Figure 1.

Chromatin model and fiber systems. (a) Our mesoscale model building block, which consists of linker DNA beads, a rigid nucleosome core with discrete charges, flexible histone tail beads, and flexible LH beads. (b) Starting configurations for four chromatin fiber systems studied with varying levels of acetylation are shown. From left to right: wild-type (WT) system, Alternating Construct 1 (AC₁) system consisting of alternating WT (blue) and acetylated regions (magenta or pink) with 25 nucleosome segments, Alternating Construct 2 (AC₂) with 10 nucleosome segments, and the all-acetylated control (red). Histone tails are not rendered here for clarity. To see this figure in color, go online.