摘要：SummaryThe nucleosome core particle (NCP) comprises a histone octamer, wrapped around by ∼146-bp DNA, while the nucleosome additionally contains linker DNA. We previously showed that, in the nucleosome, H4 N-tail acetylation enhances H3 N-tail acetylation by altering their mutual dynamics. Here, we have evaluated the roles of linker DNA and/or linker histone on H3 N-tail dynamics and acetylation by using the NCP and the chromatosome (i.e., linker histone H1.4-bound nucleosome). In contrast to the nucleosome, H3 N-tail acetylation and dynamics are greatly suppressed in the NCP regardless of H4 N-tail acetylation because the H3 N-tail is strongly bound between two DNA gyres. In the chromatosome, the asymmetric H3 N-tail adopts two conformations: one contacts two DNA gyres, as in the NCP; and one contacts linker DNA, as in the nucleosome. However, the rate of H3 N-tail acetylation is similar in the chromatosome and nucleosome. Thus, linker DNA and linker histone both regulate H3-tail dynamics and acetylation.Graphical abstractDisplay OmittedHighlights•H3 N-tail, restricted to two DNA gyres in NCP, binds to linker DNA in nucleosome•H4 acetylation affects the H3 N-tail dynamics in nucleosome but not in NCP•Gcn5 efficiently acetylates H3 N-tail in H4-acetylated nucleosome but not in NCP•In chromatosome, H3 N-tail adopts NCP-like and nucleosome-like conformationsMolecular biology; Cell biology; Structural biology
