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1Author    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 
2Author    Christine Schindler, Ruth Hracky, Jürgen SollRequires cookie*
 Title    Protein Transport in Chloroplasts: ATP is Prerequisit  
 Abstract    The energy requirem ent for protein transport into chloroplast was assayed under conditions that perm it to distinguish whether the posttranslational translocation is dependent on A TP or w hether a m em brane potential across the chloroplast envelope can drive this transport event. A m em brane potential is not required for translocation. A TP can support protein transport in the presence of protonophores and ionophores. Non-hydrolyzable A TP analogues and G TP, CTP, U T P cannot serve as ATP substitutes. Translocation could be observed when an A TP generating system was used to supply ATP. In contrast ATP degrading systems completely abolished translocation. The inner envelope mem brane localized ATP-ase is probably not involved in the transport event. The results suggest that ATP is needed at the outer chloroplast envelope. Inhibition of protein transport by A D P , pyrophosphate and NaF is studied and its con­ sequences discussed. 
  Reference    Z. Naturforsch. 42c, 103 (1987); received August 26 1986 
  Published    1987 
  Keywords    Protein T ransport, ATP-Hydrolysis, Chloroplasts, Envelope, Pisum sativum 
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 TEI-XML for    default:Reihe_C/42/ZNC-1987-42c-0103.pdf 
 Identifier    ZNC-1987-42c-0103 
 Volume    42 
3Author    Susanne Bickel-Sandkötter, K. Ordula Esser, M. Artina, H. OrbachRequires cookie*
 Title    On the Accessibility of Essential Tyrosines in Isolated and Activated Chloroplast H +-ATPase  
 Abstract    The addition o f 7-chloro-4-nitrobenzofurazan to isolated and activated CF, creates a com ­ pletely changed binding stoichiometry and subunit-distribution o f bound modifier in contrast to the binding pattern in not-activated CF,. The activation o f CF, by dithiothreitol and heat results in the accessibility o f three additional tyrosines in ß-subunits and one additional tyro­ sine in a-subunits. Binding o f pyridoxalphosphate to lysine in the active state suppresses the accessibility o f the additional tyrosines, suggesting that PLP inactivates the ATPase by induc­ ing a conformational change. Furthermore, two N BD -m olecules are bound to y-subunits when CF, is activated. These two molecules may be bound to sulfhydryl groups o f cysteines which become accessible to N B D after activation. 
  Reference    Z. Naturforsch. 46c, 71—78 (1991); received September 7 1990 
  Published    1991 
  Keywords    ATP-Hydrolysis, ATPase, Chloroplast, Covalent M odification, Subunit Labeling 
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 TEI-XML for    default:Reihe_C/46/ZNC-1991-46c-0071.pdf 
 Identifier    ZNC-1991-46c-0071 
 Volume    46 
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    KlausP. Hofmann, Georg ZundelRequires cookie*
 Title    Effect of the Protons Arising in Aqueous Hydrolysing ATP Solutions, IR Investigations  
 Abstract    IR spectra of 0.3 m aqueous solutions of Mgo.5K3_ nH w ATP were plotted. The dependence of the spectra on the hydrolysis was investigated for three different K/H ratios of the nonhydrolysed system. Changes to bands provide information as to the protons added to the phosphate groups and base residues as a function of the initial protonation and degree of hydrolysis. More and more proton addition to the — P 0 3__ groups is observed as the initial protonation increases and as the degree of hydrolysis rises. The same applies as far as the addition of protons to the base residues is concerned to the systems with a higher initial protonation. At low degrees of hydrolysis the P 0 43' ions which occur do not bind the two hydrolysis protons completely. 150% protonated P 0 43" ions first form which cross-like via 0 H +--'0 hydrogen bonds, which only become more strongly protonated in the systems with a higher initial protonation at large degrees of hydrolysis. The 0 H +---0 bonds between the 150% protonated hydrogen phosphate ions as well as the N H +,--N hydrogen bonds between the base residues cause an IR continuum and are thus easily polarizable. An extremely large change to the hydrate structure within narrow hydrolysis ranges is indicated by changes to the bands of the water molecules. The biological relevance of these findings is briefly discussed in the conclusions. Intermolecular Interaction in Systems with Energy-Rich Phosphates, II 
  Reference    (Z. Naturforsch. 29c, 29—35 [1974]; received July 10 1973) 
  Published    1974 
  Keywords    Energy-Rich Phosphate, ATP Hydrolysis, Hydrogen Bonds Polarizable, Intermolecular Interaction, Proton Addition 
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 TEI-XML for    default:Reihe_C/29/ZNC-1974-29c-0029.pdf 
 Identifier    ZNC-1974-29c-0029 
 Volume    29