Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.7.6 (RNA polymerase)
34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Reverse transcriptase from foamy virus, strain H4188 was estimated and purified. The enzyme has the following characteristics: 1. The reaction utilized preferentially oligo (dT) poly (rA) as a primer-template; however, the synthetic primer-template oligo (dT) poly (dA) could also be used to some extent. 2. The reaction utilized oligo (dG) poly (rC) as a primer-template with very low efficiency. 3. The crude virus preparation had a detectable endogenous reaction using the four deoxyribonucleotides for DNA polymerization. 4. The cation requirement for the enzyme reaction was much more biased for Mn++ than for Mg++ ions. 5. The molecular weight of the partially-purified enzyme was estimated to be about 80,000. Aggregates of 240,000 daltons were also seen. The activity of this enzyme was not inhibited by antisera against the reverse transcriptases of various type C RNA viruses, namely, feline endogenous leukemia virus, RD 114, Woolly simian sarcoma virus (SSV-1) and avian myeloblastosis virus (AMV). Antiserum against Rauscher leukemia virus (RLV) enzyme was marginally active against foamy virus enzyme, perhaps indicating a slight cross-reaction. The biochemical characteristics of foamy virus reverse transcriptase seemed to be very close to those of the type C RNA viruses, but the immunological reaction proved that the foamy virus reverse transcriptase was distinct from the others.
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PMID:Reverse transcriptase of foamy virus. Purification of the enzymes and immunological identification. 7 44

4'-(9-Acridinylamino)methanesulphon-m-anisidide (AMSA) (NSC 141549), an acridine derivative with activity against a variety of laboratory tumors in vivo, is presently undergoing Phase 1 clinical evaluation. The interaction of AMSA with DNA and its effects on nucleic acid-polymerizing enzymes were examined in an attempt to define the site of cytotoxicity of AMSA. Binding of AMSA to DNA, as demonstrated by equilibrium dialysis and spectrophotometric methods, appears to be similar to other aminoacridines, in that two types of binding sites (type 1 and type 2) were observed. Fluorescence studies and thermal denaturation studies gave strong evidence that AMSA type 1 binding was by intercalation into DNA. The binding of AMSA to DNA was without marked base-pair specificity. Furthermore, the effect of AMSA on nucleic acid-polymerizing enzyme activities (mouse embryo DNA polymerase alpha, avian myeloblastosis virus reverse transcriptase, and Escherichia coli RNA polymerase) was studied. Inhibition of enzyme activity by AMSA appeared to be independent of DNA base sequence. The relatively high concentrations of AMSA required for inhibition of these enzymes as compared to the concentrations of AMSA necessary for cytotoxicity in vitro suggest that the interaction with DNA alone might not fully explain its antitumor activity.
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PMID:Interaction of 4'-(9-acridinylamino)methanesulfon-m-anisidide with DNA and inhibition of oncornavirus reverse transcriptase and cellular nucleic acid polymerases. 7 12

Reverse transcriptase and p30 were purified from various retroviruses and the intra- and interspecific interaction between the two proteins were studied. The intraspecific complex stimulates [3H]TMP incorporation into (dT)12.(rA)n severalfold above that of the enzyme itself whereas DNA synthesis in the presence of the interspecific complex can stimulate DNA synthesis about 1.5-fold. The sedimentation rate value of the intraspecies complex varies between 12 and 16 S with an estimated molecular weight of 400,000. The molar ratio of p30:reverse transcriptase within the complex is 8:1. Both complexes can be dissociated into their original protein components by exposure to salt (kcl) solution, except that 0.3 M KCl will dissociate the interspecies complex whereas 0.8 M KCl is required for dissociation of the intraspecies complex. Competition studies in which an interspecies complex was exposed to p30 autologous to reverse transcriptase within the complex resulted in the displacement of the heterologous (p30) protein and the formation of a new intraspecific complex.
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PMID:Effect of RNA tumor virus-specific protein p30 on reverse transcriptase. Intraspecies and interspecies interaction between reverse transcriptase and p30. 8 36

In some preparations of DNA dependent RNA polymerase a new enzymatic activity has been found which catalyzes the condensation of two pyrophosphate molecules, liberated in the process of RNA synthesis, to one molecule of orthophosphate and one molecule of Mg (or Mn) - chelate complex with trimetaphosphate. This activity can also cooperate with DNA-polymerase, on condition that both enzymes originate from the same cells. These results point to two general conclusions. First, energy is conserved in the overall process of nucleic acid synthesis and turnover, so that the process does not require an energy influx from the cell's general resources. Second, the synthesis of nucleic acids is catalyzed by a complex enzyme system which contains at least two separate enzymes, one responsible for nucleic acid polymerization and the other for energy conservation via pyrophosphate condensation.
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PMID:Pyrophosphate-condensing activity linked to nucleic acid synthesis. 8 40

Five phages which are morphologically similar to coliphage T7 but attack other host bacteria have been compared to T7 and to its relative, T3, by the following criteria: (a) cross-reactivity with antisera against T7 and T3, (b) DNA base sequence homologies, as determined by the C0t technique, (c) synthesis of two phage-coded enzymes: RNA polymerase and SAMase, (d) patterns of phage-directed protein synthesis, as determined by SDS-polyacrylamide gel electrophoresis of phage coat subunits. As judged by all these criteria, Pseudomonas phage PX3 is not related to T7; thus, morphological similarity was attributed to convergent evolution. The other phages, i.e. Serratia phage IV, Psuedomonas phage gh-1, Citrobacter phage ViIII and Klebsiella phage No. 11, were considered to be related to T7 on the basis of similarities in the patterns of phage-coded proteins and because, early after infection, these phages induced, as T7 does, an RNA polymerase which specifically transcribes the DNA of thehomologous phage. Phages IV and No. 11 also induced the early synthesis of SAMase (previously only known to occur upon T3 infection). With the exception of phage IV, however, DNA base sequence homologies with T7 or T3 seem to be poor or non-existent. The tested phages, again with the exception of phage IV, did not react with antiserum against T3 or T7. It is concluded that a particular pattern of phage-directed protein synthesis (as characterized by polyacrylamide gel electrophoresis and enzyme tests) may provide evidence for phylogenetic relationships between phages, even in cases where other criteria, such as genetic recombination, serological cross-reaction, and DNA base sequence homologies, fail to indicate relatedness.
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PMID:The strategy of infection as a criterion for phylogenetic relationships of non-coli phages morphologically similar to phage T7. 9 Jan 10

Antibodies against purine nucleotides were obtained from rabbits immunized with conjugates of bovine serum albumine with AMP or GMP. The antibodies purified by affinity chromatography on nucleoside monophosphate-human serum albumine-Sepharose columns inhibited RNA synthesis on native T4 phage DNA by E. coli RNA polymerase. The inhibition of transcription was due mainly to inhibition of the initiation stage of RNA synthesis.
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PMID:[Inhibition of RNA synthesis in vitro by antibodies against mononucleotides]. 9 37

Alterations in the structure and molecular composition of avian hepatocyte nuclei were compared following administration in vivo of lethal and sub-lethal doses of alpha-amanitin. This toxin interferes with extranucleolar transcription by direct inhibition of RNA polymerase II activity. the resultant effects include: extensive condensation of chromatin, displacement of nucleoplasmic contents and fragmentation of nucleoli. Changes in nuclear morphology were quantitated by stereometry and related to variations in RNA and residual, non-histone proteins (NHP). Gross alterations in nuclear structure and depletion of RNA and NHP levels were of similar magnitude with both doses of amanitin. The effects were fully reversible, however, with a minimal dose but terminal with a lethal dose. DNA and histone protein levels remained unchanged at all stages. These results imply that the process of transciption may itself keep and/or maintain chromatin in a dispersed state, and that in the absence of transcription chromatin naturally condenses. Modification of nuclear proteins may be necessary only to maintain chromatin compacted permanently or for extended periods of time. A model of nuclear organization is proposed to incorporate these considerations and to identify the probable location of the nuclear matrix in situ.
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PMID:The organization, composition and matrix of hepatocyte nuclei exposed to alpha-amanitin. 9 80

A protein with a molecular weight of 21,000 daltons is found associated with a fraction of Bacillus subtilis RNA polymerase core. This protein (delta) does not react with antibody made against sigma factor and has a peptide map which is significantly different from sigma factor. At ratios of 2:1 to 4:1 (delta:holoenzyme) the delta displaces sigma factor completely from the core and associates in a 1:1 ratio with core to form delta-core. Under the same incubation conditions sigma factor at a ratio of 10:1 (sigma factor:delta-core) does not displace delta from the delta-core. The delta-core has much less activity as compared to holoenzyme on various DNA templates. However, sigma factor does stimulate the activity of delta-core enzyme under conditions of RNA synthesis. These observations and the results of others suggest that delta-core enzyme binds initially to specific DNA sites followed by delta release from the core-DNA complex and that the sigma factor binds to the core-DNA complex to initiate RNA synthesis. Thus both delta and sigma factors are required in a sequential fashion for specific transcription to occur in B subtilis.
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PMID:Delta factor can displace sigma factor from Bacillus subtilis RNA polymerase holoenzyme and regulate its initiation activity. 9 10

The coat protein of Bacillus subtilis spores comprises about 10% of the total dry weight of spores and 25% of the total spore protein. One protein with a molecular weight of 13,000 to 15,000 comprises a major portion of the spore coat. This mature spore coat protein has histidine at its NH2 terminus and is relatively rich in hydrophobic amino acids. Netropsin, and antibiotic which binds to A-T-rich regions of DNA and inhibits sporulation, but not growth, decreased the synthesis of this spore coat protein by 75%. A precursor spore coat protein with a molecular weight of 25,000 is made initially at t1 of sporulation and is converted to the mature spore coat protein with a molecular weight of 13,500 at t2 - t3. These data indicate that the spore coat protein gene is expressed very early in sporulation prior to the modifications of RNA polymerase which have been noted.
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PMID:Spore coat protein of Bacillus subtilis. Structure and precursor synthesis. 9 46

DNA-dependent RNA polymerase B has been extensively purified from the larval fat body of the tobacco hornworm (Manduca sexta) by employing chromatography on ion-exchange columns of DEAE-Sephadex, DEAE-cellulose and phosphocellulose and centrifugation on glycerol gradients. The isolated enzyme after electrophoresis on acrylamide gels shows one main band and one minor band, both having enzyme activity sensitive to alpha-amanitin. The catalytic and physicochemical properties of the enzyme are similar to those of other eucaryotic B-type RNA polymerases. The enzyme has an apparent molecular weight of 530000, is inhibited 50% by alpha-amanitin at 0.04 microgram/ml and shows maximum activity on denatured DNA at 5 mM Mn2+ and 100 mM ammonium sulfate. An antibody was obtained that cross-reacts with the pure enzyme and forms a precipitin line. This antibody does not cross react with either Escherichia coli RNA polymerase or with wheat germ RNA polymerase but does react with one of the B polymerases isolated from wing tissue of the silkmoth, Antheraea pernyi.
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PMID:Isolation and characterization of RNA polymerase B from the larval fat body of the tobacco hornworm, Manduca sexta. 10 73


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