Proximity‐Dependent Activation of Split DNAzyme Kinase

Binary (also known as split) nucleic acid enzymes have emerged as novel tools in biosensors. We report a new split strategy to split the DNAzyme kinase into two independent and non‐functional fragments, denoted DK1sub and DK1enz. In the presence of the specific target, their free ends are brought sufficiently close to interact with each other without the formation of Watson‐Crick base pairings between Dk1sub and Dk1enz, thus allowing the DNA phosphorylation reaction. We term this approach proximity‐dependent activation of split DNAzyme kinase (ProxSDK). The utility of ProxSDK is demonstrated by engineering a biosensing system that is capable of measuring specific DNA‐protein interactions. We envision that the approach described herein will find useful applications in biosensing, imaging, and clinical diagnosis.