Triple Helix Formation in a Topologically Controlled DNA Nanosystem

Area of Science:

• Biochemistry
• Nanotechnology
• Molecular Biology

Background:

• DNA nanostructures offer precise control over molecular interactions.
• Triple helix formation is a key DNA structure with potential applications.

Purpose of the Study:

• To demonstrate single-molecule imaging of triple helix formation in DNA nanostructures.
• To investigate the controlled binding of a third DNA strand within a DNA origami frame.

Main Methods:

• Utilized DNA origami frames to position target DNA and a third strand.
• Employed two types of triplet base pairs for triple helix formation.
• Applied high-speed atomic force microscopy (HS-AFM) for real-time observation, including with photocaged strands.

Main Results:

• Successfully visualized single-molecule triple helix formation.
• Demonstrated control over third-strand binding by regulating Watson-Crick base pairing and photocaged strand uncaging.
• Observed structural changes in DNA strands indicative of triple helix formation.

Conclusions:

• Single-molecule imaging provides detailed insights into DNA nanostructure assembly.
• Controlled triple helix formation is achievable within designed nanospaces.
• This work advances the development of DNA-based nanodevices and molecular tools.