When tryptophan is already present, a repressor protein binds to the operator and shuts the operon off. This way, the bacteria save energy by not making something they already have!

The lac repressor is a protein that represses (inhibits) transcription of the lac operon. It does this by binding to the operator, which partially overlaps with the promoter.

Overview of operons, regulatory DNA sequences, & regulatory genes. Repressor & activator proteins.

And so this right over here, this is a protein that is called the repressor, it's literally repressing the transcription, and the regulatory DNA sequence where it attaches, that is called the operator.

The Trp repressor, because it's a protein, can be altered by any type of mutation in the DNA that codes the protein, and if the repressor is disordered it won't function correctly, thus not …

One example of a repressor protein is the repressor protein associated again with the lac operon operator, which prevents the transcription of genes used in lactose metabolism unless lactose, …

O repressor lac é um proteína que reprime (inibe) a transcrição do operon lac. Ela faz isso através da ligação com o operador, o qual se sobrepõe parcialmente ao promotor.

The lac operon in E. coli regulates lactose metabolism. It consists of three genes (lacZ, lacY, and lacA) and is controlled by a promoter, operator, and CAP site. Lactose presence triggers …

Regulation of genes for lactose utilization. lac repressor, catabolite activator protein, and cAMP.

Repressors Other transcription factors repress transcription. This repression can work in a variety of ways. As one example, a repressor may get in the way of the basal transcription factors or …