Part:BBa_K4673026
LacI is a regulated repressor protein
One of the major trans-regulators of the lac operon is encoded by lacI, and it is able to form a homotetrameric repressor by assembling four identical molecules of lacI proteins together. LacI is associated with a regulatory element called lac operator that controls the synthesis of the structural genes. Within the DNA sequence, there is an overlap between the lac operon and the lac promoter. The binding of lacI to the lac operator negatively regulates or inhibits the expression of structural genes of the operon, thereby effectively obstructing the binding of RNA polymerase to the lac promoter. Consequently, this outcome leads to the inhibition of operon transcription whenever the operator site is occupied by a repressor.
In addition to its capacity for attaching to specific DNA sequences at the lac operator, another important attribution of lacI is its effect to bind with lactose. When lactose is present, lacI will change its shape in a way that prevents it from binding to the lac operon. Therefore, RNA polymerase is able to bind to the lac promoter and transcribe the lac operon, leading to the expression of the lacZ, lacY, and lacA genes.
Sequence and Features
- 10COMPATIBLE WITH RFC[10]
- 12COMPATIBLE WITH RFC[12]
- 21COMPATIBLE WITH RFC[21]
- 23COMPATIBLE WITH RFC[23]
- 25COMPATIBLE WITH RFC[25]
- 1000COMPATIBLE WITH RFC[1000]
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