Phosphorylation-Coupled Intramolecular Dynamics of Unstructured Regions in Chromatin Remodeler FACT
Phosphorylation-Coupled Intramolecular Dynamics of Unstructured Regions in Chromatin Remodeler FACT
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DOI：
10.1016/j.bpj.2013.04.007
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发表时间：
2013-05-21
影响因子：
3.4
通讯作者：
Tate, Shin-ichi
中科院分区：
文献类型：
--
作者：
Hashimoto, Manami;Kodera, Noriyuki;Tate, Shin-ichi
蛋白质的内在无序区（IDR）是分子生物学中的一个重要课题. IDR的功能意义通常涉及基因调控过程，并与翻译后修饰如磷酸化密切相关。我们以前报道，果蝇促进染色质转录（FACT）蛋白参与染色质重塑包含一个酸性ID片段（AID），其磷酸化调节FACT与核小体的结合。在这里，我们进行了动态原子力显微镜和核磁共振分析，以澄清如何密集磷酸化的AID掩盖高迁移率族结构域（HMG）的DNA结合界面。几乎完整的FACT的动态原子力显微镜显示，一个小球暂时出现，但很快消失在每个移动的尾巴样图像，对应于HMG含IDR。小球的寿命在磷酸化后增加。NMR分析表明，磷酸化诱导没有有序的结构，但增加了AID与HMG的结合位点的数量与相邻的基本段，从而保留了强大的静电分子内的相互作用，即使在DNA的存在下，在FACT。这些数据导致的结论是，核小体结合的抑制作用归因于HMG和磷酸化的IDR之间的相遇的概率增加。
The intrinsically disordered region (IDR) of a protein is an important topic in molecular biology. The functional significance of IDRs typically involves gene-regulation processes and is closely related to posttranslational modifications such as phosphorylation. We previously reported that the Drosophila facilitates chromatin transcription (FACT) protein involved in chromatin remodeling contains an acidic ID fragment (AID) whose phosphorylation modulates FACT binding to nucleosomes. Here, we performed dynamic atomic force microscopy and NMR analyses to clarify how the densely phosphorylated AID masks the DNA binding interface of the high-mobility-group domain (HMG). Dynamic atomic force microscopy of the nearly intact FACT revealed that a small globule temporally appears but quickly vanishes within each mobile tail-like image, corresponding to the HMG-containing IDR. The lifespan of the globule increases upon phosphorylation. NMR analysis indicated that phosphorylation induces no ordered structure but increases the number of binding sites in AID to HMG with an adjacent basic segment, thereby retaining the robust electrostatic intramolecular interaction within FACT even in the presence of DNA. These data lead to the conclusion that the inhibitory effect of nucleosome binding is ascribed to the increase in the probability of encounter between HMG and the phosphorylated IDR.