An oxidatively damaged G-quadruplex/hemin DNAzyme

Area of Science:

• Biochemistry
• Molecular Biology
• DNA Damage and Repair

Background:

• G-quadruplex DNA structures are crucial in various biological processes.
• Hemin-DNA complexes act as DNAzymes, catalyzing specific reactions.
• Oxidative stress can lead to DNA damage, potentially affecting DNAzyme function.

Purpose of the Study:

• To investigate the impact of guanine oxidation to 8-oxoguanine on G-quadruplex/hemin DNAzyme activity.
• To elucidate the mechanistic basis for DNAzyme deactivation following oxidative damage.

Main Methods:

• Utilizing G-quadruplex/hemin DNAzyme systems.
• Inducing oxidative damage to guanine within the DNAzyme.
• Assessing changes in DNAzyme activity, G-quadruplex stability, and hemin binding affinity.

Main Results:

• Oxidation of guanine to 8-oxoguanine resulted in a partial and variable loss of DNAzyme activity.
• This loss correlated with decreased G-quadruplex stability.
• Reduced affinity for hemin and modifications in hemin binding site nature were observed.

Conclusions:

• Oxidative damage to guanine is a significant factor in G-quadruplex/hemin DNAzyme deactivation.
• The mechanism involves destabilization of the G-quadruplex structure and impaired hemin interaction.
• Understanding these mechanisms is vital for applications involving DNAzymes in oxidative environments.