Single-molecule Mechanostructural Fingerprinting of Nucleic Acid Conformations

Area of Science:

• Biophysics
• Structural Biology
• Molecular Mechanobiology

Background:

• Understanding biomolecular mechanisms often requires knowledge of both 3D structure and mechanical response, especially when force regulates function.
• Existing methods like X-ray crystallography and single-molecule force spectroscopy provide structural or mechanical data separately, limiting integrated analysis.
• A simultaneous approach is needed to study non-equilibrium conformations and force-induced transitions for a complete structure-function understanding.

Purpose of the Study:

• To develop a novel platform for simultaneous single-molecule structural and mechanical analysis.
• To investigate the mechanostructural properties of human telomeric DNA G-quadruplexes using this new technology.

Main Methods:

• Development of a DNA nanoswitch calipers platform.
• Simultaneous measurement of intramolecular distances and mechanical unfolding of individual biomolecules.
• Application to human telomeric DNA G-quadruplexes, mapping distances and performing directional unfolding.

Main Results:

• The DNA nanoswitch calipers platform successfully measured multiple intramolecular distances to distinguish conformational states.
• Directional unfolding experiments characterized the mechanical stability of G-quadruplexes along defined axes.
• Subtle conformational and mechanical differences were revealed, demonstrating the platform's sensitivity.

Conclusions:

• DNA nanoswitch calipers provide a modular and broadly applicable method for integrated mechanostructural analysis.
• This approach offers a powerful tool for studying complex biomolecular systems where force is critical.
• The findings advance our ability to link molecular structure directly to mechanical function in biological processes.