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1Author    Hugo Scheer, Helmut Formanek, W. Olfhart RüdigerRequires cookie*
 Title    The Conformation of Bilin Chromophores in Biliproteins: Ramachandran-Type Calculations  
 Abstract    Ramachandran-type calculations are perform ed for conformations o f bilin chromophores pres­ ent in the biliproteins phycocyanin, phycoerythrin and phytochrome. The atom ic coordinates are taken from x-ray data o f crystalline model compounds, namely biliverdin for pyrrole rings B, C, D and substituted succinimides for the hydrogenated ring A including a thioether containing ^-sub­ stituent. Maxima and m inim a for steric hindrance are calculated for rotation o f the thioether side chain, the rotation of pyrrole rings at single bonds (syn-anti-forms) and at double bonds (Z-E-iso-mers) of the methine bridges. Whereas quasi-planar structures are possible for all syn, Z-forms, only twisted structures are possible if anti, E-forms are considered. The relevance for the bilin con­ formations of native biliproteins and o f the Pr ^ Pfr phototransform ation is discussed. 
  Reference    Z. Naturforsch. 34c, 1085 (1979); received June 29 1979 
  Published    1979 
  Keywords    Bilin Conformation, Phycocyanin, Phycoerythrin, Phytochrome 
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 TEI-XML for    default:Reihe_C/34/ZNC-1979-34c-1085.pdf 
 Identifier    ZNC-1979-34c-1085 
 Volume    34 
2Author    W. Olfhart Rüdiger, Thom As Brandlmeier, Inge Bios, Jens-Peter Gossauer, WellerRequires cookie*
 Title    Isolation of the Phytochrome Chromophore. The Cleavage Reaction with Hydrogen Bromide A lbert  
 Abstract    The cleavage o f the bilin chromophore from C-phycocyanin with hydrogen bromide yields 3E-configurated phycocyanobilin (4) as the major and 3 Z-configurated phycocyanobilin (5) as the minor reaction product. The reaction o f synthetic 3E-configurated phytochromobilin (2) with hydrogen bromide and methanol leads only to a methanol adduct at the C-18 side chain (7) whereas the same reaction with the 3Z-configurated phytochromobilin (3) leads to 7 and 2. The bilin chromophore was cleaved also from phytochrome after preparation o f phytochromobilin peptides. The detection o f 2 and 7 suggested that 3Z-and 3E-configurated phytochromobilin were the primary products o f cleavage from phytochrome. A reaction scheme is given which can explain the results o f the reaction with hydrogen bromide and methanol. 
  Reference    Z. Naturforsch. 35c, 763—769 (1980); received July 11 1980 
  Published    1980 
  Keywords    Phytochrome, Bile Pigments, Phytochromobilin, Thioether Cleavage, C-Phycocyanin 
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 TEI-XML for    default:Reihe_C/35/ZNC-1980-35c-0763.pdf 
 Identifier    ZNC-1980-35c-0763 
 Volume    35 
3Author    W. Kufer, H. ScheerRequires cookie*
 Title    Chemical Modification of Biliprotein Chromophores  
 Abstract    The reaction of biliproteins with sodium dithionite has been studied. The reagent is selective towards the chromophores. In denatured phycocyanin from Spirulina platensis, all three chromo­ phores react to form yellow "phycorubin", whereas only 1 /3 of the chromophores react in native phycocyanin in a non-statistical manner. From reversion experiments, it can be shown, that the thermodynamic stability of the chromophores towards reaction with dithionite is increased in the native pigment. Similarly, native phytochrome in its P r form reacts only partially to a pigment ab­ sorbing at both 420 and 660 nm. The same product is formed from native Pfr, indicating both a reversion to Pr and a partial reduction. 
  Reference    Z. Naturforsch. 34c, 776—781 (1979); received July 2 1979 
  Published    1979 
  Keywords    Biliproteins, Phycocyanin, Phytochrome, Chromophore Modification, Dithionite, Reversible De­ naturation 
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 TEI-XML for    default:Reihe_C/34/ZNC-1979-34c-0776.pdf 
 Identifier    ZNC-1979-34c-0776 
 Volume    34 
4Author    K. H. Grumbach, M. DrollingerRequires cookie*
 Title    The Effect of Phytochrome and Proteinsynthesis-Inhibitors on the Formation of Chlorophylls and Carotenoids in Radish Seedlings Treated with Photosystem II and Bleaching Herbicides  
 Abstract    Etioplasts of radish seedlings treated with photosystem II (DCM U, bentazon) and chlorotic herbicides (amitrole, SAN 6706) were tested on their ability to perform the phytochrome mediated chlorophyll and carotenoid biosynthesis. The cytoplasmic influence on the chloroplastic action o f herbicides was also investigated by inhibition of protein synthesis either in the chloro­ plast with chloramphenicol or in the cytoplasm with actidion. In all herbicide treated radish seedlings a phytochrome mediated chlorophyll and carotenoid biosynthesis was obtained as found in control plants. In plants treated with DCM U the bio­ synthesis o f carotenoids is enhanced compared to the control plants, while SAN 6706 significantly suppresses the carotenoid formation. It is concluded, that photosystem II and chlorotic herbicides do not interfere with the primary action o f phytochrome but rather do develope their effects on the terpenoid metabolism through phytochrome. Chloramphenicol applied at the time o f sowing very strongly suppresses the formation of chlorophylls and carotenoids in control plants. The sensitivity towards actidion is, however, very much lower. If chloramphenicol and actidion treated plants were also supplied with herbicides, the pigment pattern is completely different In SAN 6706-treated plants chloramphenicol acts synergistic, resulting in an even lower chlorophyll and carotenoid content than in plants supplied only with chloramphenicol. On the other hand SAN 6706 in combination with actidion enhances the formation of pigments, leading to a much higher chlorophyll and carotenoid content as in plants treated only with actidion. A stimulatory effect on the formation o f chlorophylls and carotenoids was also found for DCMU-treated plants in combination with actidion. The observation, that in plants treated with SAN 6706 together with actidion, which inhibits protein synthesis in the cytoplasm, the herbicidal response in the chloroplast is completely abolished, gives evidence that the photooxidative action of SAN 6706 in the chloroplast is developed by the cytoplasm. 
  Reference    Z. Naturforsch. 35c, 445 (1980); received February 8 1980 
  Published    1980 
  Keywords    Photosystem II Herbicides, Chlorotic Herbicides, Chlorophylls, Carotenoids, Phytochrome, Inhibitors 
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 TEI-XML for    default:Reihe_C/35/ZNC-1980-35c-0445.pdf 
 Identifier    ZNC-1980-35c-0445 
 Volume    35 
5Author    T. Hom As Brandlm, Hugo Scheer, W. Olfhart RüdigerRequires cookie*
 Title    Chromophore Content and Molar Absorptivity of Phytochrome in the Pr Form  
 Abstract    Quantitative absorption spectra in the visible and UV region were recorded for denaturated phytochrome (P r) and phytochromobilin peptides in comparison with native Pr. The method was tested with C-phycocyanin from Spirulina platensis. Based on known molar absorptivities for denaturated phycocyanin and suitable model compounds, and on the ratio ^niüve/^delrS = 2.9, ^native was determined to be 1 0 2 0 0 0 m _1 cm-1 for one phycocyanobilin chromophore in native phycocyanin. Likewise, N a t iv e was calculated to be 19000 M -1 cm-1. The corresponding ratios for Pr Were ^native/^denatured = 3*4 and A native/-^degraded = 3.7, t h l S yielded ^native = 109000 tO 118000 and eSUfcve = 36000 M _1 cm-1 for phytochromobilin in native P r. This value corresponds to one phytochromobilin per small phytochrome (60000 D) if data from the literature are corrected for the content o f colorless proteins. The latter has been asessed from (i) the purity index (A2g0/A665) and (ii) the contribution o f the phytochromobilin chromophore at 280 nm as derived from model compounds. 
  Reference    Z. Naturforsch. 36c, 431 (1981); received February 20 1981 
  Published    1981 
  Keywords    Absorption, Spectroscopy, A-Dihydrobilindiones, Isophorcabilin, Phycobiliproteins, Phytochrome, Phytochromobilin-Peptides 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0431.pdf 
 Identifier    ZNC-1981-36c-0431 
 Volume    36 
6Author    Fritz Thüm, Thom Ler, W. As Brandlmeier, Olfhart RüdigerRequires cookie*
 Title    Preparation and Properties of Chromopeptides from the Pfr Form of Phytochrome  
 Abstract    Chromopeptides were prepared from the Pfr form o f phytochrome by pepsin digestion. After separation from colorless peptides and Pr peptides by column chromatography, spectral characteristics of this Pfr peptide were determined (A^ax = 610nm, A£ax = 380nm in acid methanol). Irradiation of Pfr peptide produces Pr peptide without liberation of a detectable compound. The Pfr peptide is more sensitive to oxidation and reduction than the Pr peptide. Oxidation with iodine and reduction with dithionite leads to partial chemoconversion o f the Pfr peptide to the Pr peptide. The results favor the model o f cis-trans isomerization for the Pr ^ Pfr transformation. 
  Reference    Z. Naturforsch. 36c, 440 (1981); received February 201981 
  Published    1981 
  Keywords    Avena sativa L, Phytochrome, Pepsin Digestion, Phytochromobilin Peptide, Pfr Peptide 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0440.pdf 
 Identifier    ZNC-1981-36c-0440 
 Volume    36 
7Author    MichaelD. Partis, A.F R, R.Udolf GrimmRequires cookie*
 Title    Computer Analysis of Phytochrome Sequences from Five Species: Implications for the Mechanism of Action  
 Abstract    The amino acid sequences o f phytochrom e from A vena sativa, O ryza sativa, Curcurbita pepo, Pisum sativum and Arabidopsis thaliana have been analyzed with a variety o f computer programs, with a view to identifying areas o f the protein which contribute to the properties o f this photoreceptor. A region at the C-terminus has been shown to be amphiphilic, and by ana­ logy with surface-seeking peptides, may be responsible for interaction o f phytochrom e with lipid bilayers. Possible targeting sequences in phytochrom es have been identified, including a series o f four basic residues which correspond to those responsible for transport o f nuclear-located proteins. Sites capable o f post-translational m odification have been found in m onocot sequences, but not in dicot sequences. Areas o f the phytochrom e molecule which are exposed on the surface o f the portein, and which are therefore capable o f interaction with other cellular macromolecules, have been identified. A nalogies with other biliproteins have been used to de­ fine minimum chromophore-protein interactions. Possible enzymic activities associated with phytochromes have been discussed with respect to local amino acid sequence similarity with enzymes. 
  Reference    Z. Naturforsch. 45c, 987—9 (1990); received April 12 1990 
  Published    1990 
  Keywords    Phytochrome, Sequence Analysis, Amphiphilic Peptides, M embrane Interaction, Targeting Sequences 
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 TEI-XML for    default:Reihe_C/45/ZNC-1990-45c-0987.pdf 
 Identifier    ZNC-1990-45c-0987 
 Volume    45