title: Specific destruction of the second lac operator decreases repression of the lac operon in Escherichia coli fivefold.
abstract: The second operator of the lac operon, located within the 5'-coding region of the lacZ gene, was specifically destroyed by means of oligonucleotide-directed mutagenesis. Eight of its bases were exchanged without altering the wild-type amino acid sequence of beta-galactosidase. The mutation was transferred onto an F'lac+I+O+Z+pro+ episome. We observed a fivefold decrease in repression of beta-galactosidase expression compared to that in the wild-type.
mesh_terms: D004794:Enzyme Repression; D004926:Escherichia coli / Q000235:genetics*; D007763:Lac Operon; D009154:Mutation; D009875:Operator Regions, Genetic; D001616:beta-Galactosidase / Q000096:biosynthesis
chemical_list: D001616:beta-Galactosidase