Designed by: Royah Vaezi   Group: iGEM09_Imperial College London   (2009-10-14)

Coding Region for Temperature Sensitive Lambda cI Repressor

To be used in the composite part BBa_K200011.

The temperature sensitive lamda cI repressor protein has a cI857 mutation that results in denaturation of the repressor when the temperature is raised from 30 to 42°C, thereby allowing lambda promoter expression. cI1

The repressor normally negatively regulates the expression of genes from the bacteriophage lambda pL and pR promoters. This repressive action is strongest at 30°C. cI2

However, when the temperature is raised, typically to 42°C, the functionality of the protein is lost and the cI repressor is no longer able to bind to the operators on its promoter. Therefore, lambda promoter expression increases.

Usage and Biology

The repressor is a single-chain, acidic protein containing 236 amino acids (Monomer Mr 26,000).

The N-terminal domain is responsible for DNA binding (operator site) and contact with RNA polymerase, while the C-terminal domain is responsible for dimer formation and higher order protein–protein contacts.


<biblio> cI1 pmid=5274442 </biblio> <biblio> cI2 pmid=10235623 </biblio>