Zandian Mohamad, Gonzalez Salguero Nicole, Shannon Matthew D, Purusottam Rudra N, Theint Theint, Poirier Michael G, Jaroniec Christopher P
Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States.
Department of Physics, The Ohio State University, Columbus, Ohio 43210, United States.
J Phys Chem Lett. 2021 Jul 8;12(26):6174-6181. doi: 10.1021/acs.jpclett.1c01187. Epub 2021 Jun 29.
Chromatin is a supramolecular DNA-protein complex that compacts eukaryotic genomes and regulates their accessibility and functions. Dynamically disordered histone H3 N-terminal tails are among key chromatin regulatory components. Here, we used high-resolution-magic-angle-spinning NMR measurements of backbone amide N spin relaxation rates to investigate, with residue-specific detail, the dynamics and interactions of H3 tails in recombinant C,N-enriched nucleosome arrays containing 15, 30, or 60 bp linker DNA between the nucleosome repeats. These measurements were compared to analogous data available for mononucleosomes devoid of linker DNA or containing two 20 bp DNA overhangs. The H3 tail dynamics in nucleosome arrays were found to be considerably attenuated compared with nucleosomes with or without linker DNA due to transient electrostatic interactions with the linker DNA segments and the structured chromatin environment. Remarkably, however, the H3 tail dynamics were not modulated by the specific linker DNA length within the 15-60 bp range investigated here.
染色质是一种超分子DNA-蛋白质复合物，它压缩真核生物基因组并调节其可及性和功能。动态无序的组蛋白H3 N端尾巴是关键的染色质调节成分之一。在这里，我们使用 backbone amide N 自旋弛豫率的高分辨率魔角旋转核磁共振测量，以残基特异性细节研究了在核小体重复序列之间含有15、30或60 bp连接子DNA的重组C、N富集核小体阵列中H3尾巴的动力学和相互作用。这些测量结果与不含连接子DNA或含有两个20 bp DNA突出端的单核小体的类似数据进行了比较。由于与连接子DNA片段和结构化染色质环境的瞬时静电相互作用，发现核小体阵列中的H3尾巴动力学与有或没有连接子DNA的核小体相比有相当程度的减弱。然而，值得注意的是，在这里研究的15-60 bp范围内，H3尾巴动力学并未受到特定连接子DNA长度的调节。
