Engineering Protein Activity into Off-the-Shelf DNA Devices

DNA-based devices are relatively straightforward to design by virtue of their predictable folding, but they lack biological activity. Conversely, protein-based devices offer a myriad of biological functions but are much more difficult to design due to their complex folding. This study bridges the fields of DNA engineering and protein engineering to generate a protein switch that is activated by a specific DNA sequence. A single protein switch, engineered from nanoluciferase using the alternate frame folding mechanism and herein called nLuc-AFF, is paired with different DNA technologies to create a biosensor for a DNA or RNA sequence of choice, sensors for serotonin and ATP, and a computational device that processes two DNA inputs. nLuc-AFF is a genetically-encoded, ratiometric, blue/green-luminescent biosensor whose output can be quantified by cell phone camera. nLuc-AFF is not falsely activated by decoy DNA and it retains full ratiometric readout in 100 % serum. The design approach can be applied to other proteins and enzymes to convert them into DNA-activated switches.