Fig 4. Sensitivity test of the structure-based interaction parameter.

Free energy profiles for the left end of unwrapped DNA are plotted for a weakened interaction, ${\epsilon }_{go}^{pro-dna}=0.5{\epsilon }_{go}^{pro}$ (A) and a strengthened interaction ${\epsilon }_{go}^{pro-dna}=1.0{\epsilon }_{go}^{pro}$ (B). The default parameter used for all the other simulations is $0.8{\epsilon }_{go}^{pro}$. With the parameter ${\epsilon }_{go}^{pro-dna}=0.5{\epsilon }_{go}^{pro}$, DNA is completely unwrapped and dissociated from histone octamer at and above 300 mM NaCl. With the parameter ${\epsilon }_{go}^{pro-dna}=1.0{\epsilon }_{go}^{pro}$, DNA did not dissociate from histone octamer within the computing time even at a sufficiently high salt concentration such as 1 M.