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Title: Tension-dependent free energies of nucleosome unwrapping

Journal Article · · ACS Central Science
 [1];  [1];  [2];  [3]
  1. Univ. of Chicago, Chicago, IL (United States)
  2. Univ. of Wisconsin-Madison, Madison, WI (United States)
  3. Univ. of Chicago, Chicago, IL (United States); Argonne National Lab. (ANL), Argonne, IL (United States)

Here, nucleosomes form the basic unit of compaction within eukaryotic genomes, and their locations represent an important, yet poorly understood, mechanism of genetic regulation. Quantifying the strength of interactions within the nucleosome is a central problem in biophysics and is critical to understanding how nucleosome positions influence gene expression. By comparing to single-molecule experiments, we demonstrate that a coarse-grained molecular model of the nucleosome can reproduce key aspects of nucleosome unwrapping. Using detailed simulations of DNA and histone proteins, we calculate the tension-dependent free energy surface corresponding to the unwrapping process. The model reproduces quantitatively the forces required to unwrap the nucleosome and reveals the role played by electrostatic interactions during this process. We then demonstrate that histone modifications and DNA sequence can have significant effects on the energies of nucleosome formation. Most notably, we show that histone tails contribute asymmetrically to the stability of the outer and inner turn of nucleosomal DNA and that depending on which histone tails are modified, the tension-dependent response is modulated differently.

Research Organization:
Argonne National Laboratory (ANL), Argonne, IL (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences and Engineering Division; US Department of Commerce; National Institute of Standards and Technology (NIST); National Institutes of Health (NIH) - National Human Genome Research Institute (NHGRI)
Grant/Contract Number:
AC02-06CH11357
OSTI ID:
1332925
Journal Information:
ACS Central Science, Vol. 2, Issue 9; ISSN 2374-7943
Publisher:
American Chemical Society (ACS)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 46 works
Citation information provided by
Web of Science

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Cited By (13)

1CPN: A coarse-grained multi-scale model of chromatin journal June 2019
Critical role of histone tail entropy in nucleosome unwinding journal May 2019
In silico evidence for sequence-dependent nucleosome sliding journal October 2017
Polymer physics across scales: Modeling the multiscale behavior of functional soft materials and biological systems journal December 2019
DNA sliding in nucleosomes via twist defect propagation revealed by molecular simulations journal February 2018
Dynamic and Structural Modeling of the Specificity in Protein-DNA Interactions Guided by Binding Assay and Structure Data posted_content March 2018
Designing nucleosomal force sensors journal May 2017
Free energy profiles for unwrapping the outer superhelical turn of nucleosomal DNA journal March 2018
Dynamic and Structural Modeling of the Specificity in Protein–DNA Interactions Guided by Binding Assay and Structure Data journal May 2018
Dynamics of Chromatin Fibers: Comparison of Monte Carlo Simulations with Force Spectroscopy journal November 2018
Mechanism of Dynamic Binding of Replication Protein A to ssDNA journal September 2020
Eliminating Fitting from the Modeling of Biological Processes journal September 2016
The Free Energy Landscape of Internucleosome Interactions and Its Relation to Chromatin Fiber Structure journal January 2019

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