Bulletin of the American Physical Society
APS March Meeting 2019
Volume 64, Number 2
Monday–Friday, March 4–8, 2019; Boston, Massachusetts
Session S65: Physics of Genome Organization II
11:15 AM–2:15 PM,
Thursday, March 7, 2019
BCEC Room: 260
Sponsoring Units: DBIO DPOLY GSNP
Chair: Alexandre Morozov, Rutgers Univ
Abstract: S65.00012 : Modulation of the DNA accessibility in the nucleosome -- insights from basic physics.*
1:51 PM–2:03 PM
A simplified electrostatic model of the nucleosome reveals that at physiological conditions the complex is extremely stable, but at the same time is close to the phase boundary separating it from the “unwrapped" states where the DNA is accessible. A small drop in the charge (e.g. through acetylation of a lysine) of the globular histone core can significantly lower nucleosome stability, and thus increase DNA accessibility. The finding suggests that charge-altering post-translational modifications in the histone core might be utilized by the cell to modulate accessibility to its DNA at the nucleosome level.
A follow-up, detailed multi-state atomistic model explores virtually all possible charge-altering post-translational modifications (PTMs) in the globular histone core. The model reveals a rich and nuanced picture: the effect of PTMs varies greatly depending on location, including counter-intuitive trends such as decrease of DNA accessibility for some lysine acetylations in the core. A connection to transcription regulation in-vivo is made.
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