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1989 (1)
1986 (1)
1Author    RichardJ. Berzborn, Werner FinkeRequires cookie*
 Title    Localization and Orientation of Subunit Delta of Spinach Chloroplast ATP-Synthase within the CF0CF! Complex 1. Distinction of Shielded and Exposed Surfaces of Delta on the Thylakoid Membrane  
 Abstract    A new polyclonal antiserum against spinach CF, subunit delta was produced in rabbits. It decorates only one band at 21 kDa in Western immunoblots of thylakoid proteins and does not react in E LISA with 6-free four subunit C F ,(—6); therefore it is regarded monospecific. The polypeptide used as immunogen had been purified by HPLC. Earlier antisera against CF, 6 cross-react with CF, subunit ß. The new antiserum 306 contains different antibodies; some can be absorbed with thylakoids, i.e. by 6 within the assembled CF0CF, complex on the membrane, others still react in ELISA with isolated CF,. The former antibodies agglutinate thylakoids and inhibit PMS cyclic photophos­ phorylation. Therefore we conclude that part of the surface of CF! subunit 6 is exposed within the quaternary structure of the ATP-synthase complex of photosynthetically active thylakoids, but part of the surface of 6 is shielded. Trypsination of isolated 6 occurs at several sites, but this protease does not attack 6 in situ, nor does aminopeptidase. Staphylococcus aureus protease V8 digests CF, 6 after isolation at residues Asp53, G1u61, G1u95 and G lu 106, but has no access to these residues of 6 in situ. Thus CF, subunit 6 seems to be shielded within the CF0CF, complex to a large degree. Direct agglutination of thylakoids by anti 6 serum 306 was weak and could be improved tenfold by a Coombs serum (goat anti rabbit gammaglobulin), whereas an anti ß serum agglutinated directly. From this we conclude that 6 is not accessible at the top of the enzyme; the exposed part is extending below the large subunits a and ß and oriented towards the membrane. 
  Reference    Z. Naturforsch. 44c, 153 (1989); received June 24/October 7 1988 
  Published    1989 
  Keywords    Accessibility, Antibodies, Coupling Factor, Proteolysis, Photophosphorylation 
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 TEI-XML for    default:Reihe_C/44/ZNC-1989-44c-0153.pdf 
 Identifier    ZNC-1989-44c-0153 
 Volume    44 
2Author    R. Steiner, B. Kalumenos, H. ScheerRequires cookie*
 Title    The Photosynthetic Apparatus of Ectothiorhodospira halochloris 3. Effect of Proteolytic Digestion on the Photoactivity  
 Abstract    of Rhodopseudomonas viridis and Ectothiorhodospira halochloris were treated with proteinase K. The photochemical activity (light minus dark difference spectra) were compared to the polypeptide composition (SDS-polyacrylamide gel analysis). In E. halo­ chloris, difference bands appear at 806 (+), 838 (+) and 854 nm (-) . All three decrease in intensity upon incubation with proteinase K., but this decrease is much slower than the proteolysis of both the reaction center and antenna related polypeptides. Photochemical activity remains high as long as a small part of the RC and two lower molecular weight polypeptides M* (22.0 kDa) and B* (15.3 kDa) are present. The M subunit is the most stable polypeptide in the RC of Rp. viridis too, and the photochemical activity is related to the remainder of this and to the one newly formed polypeptide (15.3 kDa), but doesn't show the typical absorption shift of the antenna (B 800/1020 —» B 800/960). The results are discussed quantitatively a containing organisms. 
  Reference    Z. Naturforsch. 41c, 873—880 (1986); received July 17 1986 
  Published    1986 
  Keywords    Bacterial Photosynthesis, Ectothiorhodospira, Reaction Center, Proteolysis, Difference Spectro­ scopy Photosynthetic membranes 
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 TEI-XML for    default:Reihe_C/41/ZNC-1986-41c-0873.pdf 
 Identifier    ZNC-1986-41c-0873 
 Volume    41