Fig. 1

CENP-A nucleosome displays a tightening of the histone core upon lysine acetylation. a The starting structure of the acetyl CENP-A NCP is shown with CENP-A and H4 in red, CENP-A′ and H4′ in blue, and H2A/H2B monomers in tan. The pseudo-dyad is shown by a dotted black line and marked as PD. Overlay’s shown K124ac, K79ac, and CENP-A R80 and the L1 loop in more detail. This structure is after 1-μs simulation of CENP-A, and the production of the starting structure is described (“Methods” section). b Contact analysis showing CENP-A (CpA) to CENP-A′(CpA′) interface at the 4-helix bundle. The contact cutoff between Cα atoms was set to 8 Å. An increase in contacts is shown upon acetylation—a decrease in the 4-helix bundle interface distance. A value of 1, white, shows a contact formed over all simulation time steps and 0, black, never. In the acetyl NCP residues H115, A116, and G117 more frequently form contacts located in the hinge region of the 4-helix bundle. The C-terminus, specifically CENP-A′ residues I132, R133, and G134, forms increased contacts with CENP-A G134. c The center of mass (COM) of dimers was measured over all time steps, and the resulting distributions are shown for CENP-A/H4 to CENP-A′/H4′, the acetylated histones. The acetylated system, shown in blue, shows a decrease in variance and distance between the two dimer COMs