Role of Bending Energy and Knot Chirality in Knot Distribution and Their Effective Interaction along Stretched Semiflexible Polymers

Author(s)
Saeed Najafi, Rudolf Podgornik, Raffaello Potestio, Luca Tubiana
Abstract

Knots appear frequently in semiflexible (bio) polymers, including double-stranded DNA, and their presence can affect the polymer's physical and functional properties. In particular, it is possible and indeed often the case that multiple knots appear on a single chain, with effects which have only come under scrutiny in the last few years. In this manuscript, we study the interaction of two knots on a stretched semiflexible polymer, expanding some recent results on the topic. Specifically, we consider an idealization of a typical optical tweezers experiment and show how the bending rigidity of the chain-And consequently its persistence length-Influences the distribution of the entanglements; possibly more importantly, we observe and report how the relative chirality of the otherwise identical knots substantially modifies their interaction. We analyze the free energy of the chain and extract the effective interactions between embedded knots, rationalizing some of their pertinent features by means of simple effective models. We believe the salient aspect of the knot-knot interactions emerging from our study will be present in a large number of semiflexible polymers under tension, with important consequences for the characterization and manipulation of these systems-Be they artificial or biologica in origin-And for their technological application.

Organisation(s)
Computational and Soft Matter Physics
External organisation(s)
Max Planck Institute for Polymer Research, University of Ljubljana, Jožef Stefan Institute (IJS)
Journal
Polymers
Volume
8
No. of pages
16
ISSN
2073-4360
DOI
https://doi.org/10.3390/polym8100347
Publication date
10-2016
Peer reviewed
Yes
Austrian Fields of Science 2012
106006 Biophysics, 103023 Polymer physics
Keywords
ASJC Scopus subject areas
General Chemistry, Polymers and Plastics
Portal url
https://ucrisportal.univie.ac.at/en/publications/2cc26e8f-4558-4d2f-af1c-5e7434fe9781