Solution Structure of Tandem SH2 Domains from Spt6 Protein and Their Binding to the Phosphorylated RNA Polymerase II C-terminal Domain
Solution Structure of Tandem SH2 Domains from Spt6 Protein and Their Binding to the Phosphorylated RNA Polymerase II C-terminal Domain
复制标题
Spt6 蛋白串联 SH2 结构域的溶液结构及其与磷酸化 RNA 聚合酶 II C 末端结构域的结合
DOI：
10.1074/jbc.m111.252130
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发表时间：
2011-08-19
影响因子：
4.8
通讯作者：
Shi, Yunyu
中科院分区：
文献类型：
--
作者：
Liu, Jianping;Zhang, Jiahai;Shi, Yunyu
Spt6是一个高度保守的转录延伸因子和组蛋白伴侣。它通过识别RNAPII CTD磷酸化的C-末端区域直接结合RNA聚合酶II C-末端结构域（RNAPII CTD）。在本研究中，我们确定了酿酒酵母Spt6的C-末端区域的溶液结构，我们发现Spt6具有两个串联的SH2结构域。结构和系统发育分析表明，第二个SH2结构域在进化上远离经典的SH2结构域，代表了一个新的SH2亚家族，具有一个新的磷酸丝氨酸结合位点。此外，NMR化学位移扰动实验证明串联SH2结构域以毫摩尔结合亲和力识别RNAPII CTD的Tyr（1）、Ser（2）、Ser（5）和Ser（7）磷酸化。串联SH2结构域的结合不同形式的磷酸化RNAPII CTD及其生理相关性的结构基础进行了讨论。我们的研究结果还表明，Spt6可能使用串联SH2结构域模块来感知RNAPII CTD的磷酸化水平。
Spt6 is a highly conserved transcription elongation factor and histone chaperone. It binds directly to the RNA polymerase II C-terminal domain (RNAPII CTD) through its C-terminal region that recognizes RNAPII CTD phosphorylation. In this study, we determined the solution structure of the C-terminal region of Saccharomyces cerevisiae Spt6, and we discovered that Spt6 has two SH2 domains in tandem. Structural and phylogenetic analysis revealed that the second SH2 domain was evolutionarily distant from canonical SH2 domains and represented a novel SH2 subfamily with a novel binding site for phosphoserine. In addition, NMR chemical shift perturbation experiments demonstrated that the tandem SH2 domains recognized Tyr(1), Ser(2), Ser(5), and Ser(7) phosphorylation of RNAPII CTD with millimolar binding affinities. The structural basis for the binding of the tandem SH2 domains to different forms of phosphorylated RNAPII CTD and its physiological relevance are discussed. Our results also suggest that Spt6 may use the tandem SH2 domain module to sense the phosphorylation level of RNAPII CTD.