Part BBa_K2084002 is a T7 RNAP-mediated regulatory ribosome binding site that is only translated in the presence of an activating complementary oligonucleotide. The RBS is contained within a hairpin loop that is straightened by the appropriate trigger. As the data in the Registry suggest, this toehold switch provides a powerful regulatory element in any circuit. It can be activated by both RNA and DNA, and the expression of the reporter is dependent on the concentration of the toehold switch in a cell-free reaction. For more information about toehold switches and our work with them, visit the Toehold Switch sections in the Project Overview, Experiments, and Results sections.