Influence of salt on transcription by T<sub>4</sub> core RNA polymerase

Kleppe, Ruth K.

doi:10.1016/0014-5793(75)80895-7

Cited by 8 publications

(5 citation statements)

References 21 publications

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“…that increasing concentrations of salt such as KCl increase the rate of transcription (5), a finding that also was confirmed in this work. Transcription by the core enzyme is almost unaffected by salt (18), whereas T4 core RNA polymerase is inhibited by salt. Salt was also found to have a profound influence on the activity of RNA polymerase from A. calcoaceticus.…”

Section: Resultsmentioning

confidence: 98%

“…It would therefore appear that association between the a subunit, if present in A. calcoaceticus, and the core enzyme is weaker than that of the enzyme from E. coli. In this respect as well as in its sensitivity to ionic strength, the Acinetobacter enzyme resembles that of T4 RNA polymerase (18). Several other procedures were tried in order to isolate an enzyme containing the a subunit, but without success.…”

Section: Discussionmentioning

confidence: 99%

“…The effect of salt on RNA polymerase from A. calcoaceticus appears to be a unique feature. It is not specifically related to initiation of RNA synthesis as observed with T4 RNA polymerase (18). In the case of the normal RNA polymerase from E. coli, it is known that the ionic strength influences: (i) the equilibrium between the monomeric and the dimeric forms (6, 32); (ii) the initiation and termination process (3,9,27); and (iii) the binding of the enzyme to the template (24).…”

Section: Discussionmentioning

confidence: 99%

“…This laboratory has for some time been interested in the influence of ionic conditions, i.e., effect of salts and polyamines, on enzymes involved in the nucleic acid metabolism. Concerning RNA polymerizing enzymes, we have shown that salt has different effects on the RNA polymerase from T4-infected and from uninfected E. coli (18). The T4 core enzyme is inhibited by salt, whereas the enzyme from E. coli is slightly stimulated.…”

mentioning

confidence: 96%

“…Higher ionic strengths led to increasing inhibition of transcription, and at A = 0.4 complete inhibition was observed. The mechanism of inhibition of salt was not related to the initiation event as observed with T4 core RNA polymerase (R. Kleppe, 1975). In an attempt to understand the mechanism of inhibition by salt, the effect of ionic strength on the sedimentation properties of the enzyme was investigated.…”

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confidence: 99%

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Preparations and properties of ribonucleic acid polymerase from Acinetobacter calcoaceticus

Kleppe¹,

Kleppe²

1976

J Bacteriol

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Deoxyribonucleic acid (DNA)-dependent ribonucleic acid (RNA) polymerase (EC 2.7.7.6) from Acinetobacter calcoaceticus was purified to apparent homogeneity and its properties were compared with those of the Escherichia coli B enzyme. The molecular weights of the two native active enzymes as well as their a and # subunits appeared to be similar. No subunit corresponding to that of a from E. coli was found, and furthermore no separation between the ,B subunits could be detected by gel electrophoresis. A number of different DNAs were transcribed by the enzyme from A. calcoaceticus. Maximal RNA synthesis occurred at pH 8.7, 10 mM Mg2+, or 0.3 mM Mn2+ and at a total ionic strength of 0.1. Higher ionic strengths led to increasing inhibition of transcription, and at A = 0.4 complete inhibition was observed. The mechanism of inhibition of salt was not related to the initiation event as observed with T4 core RNA polymerase (R. Kleppe, 1975). In an attempt to understand the mechanism of inhibition by salt, the effect of ionic strength on the sedimentation properties of the enzyme was investigated. At low ionic strength, enzyme species with sedimentation coefficients, S20,W, of 5.8S, 12.4S, and 19.3S were present. In buffers with higher ionic strengths the relative amounts of the 12.4S species decreased. It is suggested, therefore, that the inhibition of activity at higher salt concentrations is caused by a decrease in concentration of the active enzyme species.

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Section: Resultsmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%