Operator Regions, GeneticOperonRepressor ProteinsBase SequenceEscherichia coliMolecular Sequence DataBacterial ProteinsGenes, RegulatorPromoter Regions, GeneticGene Expression Regulation, BacterialDNA, BacterialGenes, BacterialMutationProtein BindingAmino Acid SequenceBinding SitesModels, MolecularDNA-Binding ProteinsKineticsTranscription FactorsProtein Structure, TertiaryLac RepressorsLac OperonDNACrystallography, X-RayBinding, CompetitiveNucleic Acid ConformationRecombinant ProteinsViral Regulatory and Accessory ProteinsCell LineRecombinant Fusion ProteinsEscherichia coli ProteinsPlasmidsDNA FootprintingCarrier ProteinsComputer TerminalsRadiation ProtectionSequence Homology, Amino AcidCloning, MolecularROC CurveIsopropyl ThiogalactosideLigandsMutagenesis, Site-DirectedDimerizationFluoroscopyElectrophoresis, Polyacrylamide GelRadiation MonitoringProtein ConformationMacromolecular SubstancesOccupational ExposureMolecular WeightReproducibility of ResultsProtein Structure, SecondaryRadiography, InterventionalTranscription, GeneticViral Proteins