Structural studies of oligonucleotides containing G-quadruplex motifs using AFM

Area of Science:

• Biochemistry
• Nanotechnology
• Genetics

Background:

• G-quadruplex DNAs are four-guanine base structures stabilized by Hoogsteen hydrogen bonds.
• They are found in telomeric regions and oncogene regulatory elements, impacting gene expression.
• These structures are implicated in various biological processes, including immune response.

Purpose of the Study:

• To investigate the structural formation of G-quadruplex DNA oligonucleotides (G-ODN) using atomic force microscopy (AFM).
• To explore the correlation between G-ODN structure and their immunostimulatory effects.
• To understand the influence of ion and G-ODN concentration on DNA self-assembly.

Main Methods:

• High-resolution atomic force microscopy (AFM) was employed to visualize G-quadruplex DNA structures.
• Oligonucleotides with G-quadruplex motifs and palindromic sequences were studied under physiological conditions.
• Structural analysis was performed in correlation with varying ion and G-ODN concentrations.

Main Results:

• AFM revealed specific guanine tetrad-mediated complex formation in G-ODNs.
• The self-assembly of G-ODNs into DNA networks was observed to be dependent on ion and G-ODN concentration.
• Structural changes were noted with variations in environmental conditions.

Conclusions:

• G-quadruplex DNA structures exhibit concentration-dependent self-assembly into networks.
• The observed structural characteristics are linked to potential immunostimulatory effects.
• Further research into G-quadruplex DNA nanostructures could yield insights into therapeutic applications.