A parallel stranded G-quadruplex composed of threose nucleic acid (TNA)

Area of Science:

• Synthetic Biology
• Biochemistry
• Nucleic Acid Chemistry

Background:

• G-rich sequences in DNA and RNA form G-quadruplexes, stable four-stranded helical structures.
• Xeno-nucleic acids (XNA) are DNA/RNA mimics with altered backbone structures.
• The ability of XNA to form G-quadruplexes is largely unexplored.

Purpose of the Study:

• To investigate if TNA (α-l-threofuranosyl nucleic acid), an XNA, can form G-quadruplex structures.
• To characterize the stability and ion dependence of TNA G-quadruplexes.

Main Methods:

• Native polyacrylamide gel electrophoresis (PAGE) for structural analysis.
• Circular dichroism (CD) spectroscopy for structural confirmation.
• Solution-state nuclear magnetic resonance (NMR) spectroscopy for detailed structural insights.

Main Results:

• TNA self-assembles into stable G-quadruplex structures, despite a shorter backbone repeat unit than DNA/RNA.
• TNA G-quadruplexes show thermal stability comparable to DNA G-quadruplexes.
• TNA G-quadruplex formation is not ion-specific, occurring equally well with sodium (Na+) and potassium (K+) ions.

Conclusions:

• TNA is capable of forming stable G-quadruplex structures, expanding the folding potential of XNA polymers.
• The findings demonstrate the versatility of TNA in adopting complex secondary structures.
• TNA G-quadruplexes offer a potential platform for novel applications in synthetic biology and nanotechnology.