Elastic origin of chiral selection in DNA wrapping.
We investigated the mechanism that underlies the chiral selection on the direction of wrapping of DNA around a nucleosome core particle. A coarse-grained model for the formation of a nucleosome is introduced, in which DNA is treated as a semiflexible polymer and the histone core is modeled by a spherical particle. Asymmetric coupling between bending and twisting is incorporated into the model DNA, which is expected from the double-stranded helical structure of DNA. We show that the tendency of DNA to twist in a left-handed manner upon bending gives rise to the selective left-handed wrapping, provided that the size of the core particle is chosen appropriately. This result suggests the critical importance of the chiral asymmetry inherent in the bending-twisting elasticity of DNA as well as the size of the core in determining the handedness of wrapping in nucleosome formation.
Yanao
Tomohiro
T
Fukui Institute for Fundamental Chemistry, Kyoto University, Kyoto, Japan.
Yoshikawa
Kenichi
K
D003198:Computer Simulation; D004247:DNA / Q000737:chemistry* / Q000648:ultrastructure*; D004548:Elasticity; D007536:Isomerism; D008956:Models, Chemical; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D009707:Nucleosomes / Q000737:chemistry* / Q000648:ultrastructure*
D009707:Nucleosomes; D004247:DNA