An unexpected binding mode for a Pol II CTD peptide phosphorylated at Ser7 in the active site of the CTD phosphatase Ssu72.
An unexpected binding mode for a Pol II CTD peptide phosphorylated at Ser7 in the active site of the CTD phosphatase Ssu72.
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DOI：
10.1101/gad.198853.112
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发表时间：
2012-10
影响因子：
10.5
通讯作者：
K. Xiang;J. Manley;L. Tong
中科院分区：
文献类型：
--
作者：
K. Xiang;J. Manley;L. Tong
Ssu72 是一种 RNA 聚合酶 II C 末端结构域 (CTD) 磷酸 Ser5 (pSer5) 磷酸酶，最近报道也具有 pSer7 磷酸酶活性。我们在此报告了人 symplekin N 端结构域、人 Ssu72 和 10 聚体 pSer7 CTD 肽的三元复合物的晶体结构。令人惊讶的是，与 pSer5 肽相比，该肽结合在 Ssu72 活性位点，其主链方向相反。 Ssu72 的 pSer7 磷酸酶活性比其针对肽底物的 pSer5 磷酸酶活性低约 4000 倍，这与结构观察结果一致。
Ssu72, an RNA polymerase II C-terminal domain (CTD) phospho-Ser5 (pSer5) phosphatase, was recently reported to have pSer7 phosphatase activity as well. We report here the crystal structure of a ternary complex of the N-terminal domain of human symplekin, human Ssu72, and a 10-mer pSer7 CTD peptide. Surprisingly, the peptide is bound in the Ssu72 active site with its backbone running in the opposite direction compared with a pSer5 peptide. The pSer7 phosphatase activity of Ssu72 is ∼4000-fold lower than its pSer5 phosphatase activity toward a peptide substrate, consistent with the structural observations.