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)

Treatment of BHK-21 cells with purified matrix (M) protein isolated from Banzi virions resulted in decreased production of Banzi virus and in reduced levels of virus-specific positive-strand and negative-strand RNA. The M protein had no effect on the uncoating of the viral genome. This inhibition was virus-specific since the replication of unrelated togaviruses in BHK-21 cells was not affected. Purified M protein inhibited the in vitro activity of the Banzi viral RNA polymerase; prior treatment of the M protein with either trypsin or antiviral serum blocked this inhibition.
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PMID:Inhibition of Banzi viral RNA synthesis in BHK-21 cells by Banzi virion matrix protein. 300 52

The monoclonal antibody (mAb) 64D1 was found to inhibit cAMP binding by the cAMP receptor protein (CRP) from Escherichia coli (Li, X.-M., and Krakow, J. S. (1985) J. Biol. Chem. 260, 4378-4383). CRP is relatively resistant to attack by the Staphylococcus aureus V8 protease, chymotrypsin, trypsin, and subtilisin whereas both mAb 64D1-CRP and cAMP-CRP are attacked by these proteases yielding N-terminal core fragments. The fragment patterns resulting from proteolysis of mAb 64D1-CRP and cAMP-CRP differ indicating that the CRP in each complex is in a different conformation. The data presented indicate that the preferred conformation of the antigenic site for mAb 64D1 is present in unliganded CRP. Binding of mAb 64D1 to CRP is inhibited at high cAMP concentration. Formation of a stable cAMP-CRP-lac P+-RNA polymerase open promoter complex resistant to dissociation by mAb 64D1 occurs at a much lower cAMP concentration. The observed increase in resistance to mAb 64D1 may reflect a possible conformational change in CRP effected by contact with RNA polymerase in the open promoter complex.
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PMID:A monoclonal antibody that inhibits cyclic AMP binding by the Escherichia coli cyclic AMP receptor protein. 303 13

Nuclear protein factor type 1 (NPF-1) that simulates IMR-32 primase-associated DNA polymerase alpha 1 and alpha 2 activities has been purified from a high-salt extract of liver chromatin from 6-month-old rats. The final purified factor lacks DNA polymerase alpha, RNA polymerase, and DNA-unwinding or topoisomerase type I activities. The stimulatory activity is destroyed by trypsin (60 min at 37 degrees C), DNase II (60 min at 37 degrees C), and heat treatment (2 min at 68 degrees C). The 125I-labeled NPF-1 does not bind to activated calf thymus DNA or poly(dC). However, it forms a ternary complex with DNA in the presence of DNA polymerase alpha-primase complex (alpha 1 and alpha 2). The ternary complex sediments on sucrose density gradient as a heavier band (11S). The NPF-1 also stimulates (2.5-fold) primase-catalyzed incorporation of GMP and dGMP from the corresponding triphosphates on poly(dC) template even in the presence of a high concentration of alpha-amanitin (400 micrograms/ml). The labeled duplex containing the poly(dC) template, [32P]-GTP, and [3H]dGTP loses 80% of the 32P label and 70% of the 3H label after treatment with 0.3 M KOH and DNase I, respectively. The products were isolated from reaction mixtures incubated with and without NPF-1 and subjected to alkaline sucrose-density-gradient sedimentation analysis. The results suggest that the rate of synthesis of DNA short chains is increased in the presence of NPF-1 without a concomitant increase in the chain length of the newly synthesized products.
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PMID:Stimulation of human neuroblastoma DNA polymerase alpha and primase activities by a protein factor isolated from rat liver chromatin. 354 Sep 37

In experiments designed to study the mechanism of glucocorticoid hormone induced reductions in rat thymic transcription, adrenalectomized rats were injected with hydrocortisone (50 mg/kg) or control vehicle 12 h prior to sacrifice. Thymic nuclei were used to prepare soluble nuclear extracts containing RNA polymerase II. Nuclear extract RNA polymerases II were then partially purified (600-fold) on DEAE-Sephadex columns and characterized. The responses of partially purified thymic RNA polymerases II from rats treated in vivo with hydrocortisone or vehicle were similar to: pH, temperature, ionic strength, trypsin proteolysis, and inhibition by alpha-amanitin; however, RNA polymerase II from hydrocortisone treated animals was consistently reduced in activity compared to control RNA polymerase II. Determination of the apparent specific activities of peak RNA polymerase II fractions from DEAE-Sephadex columns suggested that the specific activity of RNA polymerase II from hydrocortisone treated animals was reduced compared to RNA polymerase II activity from control animals. The fact that both nuclear extract and partially purified RNA polymerases II from hydrocortisone treated rats were reduced in activity when assayed in reconstituted transcriptive systems suggests a denatured, defective or modified RNA polymerase II molecule acting as a transcription inhibitor. Thermally denatured nucleoplasmic RNA polymerase II fractions were shown to interfere with transcription by native nucleoplasmic RNA polymerase II in vitro, but did not appear to inhibit transcription to he degree observed in vitro following in vivo hydrocortisone administration.
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PMID:Studies on the mechanism of glucocorticoid hormone induced alterations in rat thymic transcription--II. Partial purification and characterization of RNA polymerases II from hydrocortisone and control vehicle treated animals. 362 50

A "nuclear fraction" prepared from Bacillus subtilis was a more efficient template than purified deoxyribonucleic acid for the synthesis of ribonucleic acid by exogenously added ribonucleic acid polymerase isolated from B. subtilis. The initial rate of synthesis with the nuclear fraction was higher and synthesis continued for several hours, yielding an amount of ribonucleic acid greater than the amount of deoxyribonucleic acid used as the template. The product was heterogenous in size, with a large portion exceeding 23S. When purified deoxyribonucleic acid was the template, a more limited synthesis was observed with a predominantly 7S product. However, the ribonucleic acids produced in vitro from these templates were very similar to each other and to in vivo synthesized ribonucleic acid as determined by the competition of ribonucleic acid from whole cells in the annealing of in vitro synthesized ribonucleic acids to deoxyribonucleic acid. Treatment of the nuclear fraction with heat (60 C for 15 min) or trypsin reduced the capacity of the nuclear fraction to synthesize ribonucleic acid to the level observed with purified deoxyribonucleic acid.
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PMID:Nuclear fraction of Bacillus subtilis as a template for ribonucleic acid synthesis. 429 12

A macromolecular factor, TF1, has been isolated from bacteriophage SP01-infected B. subtilis. TF1 selectively inhibits in vitro transcription of SP01 and related viral DNA. Evidence is presented regarding these properties of the repressor-like TF1: (1) template and conformational specificity; (2) interaction with DNA rather than RNA polymerase; (3) trypsin sensitivity; (4) reversibility of action; and (5) ability to block initiation, but not propagation, of RNA synthesis.
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PMID:A template-selective inhibitor of in vitro transcription. 497 43

Gramicidin, a peptide antibiotic produced by Bacillus brevis, inhibits initiation of transcription by RNA polymerase (nucleosidetriphosphate:RNA nucleotidyltransferase, EC 2.7.7.6). We show here that the presence of gramicidin causes an increase in the rate of cleavage of the sigma subunit of Escherichia coli RNA polymerase by trypsin, although it does not alter the cleavage rate of any of the core subunits. Furthermore, whereas isolated sigma is cleaved much faster than is sigma in holoenzyme, gramicidin substantially decreases the trypsin cleavage rate of isolated sigma. Inhibition of RNA polymerase activity by gramicidin in consistent with a sigma-specific effect: the antibiotic is a strong inhibitor of transcription of T7 phage DNA, which requires sigma for activity, but it has little effect on transcription of sigma-independent templates, such as poly(dA-dT).poly)dA-dT) and calf thymus DNA. These results are discussed in light of the hypothesized role for gramicidin in the initiation of sporulation of B. brevis.
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PMID:An interaction between gramicidin and the sigma subunit of RNA polymerase. 617 58

The primary structure of the E. coli rpoC gene (5321 base pairs) coding the beta'-subunit of RNA polymerase as well as its adjacent segment have been determined. The structure analysis of the peptides obtained by cleavage of the protein with cyanogen bromide and trypsin has confirmed the amino acid sequence of the beta'-subunit deduced from the nucleotide sequence analysis. The beta'-subunit of E. coli RNA polymerase contains 1407 amino acid residues. Its translation is initiated by codon GUG and terminated by codon TAA. It has been detected that the sequence following the terminating codon is strikingly homologous to known sequences of rho-independent terminators.
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PMID:The primary structure of E. coli RNA polymerase, Nucleotide sequence of the rpoC gene and amino acid sequence of the beta'-subunit. 628 30

The carboxymethylated beta'-subunit of DNA-dependent RNA polymerase was hydrolyzed with trypsin. The hydrolysate was separated on Bio-Gel P-4, followed by ion exchange chromatography, and was further purified by paper chromatography and electrophoresis. A mixture of large peptides was digested with Staphylococcus aureus protease, the fragments obtained were separated by an HPLC procedure. As a result, 172 peptides were isolated, the complete amino acid sequence for 162 and partial sequence for 10 of them being determined. In total, these peptides contain 862 amino acid residues.
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PMID:[Primary structure of the E. coli DNA-dependent RNA-polymerase beta'-subunit. Hydrolysis with trypsin]. 638 83

Purified calf thymus RNA polymerase II is composed primarily of species IIA and IIB. These enzymes differ in the apparent molecular weight of their largest subunit, designated IIa and IIb for enzyme forms IIA and IIB, respectively. Both enzyme forms contain an additional high molecular weight subunit designated IIc. The structural relationship between subunits IIa, IIb, and IIc, labeled with 125I under both native and denaturing conditions, has been analyzed by two-dimensional peptide mapping. Native RNA polymerase II was iodinated and subunits IIa, IIb, and IIc purified by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. The subunits were then digested with either trypsin or thermolysin and the 125I-labeled peptides resolved by thin layer electrophoresis in the first dimension and chromatography in the second dimension. Similar peptide maps were obtained for each of the three large subunits, suggesting that subunits IIa, IIb, and IIc are related in primary sequence. Alternatively, RNA polymerase subunits IIa, IIb, and IIc were purified by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate, eluted from the gel, and then iodinated. The use of denatured subunits as substrate for the iodination eliminates the differential reactivity of specific tyrosine residues imposed by the structure of the native protein. Under these labeling conditions, the tryptic and thermolytic peptide maps of subunits IIa and IIb are nearly identical but bear much less resemblance to the peptide maps of subunit IIc than with the previous labeling procedure. These results suggest that subunits IIa and IIb are closely related in primary sequence but cannot establish whether these subunits are the products of closely related genes or are related by processing at the level of primary transcript or primary translation product. Subunit IIc bears a more distant relationship to subunits IIa and IIb. Possible reasons why this homology is only apparent in peptide maps from subunits labeled in the native enzyme are discussed.
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PMID:Structural relationship between the large subunits of calf thymus RNA polymerase II. 683 37


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