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1Author    Friederike Koenig, Alfons Radunz, GeorgH. Schmid, Wilhelm MenkeRequires cookie*
 Title    Antisera to the Coupling Factor of Photophosphorylation and Its Subunits  
 Abstract    Stroma-freed chloroplasts were extracted with sucrose palmitate-stearate containing buffer. A fter the addition o f dodecyl sulfate and mercaptoethanol to the extract a series of polypeptides was isolated from the mixture by gel filtration. These polypeptides were later used for immunization. Antisera to four polypeptides reacted in the Ouchterlony double diffusion test with authentic coupling factor yielding a precipitation band. According to the observed apparent molecular weights the polypeptides are the a, ß , 8 and e subunits of the coupling factor. An antiserum to the y subunit has been obtained already previously. A ll antisera inhibit photophosphorylation reactions and electron transport considerably. Addition of gramicidin inhibits photophosphorylation com pletely whereas gramicidin restores electron transport in the assays with the antisera to the a, ß , y and 5 subunit. In the case o f the antiserum to the E subunit gramicidin does not regenerate electron transport. As in the presence of the serum to the £ subunit pH changes in the suspension medium are not observed, this serum seems to open a proton channel. Also, upon addition of dicyclohexyl carbodiimide (D C C D) pH changes in the suspension medium in the assay with antiserum do not reoccur. According to these unexpected results the identity o f the antigen with the e subunit of the coupling factor is not certain. ATP-ase reactions are only inhibited by the antisera to the a and y subunit and what is thought to be the £ subunit. The antiserum to the a subunit uncouples electron transport as the only one when used in sufficient concentrations. The dosis-effect curves o f the inhibition of the electron transport exhibits a maximum. The dosis-effect curves for the other components rise after a lag phase in an approxim ately hyperbolic manner. The inhibitory action on electron transport is exerted by all antisera in the region of the reaction center I or in its immediate vicinity. This is thought to be due to the fact that a protein of the reation center I is inhibited in its function by the increasing proton concentration inside the thylakoid. The inhibition of electron transport by the antiserum to the e subunit is considered to be a direct serum effect. Besides the increase in fluorescence yield, due to the inhibition of electron transport in the region o f photosystem I, decreases of the fluorescence yield are observed in the presence of D CM U, which do not depend on the redox state of Q but rather on the condition of the thylakoid mem­ brane. Moreover, the antisera affect in a differing manner the energy spill-over o f excitation from photosystem I I to photosystem I. 
  Reference    Z. Naturforsch. 33c, 529 (1978); received June 21 1978 
  Published    1978 
  Keywords    Coupling Factor, Antisera, Chloroplasts, Fluorescence 
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 TEI-XML for    default:Reihe_C/33/ZNC-1978-33c-0529.pdf 
 Identifier    ZNC-1978-33c-0529 
 Volume    33 
2Author    Hans-Jürgen Tiburzy, RichardJ. BerzbornRequires cookie*
 Title    Subunit II (b') and Not Subunit I (b) of Photosynthetic ATP Synthases is Equivalent to Subunit b of the ATP Synthases from Nonphotosynthetic Eubacteria. Evidence for a New Assignment of b-Type F0 Subunits  
 Abstract    Subunit I of chloroplast ATP synthase is reviewed until now to be equivalent to subunit b of Escherichia coli ATP synthase, whereas subunit II is suggested to be an additional subunit in photosynthetic ATP synthases lacking a counterpart in E. coli. A fter publication of some sequences of subunits II a revision of this assignment is necessary. Based on the analysis of 51 amino acid sequences of b-type subunits concerning similarities in primary structure, iso­ electric point and a discovered discontinuous structural feature, our data provide evidence that chloroplast subunit II (subunit b' of photosynthetic eubacteria) and not chloroplast subunit I (subunit b of photosynthetic eubacteria) is the equivalent of subunit b of nonphoto­ synthetic eubacteria, and therefore does have a counterpart in e.g. E. coli. In consequence, structural features essential for function should be looked for on subunit II (b'). 
  Reference    Z. Naturforsch. 52c, 789—798 (1997); received August 1 1997 
  Published    1997 
  Keywords    Chloroplast, Coupling Factor, Stalk, Cyanobacteria 
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 TEI-XML for    default:Reihe_C/52/ZNC-1997-52c-0789.pdf 
 Identifier    ZNC-1997-52c-0789 
 Volume    52 
3Author    Bernhard HuchzermeyerRequires cookie*
 Title    Phosphate Binding to Isolated Chloroplast Coupling Factor (CF^  
 Abstract    A single binding site for phosphate was found on isolated chloroplast coupling factor in the absence of nucleotides. In our experiments the phosphate binding site showed a K d of 170 JIM. We did not observe any differences whether the ATPase activity of CF] had been activated or not. If the enzyme was incubated with [y-32 P]ATP the amount of 32 P bound per CF, depended on the pretreatment of the enzyme: In the presence of ADP no ATP or phosphate was bound to CF,. After activation of ATPase activity one mol of ATP per mol CF, was rapidly bound and hydro-lyzed while there was a slowly occurring binding of another phosphate without concomitant nucleotide binding. We conclude that there are two different types of phosphate binding observed in our experi-ments: 1) Inorganic phosphate can be bound by one catalytic site per mol of CTv 2) The y-phosphate of ATP is able to bind to an ATP binding domain of the enzyme if this domain can exchange substrates with the incubation medium. This ATP binding domain appears to differ from the site binding inorganic phosphate, because at least a portion of the coupling factor contains more than one labelled phosphate during our ATPase tests. 
  Reference    Z. Naturforsch. 43c, 213—218 (1988); received July 27/November 19 1987 
  Published    1988 
  Keywords    Chloroplast, Coupling Factor, Binding Sites, ATPase, Phosphorylation 
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 TEI-XML for    default:Reihe_C/43/ZNC-1988-43c-0213.pdf 
 Identifier    ZNC-1988-43c-0213 
 Volume    43 
4Author    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 
5Author    Wolfgang Lockau, Susanne PfefferRequires cookie*
 Title    A Cyanobacterial ATPase Distinct from the Coupling Factor of Photophosphorylation  
 Abstract    A particle-bound, M g2+-dependent A TPase activity is investigated in cell-free extracts o f the cyanobacterium Anabaena variabilis. The enzym e can be clearly distinguished from the 
  Reference    Z. Naturforsch. 37c, 658 (1982); received March 231982 
  Published    1982 
  Keywords    Cyanobacterium, Anabaena variabilis, ATPase, Coupling Factor, Cytochrom e Oxidase 
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 TEI-XML for    default:Reihe_C/37/ZNC-1982-37c-0658.pdf 
 Identifier    ZNC-1982-37c-0658 
 Volume    37 
6Author    Bernhard Huchzermeyer, Andreas LöhrRequires cookie*
 Title    Diphenyl Ether Herbicides, a Tool to Elucidate the Mechanism of Photophosphorylation  
 Abstract    At least two different classes of A DP binding sites on chloroplast coupling factor are de­ scribed in the literature. High-affinity sites are assumed to entail regulatory functions while low-affinity sites are involved in catalysis. Diphenyl ether herbicides, acting as energy transfer inhibitors, interfere with nucleotide ex­ change on both categories of A D P binding sites. Their inhibitory potency varies depending on their substitution. We found that each diphenyl ether assayed revealed identical / 50 values for inhibition of nucleotide interaction with both classes of binding sites. We show here that diphenyl ether inhibition of energytransfer is primary based upon the interference with A DP binding to high-affinity binding sites. Thereby the control of proton permeability through the coupling factor complex is affected. Moreover, we found that the three ß-subunits are not absolutely fixed in one conformational state: After covalently block­ ing the high-affinity site by an azido-label, a new ß-subunit. 
  Reference    Z. Naturforsch. 45c, 552—557 (1990); received October 10 1989 
  Published    1990 
  Keywords    Diphenyl Ethers, Energy-Transfer Inhibition, Nitrofen, Photophosphorylation, Coupling Factor 
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 TEI-XML for    default:Reihe_C/45/ZNC-1990-45c-0552.pdf 
 Identifier    ZNC-1990-45c-0552 
 Volume    45