A Non-G-Quadruplex Hemin Aptamer Forms a Better Peroxidase Mimicking DNAzyme

Area of Science:

• Biochemistry
• Molecular Biology
• Biotechnology

Background:

• G-quadruplex DNA forms complexes with hemin, exhibiting peroxidase-like activity.
• Aptamers, like Hem1-2T, can also bind hemin and display horseradish peroxidase (HRP)-like activity.

Purpose of the Study:

• To investigate and compare the catalytic characteristics of the Hem1-2T aptamer-hemin complex with a known G-quadruplex (PS2.M).
• To evaluate Hem1-2T as a potential mechanistic mimic of HRP.

Main Methods:

• Comparative analysis of catalytic activity across a pH range (6-8).
• Assessment of hemin stability in the presence of hydrogen peroxide (H2O2).
• Nuclear Magnetic Resonance (NMR) spectroscopy to study complex formation and stability.

Main Results:

• Hem1-2T activity decreased with increasing pH (6-8), mirroring HRP behavior, unlike PS2.M.
• Hem1-2T offered better protection of hemin against H2O2 degradation, leading to more sustained catalysis.
• NMR data revealed specific complex formation between Hem1-2T and hemin, distinct from hemin's interaction with PS2.M.

Conclusions:

• The Hem1-2T-hemin complex is a more effective and stable mimic of HRP than the PS2.M G-quadruplex.
• Hem1-2T demonstrates significant potential for applications in bioanalysis and biocatalysis due to its HRP-mimicking properties.