Ensemble Force Spectroscopy of a G-Quadruplex Cluster on a Single-Molecule Platform

Area of Science:

• Biophysics
• Molecular Biology
• Nanotechnology

Background:

• Single-molecule methods offer high sensitivity but suffer from low throughput.
• Existing methods struggle to repetitively analyze the same molecular units.
• There is a need for techniques that combine high throughput with single-molecule precision.

Purpose of the Study:

• To develop a novel method for high-throughput analysis of biomolecular structures.
• To investigate the mechanical unfolding of G-quadruplexes using a tandem array.
• To introduce a new technique called differential scanning forcemetry for evaluating G-quadruplex ligands.

Main Methods:

• Utilized a tandem array of G-quadruplexes on a single DNA template.
• Employed optical tweezers for mechanical unfolding and force-jump experiments.
• Analyzed ensemble behaviors using scanning force diagrams and force-jump data.

Main Results:

• Achieved a throughput two orders of magnitude higher than single-molecule force spectroscopy.
• Identified accurate F_1/2 values for G-quadruplex unfolding, enabling ligand evaluation.
• Successfully determined G-quadruplex unfolding rate constants as a function of force.

Conclusions:

• The ensemble assay on single-molecule entities (EASE) effectively combines ensemble accuracy with single-molecule precision.
• This generic method can be applied to various biomolecules like DNA, RNA, and proteins.
• EASE offers a powerful new tool for biophysical characterization and drug discovery.