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Purification and characterization of the deoR repressor of Escherichia coli.
Author(s) -
Mortensen L.,
Dandanell G.,
Hammer K.
Publication year - 1989
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1989.tb03380.x
Subject(s) - escherichia coli , repressor , biology , lac repressor , microbiology and biotechnology , biochemistry , gene , gene expression , lac operon
The deoR gene, which encodes the deor repressor protein in Escherichia coli, was fused to the strong Ptrc promoter in plasmid pKK233‐2. The Ptrc promoter is kept repressed by lacI repressor to prevent cell killing. Induction of the Ptrc–deoR fusion plasmid resulted in the accumulation of 4% of the soluble protein as deoR protein. The deoR repressor protein was purified to 80% purity using conventional techniques; it has a mass of 28.5 kd and appears to exist as an octamer in solution. The deoR repressor is shown by DNase I footprinting to bind to the 16 bp palindromic sequence in the Pribnow box region of the deoP1 promoter. Also, the deoR repressor binds cooperatively in vitro to a DNA template with two deoR binding sites separated by 224 bp in keeping with the conclusion from genetic experiments that more than one operator is required for efficient repression of the deo operon.