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'Proteolysis' in keywords Facet   Publication Year 1989  [X]
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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