dorsal/arxiv
View SchemaNucleosome interactions in chromatin: fiber stiffening and hairpin formation
| Authors | Boris Mergell, Ralf Everaers, Helmut Schiessel |
|---|---|
| Categories | |
| ArXiv ID | q-bio/0406036 |
| URL | https://arxiv.org/abs/q-bio/0406036 |
| DOI | 10.1103/PhysRevE.70.011915 |
Abstract
We use Monte Carlo simulations to study attractive and excluded volume interactions between nucleosome core particles in 30 nm-chromatin fibers. The nucleosomes are treated as disk-like objects having an excluded volume and short range attraction modelled by a variant of the Gay-Berne potential. The nucleosomes are connected via bendable and twistable linker DNA in the crossed linker fashion. We investigate the influence of the nucleosomal excluded volume on the stiffness of the fiber. For parameter values that correspond to chicken erythrocyte chromatin we find that the persistence length is governed to a large extent by that excluded volume whereas the soft linker backbone elasticity plays only a minor role. We further find that internucleosomal attraction can induce the formation of hairpin configurations. Tension-induced opening of such configurations into straight fibers manifests itself in a quasi-plateau in the force-extension curve that resembles results from recent micromanipulation experiments. Such hairpins may play a role in the formation of higher order structures in chromosomes like chromonema fibers.
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"abstract": "We use Monte Carlo simulations to study attractive and excluded volume\ninteractions between nucleosome core particles in 30 nm-chromatin fibers. The\nnucleosomes are treated as disk-like objects having an excluded volume and\nshort range attraction modelled by a variant of the Gay-Berne potential. The\nnucleosomes are connected via bendable and twistable linker DNA in the crossed\nlinker fashion. We investigate the influence of the nucleosomal excluded volume\non the stiffness of the fiber. For parameter values that correspond to chicken\nerythrocyte chromatin we find that the persistence length is governed to a\nlarge extent by that excluded volume whereas the soft linker backbone\nelasticity plays only a minor role. We further find that internucleosomal\nattraction can induce the formation of hairpin configurations. Tension-induced\nopening of such configurations into straight fibers manifests itself in a\nquasi-plateau in the force-extension curve that resembles results from recent\nmicromanipulation experiments. Such hairpins may play a role in the formation\nof higher order structures in chromosomes like chromonema fibers.",
"arxiv_id": "q-bio/0406036",
"authors": [
"Boris Mergell",
"Ralf Everaers",
"Helmut Schiessel"
],
"categories": [
"q-bio.SC",
"q-bio.BM"
],
"doi": "10.1103/PhysRevE.70.011915",
"title": "Nucleosome interactions in chromatin: fiber stiffening and hairpin formation",
"url": "https://arxiv.org/abs/q-bio/0406036"
},
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