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1Author    HansWerner Miiller, Margareta BaltscheffskyRequires cookie*
 Title    On the Oligomycin-Sensitivity and Subunit Composition of the ATPase Complex from Rhodospirillum rubrum  
 Abstract    Two alternative procedures for isolation of the oligomycin-sensitive ATPase complex (E. C. from R. rubrum chromatophores are compared with respect to ease, rapidity, and yield. The inhibitory effect of oligomycin on the membrane-bound Ca2+ -ATPase activity is increased during storage of the chromatophores, whereas the effect of oligomycin on the membrane-bound Mg2+ -ATPase activity does not change within a week. Oligomycin-sensitivity of the solubilized ATPase complex depends on the isolation procedure. The enzyme complex consists of at least nine different polypeptides with the apparent molec­ ular weights of (. The polypeptides 2 — 4, 7, and 8 represent subunits of coupling factor 1. 
  Reference    Z. Naturforsch. 34c, 229 (1979); received January 4 1979 
  Published    1979 
  Keywords    Rhodospirillum rubrum, ATPase, Subunits, Oligomycin 
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 TEI-XML for    default:Reihe_C/34/ZNC-1979-34c-0229.pdf 
 Identifier    ZNC-1979-34c-0229 
 Volume    34 
2Author    Michaela Dane, Kerstin Steinert, Kordula Esser, Susanne Bickel-Sandkötter, Francisco Rodriguez-ValeraRequires cookie*
 Title    Properties of the Plasma Membrane ATPases of the Halophilic Archaebacteria Haloferax mediterranei and Haloferax volcanii  
 Abstract    Both, Haloferax mediterranei and Haloferax volcanii membranes contain ATPases which are capable of hydrolyzing ATP in presence of Mg2+ or M n2+. The ATPases require high con­ centrations of NaCl, a pH value of 9, and high temperatures up to 60 °C. Free manganese ions inhibited the enzyme activity of either ATPase. The ATPases of H f. mediterranei and H f. vol­ canii, respectively, show different sensitivities to inhibitors of ATP hydrolysis. ATP hydrolysis of isolated H f. mediterranei ATPase was inhibited by N aN 3, which was reported to be specific for F-ATPases, by nitrate and N-ethylmaleimide (NEM), which are specific inhibitors of V-ATPases. ATP hydrolysis of H aloferax mediterranei membranes was not inhibited by DCCD , but [14C]DCCD was bound to a 14 kDa peptide of the isolated, partially purified en­ zyme. Furthermore, the ATPase was inactivated by preincubation with 7-chloro-4-nitro-benzofurazan (NBD-C1). The ATPase activity of H f. volcanii membranes was inhibited by NEM but not by nitrate and N aN 3. SDS gel electrophoresis of the partially purified enzyme of Haloferax mediterranei showed putative ATPase subunits of 53. and 7.5 kDa. Immunoblots showed cross reactivity between a 53 kDa peptide and anti-$ (chloro­ plast F(), as well as between 53, 50 and 47 kDa peptides and an ATPase antibody of Methano-sarcina barkeri. The results will be discussed in context with the placement of the archaebac-terial ATPases (A-ATPases) between F-and V-ATPases. 
  Reference    Z. Naturforsch. 47c, 835—844 (1992); received June 29/September 10 1992 
  Published    1992 
  Keywords    Archaebacteria, Plasma Membrane, ATPase, Subunits, ATP Hydrolysis, Inhibition 
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 TEI-XML for    default:Reihe_C/47/ZNC-1992-47c-0835.pdf 
 Identifier    ZNC-1992-47c-0835 
 Volume    47 
3Author    Peter Westhoff, Kurt Zimmermann, Frank Boege, Klaus ZetscheRequires cookie*
 Title    Regulation of the Synthesis of Ribulose-l,5-bisphosphate Carboxylase and Its Subunits in the Flagellate Chlorogonium elongatum. II. Coordinated Synthesis of the Large and Small Subunits  
 Abstract    Transfer of heterotrophically grown cells of the unicellular green alga Chlorogonium elongatum to autotrophic growth conditions causes a 10 -1 5 fold increase in the amount o f the chloroplastic enzyme ribulose-1,5-bisphosphate carboxylase. This increase was found to be due to de novo synthesis. The relative proportions o f large and small subunits o f the enzyme do not change. Their ratio is close to 3.4, the proportions in weight o f the two subunits in the holoenzyme. Continous labelling with [35S]sulfate reveals that the ratios of incorporation into large and small subunits are essentially the same in autotrophic and heterotrophic cells. Pulse-chase experiments show that the subunits are degraded synchronously. The coordinated subunit synthesis cannot be uncoupled using inhibitors o f protein and RNA synthesis or high temperature of cultivation of the alga. The results suggests a very tightly coordinated synthesis o f the large and small subunits of ribulosebisphosphate carboxylase. 
  Reference    Z. Naturforsch. 36c, 942 (1981); received July 18 1981 
  Published    1981 
  Keywords    Ribulose-1, 5-bisphosphate Carboxylase, Synthesis, Subunits, Regulation, Phytoflagellate Chlorogonium elongatum 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0942.pdf 
 Identifier    ZNC-1981-36c-0942 
 Volume    36 
4Author    K. Erstin Steinert, SusanneB. Ickel-S, AndkötterRequires cookie*
 Title    Isolation, Characterization, and Substrate Specificity of the Plasma Membrane ATPase of the Halophilic Archaeon H aloferax volcanii  
 Abstract    Isolated membranes of the moderate halophilic bacterium Haloferax volcanii are able to hydrolyze ATP via an ATPase, which needs the presence of Mg2+ or Mn2+, high concentra­ tions of NaCl, a pH value of 9, and high temperatures with an optimum at 60 °C. We have not found any phosphatase activity in the preparations. We developed a purification method for the isolated enzyme with an enrichment factor o f 90. SDS-gel electrophoresis of the partially purified enzyme of Haloferax volcanii showed putative ATPase subunits of 63, 51, 37, and 12 kDa. N-ethylmaleimide (NEM) a specific inhibitor for V-ATPases, which alkylates cysteines, inhibited the enzyme slightly. Binding of tritiated NEM to the isolated ATPase fractions resulted in labelling of the 63 and 51 kDa peptides. Using PCR with degenerate oligonucleotides, we could clone and sequence a gene cluster encoding the Aj part o f the halophilic ATPase. The described genes are organized in an operon in the order D. C, E, B, A , named alphabetically according to their decreasing size. The deduced products o f 64.5, 52, 38.7, 22, and 11.6 kDa confirm the results of the partial purification o f the ATPase. Biochemical characterization of the Haloferax volcanii ATPase gave the following results: In presence of Mn2+ higher rates of ATP hydrolysis could be observed than in presence of Mg2+, but free manganese ions inhibited the enzyme activity of the ATPase. Calculation of the true concentrations of the complex between ATP and the respective divalent metal ion led to determination of M ichaelis-Menten constants for ATP in the hydrolysis direction of 1 m M in presence of MgCl2 and 0.24 m M in presence of MnCl2. Sodium chloride concentrations in the molar range induce changes in K M by a factor of about 10. The enzyme is specific for ATP; other nucleotides including GTP and A D P are competitive inhibitors o f ATP hy­ drolysis. 
  Reference    Z. Naturforsch. 51c, 29 (1996); received June 26/Novem ber 11 1995 
  Published    1996 
  Keywords    Archaeon, Haloferax volcanii, Plasma Membrane ATPase, Subunits, ATP-Hydrolysis 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0029.pdf 
 Identifier    ZNC-1996-51c-0029 
 Volume    51 
5Author    Elisabeth Langer, H. Arald Lehner, Wolfhart Rüdiger, Barbara Zickendraht, -W EndelstadtRequires cookie*
 Title    Circular Dichroism of C-Phycoerythrin: A Conformational Analysis  
 Abstract    An extensive study o f the chiroptical properties o f C-phycoerythrin and the a-and ^-subunits in the spectral region from 700 -200 nm is presented. Based on the VIS-circular dichroism inherently chiral conform ations are proposed for the co­ valently linked chromophores. By means o f mean residue ellipticities and the experimental circular dichroism spectra in the region o f the n -* n* peptide transition the a-helix contents o f the apoproteins o f the ac-and ß-subunits are estimated to amount to 60% and 40%, respectively. The circular dichroism spectrum o f native C-phycoerythrin is congruent with a linear superposition o f the a-and /?-subspectra, in the whole spectral region studied. Since a-and /?-subunits are associated in native C-phycoery-thrin as revealed by sedim entation analysis the interactions between the subunits in the native chromoprotein are not accom panied by substantial conform ational changes. In the temperature range 0 ° -4 0 °C the thermally induced changes o f the chrom ophores in native C-phycoerythrin are not associated with changes o f the secondary structure o f the apoprotein. Unfolding occurs at 60 0 -7 0 °C but slowly leads to irreversible denaturation. Protein unfolding starts at 3 M urea. The random coil secondary structure o f the apoproteins is reached at 8 M urea. At this concentration the absorbance and the optical activity o f the chrom o­ phores are reduced by a factor 3 and 10, respectively. The conformational changes in the peptide with increasing denaturant concentration are not synchronous with those induced in the Chromo­ phore indicating that a m ultistep process is operative during unfolding. The C D results on dena­ turation are supplem ented by absorption and em ission spectroscopy. 
  Reference    Z. Naturforsch. 35c, 367 (1980); received February 5 1980 
  Published    1980 
  Keywords    Phycoerythrin, Subunits, Conformation o f Chrom ophores and Apoproteins, Circular D ichroism, Denaturation 
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 TEI-XML for    default:Reihe_C/35/ZNC-1980-35c-0367.pdf 
 Identifier    ZNC-1980-35c-0367 
 Volume    35