Role of chain stiffness and end entropy in the unzipping of DNA chain

Abstract

The force induced unzipping of dsDNA was studied in Constant Force Ensembles (CFE) in presence of salt. The role of end entropy on the force required to unzip the chain has been investigated using Peyrard Bishop Dauxious (PBD) model. The effect of the stiffness and anharmonicity in the stacking interaction of the chain has been investigated. Our results show that the force require to unzip the chain increases with increasing the chain length in case when the other end is free while it decreases in case of when the other end of the chain is restricted. However, as the chain length reaches a critical length, the end effect nullifies and the critical force in both the cases are found to be same.