DNA is an excellent information medium. This is proven not only by biological history, but recent advances in which modern DNA reading and writing technologies have successfully utilized the four-base code as a substitute for the 1âs and 0âs of binary. The next frontier of this technology is to engineer a device that harnesses the information capacity of DNA to record data in real-time. Application in biological contexts would appear both obvious and advantageous, with the DNA polymerase an ideal signal transducer. Accordingly, if a DNA polymerase were engineered to have a have a functional change in response to an environmental cue, it could function as a âticker-tapeâ recorder. Here we apply a rational mutagenesis approach to graft a calmodulin-like calcium binding motif to the exonuclease domain of a DNA polymerase to deliver a step change in fidelity (loss in proof-reading capacity) upon calcium binding. Our hope is for this device to contribute to brain mapping efforts, currently lacking technologies with sufficient space-time measurement resolution, by recording the calcium spikes associated with neuronal firing into DNA.
