| | 61 | Author
| Bengt Svensson, Imre Vass, Stenbjörn Styring | Requires cookie* | | | Title
| Sequence Analysis of the D 1 and D 2 Reaction Center Proteins of Photosystem II  | | | | Abstract
| A com pilation o f 38 sequences for the D1 and 15 sequences for the D 2 reaction center pro teins o f photosystem II is presented. The sequences have been compared and a similarity index that takes into account the degree o f conservation and the quality o f the changes in each posi tion has been calculated. The similarity index is used to identify and describe functionally im portant domains in the D 1 /D 2 heterodimer. Comparative hydropathy plot are presented for the aminoacid sidechains that constitute the binding domain o f the tyrosine radicals, Tyrz and TyrD, in photosystem II. The structure around Tyrz is more hydrophilic than the structure around TyrD. The hydrophilic residues are clustered in the part o f the binding pocket for Tyrz that is turned towards the lumenal side o f the thylakoid membrane. M ost prominent is the presence o f two conserved carboxylic am inoacids, D l-A sp 170 and D l-G lu 189. Their respec tive carboxyl-groups com e close in space and are proposed to constitute a metal binding site together with D l-G ln 165. The distance between the proposed metal binding site and the cen ter o f the ring o f Tyrz is approximately 7Ä . The cavity that constitutes the binding site for TyrD is com posed o f residues from the D 2 protein. Its character is more hydrophobic than the Tyrz site and the environment around TyrD lacks the cluster o f putative metal binding side chains. | | | |
Reference
| Z. Naturforsch. 46c, 765 (1991); received March 13 1991 | | | |
Published
| 1991 | | | |
Keywords
| Photosystem II, D1 Protein, D 2 Protein, Tyrosine, M anganese, Reaction Center | | | |
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| default:Reihe_C/46/ZNC-1991-46c-0765.pdf | | | | Identifier
| ZNC-1991-46c-0765 | | | | Volume
| 46 | |
| 62 | Author
| Gudrun Wälzlein, ElfriedeK. Pistorius | Requires cookie* | | | Title
| Inactivation of Photosynthetic 0 2 Evolution in the Cyanobacterium Anacystis nidulans PCC 6301: Influence of Nitrogen Metabolites and Divalent Cation Concentration | | | | Abstract
| A n investigation about the in vivo inactivation o f photosynthetic water oxidation has been carried out in the cyanobacterium Anacystis nidulans (Synechococcus PC C 6301). Photosystem II and photosystem I activity as well as the relative am ount of the D 1 and manganese stabiliz ing peptide o f photosystem II were determined after growing the cells in nutrient media with variations in the nitrogen source and the concentration of the major divalent cations (M g 2+ and C a :+). The results show a rapid inactivation of water oxidation in A. nidulans in response to nitrogen deficiency and in response to reduced M g:+ and C a2+ concentrations. The inactiva tion o f water oxidation observed under divalent cation deficiency could be greatly accelerated when L-amino acids instead o f am m onia or nitrate were used as nitrogen source. Under these conditions inactivation o f water oxidation correlated with a rapid loss o f D 1 and with a slower loss o f the manganese stabilizing peptide from photosystem II. A possible regulation o f the photosystem II activity in A. nidulans by nitrogen metabolites is suggested. | | | |
Reference
| Z. Naturforsch. 46c, 1024—1032 (1991); received June 26/August 19 1991 | | | |
Published
| 1991 | | | |
Keywords
| Cyanobacteria, Anacystis nidulans PCC6301, Synechococcus PCC6301, Photosystem II, Photosystem I, Nitrogen Metabolism | | | |
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| default:Reihe_C/46/ZNC-1991-46c-1024.pdf | | | | Identifier
| ZNC-1991-46c-1024 | | | | Volume
| 46 | |
| 64 | Author
| Klaus-Peter Michel, ElfriedeK. Pistorius, E. Gau, G. Wälzlein, S. Gärtner, M. Kuhlmann, E. K. Pistorius | Requires cookie* | | | Title
| Isolation of a Photosystem II Associated 36 kDa Polypeptide and an Iron-Stress 34 kDa Polypeptide from Thylakoid Membranes of the Cyanobacterium Synechococcus PCC 6301 Grown under Mild Iron Deficiency | | | | Abstract
| A 36 kDa polypeptide which previously was shown to be present in purified photosystem II complexes from Synechococcus PCC 6301 and which crossreacts with the antiserum raised against the soluble L-amino acid oxidase o f 50 kD a from Synechococcus PCC 6301 (A. was isolated from thylakoid membranes o f the same cyanobacterium grown under mild iron deficiency. This peptide is present in about equal am ounts in thylakoid membranes o f Syne chococcus PCC 6301 grown under regular or iron deficient conditions. The antiserum raised against this thylakoid membrane bound 36 kD a peptide crossreacts with the soluble L-amino acid oxidase o f 50 kDa. These results further support our conclusion that the thylakoid mem brane bound 36 kD a polypeptide is a modified form o f the soluble 50 kD a L-amino acid oxi dase. In addition, a 34 kD a polypeptide was isolated from iron stressed thylakoid membranes, and an antiserum was also raised against this protein. Im m unoblot experiments with this an tiserum show that the 34 kD a peptide is present in elevated amounts in thylakoid membranes from Synechococcus cells grown under iron deficiency and that it is alm ost absent in thylakoid membranes from cells grown under regular conditions. | | | |
Reference
| Z. Naturforsch. 47c, 867—8 (1992); received August 4/O ctober 8 1992 | | | |
Published
| 1992 | | | |
Keywords
| Cyanobacteria, Synechococcus PCC 6301, Photosystem II, L-Amino Acid Oxidase, Iron Stress | | | |
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| default:Reihe_C/47/ZNC-1992-47c-0867.pdf | | | | Identifier
| ZNC-1992-47c-0867 | | | | Volume
| 47 | |
| 65 | Author
| KlausG. Tietjen, Wilfried Draber, John Goossens, JohannesR. Jansen, JoachimF. Kluth, Michael Schindler, Heinz-Jürgen, Wroblowsky Bayer, A. G. | Requires cookie* | | | Title
| Binding of Triazines and Triazinones in the QB-Binding Niche of Photosystem II | | | | Abstract
| A series o f 20 triazines (derivatives o f 2-alkylam ino-4-benzylam ino-6-chloro-l,3,5-triazines) and 37 triazinones (derivatives o f 3-alkyl-4-am ino-6-phenyl-l,2,4-triazin-5-ones) is tested for inhibitory potency in photosynthetic electron flow through photosystem II o f wild type Chla-mydomonas reinhardtii and o f five mutants with aminoacid substitutions in the D 1 protein at valine 219, alanine 251, phenylalanine 255, serine 264, and leucine 275. The data are used for computer modelling o f .the possible location o f the com pounds within a three dimensional model o f the QB-binding niche o f the D 1 protein. | | | |
Reference
| Z. Naturforsch. 48c, 205 (1993); received November 23 1992 | | | |
Published
| 1993 | | | |
Keywords
| D 1 Protein, Herbicides, Molecular M odeling, Photosystem II, Q B-Binding Niche | | | |
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| default:Reihe_C/48/ZNC-1993-48c-0205.pdf | | | | Identifier
| ZNC-1993-48c-0205 | | | | Volume
| 48 | |
| 66 | Author
| Z. Naturforsch | Requires cookie* | | | Title
| Kinetics of Electron Transfer between Q A and Q B in Wild Type and Herbicide-Resistant Mutants of Chlamydomonas reinhardtii | | | | Abstract
| A n ton y R . C ro fts*, Irene B aroli, D avid K ra m e r, and Shinichi T a o k a Biophysics Division and *D epartm ent o f M icrobiology, University o f Illinois at U rbana-Cham paign, U rb ana, We have investigated the electron transfer kinetics for reduction o f plastoquinone by photo system II in six m utant strains o f Chlamydomonas reinhardtii by following the decay o f the high fluorescence state after flash activation, and com pared the separate reactions of the two-electron gate with those o f a wild type strain. By analysis o f the electron transfer kinetics, and separate measurement o f the equilibrium constant for stabilization o f the bound semiquinone after one flash, we have been able to deconvolute the contributions o f rate constants and equi librium constants for plastoquinone binding and electron transfer to the overall process. Two mutations, S 264 A and A 251 V, led to a marked slowing o f kinetics for reduction of plastoqui none to the bound semiquinone. In S 2 6 4 A , the second electron transfer was also slower, but was normal in A 2 5 1 V. In m utant G 2 5 6 D , the electron transfer kinetics were normal after the first flash, but slowed after the second. In mutants L 2 5 7 F , V 2 1 9 I, and F 2 5 5 Y , the electron transfer kinetics after both flashes were similar to those in wild type. We discuss the results in terms of a model which provides a description o f the mechanism o f the two-electron gate in terms of measured kinetic and equilibrium constants, and we give values for these parameters in all strains tested. | | | |
Reference
| Z. Naturforsch. 48c, 259 (1993); received December 10 1992 | | | |
Published
| 1993 | | | |
Keywords
| Electron Transfer, Kinetics, Tw o-Electron G ate, Herbicide Resistance, Photosystem II | | | |
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| default:Reihe_C/48/ZNC-1993-48c-0259.pdf | | | | Identifier
| ZNC-1993-48c-0259 | | | | Volume
| 48 | |
| 67 | Author
| JeffA. Nemson, Anastasios Melis | Requires cookie* | | | Title
| Light-Induced Oxidation-Reduction Reactions of Photosystem II in Dichlorophenyl-dimethyl Urea (DCM U) Inhibited Thylakoids | | | | Abstract
| Illumination o f thylakoid membranes in the presence o f 3-(3',4'-dichlorophenyl)-1,1-di-methyl urea (D C M U) causes the reduction o f the primary quinone acceptor QA o f photosys tem II (PS II) and the storage o f a positive charge on the donor side o f the photochem ical reac tion center. These oxidation-reduction reactions are accompanied by characteristic changes o f absorbance in the ultra-violet region o f the spectrum. The PS II-related absorbance difference spectra (2 5 0 -3 5 0 nm) were compared in control and hydroxylamine-treated thylakoid mem branes, and in thylakoids suspended in the presence o f carbonyl cyanide-/7-(trifluoromethoxy)-phenylhydrazone (FCCP). The light minus dark difference spectra were dominated by the QA minus QA difference spectrum. Qualitatively, the three spectra were identical in the 3 0 0 -3 5 0 nm region, however, they showed distinct differences in the 2 5 0 -3 0 0 nm region. The latter arose because o f different contributions from the donor side o f PS II in the thylakoid membrane o f the three samples. The result suggested that FCCP acts as the ultimate electron donor in D C M U -poisoned chloroplasts. Therefore, the absorbance difference spectrum in the presence o f FCCP reflected a contribution from the QA minus QA com ponent only. D econvolu tion o f the absorbance difference spectra o f control and hydroxylamine-treated thylakoids yielded difference spectra attributed to the oxidation o f a com ponent on the donor side o f PS II. This com ponent did not conform with the known M n(III) — ■ > M n(IV) transition. R ath er, it indicated the oxidation o f a modified form o f Mn in the presence o f D C M U , probably a Mn(II) —> M n(III) transition. The results are discussed in terms o f the use o f D C M U -poisoned thylakoid membranes in the quantitation o f the primary quinone acceptor Q A by spectro-photom etric approaches. | | | |
Reference
| Z. Naturforsch. 45c, 258 (1990); received July 25/August 21. 1989 | | | |
Published
| 1990 | | | |
Keywords
| Absorbance Difference Spectra, Photosystem II, Electron Transport, Primary Quinone Acceptor, Electron D onor Tyrosine | | | |
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| default:Reihe_C/45/ZNC-1990-45c-0258.pdf | | | | Identifier
| ZNC-1990-45c-0258 | | | | Volume
| 45 | |
| 68 | Author
| R. Fromme, G. Renger | Requires cookie* | | | Title
| Studies on Herbicide Binding in Photosystem II Membrane Fragments from Spinach | | | | Abstract
| The mechanism of atrazine binding and its modification by Chelex-100-induced Ca2+ deple tion and proteolytic degradation by trypsin, was analyzed in PS II membrane fragments from spinach. It was found: 1) Chelex-100 treatment leads in a comparatively slow process (/, 2 = 5 — 10 min) to Ca2+ re moval from a site that is characterized by a high affinity as reflected by K u values of the order of 10 7 M. The number of these binding sites was found to be almost one per PS II in samples washed twice with Ca2+ -free buffer. 2) Chelex-100 treatment does not affect the affinity of atrazine binding but increases the susceptibility to proteolytic attack by trypsin. 3) The electron transport activity is only slightly affected by Chelex-100 treatment. 4) The atrazine binding exhibits a rather small T-dependence within the physiological range of 7 °C to 27 °C. The implications of these findings for herbicide binding are discussed. | | | |
Reference
| Z. Naturforsch. 45c, 373—378 (1990); received November 15 1989 | | | |
Published
| 1990 | | | |
Keywords
| Atrazine Binding, Photosystem II, Ca2+ Effects, Temperature Dependence, Mild Proteolysis | | | |
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| default:Reihe_C/45/ZNC-1990-45c-0373.pdf | | | | Identifier
| ZNC-1990-45c-0373 | | | | Volume
| 45 | |
| 69 | Author
| HimadriB. Pakrasi, KarinJ. Nyhus, HowardG. Ranok | Requires cookie* | | | Title
| Targeted Deletion Mutagenesis of the ß Subunit of Cytochrome b559 Protein Destabilizes the Reaction Center of Photosystem II | | | | Abstract
| Oligonucleotide-directed mutagenesis techniques were used to delete the psbF gene, encod ing the ß subunit o f the cytochrom e b559 protein o f the photosystem II com plex in the cyano bacterium, Synechocystis 6803. Cyt b559 is an integral com ponent o f 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 o f its neighbouring genes, psbE , psbL and p sb i were simultaneously deleted from the chrom osom e o f Synechocystis 6803 (Pakrasi, Williams and Arntzen, EMBO J. 7, 3 2 5 -3 3 2 , 1988). This mutant had no PS II activity. However, the role o f any one o f 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 o f two other protein com ponents, D1 (herbicide binding protein) and D2, o f the reaction center o f PS II, in its thylakoid membranes. In contrast, two other proteins o f PS II, CP47 and CP43 were present in appreciable amounts. Fluorescence spectra (77 K) o f the mutant showed the absence o f a peak at 695 nm that was previously believed to originate from CP47. In addition, phycobilisomes, the light-harvesting antenna system o f PS II, were found to be assembled normally in this mutant. We conclude that the presence o f the ß subunit o f Cyt b559 in the thylakoid membranes is critically important for the assembly o f PS II reaction center. | | | |
Reference
| Z. Naturforsch. 45c, 423 (1990); received November 21 1989 | | | |
Published
| 1990 | | | |
Keywords
| Photosystem II, Cytochrom e b559, Site-Directed Mutagenesis, Protein Complex Stability, Synechocystis 6803 | | | |
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| default:Reihe_C/45/ZNC-1990-45c-0423.pdf | | | | Identifier
| ZNC-1990-45c-0423 | | | | Volume
| 45 | |
| 70 | Author
| MarcelA K Jansen, Klaus Pfister | Requires cookie* | | | Title
| Conserved Kinetics at the Reducing Side of Reaction-Center II in Photosynthetic Organisms; Changed Kinetics in Triazine-Resistant Weeds | | | | Abstract
| The decay o f chlorophyll variable fluorescence after a "single turnover" flash is generally assumed to represent the reoxidation o f the reduced quinone Qa. We have observed that the kinetics o f this decay are very similar in a wide variety o f species. Comparing 28 different spe cies, we found an average half decay time o f 314 ± 4 6 (isec. N o systematic correlations were found between the decay rate and biochemical or physiological specializations such as C 2, C 4 or C A M . This indicates that structural as well as functional factors controlling photosystem II electron transfer between Qa and Qb are highly conserved. Apparently, the freedom for natural structural variations in this region is very limited. Triazine resistant plants, characterized by an altered amino acid sequence o f the D 1 protein, have clearly decreased rates o f Qa/Q b electron transfer. We found an average half decay time o f 946 ± 100 jisec (5 species). However, this three-fold decrease is much less than previously re ported. Therefore, if alterations o f photosystem II electron transfer efficiency contributes to an often reported reduction o f "ecological fitness", this contribution is smaller than was hitherto assumed. | | | |
Reference
| Z. Naturforsch. 45c, 441—4 (1990); received November 27 1989 | | | |
Published
| 1990 | | | |
Keywords
| Chlorophyll Fluorescence, Evolution, Photosystem II, Triazine Resistance, p sb A Conservation | | | |
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| default:Reihe_C/45/ZNC-1990-45c-0441.pdf | | | | Identifier
| ZNC-1990-45c-0441 | | | | Volume
| 45 | |
| 71 | Author
| Jack Dekker, RonaldG. Burmester | Requires cookie* | | | Title
| Differential Pleiotropy in a psbA Gene Mutant of Brassica napus Implies Altered Temporal Photosynthesis and Thermal Tolerance | | | | Abstract
| Studies were conducted to test the hypothesis that the mutation to the psbA. plastid gene that confers s-triazine resistance (R) also results in an altered diurnal pattern o f photosynthetic car bon reduction (CER) relative to that o f the susceptible (S) wild-type. In all experiments CER approximated the increasing and decreasing light levels during the diurnal. S C ER exceeded that o f R during the midday period, but R CER was greater early and late in the diurnal at 25 °C. R CER exceeded that o f S for most o f the diurnal at 35 °C and in older, crowded, nitrogen-starved plants. These studies support the stated hypothesis and indicate a more complex model o f photosynthetic productivity than previously observed. An assessment o f the photosynthetic competence o f either biotype may be a function o f the time o f day or the environmental condi tions the plants are exposed to, especially temperature. | | | |
Reference
| Z. Naturforsch. 45c, 474 (1990); received October 18 1989 | | | |
Published
| 1990 | | | |
Keywords
| Photosystem II, D -l Protein, Electron Transport, C hronobiology, Diurnal Rhythms | | | |
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| default:Reihe_C/45/ZNC-1990-45c-0474.pdf | | | | Identifier
| ZNC-1990-45c-0474 | | | | Volume
| 45 | |
| 72 | Author
| S. C. Sabat, V. Vijayavergiya, B. C. Tripathy, PrasannaM. Ohanty | Requires cookie* | | | Title
| Inhibitory Effect of Crown Compound on Photoelectron Transport Activity of Beet Spinach Thylakoid Membranes | | | | Abstract
| The effect o f K-picrate-18-crown-6 (crown) on the photoelectron transport activity o f beet spinach thylakoid membranes was investigated. A ddition o f micromolar concentration o f crown to thylakoid preparation inhibited p-benzoquinone, chloride-indophenol, methyl violo-gen supported Hill activities maximally by 75 per cent in a concentration dependent manner. However, the photosystem I catalyzed reaction remained insensitive to crown suggesting that crown specifically inhibits photosystem II electron transport. Addition o f exogenous electron donors like hydroxylamine or diphenylcarbazide failed to restore the crown induced inhibition o f photosystem II electron transport and lowering o f steady state chlorophyll a fluorescence yield. These observations suggest that crown also inhibits photosystem II catalyzed electron transport after the donation sites o f these exogenous donors. Washing o f the crown pre-treat-ed thylakoids with isolation buffer, relieved the crown inhibited electron transport activity, indicating that this inhibition is reversible. Furthermore, in hydroxylamine washed thylakoids which are devoid o f 0 2 evolution capacity, the hydroxylamine induced increase in chlorophyll a fluorescence o f variable yield was quenched by the addition o f crown. These observations suggest that crown affects the oxygen evolution and inhibits at a site close to photosystem II reaction centres. | | | |
Reference
| Z. Naturforsch. 46c, 87 (1991); received August 14 1990 | | | |
Published
| 1991 | | | |
Keywords
| Crown-Ether, Electron Transport, Photosystem II, Thylakoids, Beet Spinach ( Beta vulgaris) | | | |
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| default:Reihe_C/46/ZNC-1991-46c-0087.pdf | | | | Identifier
| ZNC-1991-46c-0087 | | | | Volume
| 46 | |
| 73 | Author
| J. K. Ru K, K. B., Rd Ab>, A. R. Adunzc, K. Strzałka3, G. H. Schm | Requires cookie* | | | Title
| Antagonistic Effects of a-Tocopherol and a-Tocoquinone in the Regulation of Cyclic Electron Transport around Photosystem II | | | |
Reference
| Z. Naturforsch. 52c, 766—774 (1997); received August 22/ | | | |
Published
| 1997 | | | |
Keywords
| a-Tocopherol, a-Tocoquinone, Plastoquinone-A, Photosystem II, Cyclic Electron Transport, Oxygen Evolution, Thylakoid Membrane | | | |
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| default:Reihe_C/52/ZNC-1997-52c-0766.pdf | | | | Identifier
| ZNC-1997-52c-0766 | | | | Volume
| 52 | |
| 74 | Author
| G. Ábor Bernát3, Subhash Padhyeb, Csilla Barta3, L. Ászló Kovács3, Sándor Demeter3 | Requires cookie* | | | Title
| Chemical Probes for Water-Oxidation: Synthetic Manganese Complexes in Photoactivation of Water Splitting Complex and as Exogenous Electron Donors to Photosystem II | | | | Abstract
| , Hungary. Fax: + 3 6 -6 2 -4 3 3 -4 3 4 . E-m ail: tudor@nucleus.szbk.u-szeged.hu b D epartm ent Photoactivation of the water splitting enzyme was perform ed with 13 different synthetic manganese complexes and characterized by oxygen evolution yield, thermoluminescence and chlorophyll fluorescence induction kinetics. The efficiency of different compounds in photo activation correlated with the rate of linear electron transport in the presence of these com pounds. The organic ligands, associated with the manganese ions, do not prevent the photoac tivation of the water splitting complex (W O C). Photoactivation with different manganese complexes depended on the number of the Mn-ions in the complex, their valence state and the nature of their donor atoms. The most efficient restorations were achieved by using tetram eric complexes having a dimer+dimer structure, complexes containing M n(II) ions, and having 4 -6 oxygen and 0 -2 nitrogen atoms as donor atoms. Further, the effectiveness of photoactivation depended largely on the structure of the complexes. Our data support the notion that W O C in intact thylakoids requires the cooperation and well determined arrange ment of all four manganese ions, and argue against the hypothesis that two manganese ions are sufficient for water splitting. Photoactivation by some complexes led to anomalous flash-oxygen patterns, which are explained by a modified/perturbed water splitting complex. | | | |
Reference
| Z. Naturforsch. 56c, 755 (2001); received April 9/M ay 28 2001 | | | |
Published
| 2001 | | | |
Keywords
| Photosystem II, W ater Splitting Complex, Synthetic M anganese Complexes Abbreviations: Chi, chlorophyll; DCMU, 3-(3', 4'-dichloro- | | | |
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| default:Reihe_C/56/ZNC-2001-56c-0755.pdf | | | | Identifier
| ZNC-2001-56c-0755 | | | | Volume
| 56 | |
|
