Conformational dynamics of the TTD-PHD histone reader module of the UHRF1 epigenetic regulator reveals multiple histone-binding states, allosteric regulation, and druggability.
Conformational dynamics of the TTD-PHD histone reader module of the UHRF1 epigenetic regulator reveals multiple histone-binding states, allosteric regulation, and druggability.
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DOI：
10.1074/jbc.m117.799700
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发表时间：
2017-12-22
期刊：
影响因子：
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通讯作者：
Arrowsmith CH
中科院分区：
文献类型：
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作者：
Houliston RS;Lemak A;Iqbal A;Ivanochko D;Duan S;Kaustov L;Ong MS;Fan L;Senisterra G;Brown PJ;Wang YX;Arrowsmith CH
UHRF 1是细胞分裂过程中表观遗传DNA甲基化模式遗传的关键介质，并且是癌症治疗的假定靶点。最近的研究表明，结构域间的相互作用严重影响UHRF 1的染色质结合特性，包括其组蛋白结合的变构调节。在这里，使用一个综合的方法，结合小角X射线散射，NMR光谱，和分子动力学模拟，我们的特点是动态的串联都铎结构域植物同源结构域（TTD-PHD）组蛋白阅读器模块，包括其20个残基的域间连接器。我们发现，载脂蛋白TTD-PHD模块在溶液中包括一个动态的整体构象，其中约有一半是紧凑的构象，与连接器躺在TTD肽结合槽。这些紧凑的构象适合于协作的、高亲和力的组蛋白结合。在其余的构象中，连接体的位置是不稳定的，读者采用了扩展和紧凑的状态。使用小分子片段筛选方法，我们确定了一种化合物，4-苄基哌啶-1-甲脒，其结合TTD沟，与接头结合竞争，并促进开放的TTD-PHD构象，其在H3 K9 me 3结合时效率较低。我们的工作揭示了一种机制，通过这种机制，动态TTD-PHD模块可以用小分子变构靶向，以调节其组蛋白阅读器功能，用于治疗或实验目的。
UHRF1 is a key mediator of inheritance of epigenetic DNA methylation patterns during cell division and is a putative target for cancer therapy. Recent studies indicate that interdomain interactions critically influence UHRF1's chromatin-binding properties, including allosteric regulation of its histone binding. Here, using an integrative approach that combines small angle X-ray scattering, NMR spectroscopy, and molecular dynamics simulations, we characterized the dynamics of the tandem tudor domain–plant homeodomain (TTD–PHD) histone reader module, including its 20-residue interdomain linker. We found that the apo TTD–PHD module in solution comprises a dynamic ensemble of conformers, approximately half of which are compact conformations, with the linker lying in the TTD peptide–binding groove. These compact conformations are amenable to cooperative, high-affinity histone binding. In the remaining conformations, the linker position was in flux, and the reader adopted both extended and compact states. Using a small-molecule fragment screening approach, we identified a compound, 4-benzylpiperidine-1-carboximidamide, that binds to the TTD groove, competes with linker binding, and promotes open TTD–PHD conformations that are less efficient at H3K9me3 binding. Our work reveals a mechanism by which the dynamic TTD–PHD module can be allosterically targeted with small molecules to modulate its histone reader function for therapeutic or experimental purposes.