Dynamics of Chromatin Fibers: Comparison of Monte Carlo Simulations with Force Spectroscopy.

ABSTRACT: To elucidate conformational dynamics of chromatin fibers, we compared available force-spectroscopy measurements with extensive Monte Carlo simulations of nucleosome arrays under external force. Our coarse-grained model of chromatin includes phenomenological energy terms for the DNA-histone adhesion and the internucleosome stacking interactions. We found that the Monte Carlo fiber ensembles simulated with increasing degrees of DNA unwrapping and the stacking energy 8 kT can account for the intricate force-extension response observed experimentally. Our analysis shows that at low external forces (F < 3.0 picoNewtons), the DNA ends in nucleosomes breathe by ∼10 bp. Importantly, under these conditions, the fiber is highly dynamic, exhibiting continuous unstacking-restacking transitions, allowi

SUBMITTER: Norouzi D 

PROVIDER: S-EPMC6225046 | biostudies-literature | 2018 Nov

REPOSITORIES: biostudies-literature