Selection of RNA‐Cleaving TNA Enzymes for Cellular Mg<sup>2+</sup> Imaging
Mingmei Gao, Dongying Wei, Siqi Chen, Bohe Qin, Yueyao Wang, Zhe Li, Hanyang Yu
Abstract
Abstract Catalytic DNA‐based fluorescent sensors have enabled cellular imaging of metal ions such as Mg 2+ . However, natural DNA is prone to nuclease‐mediated degradation. Here, we report the in vitro selection of threose nucleic acid enzymes (TNAzymes) with RNA endonuclease activities. One such TNAzyme, T17–22, catalyzes a site‐specific RNA cleavage reaction with a k cat of 0.017 min −1 and K M of 675 nM. A fluorescent sensor based on T17–22 responds to an increasing concentration of Mg 2+ with a limit of detection at 0.35 mM. This TNAzyme‐based sensor also allows cellular imaging of Mg 2+ . This work presents the first proof‐of‐concept demonstration of using a TNA catalyst in cellular metal ion imaging.