Parallel High Throughput Single Molecule Kinetic Assay for Site-Specific DNA Cleavage

Area of Science:

• Molecular Biology
• Biophysics
• Biochemistry

Background:

• Site-specific DNA cleavage (SSDC) is fundamental to cellular processes and gene editing technologies.
• Accurate measurement of SSDC kinetics is essential for understanding DNA-protein interactions and enzyme mechanisms.

Purpose of the Study:

• To develop and validate a high-throughput kinetic assay for measuring single-molecule site-specific DNA cleavage.
• To enable simultaneous monitoring of SSDC in thousands of individual DNA molecules.

Main Methods:

• Utilizing bead-tethered substrate DNAs within a microfluidic flow channel.
• Employing magnetic manipulation and darkfield imaging for real-time DNA integrity monitoring.
• Observing bead displacement via video microscopy to pinpoint cleavage events and quantify reaction rates.

Main Results:

• Simultaneous monitoring of up to 1,000 individual DNA cleavage events.
• Accurate quantification of reaction kinetics through frame-by-frame bead counting and exponential fitting.
• Generation of statistically significant data from single-molecule SSDC reactions in a single experiment.

Conclusions:

• The developed assay provides a powerful, quantitative, and high-throughput method for studying SSDC.
• This technique significantly advances the ability to analyze DNA cleavage dynamics at the single-molecule level.
• The assay has broad applications in gene editing research and understanding DNA-modifying enzymes.