SKM 2021 – wissenschaftliches Programm
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SYSM: Symposium Topological constraints in biological and synthetic soft matter
SYSM 1: Topological constraints in biological and synthetic soft matter
SYSM 1.4: Hauptvortrag
Montag, 27. September 2021, 11:45–12:15, Audimax 1
Topological Tuning of DNA Mobility in Entangled Solutions of Supercoiled Plasmids — •Jan Smrek1, Jonathan Garamella2, Rae Robertson-Anderson2, and Davide Michieletto3,4 — 1Faculty of Physics, University of Vienna, Austria — 2Department of Physics and Biophysics, University of San Diego, USA — 3School of Physics and Astronomy, University of Edinburgh, UK — 4MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, UK
Ring polymers in dense solutions are among the most intriguing problems in polymer physics. Thanks to its natural occurrence in circular form, DNA has been extensively employed as a proxy to study the fundamental physics of ring polymers in different topological states. Yet, torsionally constrained -- such as supercoiled -- topologies have been largely neglected so far. Here we address this gap by coupling large-scale Molecular Dynamics simulations with Differential Dynamic Microscopy of entangled supercoiled DNA plasmids. We discover that, unexpectedly, larger supercoiling increases the size of entangled plasmids and concomitantly induces an enhancement in DNA mobility. These findings are reconciled as due to supercoiling-driven asymmetric and double-folded plasmid conformations which reduce inter-plasmids entanglements and threadings. Our results suggest a way to topologically tune DNA mobility via supercoiling. In addition, I will highlight the importance of threading topological constraints in other complex polymeric fluids in- and out of equilibrium.