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Related papers: Getting DNA twist rigidity from single molecule ex…

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By combining analytical results and simulations of various coarse-grained models we investigate the minimal energy shape of DNA minicircles which are torsionally constrained by an imposed over or undertwist. We show that twist-bend…

Soft Condensed Matter · Physics 2019-08-08 Michele Caraglio , Enrico Skoruppa , Enrico Carlon

We examine the conformations of a model for under- and overwound DNA. The molecule is represented as a cylindrically symmetric elastic string subjected to a stretching force and to constraints corresponding to a specification of the link…

Soft Condensed Matter · Physics 2009-10-28 Boris Fain , Joseph Rudnick , Stellan Ostlund

A theory is presented for the binding of small molecules such as surfactants to semiflexible polymers. The persistence length is assumed to be large compared to the monomer size but much smaller than the total chain length. Such polymers…

Soft Condensed Matter · Physics 2009-09-25 Haim Diamant , David Andelman

We investigate the measurement of DNA supercoiling density ($\sigma$) along chromosomes using interaction frequencies between DNA and DNA-anchored clusters of proteins. Specifically, we show how the physics of DNA supercoiling leads, in…

Clarification of the detailed mechanisms involved in the DNA polymorphism is an important challenge for computational molecular biophysics. This paper reports about reversible A/B transitions in DNA observed in silico in a simulated…

Biological Physics · Physics 2007-05-23 Alexey K. Mazur

The folding of biological macromolecules is a fundamental process of which we lack a full comprehension. Mostly studied in proteins and RNA, single-stranded DNA (ssDNA) also folds, at physiological salt conditions, by forming non-specific…

Soft Condensed Matter · Physics 2021-09-23 X. Viader Godoy , C. R. Pulido , B. Ibarra , M. Manosas , F. Ritort

The proper design of DNA sequences allows for the formation of well defined supramolecular units with controlled interactions via a consecution of self-assembling processes. Here, we benefit from the controlled DNA self-assembly to…

Soft Condensed Matter · Physics 2018-02-14 Javier Fernandez-Castanon , Francesca Bomboi , Francesco Sciortino

Magnetic tweezers are used to study the mechanical response under torsion of single nucleosome arrays reconstituted on tandem repeats of 5S positioning sequences. Regular arrays are extremely resilient and can reversibly accommodate a large…

The sequence-dependent structural variability and conformational dynamics of DNA play pivotal roles in many biological milieus, such as in the site-specific binding of transcription factors to target regulatory elements. To better…

Biomolecules · Quantitative Biology 2014-07-22 Cameron Mura , J. Andrew McCammon

DNA toroids are compact torus-shaped bundles formed by one or multiple DNA molecules being condensed from the solution due to various condensing agents. It has been shown that the DNA toroidal bundles are twisted. However, the global…

Soft Condensed Matter · Physics 2025-04-01 Nhung T. T. Nguyen , Anh T. Ngo , Trinh X. Hoang

The structural flexibility of nucleic acids plays a key role in many fundamental life processes, such as gene replication and expression, DNA-protein recognition, and gene regulation. To obtain a thorough understanding of nucleic acid…

Biological Physics · Physics 2015-09-24 Lei Bao , Xi Zhang , Lei Jin , Zhi-Jie Tan

Three-dimensional DNA networks, composed of tri- or higher valent nanostars with sticky, single-stranded DNA overhangs, have been previously studied in the context of designing thermally responsive, viscoelastic hydrogels. In this work, we…

The double-helical structure of DNA results from canonical base pairing and stacking interactions. However, variations from steady-state conformations result from mechanical perturbations in cells. These different topologies have…

Biomolecules · Quantitative Biology 2019-04-05 Jack W Shepherd , Robert J Greenall , Matt I J Probert , Agnes Noy , Mark C Leake

Trapping, linearization, and imaging of single molecule DNA is of broad interest to both biophysicists who study polymer physics and engineers who build nucleic acid analyzing methods such as optical mapping. In this study, single DNA…

Using Langevin dynamics simulations, we study elastic response of single semiflexible polyelectrolytes to an external force pulling on the chain ends, to mimic the stretching of DNA molecules by optical tweezers. The linear chains are…

Soft Condensed Matter · Physics 2019-06-19 Paul Cardenas-Lizana , Pai-Yi Hsiao

Twisting DNA under a constant applied force reveals a thermally activated transition into a state with a supercoiled structure known as a plectoneme. Using transition state theory, we predict the rate of this plectoneme nucleation to be of…

Biological Physics · Physics 2015-03-17 Bryan C. Daniels , James P. Sethna

Topological defects are a ubiquitous phenomenon in diverse physical systems. In nematic liquid crystals (LCs), they are dynamic, physicochemically distinct, sensitive to stimuli, and are thereby promising for a range of applications.…

Soft Condensed Matter · Physics 2023-12-25 Shengzhu Yi , Hao Chen , Xinyu Wang , Miao Jiang , Bo Li , Qi-huo Wei , Rui Zhang

The conformation of circular DNA molecules of various lengths adsorbed in a 2D conformation on a mica surface is studied. The results confirm the conjecture that the critical exponent $\nu$ is topologically invariant and equal to the SAW…

Biomolecules · Quantitative Biology 2009-11-13 G. Witz , K. Rechendorff , J. Adamcik , G. Dietler

We studied the unzipping kinetics of single molecules of double-stranded DNA by pulling one of their two strands through a narrow protein pore. PCR analysis yielded the first direct proof of DNA unzipping in such a system. The time to unzip…

Soft Condensed Matter · Physics 2009-11-07 Alexis F. Sauer-Budge , Jacqueline A. Nyamwanda , David K. Lubensky , Daniel Branton

This article proposes a model including thermal effects for closed supercoiled DNA. Existing models include an elastic rod. Euler's elastica, ideal elastic rods on a plane, have only two kinds of closed shapes, the circle and a…

Soft Condensed Matter · Physics 2022-01-05 Shigeki Matsutani , Emma Previato