.2013.01.005.

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Pishchalnikov, Roman Y., Denis D. Chesalin, and Andrei P. Razjivin. "The Relationship between the Spatial Arrangement of Pigments and Exciton Transition Moments in Photosynthetic Light-Harvesting Complexes." International Journal of Molecular Sciences 22, no. 18 (September 17, 2021): 10031. http://dx.doi.org/10.3390/ijms221810031.

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Considering bacteriochlorophyll molecules embedded in the protein matrix of the light-harvesting complexes of purple bacteria (known as LH2 and LH1-RC) as examples of systems of interacting pigment molecules, we investigated the relationship between the spatial arrangement of the pigments and their exciton transition moments. Based on the recently reported crystal structures of LH2 and LH1-RC and the outcomes of previous theoretical studies, as well as adopting the Frenkel exciton Hamiltonian for two-level molecules, we performed visualizations of the LH2 and LH1 exciton transition moments. To make the electron transition moments in the exciton representation invariant with respect to the position of the system in space, a system of pigments must be translated to the center of mass before starting the calculations. As a result, the visualization of the transition moments for LH2 provided the following pattern: two strong transitions were outside of LH2 and the other two were perpendicular and at the center of LH2. The antenna of LH1-RC was characterized as having the same location of the strongest moments in the center of the complex, exactly as in the B850 ring, which actually coincides with the RC. Considering LH2 and LH1 as supermolecules, each of which has excitation energies and corresponding transition moments, we propose that the outer transitions of LH2 can be important for inter-complex energy exchange, while the inner transitions keep the energy in the complex; moreover, in the case of LH1, the inner transitions increased the rate of antenna-to-RC energy transfer.

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Greenwold, Matthew J., Brady R. Cunningham, Eric M. Lachenmyer, John Michael Pullman, Tammi L. Richardson, and Jeffry L. Dudycha. "Diversification of light capture ability was accompanied by the evolution of phycobiliproteins in cryptophyte algae." Proceedings of the Royal Society B: Biological Sciences 286, no. 1902 (May 15, 2019): 20190655. http://dx.doi.org/10.1098/rspb.2019.0655.

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Evolutionary biologists have long sought to identify phenotypic traits whose evolution enhances an organism's performance in its environment. Diversification of traits related to resource acquisition can occur owing to spatial or temporal resource heterogeneity. We examined the ability to capture light in the Cryptophyta, a phylum of single-celled eukaryotic algae with diverse photosynthetic pigments, to better understand how acquisition of an abiotic resource may be associated with diversification. Cryptophytes originated through secondary endosymbiosis between an unknown eukaryotic host and a red algal symbiont. This merger resulted in distinctive pigment–protein complexes, the cryptophyte phycobiliproteins, which are the products of genes from both ancestors. These novel complexes may have facilitated diversification across environments where the spectrum of light available for photosynthesis varies widely. We measured light capture and pigments under controlled conditions in a phenotypically and phylogenetically diverse collection of cryptophytes. Using phylogenetic comparative methods, we found that phycobiliprotein characteristics were evolutionarily associated with diversification of light capture in cryptophytes, while non-phycobiliprotein pigments were not. Furthermore, phycobiliproteins were evolutionarily labile with repeated transitions and reversals. Thus, the endosymbiotic origin of cryptophyte phycobiliproteins provided an evolutionary spark that drove diversification of light capture, the resource that is the foundation of photosynthesis.

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Gruber, J. Michael, Pavel Malý, Tjaart P. J. Krüger, and Rienk van Grondelle. "From isolated light-harvesting complexes to the thylakoid membrane: a single-molecule perspective." Nanophotonics 7, no. 1 (January 1, 2018): 81–92. http://dx.doi.org/10.1515/nanoph-2017-0014.

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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.

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Klug, G., R. Liebetanz, and G. Drews. "The influence of bacteriochlorophyll biosynthesis on formation of pigment-binding proteins and assembly of pigment protein complexes in Rhodopseudomonas capsulata." Archives of Microbiology 146, no. 3 (December 1986): 284–91. http://dx.doi.org/10.1007/bf00403231.

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Golub, Maksym, Adrian Kölsch, Artem Feoktystov, Athina Zouni, and Jörg Pieper. "Insights into Solution Structures of Photosynthetic Protein Complexes from Small-Angle Scattering Methods." Crystals 11, no. 2 (February 19, 2021): 203. http://dx.doi.org/10.3390/cryst11020203.

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High-resolution structures of photosynthetic pigment–protein complexes are often determined using crystallography or cryo-electron microscopy (cryo-EM), which are restricted to the use of protein crystals or to low temperatures, respectively. However, functional studies and biotechnological applications of photosystems necessitate the use of proteins isolated in aqueous solution, so that the relevance of high-resolution structures has to be independently verified. In this regard, small-angle neutron and X-ray scattering (SANS and SAXS, respectively) can serve as the missing link because of their capability to provide structural information for proteins in aqueous solution at physiological temperatures. In the present review, we discuss the principles and prototypical applications of SANS and SAXS using the photosynthetic pigment–protein complexes phycocyanin (PC) and Photosystem I (PSI) as model systems for a water-soluble and for a membrane protein, respectively. For example, the solution structure of PSI was studied using SAXS and SANS with contrast matching. A Guinier analysis reveals that PSI in solution is virtually free of aggregation and characterized by a radius of gyration of about 75 Å. The latter value is about 10% larger than expected from the crystal structure. This is corroborated by an ab initio structure reconstitution, which also shows a slight expansion of Photosystem I in buffer solution at room temperature. In part, this may be due to conformational states accessible by thermally activated protein dynamics in solution at physiological temperatures. The size of the detergent belt is derived by comparison with SANS measurements without detergent match, revealing a monolayer of detergent molecules under proper solubilization conditions.

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Yurkov, Vladimir V., Steven Krieger, Erko Stackebrandt, and J. Thomas Beatty. "Citromicrobium bathyomarinum, a Novel Aerobic Bacterium Isolated from Deep-Sea Hydrothermal Vent Plume Waters That Contains Photosynthetic Pigment-Protein Complexes." Journal of Bacteriology 181, no. 15 (August 1, 1999): 4517–25. http://dx.doi.org/10.1128/jb.181.15.4517-4525.1999.

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Abstract:

ABSTRACT We have taxonomically and phylogenetically characterized a new aerobic bacterial strain (JF-1) that contains photosynthetic pigment-protein complexes and which was recently isolated from black smoker plume waters of the Juan de Fuca Ridge. Strain JF-1 is a gram-negative, yellow-pigmented, motile bacterium that is salt-, pH-, and thermotolerant. These properties are consistent with an oligotrophic adaptation to varied environmental conditions thought to exist around deep-sea hydrothermal vents. The analysis of 16S rDNA sequences revealed that strain JF-1 forms a separate phylogenetic branch between the genus Erythromonas and theErythromicrobium-Porphyrobacter-Erythrobacter cluster within the α subclass of the Proteobacteria. The taxonomic name Citromicrobium bathyomarinum (gen. nov., sp. nov.) is proposed for strain JF-1.

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Journal articles on the topic 'Pigment proteine complexe'

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