Structure and Ligand Binding of the Extended Tudor Domain of D. melanogaster Tudor-SN
Structure and Ligand Binding of the Extended Tudor Domain of D. melanogaster Tudor-SN
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DOI：
10.1016/j.jmb.2009.02.018
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发表时间：
2009-04-10
影响因子：
5.6
通讯作者：
Sattler, Michael
中科院分区：
文献类型：
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作者：
Friberg, Anders;Corsini, Lorenzo;Sattler, Michael
Tudor-SN蛋白(P100，SND1)参与了多种细胞过程，如转录、编辑双链RNA的加工和剪接调控。这些功能的分子细节并不为人所知。Tudor结构域此前已被证明与甲基化配体结合，如甲基化赖氨酸和精氨酸。有人认为，Tudor-SN在剪接中的作用可能涉及与这种甲基化的配体或剪接体SnRNA的甲基化的5‘端结合。在这里，我们报告了果蝇Tudor-SN的扩展Tudor结构域的晶体结构，分辨率为2.1埃。核磁共振二次化学位移、弛豫数据和剩余偶极耦合表明，溶液和晶体结构相似。用核磁共振研究了不同配体的结合情况。结合部位和亲和力由化学位移微扰表征。我们发现，Tudor结构域的芳香族笼子与含有对称二甲基精氨酸(SBMA)的多肽以微摩尔亲和力特异性结合，而含有非甲基化精氨酸的多肽没有表现出显著的化学位移扰动。Tudor-SN优先识别SDMA而不是不对称二甲基精氨酸(ADMA)。相反，两个具有不同甲基化模式的5‘帽类似物，以及单甲基、双甲基和三甲基赖氨酸，没有结合。我们的数据表明，Tudor-SN的Tudor结构域特异性地识别含有SDMA的配体。Tudor-SN的芳香笼与运动神经元存活蛋白Tudor结构域中的芳香笼非常相似，也识别SDMA多肽，表明这个甲基化标记具有保守的结合基序。在剪接体Sm蛋白的C末端识别SDMA表明Tudor-SN在剪接调控过程中可能如何与小的核核糖核蛋白颗粒相互作用。(C)2009爱思唯尔有限公司。保留所有权利。
The Tudor-SN protein (p100, SND1) has been implicated in a variety of cellular processes, Such as transcription, processing of edited double-stranded RNA, and splicing regulation. Molecular details of these functions are not vet understood. Tudor domains have previously been shown to bind methylated ligands, such as methylated lysines and arginines. It has been suggested that the role of TUdor-SN in splicing may involve binding to such methylated ligands or to the methylated 5' cap of spliceosomal snRNAs. Here, we report the crystal structure of the extended Tudor domain of Tudor-SN from Drosophila melanogaster to a resolution of 2.1 angstrom. NMR secondary chemical shifts, relaxation data, and residual dipolar Couplings indicate that the solution and Crystal Structures are similar. Binding of various ligands was investigated by NMR. Binding sites and affinities were characterized by chemical shift perturbations. We show that the aromatic cage of the Tudor domain specifically binds a peptide containing symmetrically dimethylated arginines (sbMA) with micromolar affinity, while the same peptide comprising nonmethylated arginines does not show significant chemical shift perturbations. Tudor-SN preferentially recognizes sDMA over asymmetrically dimethylated arginine (aDMA). In contrast, two 5' cap analogues with different methylation patterns, as well as mono-, di-, and trimethyllysines, show no binding. Our data demonstrate that the Tudor domain of Tudor-SN specifically recognizes sDMA-containing ligands. The aromatic cage of TUdor-SN is very similar to the one in the Tudor domain of the survival of motor neuron protein, which also recognizes sDMA peptides, indicating a conserved binding motif for this methylation mark. Recognition of sDMA in the C-terminal tails of spliceosomal Sm proteins suggests how Tudor-SN may interact with small nuclear ribonucleoprotein particles during the regulation of splicing. (C) 2009 Elsevier Ltd. All rights reserved.