Simulations of DNA denaturation dynamics under constrained conditions
A Al Qanobi1, D Marenduzzo2, I Ali1
1Department of Physics, College of Science, Sultan Qaboos University, PO Box 36, Al-Khod 123, Oman.
Summary
Free DNA denatures faster than tethered DNA due to greater entropy gains. DNA melting dynamics in nanochannels depend on confinement, with tight spaces accelerating denaturation at high temperatures.
Area of Science:
- Biophysics
- Computational Biology
- Materials Science
Background:
- DNA denaturation is crucial for biological processes and nanotechnology.
- Understanding DNA dynamics under confinement is essential for nanoscale device design.
Purpose of the Study:
- To investigate the influence of end-tethering and nanochannel confinement on double-stranded DNA (dsDNA) denaturation dynamics.
- To compare melting rates and critical temperatures for free, tethered, and confined DNA.
Main Methods:
- Brownian dynamics simulations utilizing a coarse-grained single nucleotide model for dsDNA.
- Comparison of melting dynamics for free DNA versus end-tethered DNA (300 base pairs).
- Analysis of DNA melting in nanochannels of varying widths relative to the DNA's radius of gyration (Rg).
Main Results:
- Free DNA exhibits faster denaturation than end-tethered DNA due to larger entropic gains.
- Confinement in nanochannels (width ⩾ Rg/2) shows no significant effect on melting temperature or rate.
- At a channel width of Rg/4, only partial denaturation occurs at the free DNA melting temperature.
- Unexpectedly, at 110 °C, tight confinement accelerates DNA melting by promoting single-strand segregation and acting as an entropic force.
Conclusions:
- End-tethering reduces DNA denaturation rates compared to free DNA.
- Nanochannel confinement significantly impacts DNA melting dynamics, with effects dependent on channel width and temperature.
- Tight confinement can enhance DNA denaturation at elevated temperatures through entropic effects.
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