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The ionic strength‐dependent aggregation of DNA‐dependent RNA polymerase from Escherichia coli
Author(s) -
Heumann Hermann,
Stöckel Peter,
May Roland
Publication year - 1982
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(82)81249-0
Subject(s) - ionic strength , rna polymerase , polymerase , dna , chemistry , ionic bonding , enzyme , specificity factor , escherichia coli , monomer , biophysics , dna clamp , promoter , microbiology and biotechnology , rna , biochemistry , biology , gene , polymer , ion , rna dependent rna polymerase , reverse transcriptase , organic chemistry , gene expression , aqueous solution
Stable binding of DNA-dependent RNA polymerase to promoter sites of DNA templates is restricted to low ionic strength when the enzyme can aggregate. It was found by sedimentation measurements [1,2] that with decreasing ionic strength (~0.3) core enzyme E (Mr 385 000) aggregates into oligomers, containing up to 6 promoters, whereas holoenzyme Ea (Mr 455 000) the complex of core enzyme and u factor (Mr 70 000) forms only dimers. At high ionic strength (< 0.3) both types of polymerase exist as monomers [2]. The knowledge of the association constants for holoenzyme at different ionic strengths is of interest for several reasons: (9