The Stoichiometries of Supramolecular Complexes in Thylakoid Membranes From Spinach Chloroplasts

1987 ◽  
Vol 14 (1) ◽  
pp. 21 ◽  
Author(s):  
WS Chow ◽  
AB Hope
Keyword(s):  
Photosystem Ii ◽  
Atpase Activity ◽  
Thylakoid Membranes ◽  
Coupling Factor ◽  
Supramolecular Complexes ◽  
Cyt B ◽  
Ps Ii ◽  
Ps I ◽  
The Mean ◽  
Isolated Chloroplasts

The concentrations of photosystem II (PS II), photosystem I (PS I) and cytochrome b/f complexes on a chlorophyll basis have been determined for chloroplasts of spinach grown under three irradiances in a glasshouse. Assaying PS II by atrazine binding gave concentrations that exceeded the estimates from flash-induced O2 or H+ yield by a factor of 1.21 � 0.04 (23). Since part of this factor (1.14) is expected to arise from missed turnovers in excited reaction centres, it is concluded that both methods are valid to determine [PS II] in gently isolated chloroplasts. The agreement between the methods also suggests that atrazine does not bind to additional sites of quenchers such as 'Q400', contrary to the suggestion of R. J. Dennenberg and P. A. Jursinic [Biochim. Biophys. Acta 808 (1985), 192-200]. Whilst [PS I] was independent of growth irradiances, [PS II] and [cyt f ] increased with irradiance, as did the latent ATPase activity, a measure of the concentration of coupling factor 1. If [PS I] is taken as constant at 1.65 mmol (mol Chl)-1, the mean stoichiometries of PS II : cyt b/f complex : PS I obtained at the minimum and maximum irradiances were 1.2 : 0.7 : 1 and 1.6 : 1.0 : 1 respectively, PS II being determined by atrazine binding.

Targeted Deletion Mutagenesis of the β Subunit of Cytochrome b559 Protein Destabilizes the Reaction Center of Photosystem II

1990 ◽  
Vol 45 (5) ◽  
pp. 423-429 ◽  
Author(s):  
Himadri B. Pakrasi ◽  
Karin J. Nyhus ◽  
Howard Granok
Keyword(s):  
Photosystem Ii ◽  
Reaction Center ◽  
Thylakoid Membranes ◽  
Antenna System ◽  
Β Subunit ◽  
Cyt B ◽  
Synechocystis 6803 ◽  
Cytochrome B559 ◽  
Ps Ii ◽  
Individual Gene

Abstract Oligonucleotide-directed mutagenesis techniques were used to delete the psbF gene, encoding the β subunit of the cytochrom e b559 protein of the photosystem II complex in the cyano­ bacterium, Synechocystis 6803. Cyt b559 is an integral com ponent of PS II complex. However, its precise functional role in PS II remains to be determined. Previously, we created a mutant in which the psbF gene as well as three of its neighbouring genes, psbE , psbL and p sb i were simultaneously deleted from the chrom osom e of Synechocystis 6803 (Pakrasi, Williams and Arntzen, EMBO J. 7, 325 -332 , 1988). This mutant had no PS II activity. However, the role of any one of the four individual gene products could not be determined by studying this mutant. The newly generated mutant, T 256, had only one gene, p sbF , deleted from the genome. This mutant was also impaired in its PS II activities. In addition, it had barely detectable levels of two other protein com ponents, D1 (herbicide binding protein) and D2, of the reaction center of PS II, in its thylakoid membranes. In contrast, two other proteins of PS II, CP47 and CP43 were present in appreciable amounts. Fluorescence spectra (77 K) of the mutant showed the absence of a peak at 695 nm that was previously believed to originate from CP47. In addition, phycobilisomes, the light-harvesting antenna system of PS II, were found to be assembled normally in this mutant. We conclude that the presence of the β subunit of Cyt b559 in the thylakoid membranes is critically important for the assembly of PS II reaction center.

Photosystem II Inhibition by Pyran-enamine Derivatives

1993 ◽  
Vol 48 (3-4) ◽  
pp. 163-167
Author(s):  
Koichi Yoneyama ◽  
Yoshihiro Nakajima ◽  
Masaru Ogasawara ◽  
Hitoshi Kuramochi ◽  
Makoto Konnai ◽  
...  
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Thylakoid Membranes ◽  
Major Determinant ◽  
Ps Ii ◽  
Structure Activity Relationships ◽  
Structure Activity

Abstract Through the studies on structure-activity relationships of 5-acyl-3-(1-aminoalkylidene)-4-hydroxy-2 H-pyran-2,6(3 H)-dione derivatives in photosystem II (PS II) inhibition, overall lipophilicity of the molecule was found to be a major determinant for the activity. In the substituted N -benzyl derivatives, not only the lipophilicity but also the electronic and steric characters of the substituents greatly affected the activity. Their mode of PS II inhibition seemed to be similar to that of DCMU , whereas pyran-enamine derivatives needed to be highly lipophilic to block the electron transport in thylakoid membranes, which in turn diminished the permeability through biomembranes.

The Polyphasic Rise of Chlorophyll Fluorescence upon Onset of Strong Continuous Illumination: II. Partial Control by the Photosystem II Donor Side and Possible Ways of Interpretation

1987 ◽  
Vol 42 (11-12) ◽  
pp. 1255-1264 ◽  
Author(s):  
Ulrich Schreiber ◽  
Christian Neubauer
Keyword(s):  
Photosystem Ii ◽  
Intermediate Level ◽  
Continuous Illumination ◽  
Photochemical Quenching ◽  
Cyt B ◽  
Donor Side ◽  
Ps Ii ◽  
Donation Rate ◽  
Fluorescence Rise ◽  
Level I

The fluorescence rise kinetics in saturating light display two well separated components with largely different properties. The rapid rise from F0 to a first intermediate level, I1 is photochemically controlled, while the following phases leading to a secondary intermediate level, I2 and to a peak level, P, are limited by thermal reactions. Treatments which primarily affect components at the photosystem II donor side are shown to increase quenching at I1 and/or to suppress the secondary fluorescence rise to I2. Preillumination by single turnover saturating flashes causes I1- quenching oscillating with period-4 in dependence of flash number. It is suggested that this quenching correlates with (S2 + S3) states of the watersplitting enzyme system. Suppression of the secondary, I1 - I2 rise component is invariably found with treatments which lower electron donation rate by the watersplitting system and are known to favor the low potential form of cyt b 559. Three different mechanisms are discussed on the basis of which donor-side dependent quench­ing could be interpreted: 1) Non-photochemical quenching by accumulation of the P 680+ radical cation. 2) Dissipative photochemical quenching at a special population of PS II centers (β- or non- B centers) displaying low donor capacity and high rates of charge recombination. 3) Dissipative photochemical quenching via cyclic electron flow around PS II, involving alternate donors to P 680+ (like cyt b 559 or carotenoid in their low potential forms), which can compete when donation rate from the water splitting system is slowed down. The possibility of donor-side limitation also being involved in “energy dependent” quenching is discussed.

Acclimation of the Photosynthetic Apparatus to Photosystem I or Photosystem II Light: Evidence from Quantum Yield Measurements and Fluorescence Spectroscopy of Cyanobacterial Cells

1989 ◽  
Vol 44 (1-2) ◽  
pp. 109-118 ◽  
Author(s):  
Anastasios Melis ◽  
Conrad W. Mullineaux ◽  
John F. Allen
Keyword(s):  
Quantum Yield ◽  
Photosystem Ii ◽  
Excitation Energy ◽  
Oxygen Evolution ◽  
Photosystem I ◽  
Light Harvesting ◽  
Ps Ii ◽  
Ps I ◽  
Synechococcus 6301 ◽  
Light Harvesting Antenna

Abstract Cells of the cyanobacterium Synechococcus 6301 were grown under illumination whose spectral composition favoured absorption either by the phycobilisome (PBS) light-harvesting antenna of photosystem II (PS II) or by the chlorophyll (Chi) a light-harvesting antenna of photosystem I (PS I). Cells grown under PS I-light developed relatively high PS II/PS I and PBS/Chl ratios. Cells grown under PS II-light developed relatively low PS II/PS I and PBS/Chl ratios. Thus, the primary difference between cells in the two acclimation states appeared to be the relative concentration of PBS-PS II and PS I complexes in the thylakoid membrane. Measurements of the quantum yield of oxygen evolution suggested a higher efficiency of cellular photosynthesis upon the adjustment of photosystem stoichiometry to a specific light condition. The quantum yield of oxygen evolution was nevertheless lower under PBS than Chi excitation, suggesting quenching of excitation energy in the photochemical apparatus of PS II in Synechococcus 6301. This phenomenon was more pronounced in the PS II-light than in the PS I-light grown cells. Room temperature and 77 K fluorescence emission spectroscopy indicated that excess excitation energy in the PBS was not transferred to PS I, suggesting the operation of a non-radiative and non-photochemical decay of excitation energy at the PBS-PS II complex. This non-photochemical quenching was specific to conditions where excitation of PS II occurred in excess of its capacity for useful photochemistry.

A Fluorescence Method for Measuring the Retention of Coupling Factor (CF1) in Reconstitution Experiments of Photophosphorylation

1977 ◽  
Vol 32 (5-6) ◽  
pp. 392-397 ◽  
Author(s):  
Götz Harnischfeger ◽  
Reinhard Schopf
Keyword(s):  
Atpase Activity ◽  
Thylakoid Membranes ◽  
Coupling Factor ◽  
Fluorescence Method ◽  
Double Labeling ◽  
Atp Formation ◽  
Chloroplast Coupling Factor ◽  
Chloroplast Coupling Factor 1 ◽  
Covalently Bound

Abstract The recombination of chloroplast coupling factor 1 (CF1) and thylakoid membranes in reconsti­ tution experiments was studied through the fluorescence of paired labels covalently bound to NH2-groups. It was found that maximum recombination is achieved at a ratio of 1.5 -3,μg CF1 /μg chlorophyll. The addition of chloroplast lipids to the medium enhances the incorporation of CF1 into the membranes. The rates of ATP formation of the regenerated but labeled system are decreased to 50% of those found in unlabeled control experiments. This is discussed in context with the previous observation, that labeling of CF1 at similar concentrations inhibits the ATPase activity of the isolated protein completely. The possible use of double labeling in the study of the physical aspects of the reconstitution of the photophosphorylating system is discussed.

scholarly journals Acyl lipids in the supramolecular chlorophyll-protein complexes of photosystems - isolation artifacts or integral components regulating their structure and functions?

2014 ◽  
Vol 57 (3) ◽  
pp. 401-418 ◽  
Author(s):  
Zbigniew Krupa
Keyword(s):  
Photosystem Ii ◽  
Lipid Content ◽  
Protein Complexes ◽  
Thylakoid Membranes ◽  
Supramolecular Complexes ◽  
Hexadecenoic Acid ◽  
Acyl Lipids ◽  
Chlorophyll Protein Complexes ◽  
Chlorophyll Protein ◽  
Structure And Functions

The precise nature of interactions between the chloropnyll-protein complexes related to photosystem I or photosystem II and the acyl lipids in the thylakoid membranes is not yet fully elucidated. Analyses of the lipid content of isolated photosystem supramolecular complexes reveal that they are integral components of these complexes. However, the relations between certain acyl lipids and the specific structure and functions of the complexes investigated are still widely discussed. The most generally accepted phenomenon is the fact of participation of phosphatidylglycerol containing the unique <em>trans-</em>Δ<sup>3</sup> -hexadecenoic acid in the oligomerization of the light-harvesting chlorophyll a/b protein complex II.

Freeze-fracture analysis of thylakoid membranes and photosystem I and II enriched fractions from Phormidium laminosum

1986 ◽  
Vol 80 (1) ◽  
pp. 57-73
Author(s):  
R.E. Glick ◽  
R.E. Triemer ◽  
B.A. Zilinskas
Keyword(s):  
Photosystem Ii ◽  
Photosystem I ◽  
Freeze Fracture ◽  
Thylakoid Membranes ◽  
Coupling Factor ◽  
Fracture Face ◽  
Phormidium Laminosum ◽  
Hydrophobic Component ◽  
Photosystem I And Ii ◽  
Protoplasmic Fracture Face

Thylakoid membranes of the thermophilic cyanobacterium Phormidium laminosum have been fractionated into photosystem II and photosystem I particles. These fractions have been characterized by their partial electron transport activities, and biochemical and spectral properties. Exoplasmic fracture face and protoplasmic fracture face particles in the unfractionated thylakoid membranes were shown to correspond in size to particles in freeze-fractured photosystem II and photosystem I fractions, respectively. Differences between the histograms of the thylakoid membrane protoplasmic fracture face particles and the isolated photosystem I particles suggest that in addition to photosystem I complexes some of the particles on the thylakoid protoplasmic fracture face may be related to cytochrome b/f complexes, the hydrophobic component of the coupling factor, or respiratory complexes.

Studies on the Retention of CF1 with or without Induced ATPase Activity by Pyrophosphate Treated Thylakoids and Its Relation to the Regeneration of Photophosphorylation

1977 ◽  
Vol 32 (5-6) ◽  
pp. 398-404 ◽  
Author(s):  
R. Schopf ◽  
G. Harnischfeger
Keyword(s):  
Atpase Activity ◽  
Differential Effect ◽  
Atp Synthesis ◽  
Thylakoid Membranes ◽  
Coupling Factor ◽  
Trypsin Treatment ◽  
Atp Formation ◽  
Chloroplast Coupling Factor ◽  
Reconstitution Experiment ◽  
Chloroplast Coupling Factor 1

Abstract The reconstitution of chloroplast coupling factor 1 (CF1) into thylakoid membranes was investigated by the fluorescence of the covalently attached label fluorescamine. In contrast to a func­tional regeneration of ATP synthesis, a rebinding of CF1 was observed regardless if the protein was in its native, purified state or had been activated for ATPase activity by heat, dithiothreitol (DTT) or trypsin treatment. The reintegration of CF1 into the thylakoid membrane was estimated to be almost quantitative. Since the label binds covalently and irreversibly to free NH2-groups, its effects on the various functional parameters were investigated. Blocking of NH2 groups leads to inhibition of ATPase activity in isolated CF1 . Labeled factor used in a reconstitution experiment on the other hand, does still result in considerable regeneration of ATP formation. Attaching the label to whole thylakoids leads to a differential effect on phosphorylation, which is inhibited, and the H+-uptake which seems largely unaffected. A differential effect is also observed on coupled and uncoupled electron transport. The results are interpreted as evidence for an involvement of free NH2-groups in the mechanism of photophosphorylation.

scholarly journals Thylakoid grana stacking revealed by multiplex genome editing of LHCII encoding genes

2022 ◽  
Author(s):  
Zeno Guardini ◽  
Rodrigo Lionel Gomez ◽  
Roberto Caferri ◽  
Johannes Stuttmann ◽  
Luca Dall'Osto ◽  
...  
Keyword(s):  
Energy Balance ◽  
Light Exposure ◽  
Thylakoid Membranes ◽  
Land Plant ◽  
Ps Ii ◽  
Antenna Complex ◽  
Ps I ◽  
Repair Efficiency ◽  
Rapid Changes ◽  
Encoding Genes

Land plant chloroplasts differ from algal ones for their thylakoid membranes being organized in grana: piles of vesicles paired by their stromal surface, forming domains including Photosystem (PS) II and its antenna while excluding PS I and ATPase to stroma membranes, connecting grana stacks. The molecular basis of grana stacking remain unclear. We obtained genotypes lacking the trimeric antenna complex (Lhcb1-2-3), the monomeric Lhcb4-5-6, or both. Full deletion caused loss of grana, while either monomers or trimers support 50% stacking. The expression of Lhcb5 alone restored stacking at 50%, while Lhcb2 alone produced huge grana which broke down upon light exposure. Cyclic electron transport was maintained in the lack of stacking, while excitation energy balance between photosystems and the repair efficiency of damaged Photosystem II were affected. We conclude that grana evolved for need of regulating energy balance between photosystems under terrestrial canopy involving rapid changes in photon spectral distribution.

Atrazine Phytotoxicity to Common Bean and Redroot Pigweed under Different Temperatures

Weed Science ◽  
1992 ◽  
Vol 40 (3) ◽  
pp. 364-370 ◽  
Author(s):  
Kassim Al-Khatib ◽  
Rick Boydston ◽  
Robert Parker ◽  
E. Patrick Fuerst
Keyword(s):  
High Temperature ◽  
Photosystem Ii ◽  
Common Bean ◽  
Thylakoid Membranes ◽  
Ps Ii ◽  
Foliar Absorption ◽  
Redroot Pigweed ◽  
Temperature Regimes ◽  
Different Temperatures ◽  
Ps Ii Activity

The basis for increased phytotoxicity of foliar-applied atrazine at high temperature in common bean and redroot pigweed was investigated. Plants were grown under low (15/10 C), medium (25/20 C), or high (35/30 C) temperature regimes. Atrazine absorption by plants grown under different temperatures increased with increasing temperatures in both species. Greater than 90% of absorbed atrazine remained in treated leaves and translocation was not altered by temperature in both species. Metabolism of atrazine by both hydroxylation and glutathione-conjugation was greater in plants grown at 35/30 than 15/10 C in both species. Foliar-applied atrazine reduced extractable photosystem II (PS II) activity as temperature increased in both species. Studies were also conducted on thylakoid membranes from plants not treated with atrazine. The I50for atrazine inhibition of PS II decreased and affinity of atrazine binding to thylakoid membranes increased as temperature increased in both species. We concluded that the increased phytotoxicity of atrazine at high temperatures is caused by enhanced foliar absorption and greater affinity of atrazine for the binding site.

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