Fig. 4

Ala57 allows the mobility of the H3mm7 nucleosome. a T32I and S57A are only the differences between H3.3 and H3mm7. N-terminals of the amino acid sequence of H3.3 and H3mm7 are shown in the illustration of the secondary structure. b High-resolution crystal structure of an H3mm7-containing nucleosome shows the loss of interaction between H3.3S57 and H4R40 in the H3mm7 nucleosome. An overview of the crystal structure of the H3mm7-containing nucleosome (left) and the comparative view around S57 in H3.3 and A57 in H3mm7 (right). c H3mm7 nucleosomes were dissociated at a concentration of 600 mM NaCl. The salt-titration assay of H3mm7, H3.3, and the mutant (H3.3S57A and T32I) containing nucleosomes is shown. The positions of the bands that correspond with the intact nucleosome core particle and naked DNA are indicated on the right. d H3.3S57A and H3mm7 dissociated from the H2A:H2B dimer faster than the other H3 variant-containing nucleosomes. Thermal stability assay of H3mm7, H3.3, and the point mutants H3.3T32I and H3.3S57A. The lines show the fluorescent intensity that indicates nucleosome dissociation at each temperature. The error bars are ± 1 SD (n = 4). e H3mm7 and H3.3S57A showed a fast histone turnover. FRAP analysis of nucleosomes containing GFP-fused H3mm7, H3.3, and the point mutants. Representative confocal images of FRAP analysis in each H3 variant nucleosome is shown on the left. Plot of average GFP fluorescent recovery rate at each time point after photobleaching is shown on the right. The error bars are ± 1 SD. The number of replicates is indicated in parentheses