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)

Using the in vitro mixed transcription system (Kajitani, M. and Ishihama, A. (1983) Nucleic Acids Res. 11, 671-686), we determined the two parameters of the promoter strength, i.e., the rate of open complex formation between RNA polymerase and promoter, and the saturation level of the open complex formation at equilibrium, for the promoters of ribosomal RNA (rrnE), ribosomal protein S1 (rpsA) and recA protein (recA) operons from Escherichia coli. Taken together with the previous determinations for lactose (lac(UV5)), tryptophan (trp) and ribosomal protein L10 (rp1J) operons, these studies revealed that the relative promoter strengths with respect to the kinetic parameter are 200, 70, 50, 40, 30, 20 and 2% of the reference promoter lacP(UV5) for recAp, rp1Jp, rpsAp3, trpP, rpsAp1, rrnEp1 and rrnEp2, respectively, under our standard reaction conditions (50 mM NaCl and 37 degrees C); and those with respect to the thermodynamic parameter are 70, 35, 20, 10, 10, 10 and 5% the level of lacP(UV5) for rrnEp2, trpP, rpsAp3, rp1Jp, rpsAp1, rrnEp1 and recAp, respectively. The order of the promoter strength, however, changes with variation of the salt concentration or reaction temperature.
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PMID:Determination of the promoter strength in the mixed transcription system. II. Promoters of ribosomal RNA, ribosomal protein S1 and recA protein operons from Escherichia coli. 634 67

The DNA-dependent in vitro synthesis of Escherichia coli ribosomal protein L10 was inhibited when L10 was added to the protein-synthesizing incubations. Addition of L10 had little or no effect on the synthesis of ribosomal protein L12, elongation factor Tu (tufB), or the beta and beta' subunits of RNA polymerase. In addition, ribosomal protein L12 did not inhibit its own synthesis or the synthesis of L10. Experiments using a mRNA-directed system showed that the inhibition of the synthesis of L10 by itself is at the level of translation of protein synthesis. The mechanism of inhibition does not appear to be due to increased degradation of L10 mRNA.
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PMID:Autogenous control of Escherichia coli ribosomal protein L10 synthesis in vitro. 699 2

Using the promotor-cloning vehicle described by An and Friesen (J. Bacteriol. 140:400-410, 1979), Escherichia coli chromosomal deoxyribonucleic acid fragments derived from the lambda drifd18 transducing phage were cloned in one of several unique restriction endonuclease sites adjacent to tetracycline(tet) genes that lack their own promotor. One of these plasmids has been used to isolate nine variants having mutations that lie in a putative internal promoter which is located between rplL and rpoB. Deoxyribonucleic acid sequence analysis revealed that, in all nine mutants, a single base change, C to T, in the ribonucleic acid polymerase recognition site led to a large increase in promoter activity. Analysis of a variety of plasmids in which tet is fused to various promoters yielded the following results: (i) rplK and rplA, genes for ribosomal protein L11 and L1, respectively, were cotranscribed from a common promoter located upstream from rplK; (ii) there was a strong promoter in the region between the rplKA operon and rplJ, the gene for ribosomal protein L10; (iii) an attenuator region was located between rplL, the gene for ribosomal protein L12, and rpoB, the gene for ribonucleic acid polymerase subunit beta; (iv) transcription terminated immediately after rpoC, the gene for ribonucleic acid polymerase subunit beta'; (v) a gene coding for unknown protein U, which is located between tufB and the rplKA operon, had its own promoter; (vi) the tufB gene was separated from all of the genes described above and had its own promoter.
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PMID:Characterization of promoter-cloning plasmids: analysis of operon structure in the rif region of Escherichia coli and isolation of an enhanced internal promoter mutant. 700 14

E. coli ribosomal protein L12, because of its unique features, has been studied in more detail than perhaps any of the other ribosomal proteins. Unlike the other ribosomal proteins that are generally present in stoichiometric amounts, there are four copies of L12 per ribosome, some of which are acetylated on the N-terminal serine. The acetylated species, referred to as L7, has not been shown, as yet, to possess any different biological activity than L12. A specific enzyme that acetylates L12 to form L7, using acetyl-CoA as the acetyl donor, has been purified from E. coli extracts. L12 is also unique in that it does not contain cysteine, tryptophan, histidine, or tyrosine, is very acidic (pI: 4.85) and has a high content of ordered secondary structure (approximately 50%). The protein is normally found in solution as a dimer and also forms a tight complex with ribosomal protein L10. There are three methionine residues in L12, located in the N-terminal region of the protein, one or more of which are essential for biological activity. Oxidation of the methionines to methionine sulfoxide prevents dimer formation and inactivates the protein. The four copies of L12 are located in the crest region(s) of the 50S ribosomal subunit. There is good evidence that the soluble factors, such as IF-2, EF-Tu, EF-G and RF, interact with L12 on the ribosome during the process of protein synthesis. This interaction is essential for the proper functioning of each of the factors and for GTP hydrolysis associated with the individual partial reactions of protein synthesis. The L12 gene is located on an operon that contains the genes for L10 and beta beta' subunits of RNA polymerase at about 88 min on the bacterial chromosome. DNA-directed in vitro systems have been used to study the unique regulation of the expression of these genes. Autogenous regulation, translational control, and transcription attenuation are regulatory mechanisms that function to control the synthesis of these proteins.
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PMID:Chemistry and biology of E. coli ribosomal protein L12. 701 80