Annotated crystal structure of dimeric LacI. Two monomers (of four total) co-operate to bind each DNA operator sequence. Monomers (red and blue) contain DNA binding and core domains (labeled) which are connected by a linker (labeled). The C-terminal tetramerization helix is not shown. The repressor is shown in complex with operator DNA (gold) and ONPF (green), an anti-inducer ligand (i.e. a stabilizer of DNA binding)
The lac repressor (LacI) is a DNA-binding protein that inhibits the expression of genes coding for proteins involved in the metabolism of lactose in bacteria. These genes are repressed when lactose is not available to the cell, ensuring that the bacterium only invests energy in the production of machinery necessary for uptake and utilization of lactose when lactose is present. When lactose becomes available, it is firstly converted into allolactose by β-Galactosidase (lacZ) in bacteria. The DNA binding ability of lac repressor bound with allolactose is inhibited due to allosteric regulation, thereby genes coding for proteins involved in lactose uptake and utilization can be expressed.
The lacrepressor (LacI) is a DNA-binding protein that inhibits the expression of genes coding for proteins involved in the metabolism of lactose in bacteria...
the repressor. The relative distribution of repressor and operator mutants is affected by the target size. Since the lacI gene encoding repressor is about...
the lacrepressor to the lac operator, thereby dissociating it from the lac operator. The absence of the repressor allows the transcription of the lac operon...
the lacrepressor to RNA polymerase's binding site inhibits the transcription of the lac genes. Only when an inducer is bound to the lacrepressor will...
the control of a lac promoter. Normally, both the lac promoter and the T7 promoter are repressed in the E. coli cell by the Lacrepressor. In order to initiate...
in the context of the lac operon of Escherichia coli. In the absence of lactose, the constitutively expressed lacrepressor protein binds to the operator...
proteins creates an osmotic pressure which brings searcher proteins (e.g. LacRepressor) closer to the DNA to increase their attraction and enable them to bind...
O3 are located at -82 and +412, respectively. In the case of a repressor, the repressor protein physically obstructs the RNA polymerase from transcribing...
central to the operations of genes and gene regulatory networks. Repressor (see Lacrepressor) and activator proteins are used to create genetic operons, which...
PhD student Benno Müller-Hill, Gilbert was the first to purify the lacrepressor, just beating out Mark Ptashne for purifying the first gene regulatory...
lactose, is sensed through the activity of the lacrepressor, which inhibits transcription of the lac operon until lactose is present. Thus, if glucose...
DNA association kinetics of the Lacrepressor tetramer, its dimeric mutant LacIadi, and the native dimeric Gal repressor". J. Biol. Chem. 272 (35): 22092–6...
DNA association kinetics of the Lacrepressor tetramer, its dimeric mutant LacIadi, and the native dimeric Gal repressor". The Journal of Biological Chemistry...
inducible T7 expression system by blocking the target T7 promoter with lacrepressor". Journal of Molecular Biology. 219 (1): 45–59. doi:10.1016/0022-2836(91)90856-2...
Fried M, Crothers DM (December 1981). "Equilibria and kinetics of lacrepressor-operator interactions by polyacrylamide gel electrophoresis". Nucleic...
The Ribose repressor (RbsR) is a bacterial DNA-binding transcription repressor protein and a member of the LacI/GalR protein family. In Escherichia coli...
Global Information