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Updated: May 16, 2026

Stretching Short Sequences of DNA with Constant Force Axial Optical Tweezers
Published on: October 13, 2011
Definition of the persistence length in the coarse-grained models of DNA elasticity
A Fathizadeh1, B Eslami-Mossallam, M R Ejtehadi
1Sharif University of Technology, Institue for Nanoscience and Nanotechnology, Post Office Box 14588-89694, Tehran, Iran.
Abstract:
By considering the detailed structure of DNA in the base pair level, two possible definitions of the persistence length are compared. One definition is related to the orientation of the terminal base pairs, and the other is based on the vectors which connect two adjacent base pairs at each end of the molecule. It is shown that although these definitions approach each other for long DNA molecules, they are dramatically different on short length scales. We show analytically that the difference mostly comes from the shear flexibility of the molecule and can be used to measure the shear modulus of DNA.
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