A dsDNA model optimized for electrokinetic applications | JoVE Visualize

Area of Science:

Computational physics
Biophysics
Materials science

Background:

Accurate modeling of DNA behavior in solution is crucial for understanding biological processes and developing nanotechnology.
Existing coarse-grained (CG) models often lack the necessary flexibility and mobility to capture complex DNA dynamics, such as nanopore translocation.
Simulating DNA electrokinetics requires models that can integrate hydrodynamic interactions and ion behavior.

Purpose of the Study:

To develop and validate a novel coarse-grained (CG) model for charged double-stranded DNA (dsDNA) in an electrolyte solution.
To incorporate semi-flexibility and mobility into the CG DNA model for accurate simulation of dynamic processes like nanopore translocation.
To parametrize and validate the model against experimental and all-atom simulation data for electrokinetic applications.

Main Methods:

Coupling the CG DNA model hydrodynamically to a lattice-Boltzmann fluid using a raspberry approach.
Parametrizing counterions with distance-dependent friction and DNA stiffness via a harmonic angle potential.
Fitting the model's electrokinetic properties within an infinite cylinder against experimental data (Smeets et al.) and all-atom simulations (Kesselheim et al.).

Main Results:

The developed CG DNA model successfully captures semi-flexibility and mobility, essential for simulating DNA dynamics.
Model parameters were validated against experimental data for DNA stiffness (Brunet et al.) and electrokinetic properties.
Electrophoretic mobility measurements showed excellent agreement with experimental data (Stellwagen et al., Hoagland et al.) across various base pair numbers and salt concentrations.

Conclusions:

The new CG DNA model provides a robust and accurate tool for simulating electrokinetic phenomena and DNA translocation.
The model's ability to capture DNA dynamics and ion interactions opens possibilities for designing and optimizing DNA-based nanodevices.
This work bridges the gap between simplified rigid models and complex all-atom simulations for studying DNA in solution.