Heat-Induced Alterations in Thylakoid Membrane Protein Composition in Barley

1994 ◽  
Vol 21 (6) ◽  
pp. 759 ◽  
Author(s):  
TS Takeuchi ◽  
JP Thornber
Keyword(s):  
Thylakoid Membrane ◽  
Elevated Temperatures ◽  
Quaternary Structure ◽  
Protein Complexes ◽  
Protein Composition ◽  
Spectroscopic Studies ◽  
Lhc Ii ◽  
Ps Ii ◽  
Ps I ◽  
Pigment Protein Complexes

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.

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.

Inhibition of State Transition and Light-Harvesting Complex II Phosphorylation-Mediated Changes in Excitation Energy Distribution in the Thylakoids of SANDOZ 9785-Treated Plants

1995 ◽  
Vol 50 (1-2) ◽  
pp. 77-85
Author(s):  
Manoj K. Joshi ◽  
Prasanna Mohanty ◽  
Salil Bose
Keyword(s):  
Energy Distribution ◽  
State Transition ◽  
Light Harvesting ◽  
Lhc Ii ◽  
Ps Ii ◽  
Light Harvesting Complex ◽  
Antenna Size ◽  
Complex Ii ◽  
Ps I ◽  
Light Harvesting Complex Ii

Abstract Thylakoids isolated from SAN 9785 (4-chloro-5-dimethylamino-2-phenyl-3(2H)-pyridazi-none)-treated pea plants showed an inhibition of “state transition” and the light-harvesting complex II (LHC II) phosphorylation-mediated changes in the energy distribution between photosystem II (PS II) and photosystem I (PS I) as measured by a decrease in PS II and an increase in PS I fluorescence yield. Interestingly, in these thylakoids the extent of phosphorylation-induced migration of light-harvesting complex (LHC II-P) to non-appressed mem­brane regions was only marginally inhibited. We propose that the suppression in the ability for “state transition” by SANDOZ 9785 (SAN 9785) treatment occurs due to a lack of effec­tive coupling of the migrated LHC II-P and PS I. Since we observed a decrease in the antenna size of PS I of the treated plants, the lack of effective coupling is attributed to this decrease in the antenna size of PS I.

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.

Photosynthetic Responses of Pisum sativum to an Increase in Irradiance During Growth. II. Thylakoid Membrane Components

1987 ◽  
Vol 14 (1) ◽  
pp. 9 ◽  
Author(s):  
WS Chow ◽  
JM Anderson
Keyword(s):  
Thylakoid Membrane ◽  
High Light ◽  
Cytochrome F ◽  
Reaction Centre ◽  
Leaf Photosynthesis ◽  
Low Light ◽  
Ps Ii ◽  
Reaction Centres ◽  
Ps I ◽  
Membrane Components

Following the transfer of pea plants grown at low irradiance (60 �mol photons m-2 s-1, 16 h light/8 h dark cycles) to high irradiance (390 �mol photons m-2 s-1), the extents and time courses of the increase in the concentrations of thylakoid membrane components on a chlorophyll basis have been determined. The increase in cytochrome f (~ 70%) and plastoquinone (~ 50%) contents occurred with no noticeable lag phase. The increase in photosystem Il reaction centres (PS II, ~ 35%) and ATP synthetase (~ 90%) occurred possibly with a lag period of 1-2 days. In contrast, there was no significant increase in the concentration of P700 (reaction centre) of PS I complex. The concentration of PS II reaction centres measured by atrazine-binding exceeded that from the O2 yield per single-turnover flash by a factor of 1.17 (compared with the expected value of 1.14); this contrasts with the factor of 1.8 obtained by P. A. Jursinic and R. Dennenberg [Arch. Biochem. Biophys. (1985) 241, 540-9]. It is suggested that both methods are equivalent for the determination of PS II reaction centres in active chloroplasts. The stoichiometry of PS II : cyt f: PS I was highly flexible, and not fixed at 1 : 1 : 1. We obtained the stoichiometries of 1.25 : 0.7 : 1.0 for low-light pea chloroplasts and 1.7 : 1.25 : 1.0 for chloroplasts in pea plants that had been transferred to high light for about 10 days, demonstrating the dynamic nature of thylakoid composition and function. In the first 2 days after transferring low light pea plants to high light, the time course of the increase in CO2- and light-saturated rate of leaf photosynthesis corresponded better with that of cyt f and plastoquinone than that of other chloroplast components examined. This suggests that, during the transition period, the relatively prompt increase of cyt b/f and plastoquinone plays a part in enhancing the CO2- and light-saturated rate of leaf photosynthesis.

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 Role of Galactolipids in Plastid Differentiation Before and After Light Exposure

Plants ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 357 ◽  
Author(s):  
Fujii ◽  
Wada ◽  
Kobayashi
Keyword(s):  
Thylakoid Membrane ◽  
Protein Complexes ◽  
Light Exposure ◽  
Chlorophyll Biosynthesis ◽  
Membrane Structures ◽  
Plastid Differentiation ◽  
Internal Membrane ◽  
Before And After ◽  
Pigment Protein Complexes ◽  
Cotyledon Cells

Galactolipids, monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG), are the predominant lipid classes in the thylakoid membrane of chloroplasts. These lipids are also major constituents of internal membrane structures called prolamellar bodies (PLBs) and prothylakoids (PTs) in etioplasts, which develop in the cotyledon cells of dark-grown angiosperms. Analysis of Arabidopsis mutants defective in the major galactolipid biosynthesis pathway revealed that MGDG and DGDG are similarly and, in part, differently required for membrane-associated processes such as the organization of PLBs and PTs and the formation of pigment–protein complexes in etioplasts. After light exposure, PLBs and PTs in etioplasts are transformed into the thylakoid membrane, resulting in chloroplast biogenesis. During the etioplast-to-chloroplast differentiation, galactolipids facilitate thylakoid membrane biogenesis from PLBs and PTs and play crucial roles in chlorophyll biosynthesis and accumulation of light-harvesting proteins. These recent findings shed light on the roles of galactolipids as key facilitators of several membrane-associated processes during the development of the internal membrane systems in plant plastids.

Herbicides which Interfere with the Biosynthesis of Carotenoids and Their Effect on Pigment Excitation, Chlorophyll Fluorescence and Pigment Composition of the Thylakoid Membrane

1984 ◽  
Vol 39 (5) ◽  
pp. 455-458 ◽  
Author(s):  
K. H. Grumbach
Keyword(s):  
Chlorophyll Fluorescence ◽  
Thylakoid Membrane ◽  
Protein Complexes ◽  
Red Light ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Pigment Composition ◽  
Fluorescence Emission Spectra ◽  
Characteristic Emission ◽  
Pigment Protein Complexes

Plants grown in the presence of the herbicides assayed synthesized chlorophylls during growth at low fluence rates. Subsequent irradiation with higher fluence rates of red light induced a strong chlorosis with SAN 6706 being a much stronger herbicide than J 852 or amino-triazole. All herbicides assayed also changed the content and composition of chlorophylls, carotenoids and pigment-protein-complexes of the thylakoid membrane and therefore the pigment excitation and chlorophyll fluorescence emission spectra of the plastid. With increasing herbicide toxicity the main characteristic emission bands at 690 and 730 nm disappeared and new emission bands at 715 (J 852) and 700 nm (SAN 6706) appeared. Such “artificial” membranes with a changed pigment composition were very susceptible to light. Presented data may be taken as evidence, that the lack of photoprotective cyclic carotenoids caused by the specific action of a bleaching herbicide is the primary event that may lead to a disturbed formation of the thylakoid membrane and its destruction by light and oxygen.

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.

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