The Occurrence of β-Carotene-5,6-epoxide in the Photosynthetic Apparatus of Higher Plants

1989 ◽  
Vol 44 (11-12) ◽  
pp. 959-965 ◽  
Author(s):  
Andrew Young ◽  
Paul Barry ◽  
George Britton
Keyword(s):  
Higher Plants ◽  
Protein Complexes ◽  
Photosynthetic Apparatus ◽  
Reaction Centre ◽  
Higher Plant ◽  
Ps Ii ◽  
Photooxidative Damage ◽  
Pigment Protein Complexes ◽  
The Individual ◽  
Β Carotene

Abstract The occurrence of β-carotene-5,6-epoxide in higher plant photosynthetic tissue is described. The compound is found in isolated chloroplasts, thylakoids and other subchloroplast particles but can only be detected in intact leaves or cotyledons of higher plants when these are exposed to very high light intensities or to inhibitors such as monuron or paraquat. The distribution of the epoxide within the individual pigment-protein complexes is given. It is particularly associated with the PS I reaction centres (C P I and CP la) and less so with the PS II reaction centre (CPa). Circular dichroism shows that the β-carotene-5,6-epoxide isolated from photosynthetic tissue is optically inactive. It is therefore not produced enzymically but is a product of photooxidative events in the photosynthetic apparatus. Its presence in photosynthetic tissue is a reliable indicator of photooxidative damage to the thylakoid membrane involving oxidation of β-carotene.

scholarly journals Pre-purification of diatom pigment protein complexes provides insight into the heterogeneity of FCP complexes

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Marcel Kansy ◽  
Daniela Volke ◽  
Line Sturm ◽  
Christian Wilhelm ◽  
Ralf Hoffmann ◽  
...  
Keyword(s):  
Spatial Organization ◽  
Higher Plants ◽  
Protein Complexes ◽  
Photosynthetic Apparatus ◽  
Thalassiosira Pseudonana ◽  
Photochemical Quenching ◽  
Complex Nature ◽  
Published Data ◽  
Core Complex ◽  
Pigment Protein Complexes

Abstract Background Although our knowledge about diatom photosynthesis has made huge progress over the last years, many aspects about their photosynthetic apparatus are still enigmatic. According to published data, the spatial organization as well as the biochemical composition of diatom thylakoid membranes is significantly different from that of higher plants. Results In this study the pigment protein complexes of the diatom Thalassiosira pseudonana were isolated by anion exchange chromatography. A step gradient was used for the elution process, yielding five well-separated pigment protein fractions which were characterized in detail. The isolation of photosystem (PS) core complex fractions, which contained fucoxanthin chlorophyll proteins (FCPs), enabled the differentiation between different FCP complexes: FCP complexes which were more closely associated with the PSI and PSII core complexes and FCP complexes which built-up the peripheral antenna. Analysis by mass spectrometry showed that the FCP complexes associated with the PSI and PSII core complexes contained various Lhcf proteins, including Lhcf1, Lhcf2, Lhcf4, Lhcf5, Lhcf6, Lhcf8 and Lhcf9 proteins, while the peripheral FCP complexes were exclusively composed of Lhcf8 and Lhcf9. Lhcr proteins, namely Lhcr1, Lhcr3 and Lhcr14, were identified in fractions containing subunits of the PSI core complex. Lhcx1, Lhcx2 and Lhcx5 proteins co-eluted with PSII protein subunits. The first fraction contained an additional Lhcx protein, Lhcx6_1, and was furthermore characterized by high concentrations of photoprotective xanthophyll cycle pigments. Conclusion The results of the present study corroborate existing data, like the observation of a PSI-specific antenna complex in diatoms composed of Lhcr proteins. They complement other data, like e.g. on the protein composition of the 21 kDa FCP band or the Lhcf composition of FCPa and FCPb complexes. They also provide interesting new information, like the presence of the enzyme diadinoxanthin de-epoxidase in the Lhcx-containing PSII fraction, which might be relevant for the process of non-photochemical quenching. Finally, the high negative charge of the main FCP fraction may play a role in the organization and structure of the native diatom thylakoid membrane. Thus, the results present an important contribution to our understanding of the complex nature of the diatom antenna system.

Lipids in and around photosynthetic reaction centres

2005 ◽  
Vol 33 (5) ◽  
pp. 924-930 ◽  
Author(s):  
P.K. Fyfe ◽  
M.R. Jones
Keyword(s):  
Membrane Lipids ◽  
Protein Complexes ◽  
Reaction Centre ◽  
Photosynthetic Membrane ◽  
Ps Ii ◽  
X Ray Crystallography ◽  
Structural Support ◽  
Reaction Centres ◽  
Ps I ◽  
Pigment Protein Complexes

Reaction centres are membrane-embedded pigment–protein complexes that transduce the energy of sunlight into a biologically useful form. The most heavily studied reaction centres are the PS-I (Photosystem I) and PS-II complexes from oxygenic phototrophs, and the reaction centre from purple photosynthetic bacteria. A great deal is known about the compositions and structures of these reaction centres, and the mechanism of light-activated transmembrane electron transfer, but less is known about how they interact with other components of the photosynthetic membrane, including the membrane lipids. X-ray crystallography has provided high-resolution structures for PS-I and the purple bacterial reaction centre, and revealed binding sites for a number of lipids, either embedded in the protein interior or attached to the protein surface. These lipids play a variety of roles, including the binding of cofactors and the provision of structural support. The challenges of modelling surface-associated electron density features such as lipids, detergents, small amphiphiles and ions are discussed.

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.

Isolation of PS II reaction centre and its relationship to the minor chlorophyll-protein complexes

1983 ◽  
Vol 23 (1-4) ◽  
pp. 171-179 ◽  
Author(s):  
Edith L. Camm ◽  
Beverley R. Green
Keyword(s):  
Protein Complexes ◽  
Reaction Centre ◽  
Ps Ii ◽  
Chlorophyll Protein Complexes ◽  
Chlorophyll Protein

Difference picosecond spectroscopy of pigment-protein complexes of photosystem I from higher plants

1984 ◽  
Vol 767 (3) ◽  
pp. 501-506 ◽  
Author(s):  
Marina D. Il'ina ◽  
Vitautas V. Krasauskas ◽  
Richardas J. Rotomskis ◽  
Alexander Yu. Borisov
Keyword(s):  
Photosystem I ◽  
Higher Plants ◽  
Protein Complexes ◽  
Picosecond Spectroscopy ◽  
Pigment Protein Complexes

Photoreduction of NADP+ in Photosystem II of Higher Plants: Requirement for Manganese

1992 ◽  
Vol 47 (1-2) ◽  
pp. 57-62 ◽  
Author(s):  
Suleyman I. Allakhverdiev ◽  
Vyacheslav V. Klimov
Keyword(s):  
Photosystem Ii ◽  
Higher Plants ◽  
Complete Removal ◽  
Reaction Centers ◽  
Higher Plant ◽  
Ps Ii ◽  
Alternate Pathway ◽  
Manganese Extraction ◽  
Quinone Acceptor ◽  
Reduced State

Abstract The effects of reversible manganese extraction on NADP+ photoreduction were studied with higher plant subchloroplast preparations of photosystem II (PS II). Under anaerobic conditions, when the reaction centers (RCs) of PS II are “closed” (i.e. in the state [P680 Pheo] QA), and in the presence of ferredoxin-ferredoxin-NADP+ reductase, NADP+ reduction is observed at a rate of 0.8 -1.1 nmol/mg × chlorophyll × h. After complete removal of manganese from PS II, the rate of NADP+ reduction is reduced 40 - 50-fold. Upon the addition of Mn at a concentration of approx. 4 Mn atoms per reaction center, the NADP+ reduction is restored up to 85 -90% of the initial value. When half of this amount of Mn is combined with about 40 times of the equivalent concentration of other divalent ions (Ca2+, Sr2+, Mg2+ etc.) the reaction is also reactivated. Dinoseb (10-6 m) an inhibitor of electron transfer in PS II prevents NADP+ photoreduction. It is concluded that under conditions when the first quinone acceptor, QA, is in its reduced state (QA-) electrons are transferred from reduced pheophytin (Pheo·̅) to NADP+, indicating that PS II can reduce NADP+ without the participation of PS I. On the basis of these and literature data, an alternate pathway for electron phototransfer in PS II reaction centers of higher plants is suggested. Some problems concerning the Z-scheme are discussed.

Occurrence of Secondary Carotenoids in PS I Complexes Isolated from Eremosphaera viridis De Bary (Chlorophyceae)

1992 ◽  
Vol 47 (1-2) ◽  
pp. 51-56 ◽  
Author(s):  
Burkhard Vechtel ◽  
Elfriede K. Pistorius ◽  
Hans Georg Ruppel
Keyword(s):  
Green Algae ◽  
Photosystem I ◽  
Protein Complexes ◽  
Pigment Composition ◽  
Eremosphaera Viridis ◽  
Ps I ◽  
Pigment Protein Complexes ◽  
Secondary Carotenoids ◽  
Lhc I ◽  
Β Carotene

Abstract Photosystem I complexes of Eremosphaera viridis De Bary (Chlorophyceae, Chlorococcales) were isolated and partially characterized. In the isolated PS I complexes, peptides of 64-60, 26, 23, 20, 15, 11 and 8.5 kDa could be detected. When Eremosphaera was grown under regular conditions the pigment composition of the isolated PS I complexes was similar to that found in PS I complexes from other green algae. However, when Eremosphaera was grown under nitrogen deficient conditions, PS I complexes contained the secondary carotenoids canthaxanthin and traces of astaxanthin and echinenone in addition to β-carotene, violaxanthin and lutein. The results presented indicate that the secondary carotenoids are associated with the LHC I of PS I. To our knowledge this represents the first report about the association of secondary carotenoids with light harvesting pigment protein complexes of green algae.

scholarly journals Demonstration of a relationship between state transitions and photosynthetic efficiency in a higher plant

2019 ◽  
Vol 476 (21) ◽  
pp. 3295-3312 ◽  
Author(s):  
Craig R. Taylor ◽  
Wim van Ieperen ◽  
Jeremy Harbinson
Keyword(s):  
Photosynthetic Efficiency ◽  
State Transition ◽  
Higher Plants ◽  
Photosynthetic Apparatus ◽  
State Transitions ◽  
Short Term ◽  
Higher Plant ◽  
Series Configuration ◽  
Use Efficiency ◽  
Sun And Shade

A consequence of the series configuration of PSI and PSII is that imbalanced excitation of the photosystems leads to a reduction in linear electron transport and a drop in photosynthetic efficiency. Achieving balanced excitation is complicated by the distinct nature of the photosystems, which differ in composition, absorption spectra, and intrinsic efficiency, and by a spectrally variable natural environment. The existence of long- and short-term mechanisms that tune the photosynthetic apparatus and redistribute excitation energy between the photosystems highlights the importance of maintaining balanced excitation. In the short term, state transitions help restore balance through adjustments which, though not fully characterised, are observable using fluorescence techniques. Upon initiation of a state transition in algae and cyanobacteria, increases in photosynthetic efficiency are observable. However, while higher plants show fluorescence signatures associated with state transitions, no correlation between a state transition and photosynthetic efficiency has been demonstrated. In the present study, state 1 and state 2 were alternately induced in tomato leaves by illuminating leaves produced under artificial sun and shade spectra with a sequence of irradiances extreme in terms of PSI or PSII overexcitation. Light-use efficiency increased in both leaf types during transition from one state to the other with remarkably similar kinetics to that of F′m/Fm, F′o/Fo, and, during the PSII-overexciting irradiance, ΦPSII and qP. We have provided compelling evidence for the first time of a correlation between photosynthetic efficiency and state transitions in a higher plant. The importance of this relationship in natural ecophysiological contexts remains to be elucidated.

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