Abstract

A new 10-23 hairpin DNAzyme with a G-quadruplex structure stem was designed. The formation and stability of the G-quadruplex structure as the DNAzyme stem in the absence or the presence of TMPyP₄ were investigated by UV-visiblespectroscopy, circular dichroism (CD) and differential scanning calorimetry (DSC) methods, respectively. The results showed that the stability of this DNAzyme can be enhanced greatly due to the interaction between TMPyP₄ and the DNAzyme. The relationship between structural stability and activity of the DNAzyme was studied by in vitro catalytic reaction. The activity of this DNAzyme was regulated by the stability of DNAzyme when TMPyP₄ was intercalated into G-quadruplex structure stem. The catalytic activity of the 10-23 hairpin DNAzyme decreased and even inactivated due to the enhanced stability of G-quadruplex structure by TMPyP₄molecules. This DNAzyme is controllable to cleavage substrate and has some potential significance in gene therapy.

Key words: 10-23 DNAzyme, hairpin DNAzyme, G-quadruplex structure, TMPyP₄.