Translocation of RecA-coated double-stranded DNA through solid-state nanopores

Area of Science:

• Biophysics
• Nanotechnology
• Molecular Biology

Background:

• RecA protein plays a crucial role in DNA repair and recombination.
• Nanopore technology offers a high-resolution platform for analyzing single molecules.

Purpose of the Study:

• To investigate the translocation dynamics of RecA-coated double-stranded DNA (dsDNA) through solid-state nanopores.
• To characterize the electrical signatures associated with this translocation process.

Main Methods:

• Solid-state nanopore measurements of RecA-dsDNA filament translocation.
• Analysis of current blockade events, including duration and conductance values.
• Confirmation using varying molecular lengths and optical tweezer-based delivery.
• Investigation of translocation behavior across different voltage regimes.

Main Results:

• Observed current blockade events with durations from 10^-4 to 10^-1 s and conductance blockades of 3-14 nS.
• Identified large blockades (11.4+/-0.7 nS) corresponding to RecA-dsDNA filament translocations.
• Distinguished between low-voltage (exponential rate increase) and high-voltage (constant rate) translocation regimes.

Conclusions:

• RecA-coated dsDNA translocation through nanopores generates measurable and distinct electrical signals.
• The findings support the potential of this technique for fundamental biophysical studies and genomic screening.
• This work paves the way for future experiments involving protein-DNA complexes in nanopores.