title: Opening of DNA chain due to force applied on different locations.
abstract: We consider a homogeneous DNA molecule and investigate the effect of random force applied on the unzipping profile of the molecule. How the critical force varies as a function of the chain length or number of base pairs is the objective of this study. In general, the ratio of the critical forces that is applied on the middle of the chain to that which is applied on one of the ends is two. Our study shows that this ratio depends on the length of the chain. This means that the force which is applied to a point can be experienced by a section of the chain. Beyond a length, the base pairs have no information about the applied force. In the case when the chain length is shorter than this length, this ratio may vary. Only in the case when the chain length exceeds a critical length, this ratio is found to be two. Based on the de Gennes formulation, we developed a method to calculate these forces at zero temperature. The exact results at zero temperature match numerical calculations.
authors.affiliation: Department of Physics, Birla Institute of Technology & Science Vidya Vihar, Pilani, 333 031, Rajasthan, India.
authors.forename: Amar
authors.initials: A
authors.lastname: Singh
authors.affiliation: Department of Physics, Arizona State University, Tempe, Arizona 85287, USA.
authors.forename: Tushar
authors.initials: T
authors.lastname: Modi
authors.affiliation: Department of Physics, Birla Institute of Technology & Science Vidya Vihar, Pilani, 333 031, Rajasthan, India.
authors.forename: Navin
authors.initials: N
authors.lastname: Singh
mesh_terms: D055592:Biophysical Phenomena; D004247:DNA / Q000737:chemistry*; D009690:Nucleic Acid Conformation; D009691:Nucleic Acid Denaturation
chemical_list: D004247:DNA