scholarly journals A procedure for the rapid purification of Escherichia coli deoxyribonucleic acid-dependent ribonucleic acid polymerase (Short Communication)

1973 ◽  
Vol 133 (1) ◽  
pp. 201-203 ◽  
Author(s):  
Peter Humphries ◽  
David J. McConnell ◽  
Robert L. Gordon

A rapid procedure involving DNA–cellulose chromatography followed either by sedimentation in a high-salt glycerol gradient or by gel filtration is described for the complete purification of Escherichia coli DNA-dependent RNA polymerase.

1970 ◽  
Vol 117 (3) ◽  
pp. 623-631 ◽  
Author(s):  
Volker Neuhoff ◽  
Wolf-Bernhard Schill ◽  
Hans Sternbach

By using micro disc electrophoresis and micro-diffusion techniques, the interaction of pure DNA-dependent RNA polymerase (EC 2.7.7.6) from Escherichia coli with the template, the substrates and the inhibitors heparin and rifampicin was investigated. The following findings were obtained: (1) heparin converts the 24S and 18S particles of the polymerase into the 13S form; (2) heparin inhibits RNA synthesis by dissociating the enzyme–template complex; (3) rifampicin does not affect the attachment of heparin to the enzyme; (4) the substrates ATP and UTP are bound by enzyme loaded with rifampicin; (5) rifampicin is bound by an enzyme–template complex to the same extent as by an RNA-synthesizing enzyme–template complex. From this it is concluded that the mechanism of the inhibition of RNA synthesis by rifampicin is radically different from that by heparin. As a working hypothesis to explain the inhibitory mechanism of rifampicin, it is assumed that it becomes very firmly attached to a position close to the synthesizing site and only blocks this when no synthesis is in progress.


Weed Science ◽  
1972 ◽  
Vol 20 (4) ◽  
pp. 364-366 ◽  
Author(s):  
Donald Penner ◽  
Roy W. Early

Trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) at 10−5M applied to etiolated corn(Zea maysL. ‘Michigan 500′) seedlings 6 or 12 hr before the isolation of chromatin from the roots markedly reduced ribonucleic acid (RNA) synthesis supported by the chromatin. The addition ofEscherichia coliRNA polymerase failed to overcome the inhibition. Trifluralin increased the melting temperature of the chromatin. The presence of trifluralin during the isolation and reaction procedure inhibited RNA synthesis indicating possible trifluralin binding to the chromatin with subsequent reduction of template availability for transcription. Trifluralin did not inhibit chromatin activity in soybean [Glycine max(L.) Merr. ‘Hark’] seedlings.


1978 ◽  
Vol 175 (1) ◽  
pp. 189-192 ◽  
Author(s):  
A D B Malcolm ◽  
J R Moffatt

1. Periodate oxidation of the ribose ring was used to synthesize derivatives of nucleoside triphosphates. 2. These oxidized nucleoside triphosphates. 2. These oxidized nucleoside triphosphates are competitive inhibitors of RNA polymerase. 3. On incubation, together with NaBH4, these oxidized labelled nucleotides are covalently bound to Escherichia coli RNA polymerase. 4. Nucleoside triphosphate substrates decrease the extent of labelling. 5. A lysine residue in an alpha-subunit is labelled. 6. The significance of these results in relation to the location of the nucleotide-binding site is discussed.


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