| 초록 |
The loop formation of a polymer is a process by which two ends of a linear chain meet each other. The polymer loop formation can be a simple model system to study the kinetics of protein folding and DNA hairpin formation. The Kramers theory (KT) based on the local equilibrium approximation (LEA) predicted that the rate constant krxn of the loop formation should be inversely proportional to the viscosity. However, several studies showed that the KT worked properly only when the viscosity was sufficiently large. For example, Ansari showed that the fractional viscosity dependence (FVD) of appeared in low viscosity medium in case of myoglobin and the KT might fail. Recently, Kwon also showed the FVD appeared in glassy medium. We perform coarse-grained MD simulations for a polymer chain in both low viscosity medium and glasses, and reproduce the FVD of krxn. We illustrate that such a breakdown of KT could be quantified by the mutual information, a measure for the validation of LEA. |
