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)

The gene product of braB encoding the Na+(Li+)-coupled carrier protein for L-leucine, L-isoleucine, and L-valine (LIV-II carrier) of Pseudomonas aeruginosa PML strain was identified and overexpressed using a T7 RNA polymerase/promoter plasmid system. The gene product was pulse-labeled with [35S]methionine as a protein of an apparent Mr of 34,000 on a sodium dodecyl sulfate-polyacrylamide gel. Cell membranes overproducing the LIV-II carrier were solubilized with n-dodecyl beta-D-maltopyranoside. The carrier protein was purified from the detergent extract by two purification steps: (i) immunoaffinity column chromatography using purified polyclonal antibody directed against synthetic 13-mer peptide corresponding to the carboxyl terminus region of the carrier and (ii) subsequent DEAE-cellulose column chromatography. The detergent was replaced by n-octyl beta-D-glucopyranoside prior to the first elution and phospholipid was present during purification. Proteoliposomes reconstituted with the purified LIV-II carrier exhibited Na+ or Li+ concentration gradient-driven transport of leucine, isoleucine, and valine. These results show that the LIV-II carrier was purified to be in a functional form.
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PMID:Immunoaffinity purification and reconstitution of sodium-coupled branched-chain amino acid carrier of Pseudomonas aeruginosa. 154 99

The DNA-dependent RNA polymerase (EC 2.7.7.6) of the myxobacterium Stigmatella aurantiaca has been purified. It shows three main polypeptide bands with apparent molecular weights of 146,000, 105,000, and 40,000 in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. beta and beta' subunits of the S. aurantiaca polymerase were shown to migrate in the 146,000-molecular-weight polypeptide band and the main sigma factor was shown to migrate in the 105,000-molecular-weight band by using heterologous antisera.
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PMID:Purification of the DNA-dependent RNA polymerase from the myxobacterium Stigmatella aurantiaca. 155 92

Human sebaceous glands (SG) and hair follicles (HF) are target structures in the skin for androgen action. They contain steroid enzymes, capable of transforming weak androgens into the target-tissue-active androgens testosterone (T) and dihydrotestosterone (DHT), which bind to the androgen receptor (AR) to regulate cellular transcription. The AR from HF and SG from human scalp tissue has been purified greater than 86,000 times by phenyl-sepharose, DEAE-sephacel, gel filtration chromatography, and ultrafiltration. Sucrose density gradient analysis and non-denaturing gradient polyacrylamide gel electrophoresis (PAGE) and sodium dodecyl sulfate (SDS)-PAGE revealed two molecular species of AR, an active form called monomer, capable of binding DHT with great specificity (4S, m = 62,000 Da, Kd = 0.6 nM, Bmax 8260 fmol/micrograms protein), and the other, an inactive form of the monomer called tetramer (10.8S, m = 252,000 Da, Kd = 2.9 nM). The two species are interconvertible, and after purification each appeared as a single band on SDS-PAGE. The conversion of the monomer to the tetramer AR form is influenced by reduced and oxidized glutathione, and possibly by an endogenous disulfide converting factor (DCF). Furthermore, biochemical events in the androgenic signal transduction sequence were shown to be stimulated by androgens via the AR. These include the total nuclear AR content, chromatin binding of AR complexes, and stimulation of RNA polymerase II, thus influencing gene expression, which is important in understanding regulation of HF growth and SG proliferation.
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PMID:Purification of androgen receptors in human sebocytes and hair. 158 31

The ICP18.5 gene (UL28) of herpes simplex virus type 1 is a member of a well-conserved gene family among herpesviruses and is thought to play a role in localization of viral glycoproteins. We have cloned, sequenced, and expressed the entire pseudorabies virus (PRV) ICP18.5 open reading frame in Escherichia coli as a Cro-ICP18.5 fusion protein. Rabbit antiserum against Cro-ICP18.5 immunoprecipitated a 79-kDa protein from PRV-infected cells as well as a 79-kDa protein from in vitro translation of a T7 RNA polymerase transcript of the ICP18.5 gene. ICP18.5 could be detected in infected cells by 2 h postinfection. Analysis by indirect immunofluorescence demonstrated that ICP18.5 became associated with the nucleus. Subcellular fractionation confirmed that ICP18.5 synthesized during a pulse-chase experiment appeared in the nuclear fraction with time and was stable for at least 2.5 h after synthesis. Pulse-chase analysis revealed that ICP18.5 was synthesized as a monomer during a 2-min pulse labeling but formed faster sedimenting complexes which were sensitive to sodium dodecyl sulfate (SDS) treatment. The majority of ICP18.5 appeared in complexes with an antigenically unrelated 70-kDa protein. Immunoblot analysis of total infected-cell extracts using polyvalent anti-ICP18.5 serum demonstrated that a 74-kDa cellular protein in addition to the 79-kDa ICP18.5 was detected. This cellular protein was present at similar levels in uninfected cells and in PRV-infected cells at least 12 h into the infectious cycle.
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PMID:Overexpression in bacterial and identification in infected cells of the pseudorabies virus protein homologous to herpes simplex virus type 1 ICP18.5. 164 90

Poliovirus RNA encodes an RNA-dependent RNA polymerase, designated 3Dpol, that catalyzes the synthesis of both plus and minus strand viral RNA. This enzyme was purified to near homogeneity from poliovirus-infected HeLa cells, recombinant baculovirus-infected insect cells, and from Escherichia coli transformed with an expression plasmid containing poliovirus 3D sequences. The two recombinant expression systems produced significantly higher yields of active enzyme than could be attained from virus-infected HeLa cells. All preparations contained a 52-kDa protein, recognized by antisera raised against 3D expressed as a fusion protein in E. coli. Immunoreactive protein resolved into 3-4 species on isoelectric focusing sodium dodecyl sulfate-polyacrylamide gel electrophoresis two-dimensional gels. Efforts to demonstrate that the multiple spots resulted from phosphorylation were negative. Furthermore, no evidence for autophosphorylation of purified 3Dpol was obtained. Purified 3Dpol from recombinant sources manifested the same specific activities as enzyme from poliovirus-infected HeLa cells in both a poly(A)-dependent poly(U) polymerase assay and a poliovirus RNA-dependent RNA polymerase assay. The products of the latter reaction reached the length of the template (7.5 kilobases) in 20-30 min, indicating an elongation rate of approximately 300 nucleotides/min at 30 degrees C. No products exceeded the length of the template. Intermediate length products were detected, which presumably resulted from pauses in transcription due to template structure. All transcription was dependent on primer. The kinetic parameters of all three purified enzyme preparations were the same; the Km for UTP was 2.4 +/- 0.1 microM in an RNA polymerase activity assay. Product formation was linear for up to 45 min, except for a 3-5-min lag before synthesis began. The lag was independent of enzyme concentration, and independent of the template used. The lag was eliminated by preincubating enzyme, template, primer, and three of the four nucleotide triphosphates, but not by preincubating any subset of these components. This suggested that a preinitiation complex must form as a prerequisite to RNA synthesis. Partially purified preparations of 3Dpol from the three sources showed significant differences in activities and products, including the appearance of primer-independent polymerase activity and production of dimer-length RNA products. These variable properties are likely due to different contaminating activities provided by the different cellular hosts, since upon further purification, all three enzymes exhibited identical properties.
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PMID:Purification, characterization, and comparison of poliovirus RNA polymerase from native and recombinant sources. 166 Aug 94

To reduce the toxicity of amphotericin B methyl ester (AME), which shows some anti-HIV-1 activity, sulfated amphotericin B (SAB) was prepared from amphotericin B (AB), and its anti-HIV-1 activity was examined in vitro. SAB at concentration of 7.8 micrograms/ml completely suppressed the HIV-1-induced cytopathic effect in MT-4 cells, at 3.9 micrograms/ml inhibited the expression of HIV-1 antigen in peripheral blood mononuclear cells infected with freshly isolated HIV-1 and at 22 micrograms/ml completely suppressed formation of giant cells in cocultures of MOLT-4 with MOLT-4/HIV-1 cells. Reverse transcriptase activity was inhibited by SAB, but only at higher concentrations (0.2-1 mg/ml). Furthermore, the toxicity of SAB was lower than that of AME or AB, and SAB did not affect the proliferation of MT-4 cells at concentrations up to 0.5 mg/ml. The anti-coagulant effect of SAB was 10-fold less than that of dextran sulfate (MW = 8000). The anti-HIV-1 effect of SAB is attributed to inhibition of binding of virions to target cells.
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PMID:Anti-HIV-1 activity of sulfated amphotericin B in vitro. 180 84

H1 histones were purified from extracts of salt-treated nuclei as a co-product of RNA polymerase II transcription factors from both Drosophila embryos and HeLa cells by a simple and general method. This procedure was also used to purify H1 as co-product of the core histones from calf thymus. The key steps in this purification exploit the solubility of H1 in 2.26 M ammonium sulfate and the chromatographic properties of the highly charged H1 molecules on a phenyl-Sepharose resin. H1 that is prepared by this procedure is active for in vitro repression of basal RNA polymerase II transcription. This method provides a new means of purifying H1 by a mild procedure that is likely to be generally useful for studies of transcription and chromatin structure.
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PMID:A general method for purification of H1 histones that are active for repression of basal RNA polymerase II transcription. 182 86

A T7 RNA polymerase expression system has been used for the efficient expression of the yeast RNA polymerase general transcription factor TFIID (TFIIDY), the TATA-box factor (previously called BTF1) in Escherichia coli. Expression of the gene was performed at 25 degrees C instead of 37 degrees C to increase the total amount of soluble TFIIDY. Soluble TFIIDY was purified in three chromatographic steps and was eluted from the final column, a heparin-5PW HPLC column, in two peaks at 0.38 M (peak I) and 0.42 M (peak II) KCl in which this protein was 52% and greater than 95% pure, respectively. The protein in both peaks was active in an in vitro transcription assay. However, while TFIIDY from peak II was essentially indistinguishable from the material isolated from yeast, the protein of peak I differed in a number of biochemical characteristics, having a lower specific activity in an in vitro transcription assay and displaying an altered pattern of bands in a DNA band shift assay. Despite these differences, the proteins in both peaks have identical molecular weights on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, have indistinguishable N-terminal amino acid sequences, and apparently exist as monomers under the conditions used for the heparin-5PW chromatography.
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PMID:Expression in Escherichia coli: purification and properties of the yeast general transcription factor TFIID. 182 18

The tellurite resistance (Ter) determinant of the IncP alpha plasmid RK2Ter, a variant of RK2 (also called RP4), is located between the kilA and korA genes involved in plasmid replication control. Transcriptional and translational fusions were constructed between the gene for beta-galactosidase and the kilA and Ter genes by using the transpositional phage mini-Mu. These fusions indicated that the Ter genes are transcribed in the same direction as kilA and that transcription and translation of the cloned kilA gene are occurring and may not be lethal to the bacterial cell even in the absence of korA. The nucleotide sequence of this region was determined, and three open reading frames (ORFs) were identified. The first ORF codes for KilA, a 28-kDa hydrophilic protein. The second ORF, telA, codes for a hydrophilic protein of 42 kDa. The third ORF, telB, codes for a hydrophobic protein of 32 kDa. This protein appears to be located in the inner membrane of the bacterial cell, since fusions of TelB to alkaline phosphatase were obtained by using TnphoA. All three proteins were detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis after overproduction using the T7 RNA polymerase/promoter system. The same three proteins were produced when Tes and Ter derivatives of RP4 were expressed in an in vitro transcription-translation system. A single Ser-to-Cys missense mutation in telB was found to be responsible for mutation of RK2 to Ter.
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PMID:Transcriptional analysis, translational analysis, and sequence of the kilA-tellurite resistance region of plasmid RK2Ter. 184 56

Encephalomyocarditis (EMC) virus RNA-dependent RNA polymerase was expressed in Escherichia coli as a fusion protein with glutathione S-transferase (GST), which allowed easy purification of the fusion protein by affinity chromatography on immobilized glutathione. Inclusion of a thrombin cleavage site between the GST carrier and the viral enzyme facilitated the release of purified mature EMC virus RNA polymerase from the GST carrier by proteolysis with thrombin. The purified recombinant enzyme has a molecular mass of about 52 kDa and is recognized by polyclonal immune serum raised against a peptide sequence corresponding to the C-terminal region of the protein. The recombinant enzyme comigrates with immunoprecipitated EMC virus RNA polymerase from infected mouse L929 cell extracts when run in parallel lanes on a sodium dodecyl sulfate-polyacrylamide gel. The enzyme exhibits rifampin-resistant, poly(A)-dependent poly(U) polymerase activity and RNA polymerase activity, which are both oligo(U) dependent. Template-size products are synthesized in in vitro reactions with EMC virus genomic RNA or globin mRNA. The availability of recombinant EMC virus RNA polymerase in a purified form will allow biochemical analysis of its role in the replication of the virus as well as structure-function studies of this unique class of enzyme.
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PMID:Expression, purification, and properties of recombinant encephalomyocarditis virus RNA-dependent RNA polymerase. 185 68


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