title: Effect of DNA denaturants on the lac repressor-operator interaction.
abstract: The nitrocellulose filter assay was used to study the effect of the DNA denaturants glycerol and dimethylsulfoxide (Me2SO) on the lac repressor-operator interaction. Both glycerol and Me2SO decrease the rate of dissociation (kb) of the repressor-operator complex but do not significantly alter the rate of association of repressor and operator. In the presence of 10% Me2SO an almost 10-fold increase of affinity of repressor for operator is observed. A small increase in affinity of repressor for Escherichia coli DNA, chicken blood DNA, and poly(dA-dT) is also found. The results lead to the conclusion that lac repressor when interacting with the operator causes local destabilization of the DNA.
mesh_terms: D000818:Animals; D055598:Chemical Phenomena; D002621:Chemistry; D002645:Chickens; D004247:DNA / Q000097:blood; D004269:DNA, Bacterial; D004121:Dimethyl Sulfoxide; D004926:Escherichia coli; D005990:Glycerol; D007700:Kinetics; D007763:Lac Operon; D009691:Nucleic Acid Denaturation; D012097:Repressor Proteins; D014157:Transcription Factors
chemical_list: D004269:DNA, Bacterial; D012097:Repressor Proteins; D014157:Transcription Factors; D004247:DNA; D005990:Glycerol; D004121:Dimethyl Sulfoxide