PDF(Pubmed)
Abstract：
The nucleosome remodeling and deacetylase (NuRD) complex plays a pivotal role in chromatin regulation and transcriptional repression. In mice, methyl-CpG binding domain 3 isoform C (MBD3C) interacts specifically with the histone H3 binding protein WD repeat-containing protein 5 (WDR5) and forms the WDR5-MBD3C/Norde complex. Despite the functional significance of this interaction on embryonic stem cell gene regulation, the molecular mechanism underlying MBD3C recognition by WDR5 remains elusive. Here, we determined the crystal structure of WDR5 in complex with the peptide (residues 40-51) derived from the MBD3C protein at a resolution of 1.9 Å. Structural analysis revealed that MBD3C utilizes a unique binding mode to interact with WDR5, wherein MBD3C Arg43 and Phe47 are involved in recognizing the WDR5-interacting (WIN) site and Tyr191-related B site on the small surface of WDR5, respectively. Notably, the binding induces a ∼91° rotation of WDR5 Tyr191, generating the hydrophobic B site. Furthermore, mutation experiments combined with isothermal titration calorimetry (ITC) assays confirmed the importance of both Arg43 and Phe47 in mediating WDR5 binding affinity. By determining structures of various peptides bound to WDR5, we demonstrated that the WDR5 WIN site and B site can be concurrently recognized by WIN motif peptides containing \'\'Arg-Cies/Ser-Arg-Val-Phe\'\' consensus sequence. Overall, this study reveals the structural basis for the formation of the WDR5-MBD3C subcomplex and provides new insights into the recognition mode of WDR5 for the WIN motif. Moreover, these findings shed light on structural-based designs of WDR5-targeted anti-cancer small molecule inhibitors or peptide-mimic drugs.
摘要：
核小体重塑和脱乙酰酶（NuRD）复合物在染色质调节和转录抑制中起关键作用。在老鼠身上,甲基-CpG结合结构域3同工型C（MBD3C）与组蛋白H3结合蛋白WD含重复序列的蛋白5（WDR5）特异性相互作用，并形成WDR5-MBD3C/NuRD复合物。尽管这种相互作用对胚胎干细胞基因调控具有功能意义，WDR5识别MBD3C的分子机制仍然难以捉摸。这里,我们确定了WDR5与MBD3C蛋白衍生的肽（残基40-51）复合的晶体结构，分辨率为1.9µ。结构分析显示，MBD3C利用独特的结合模式与WDR5相互作用，其中MBD3CArg43和Phe47分别参与识别WDR5小表面上的WDR5相互作用（WIN）位点和Tyr191相关B位点。值得注意的是,该结合诱导WDR5Tyr191~91°旋转，产生疏水B位点。此外，突变实验结合等温滴定量热法(ITC)测定证实了Arg43和Phe47在介导WDR5结合亲和力中的重要性.通过确定与WDR5结合的各种肽的结构，我们证明了WDR5WIN位点和B位点可以同时被含有\'\'Arg-Cys/Ser-Arg-Val-Phe\'共有序列的WIN基序肽识别。总的来说,这项研究揭示了WDR5-MBD3C亚复合物形成的结构基础，并为WDR5对WIN基序的识别模式提供了新的见解。此外，这些发现揭示了WDR5靶向抗癌小分子抑制剂或肽模拟药物的基于结构的设计.
