Instantaneous Iodine-Assisted DNAzyme Cleavage of Phosphorothioate RNA

We show that Ce13d DNAzymes can use non-electrostatic interactions to assist RNA cleavage by making simple Phosphorothioate (PS) modifications at the cleavage junction. In this case, Iodine can replace the role of a metal cofactor, acting directly on the scissile phosphate group. This finding has broadened the scope of DNAzyme catalysis. This DNAzyme was further engineered for fluorescence-based I2 detection with a detection limit of 4.7 nM. In addition, Oxidation of I− with Fe3+ produced I2 in situ, allowing detection of Fe3+ down to 78 nM.