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'D 1 Protein' in keywords Facet   Publication Year 1990  [X]
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1Author    John Bowyer1, Mark Hiltonb, Julian Whitelegge3, Philip Jewess6, Patrick Camillerib, Antony Croftsc, Howard RobinsoncRequires cookie*
 Title    Molecular Modelling Studies on the Binding of Phenylurea Inhibitors to the D 1 Protein of Photosystem II  
 Abstract    A hypothetical molecular model of part of the D 1 protein of photosystem II, based on the analogous portion of the L subunit of the Rhodopseudomonas viridis reaction centre, has been used to study the binding of an extended hydrophobic phenylurea inhibitor (N,N-dimethyl-carbamoyl)4 -amino-4 '-chloro-rra«5 -stilbene) (I) to the Q B site. The inhibitor was fitted by eye into a cleft in the site, and a limited part of the inhibitor/D 1 complex was energy minimized. The gross orientation of the inhibitor placed the dimethylurea moiety towards the predicted binding domain of the plastoquinone head group, and the stilbene moiety directed along the quinone isoprenoid side chain binding domain, suggesting a similar pathway of approach of the two molecules from the membrane into the binding site. Binding interactions of the inhibi­ tor included hydrogen bonds to the side chain hydroxyl of ser 264 and the peptide carbonyl group of ala 251, with the side chain hydroxyl of ser 268 as an alternative ligand. Numerous hydrophobic contacts were also possible. Although phenylureas do not bind to reaction centres of Rp. viridis, many of the binding interactions to D 1 could also be detected in Rp. viridis. However, the ß-CH2 and 5-C02-groups of glu 212 in Rp. viridis are located in the corresponding region of D 1 occupied by the dimethylurea moiety of the inhibitor in our model of its binding to D 1. This may explain why diuron (D C M U) does not bind to Rp. viridis reac­ tion centres. 
  Reference    Z. Naturforsch. 45c, 379—387 (1990); received November 23 1989 
  Published    1990 
  Keywords    Phenylureas, Photosystem II, D 1 Protein, Molecular Modelling 
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 TEI-XML for    default:Reihe_C/45/ZNC-1990-45c-0379.pdf 
 Identifier    ZNC-1990-45c-0379 
 Volume    45 
2Author    SudhirK. Sopory3, M. Bruce, Greenbergb, RoshniA. Mehtaac, Marvin Edelmanab, AutarK. MattooaRequires cookie*
 Title    Free Radical Scavengers Inhibit Light-Dependent Degradation of the 32 kDa Photosystem II Reaction Center Protein  
 Abstract    Involvement of oxygen-free radicals in the rapid, light-dependent degradation of the 32 kDa photosystem II reaction center protein was investigated. The free radical scavengers propyl-gallate and uric acid inhibited 32 kDa protein degradation without affecting linear electron flow. The involvement of singlet oxygen was excluded. Protection from degradation was also afforded under ultra-violet and far-red radiations. These data implicate free-radical damage as a common step in the degradation process, and emphasize the oxygen environment as a causa­ tive factor in destabilization of the 32 kDa protein. 
  Reference    Z. Naturforsch. 45c, 412—417 (1990); received December 28 1989 
  Published    1990 
  Keywords    Spirodela oligorrhiza, Chloroplast, D 1 Protein, Photosynthesis 
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 TEI-XML for    default:Reihe_C/45/ZNC-1990-45c-0412.pdf 
 Identifier    ZNC-1990-45c-0412 
 Volume    45