Affinity, stoichiometry and cooperativity of heterochromatin protein 1 (HP1) binding to nucleosomal arrays
Affinity, stoichiometry and cooperativity of heterochromatin protein 1 (HP1) binding to nucleosomal arrays
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异染色质蛋白 1â(HP1) 与核小体阵列结合的亲和力、化学计量和协同性
DOI：
10.1088/0953-8984/27/6/064110
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
Karsten Rippe
中科院分区：
文献类型：
--
作者：
Vladimir B Teif;Nick Kepper;Klaus Yserentant;Gero Wedemann;Karsten Rippe
异染色质蛋白1（HP1）通过其组蛋白修饰依赖的染色质相互作用参与异染色质的建立和维持。在最近的论文中，在体外测量了HP1与核小体阵列的结合，并解释了最近邻合作结合。这种染色质相互作用的模式可能导致HP 1沿着核小体链扩散。在这里，我们重新分析了以前的数据，通过代表核小体链作为一个一维结合晶格，并显示了如何实验HP1结合等温线可以解释一个更简单的模型，相邻的HP1二聚体之间没有合作的相互作用。基于这些计算和dinucleosomes和核小体链的空间模型，我们提出，结合的化学计量取决于核小体重复长度（NRL），而不是蛋白质之间的相互作用HP 1二聚体。根据我们的计算，与具有短NRL的链相比，具有长DNA接头的更开放的核小体阵列的特征是具有更多的结合位点。此外，我们通过Monte Carlo模拟证明，核小体链的NRL依赖性折叠可以诱导HP 1结合位点的变构变化。因此，HP1染色质的相互作用可以通过改变结合化学计量和结合类型的凝聚（甲基化）和非凝聚（非甲基化）的核小体阵列在HP1二聚体之间的直接相互作用的情况下进行调制。
Heterochromatin protein 1 (HP1) participates in establishing and maintaining heterochromatin via its histone-modification-dependent chromatin interactions. In recent papers HP1 binding to nucleosomal arrays was measured in vitro and interpreted in terms of nearest-neighbour cooperative binding. This mode of chromatin interaction could lead to the spreading of HP1 along the nucleosome chain. Here, we reanalysed previous data by representing the nucleosome chain as a 1D binding lattice and showed how the experimental HP1 binding isotherms can be explained by a simpler model without cooperative interactions between neighboring HP1 dimers. Based on these calculations and spatial models of dinucleosomes and nucleosome chains, we propose that binding stoichiometry depends on the nucleosome repeat length (NRL) rather than protein interactions between HP1 dimers. According to our calculations, more open nucleosome arrays with long DNA linkers are characterized by a larger number of binding sites in comparison to chains with a short NRL. Furthermore, we demonstrate by Monte Carlo simulations that the NRL dependent folding of the nucleosome chain can induce allosteric changes of HP1 binding sites. Thus, HP1 chromatin interactions can be modulated by the change of binding stoichiometry and the type of binding to condensed (methylated) and non-condensed (unmethylated) nucleosome arrays in the absence of direct interactions between HP1 dimers.
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影响因子：
2
作者：
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通讯作者：
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DOI：
10.1016/j.bbrc.2011.08.059
发表时间：
2011-09-23
影响因子：
3.1
作者：
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影响因子：
3.4
作者：
Ruazvan V. Chereji;A. Morozov
通讯作者：
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