Spermine Enhances the Peroxidase Activities of Multimeric Antiparallel G-quadruplex DNAzymes

Area of Science:

• Biochemistry
• Nanotechnology
• Molecular Biology

Background:

• G-quadruplex (G4) DNAzymes exhibit peroxidase activity, making them promising for biosensing.
• Current G4 DNAzymes are less efficient than natural peroxidases, necessitating structural and mechanistic studies for improvement.
• Spermine is known to modulate G4 DNAzyme structure and activity, but its effect on multimeric G4 DNAzymes requires investigation.

Purpose of the Study:

• To investigate the impact of spermine on the catalytic activities of multivalent G4 DNAzymes.
• To determine if spermine can enhance the peroxidase activity of specific G4 DNAzyme structures, including antiparallel and parallel conformations.
• To assess the potential of spermine as a strategy for improving G4 DNAzyme performance in biosensing.

Main Methods:

• Synthesis and characterization of multivalent G4 DNAzyme constructs (Bcl2, c-MYC, PS2.M, PS5.M).
• Assay of peroxidase-like activity of G4 DNAzymes in the presence and absence of spermine.
• Kinetic analysis, including determination of initial velocities, to quantify the effect of spermine.

Main Results:

• Spermine significantly enhanced the peroxidase activity of the antiparallel G4 DNAzyme PS2.M and its multimeric form by approximately twofold.
• No significant activity enhancement was observed for the parallel G4 DNAzyme c-MYC in the presence of spermine.
• The findings indicate a structure-dependent effect of spermine on G4 DNAzyme catalytic efficiency.

Conclusions:

• Spermine is an effective enhancer for specific G4 DNAzymes, particularly antiparallel structures like PS2.M.
• Spermine-mediated enhancement of catalytic activity offers a viable strategy to improve G4 DNAzymes for biosensing.
• This study expands the toolkit for designing more efficient DNAzyme-based biosensors.