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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

On integrating experimental data published previously, the following picture of the mitochondrial adenine nucleotide (AdN) translocation system is being presented: 1. The AdN translocation system serves not only to transport ATP synthesized within mitochondria into the cytosol but also to transport cytosolic ATP into the mitochondria when oxidative phosphorylation is not functioning. 2. The AdN translocator is coded for by nuclear genes and the mitochondrial protein synthesis is not involved in its formation. 3. The AdN translocation system must be preserved and functioning even in cells which could dispense with oxidative phosphorylation. It assures appropriate concentrations of intramitochondrial ATP. 4. The intramitochondrial ATP is required for normal replication of mitochondrial DNA. Tis supports the view that the mitochondrion is a self-replicating semi-autonomous organelle. 5. The appropriate concentration of ATP must be present in mitochondria to make possible cell growth or multiplication. This points to a direct or indirect role of mitochondria in the control of cell proliferation.
Mol Cell Biochem 1977 Feb 04
PMID:Genetic determination of the mitochondrial adenine nucleotide translocation system and its role in the eukaryotic cell. 32 82

Genetic recombination of phage lambda DNA mediated by Rec function of Escherichia coli was studied in the absence of duplication, transcription, translation, and maturation. Cells were jointly infected with double amber mutants, lambda D-F-I and lambda S-R-, and incubated in the presence of chloramphenicol and rifampin. The am+ recombinant DNA molecules formed within the cell were detected by in vitro packaging as viable recombinant phages. This system was used to measure the recombination activity of rec- bacteria. In recA or recA recB bacteria, the number of recombinant DNA molecules was about 1% of the rec+ level. In contrast, almost normal numbers of recombinant DNA molecules were formed in recB or recC cells. Therefore, (1) the recombination mediated by recA function does not need de novo protein synthesis; all gene products required for the recombination are present in the cell. (2) It can occur without duplication, transcription, and maturation of recombining DNA molecules. (3) The ATP dependent DNase (exonuclease V) controlled by recB and recC genes is not required for formation of recombinant DNA molecules.
Mol Gen Genet 1977 Jun 24
PMID:Formation of recombinant DNA of bacteriophage lambda by recA function of Escherichia coli without duplication, transcription, translation, and maturation. 33 Oct 71

The evidence that all energy transducing membranes can generate a proton electrochemical potential difference, delta micronH, across the membrane and that this potential can be used to transfer energy among energy transducing units and to generate ATP, has increased the interest for the view that delta micronH plays an obligatory role in energy transduction and ATP synthesis. In the present article we shall concentrate on two experimental questions related with the generation and role of delta micronH: (a) the charge/site ratio; (b) the relation between the proton electrochemical potential on one side and the cation electrochemical potential, the phosphate potential and the redox potential on the other. We shall then discuss the view that energy transduction corresponds to a molecular energy machine rather than to a fuel cell.
Mol Cell Biochem 1977 Sep 09
PMID:The generation of the proton electrochemical potential and its role in energy transduction. 33 72

Toluene treated cells have been used to study the processes of DNA synthesis and DNA degradation in ultra-violet irradiated Escherichia coli K12. Synthesis and degradation are both shown to occur extensively if polynucleotide ligase is inhibited, and to occur to a much lesser extent if ligase activity is optimal. Extensive UV-induced DNA synthesis in toluene-treated cells requires ATP for the initial incision step, and DNA polymerase I. Extensive degradation also depends on the early ATP-dependent incision step, and the subsequent degradation shows a partial requirement for ATP. Curtailment of degradation by ligase requires DNA polymerase activity, but is not dependent upon DNA polymerase I. Apparently this process can be carried out with equal facility by either DNA polymerase II or polymerase III. These observations suggest that extensive DNA polymerase I-dependent repair synthesis and extensive DNA degradation are facets of two divergent pathways of excision repair, both of which depend upon the early uvrABC determined ATP-dependent incision step.
Mol Gen Genet 1977 Nov 29
PMID:DNA synthesis and degradation in UV-irradiated toluene treated cells of E. coli K12: the role of polynucleotide ligase. 34 Sep 17

Glucokinase from baker's yeast has been purified to homogeneity. The molecular weight of the subunit is 51,000. The native enzyme sediments with S20,w values in the range of 19 to nearly 4S. The presence of glucose and phosphate favors the heavier species while ATP causes depolymerization. Titration experiments with the Ellman reagent support this view. The enzyme subunit has four sulfhydryl residues of which one is more reactive than the other three. However, it does not seem to be directly responsible for the catalytic activity. The amino acid composition of the enzyme is similar to those of the hexokinases P1 and P2 but for aspartic acid and histidine.
Mol Cell Biochem 1977 Nov 25
PMID:Molecular properties of yeast glucokinase. 34 Sep 36

Recent advances in the studies of the aggregation of G-actin monomers, containing one molecule of ATP, to long filaments of F-actin, with a concomitant hydrolysis of the nucleotide to ADP, are reviewed. With the aid of omega-ATP, the association and dissociation rate constant of the nucleotide could be determined. The binding of the nucleotide is enhanced by the binding of one Ca++ ion, probably at a different site. The delta G value of the Mg++ or Ca++ induced polymerization has been determined to --39 to--59 kJ/mole, the critical protein concentration for the ATP-G-actin to ADP-F-actin conversion is very strongly influenced by the concentration of bivalent cations. The rate constants of the protein monomers, and the rate and equilibrium constants for the propagation step show the process to be extremely cooperative. Actin shows the interesting phenomenon of translocational head-to-tail polymerization, which may be regulated by ATP. The contact sites between the monomers in F-actin have been labeled by chemical modification. Two tryosine residues, 53 and 69, are probably close to one of the two sites. The ATP binding sites has been labeled by an ATP analog, and there is evidence that it is close to the contact site.
Mol Cell Biochem 1977 Nov 25
PMID:The polymerization reaction of muscle actin. 34 Sep 37

The entry of newly labeled ribosomal subunits and mRNA into polysomes was examined in the yeast mutant rna1. The entry of both types of RNA into polysomes is inhibited rapidly at the restrictive temperature. Analysis of the labeling of the ATP pool and the kinetics of synthesis and processing of mRNA at the restrictive temperature leads to the conclusion that the primary defect in the mutant affects transport of both ribosomes and messenger across the nuclear membrane.
Mol Gen Genet 1978 Jul 04
PMID:Yeast mutant, rna 1, affects the entry into polysomes of ribosomal RNA as well as messenger RNA. 35 36

The spontaneous DNA breakdown exhibited by recA strains, is reduced after heat induction of a thermoinducible Mu-1 prophage. This inhibition is dependent upon RNA synthesis, suggesting that Mu-1 directs synthesis of a recBC nuclease inhibitor, analogous to the product of the lambda gam gene. The genetic evidence presented here shows that Mu-1 enables a lambda red gam phage to grow on a recA host. The in vitro assay for ATP-dependent exonuclease activity reveals a complete inhibition of this activity 30 min after induction of the Mu-1 prophage.
Mol Gen Genet 1978 Aug 04
PMID:Mu-1 directed inhibition of DNA breakdown in Escherichia coli, recA cells. 36 37

Affinity labelling of phenylalanyl-tRNA synthetase from E. coli MRE-600 with N-chlorambucilyl-phenylalanyl-tRNA results in a binding of 1 mole of the reagent per 1 mole of the enzyme. Exhaustive alkylation of phenylalanyl-tRNA synthetase completely blocks the aminoacylation and partially inhibits the reaction of ATP--[32P]pyrophosphate exchange. Removal of the tRNA moiety of the reagent by hydrolysis of the ester bond N-chlorambucilyl-phenylalanine and terminal adenosine does not result in a restoration of ATP--[32P]pyrophosphate exchange and aminoacylation activity. The latter result may testify a chemical modification of amino acid residues essential for enzymatic activity. Possibility of blocking one of the two tRNA binding sites is discussed.
Mol Biol (Mosk)
PMID:[Modification of one tRNA recognition site of phenylalanyl-tRNA synthetase from E. coli MRE-600 with N-chlorambucilyl-phenylalanyl-tRNA]. 36

The effect of 2,4-pentandione on the activity of phenylalanyl-tRNA synthetase (Phe-RSase) from E. coli MRE-600 was investigated. It was shown that modification of Phe-RSase with 2,4-pentandione leads to decrease of the aminoacylation rate without an influence on the ATP--[32P]pyrophosphate exchange reaction rate. tRNAPhe protects the enzyme against inactivation. Neither L-Phe and ATP nor the analog fo aminoacyladenylate protects the enzyme against inactivation. There are no changes in Km for amino acid and ATP in the aminoacylation reaction after modification while Km for tRNAPhe decreases three times. The dissociation constant of Phe-RSase: [14C]Phe-tRNA complex increases 4--8 times after modification. It is assumed that there are some lysine residues in Phe-RSase essential for the Phe-RSase-tRNA interaction.
Mol Biol (Mosk)
PMID:[Role of the lysine residues in the phenylalanyl-tRNA synthetase substrates interaction]. 36 1


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