The formation of adjacent triplex-duplex domainsin DNA

Area of Science:

• Molecular Biology
• Biochemistry
• Structural Biology

Background:

• Single-stranded DNA (ssDNA) oligomers can adopt complex structures.
• DNA structural motifs like hairpins and duplexes with dangling ends are crucial in molecular biology.

Purpose of the Study:

• To investigate the ability of ssDNA oligomers to form adjacent triplex and duplex domains.
• To characterize the interaction of ssDNA oligomers with DNA hairpins and duplexes with dangling ends.

Main Methods:

• Helix-coil transition curves were employed to analyze DNA structural changes.
• Gel mobility shift assays were used to study DNA-oligonucleotide interactions.
• Melting curve analysis and gel competition assays provided stability data.

Main Results:

• A 12-nucleotide (nt) 5'-end of ssDNA oligomers formed triplex structures with DNA hairpins and duplexes.
• The 3'-ends of longer ssDNA oligomers (17-20 nt) formed Watson-Crick pairs with hairpin loops or duplex dangling ends.
• Complexes of hairpin DNA with shorter ssDNA oligomers showed greater stability than those with longer strands.
• Extended ssDNA oligomers enhanced the stability of adjacent triplex regions in duplex DNA.

Conclusions:

• ssDNA oligomers can form distinct triplex and duplex domains with specific DNA structures.
• The length and end-structure of ssDNA oligomers dictate their binding and stabilization capabilities.
• These findings contribute to understanding DNA structural versatility and potential applications in nanotechnology and therapeutics.