Biomaterial Database

How lac repressor recognizes lac operator. 1978

D V Goeddel, and D G Yansura, and M H Caruthers

Nucleotide analogs were substituted for unmodified nucleotides at specific sites in the lac operator sequence by a combination of chemical and enzymatic procedures. The nitrocellulose filter assay was used to study the interactions of these modified operators with wild-type (SQ) and tight-binding (QX86) lac repressors. These studies implicate directly the 5 methyl of thymine and the 2 amino of guanine as important operator-repressor contact sites. Furthermore, when these findings are combined with published results from other laboratories, a model for the lac operator-lac repressor interaction can be derived. Two important postulates follow from this model. (i) The repressor interacts at specific and defined sites with the N7 of guanine, the 5 methyl of thymine, the 2 amino of guanine, and the central major groove of the operator. (ii) The repressor binds to one side of the operator.

UI	MeSH Term	Description	Entries
D007763	Lac Operon	The genetic unit consisting of three structural genes, an operator and a regulatory gene. The regulatory gene controls the synthesis of the three structural genes: BETA-GALACTOSIDASE and beta-galactoside permease (involved with the metabolism of lactose), and beta-thiogalactoside acetyltransferase.	Lac Gene,LacZ Genes,Lactose Operon,Gene, Lac,Gene, LacZ,Genes, Lac,Genes, LacZ,Lac Genes,Lac Operons,LacZ Gene,Lactose Operons,Operon, Lac,Operon, Lactose,Operons, Lac,Operons, Lactose
D008954	Models, Biological	Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.	Biological Model,Biological Models,Model, Biological,Models, Biologic,Biologic Model,Biologic Models,Model, Biologic
D012097	Repressor Proteins	Proteins which maintain the transcriptional quiescence of specific GENES or OPERONS. Classical repressor proteins are DNA-binding proteins that are normally bound to the OPERATOR REGION of an operon, or the ENHANCER SEQUENCES of a gene until a signal occurs that causes their release.	Repressor Molecules,Transcriptional Silencing Factors,Proteins, Repressor,Silencing Factors, Transcriptional
D001483	Base Sequence	The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.	DNA Sequence,Nucleotide Sequence,RNA Sequence,DNA Sequences,Base Sequences,Nucleotide Sequences,RNA Sequences,Sequence, Base,Sequence, DNA,Sequence, Nucleotide,Sequence, RNA,Sequences, Base,Sequences, DNA,Sequences, Nucleotide,Sequences, RNA
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining
D014157	Transcription Factors	Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.	Transcription Factor,Factor, Transcription,Factors, Transcription