Das Subhra Kanti, Kumar Ashok, Hao Fanfan, DiPiazza Amber R Cutter, Lee Tae-Hee, Hayes Jeffrey J
bioRxiv. 2023 May 12:2023.05.11.540398. doi: 10.1101/2023.05.11.540398.
Despite their importance, how linker histone H1s interact in chromatin and especially how the highly positively charged and intrinsically disordered H1 C-terminal domain (CTD) binds and stabilizes nucleosomes and higher-order chromatin structures remains unclear. Using single-molecule FRET we found that about half of the H1 CTDs in H1-nucleosome complexes exhibit well-defined FRET values indicative of distinct, static conformations, while the remainder of the population exhibits dynamically changing values, similar to that observed for H1 in the absence of nucleosomes. We also find that the first 30 residues of the CTD participate in relatively localized interactions with the first ∼20 bp of linker DNA, and that two separate regions in the CTD contribute to H1-dependent organization of linker DNA, consistent with some non-random CTD-linker DNA interactions. Finally, our data show that acetylation mimetics within the histone H3 tail induce decondensation and enhanced dynamics of the nucleosome-bound H1 CTD. (148 words).
尽管连接组蛋白H1很重要，但它们在染色质中如何相互作用，特别是高度带正电荷且内在无序的H1 C末端结构域（CTD）如何结合并稳定核小体及高阶染色质结构仍不清楚。利用单分子荧光共振能量转移技术，我们发现H1-核小体复合物中约一半的H1 CTD表现出明确的荧光共振能量转移值，表明其具有独特的静态构象，而其余部分则表现出动态变化的值，这与在没有核小体的情况下观察到的H1相似。我们还发现CTD的前30个残基与连接DNA的前约20个碱基对参与相对局部的相互作用，并且CTD中的两个独立区域有助于连接DNA的H1依赖性组织，这与一些非随机的CTD-连接DNA相互作用一致。最后，我们的数据表明组蛋白H3尾巴内的乙酰化模拟物会诱导核小体结合的H1 CTD发生解聚并增强其动态变化。 （148字）
