On the stability of fractal globules
| Autor: | Helmut Schiessel, Gerard T. Barkema, Raoul D. Schram |
|---|---|
| Rok vydání: | 2013 |
| Předmět: |
chemistry.chemical_classification
Quantitative Biology::Biomolecules Polymers Chemistry Monte Carlo method Molecular Conformation General Physics and Astronomy Collapse (topology) DNA Polymer Molecular Dynamics Simulation Stability (probability) Molten globule Condensed Matter::Soft Condensed Matter Molecular dynamics Fractals Fractal Chain (algebraic topology) Chemical physics Statistical physics Physical and Theoretical Chemistry Monte Carlo Method |
| Zdroj: | The Journal of Chemical Physics. 138:224901 |
| ISSN: | 1089-7690 0021-9606 |
| DOI: | 10.1063/1.4807723 |
| Popis: | The fractal globule, a self-similar compact polymer conformation where the chain is spatially segregated on all length scales, has been proposed to result from a sudden polymer collapse. This state has gained renewed interest as one of the prime candidates for the non-entangled states of DNA molecules inside cell nuclei. Here, we present Monte Carlo simulations of collapsing polymers. We find through studying polymers of lengths between 500 and 8000 that a chain collapses into a globule, which is neither fractal, nor as entangled as an equilibrium globule. To demonstrate that the non-fractalness of the conformation is not just the result of the collapse dynamics, we study in addition the dynamics of polymers that start from fractal globule configurations. Also in this case the chain moves quickly to the weakly entangled globule where the polymer is well mixed. After a much longer time the chain entangles reach its equilibrium conformation, the molten globule. We find that the fractal globule is a highly unstable conformation that only exists in the presence of extra constraints such as cross-links. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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