Part:BBa_K3467007:Design

CarH protein is from Thermus thermophilus. This protein has cobalamine (Vitamin B12), which has a photosensitive Co-C bond, as a prosthetic group. In the dark, CarH is a tetramer that binds strongly to CarO DNA operon and represses downstream protein translation. When excited by green light, the photosensitive Co-C bond breaks, this disrupts the tetramer structure, and then gene expression can start. From the research we know CarH maximum absorption spectrum is 525nm, we decided to apply green light control system to manipulate yeast dsRNA synthesis. When the yeast is incubated in dark condition, CarH will bind to dsRNA synthesis part which will block the dsRNA synthesis. When exposing to 525nm light environment, CarH tetramer photolysis which resulted in dsRNA synthesis expression.