@misc{oai:repo.qst.go.jp:00079043,
 author = {Ishida, Hisashi and Kono, Hidetoshi and Ishida, Hisashi and Kono, Hidetoshi},
 month = {Feb},
 note = {Torsional stress has a significant impact on the structure and stability of the nucleosome.  RNA polymerase imposes torsional stress on the DNA in chromatin and unwraps the DNA from the nucleosome to access the genetic information encoded in the DNA.  Some chromatin Remodelers are thought to change nucleosome positioning by adding torsional stress on DNA. To understand how such torsional stress affects the stability of the nucleosome, we examined the unwraping of the outer superhelical turn of the nucleosomal DNA under positive or negative torsional stress with all-atom molecular dynamics simulations.  The free energies for unwrapping the DNA indicate that positive stress that overtwists DNA facilitates asymmetric unwrapping of the DNA while negative stress that undertwists DNA does not.  Under positive stress, DNA was straightened and rigid, which facilitated a large-scale asymmetric unwrapping of the DNA without a large extension of two DNA.In the structure, one end of the DNA was disconnected from H3 and H2A/H2B while the other end of the DNA stably remained wrapped.  Under negative stress, the DNA became more bendable and flexible, which facilitated the binding of the unwrapped DNA to the octamer in a stable state.  Our results suggest that the stability of individual nucleosomes in the chromatin can be changed by torsional stress, thereby DNA accessibility of regulatory proteins can be produced to maintain gene
expression without large conformational changes even in heterochromatin., Biophysical Society Annual Meeting 2020},
 title = {Positive torsional stress on DNA enhances unwrapping of nucleosomal DNA},
 year = {2020}
}