Synthesis of and triplex formation in oligonucleotides containing 2'-deoxy-6-thioxanthosine

Area of Science:

• Nucleic acid chemistry
• Biotechnology

Background:

• Triplex-forming oligonucleotides (TFOs) are crucial for targeted DNA interactions.
• Modifications to TFOs can enhance their stability and binding affinity.
• Exploring novel nucleotide analogs is key to advancing TFO applications.

Purpose of the Study:

• To synthesize and characterize TFOs incorporating 2 -deoxy-6-thioxanthosine (s⁶X) and 2 -deoxy-6-thioguanosine (s⁶Gs) residues.
• To evaluate the impact of these modifications on triplex-forming ability and stability.
• To explore the potential applications of these modified TFOs in gene therapy and DNA nanotechnology.

Main Methods:

• Chemical synthesis of modified oligonucleotides containing s⁶X and s⁶Gs residues.
• Assessment of triplex formation and stability using biophysical techniques.
• Analysis of mismatched base pair formation and stability.

Main Results:

• Consecutive s⁶X and s⁶Gs residues significantly enhanced TFO triplex-forming ability (>50-fold increase).
• Modified TFOs demonstrated improved stability compared to unmodified counterparts.
• s⁶X residues could form mismatched pairs via tautomerization, influencing triplex stability.

Conclusions:

• Modified TFOs with s⁶X and s⁶Gs exhibit superior triplex-forming properties.
• These modified oligonucleotides hold significant potential for gene therapy and DNA nanotechnology.
• Further research into these modified TFOs could unlock new therapeutic and technological avenues.