Structural characterization of H3K56Q nucleosomes and nucleosomal arrays
Structural characterization of H3K56Q nucleosomes and nucleosomal arrays
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DOI：
10.1016/j.bbagrm.2010.01.009
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发表时间：
2010-05-01
影响因子：
4.7
通讯作者：
Luger, Karolin
中科院分区：
文献类型：
--
作者：
Watanabe, Shinya;Resch, Michael;Luger, Karolin
组蛋白的翻译后修饰是调控DNA可及性的关键机制。组蛋白H3中的乙酰化赖氨酸56与复制和DNA修复过程中的核小体组装有关，因此可能在含有核小体的染色质区域中占主导地位。在这里，我们通过x射线晶体学显示H3赖氨酸56突变为谷氨酰胺（模拟乙酰化）或谷氨酸（引起电荷反转）对核小体的结构没有可检测到的影响。在高阶染色质结构水平上，无论核小体密度如何，K到Q的替换对顺式模式核小体阵列的折叠没有影响。相反，对于含有核小体无区的突变H3赖氨酸56阵列，可以选择性地观察到反式阵列-阵列相互作用的缺陷（“寡聚化”）。我们的数据表明，H3K56乙酰化是一种分子机制，用于保持染色质无核小体区域可进入DNA复制和修复机制。(C) 2010 Elsevier B.V.版权所有
The post-translational modification of histones is a key mechanism for the modulation of DNA accessibility. Acetylated lysine 56 in histone H3 is associated with nucleosome assembly during replication and DNA repair, and is thus likely to predominate in regions of chromatin containing nucleosome-free regions. Here we show by X-ray crystallography that mutation of H3 lysine 56 to glutamine (to mimic acetylation) or glutamate (to cause a charge reversal) has no detectable effects on the structure of the nucleosome. At the level of higher order chromatin structure, the K to Q substitution has no effect on the folding of model nucleosomal arrays in cis, regardless of the degree of nucleosome density. In contrast, defects in array-array interactions in trans ('oligomerization') are selectively observed for mutant H3 lysine 56 arrays that contain nucleosome-free regions. Our data suggests that H3K56 acetylation is one of the molecular mechanisms employed to keep chromatin with nucleosome-free regions accessible to the DNA replication and repair machinery. (C) 2010 Elsevier B.V. All rights reserved.