Alpha-Deoxyguanosine to Reshape the Alpha-Thrombin Binding Aptamer

Area of Science:

• Biochemistry
• Molecular Biology
• Medicinal Chemistry

Background:

• DNA aptamers offer therapeutic potential but require modifications for stability and efficacy.
• G-quadruplex DNA aptamers, while promising, face challenges in structural modification without losing affinity.
• Enhancing thermodynamic stability and resistance to biodegradation is crucial for aptamer applications.

Purpose of the Study:

• To develop modified G-quadruplex DNA aptamers with improved thermodynamic stability.
• To investigate the impact of non-natural alpha-deoxyguanosines on aptamer structure and function.
• To assess and restore the anticoagulant activity of modified thrombin binding aptamers.

Main Methods:

• Synthesis of three- and four-layer modified analogues of the thrombin binding aptamer.
• Incorporation of non-natural anti-preferred alpha-deoxyguanosines into G-tetrads.
• Evaluation of thermal stability, structural topology, and anticoagulant activity against alpha-thrombin.
• Conjugation with optimized tripeptide sequences to compensate for activity loss.

Main Results:

• Developed modified aptamers exhibiting high thermal stability.
• Controlled aptamer topology using non-natural tetrads.
• Observed a decrease in anticoagulant activity due to non-natural tetrads.
• Fully compensated for activity loss through tripeptide conjugation.

Conclusions:

• Modified G-quadruplex aptamers can achieve enhanced stability while retaining biological function.
• Non-natural nucleotides offer a route to control aptamer structure and properties.
• Peptide conjugation is an effective strategy to restore or enhance aptamer activity.