The second-sphere residue T263 is important for the function and catalytic activity of PTP1B via interaction with the WPD-loop.
The second-sphere residue T263 is important for the function and catalytic activity of PTP1B via interaction with the WPD-loop.
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第二球残基 T263 通过与 WPD 环相互作用，对于 PTP1B 的功能和催化活性非常重要。
DOI：
10.1016/j.biocel.2014.10.004
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发表时间：
2014-12
期刊：
影响因子：
--
通讯作者：
Sun, Jin-Peng
中科院分区：
文献类型：
--
作者：
Xiao, Peng;Wang, Xiao;Wang, Hong-Mei;Fu, Xiao-Lei;Cui, Fu-Ai;Yu, Xiao;Wen, Shi-Shuai;Bi, Wen-Xiang;Sun, Jin-Peng
蛋白酪氨酸磷酸酶具有多种底物特异性和内在活性，为精细调节磷酸化网络以精确调节细胞信号转导奠定了基础。所有经典的PTP都具有共同的催化机制，其活性中心第一球中的重要催化残基已被很好地表征。然而，很少有人注意到第二球残基，这是潜在的重要定义的内在活性和底物特异性的PTP。在这里，我们发现，一个保守的第二球残基，Thr 263，位于表面Q环是重要的功能和活动的PTP。以PTP 1B为研究模型，我们发现Thr 263突变削弱了PTP 1B在胰岛素信号转导中的负调控作用。利用稳态动力学、Brønsted分析和pH依赖性在pNPP或磷酸肽底物存在下的详细机理研究表明，Thr 263是催化过程中稳定离去基团所必需的。进一步的晶体学研究和结构比较表明，Thr 263通过T263：F182/Y/H相互作用对WPD环的调节来调节一般的酸功能，这在32个经典PTP中的26个中是保守的。此外，胰岛素受体的Thr 263和Arg 1159之间的疏水相互作用有助于PTP 1B的底物特异性。两者合计，我们的研究结果表明，第二球残基Thr 263在PTP催化的一般作用。我们的研究结果表明，PTP活性位点的第二球残基可能在正常和疾病状态下PTP介导的功能中起重要作用。
Protein tyrosine phosphatases have diverse substrate specificities and intrinsic activities that lay the foundations for the fine-tuning of a phosphorylation network to precisely regulate cellular signal transduction. All classical PTPs share common catalytic mechanisms, and the important catalytic residues in the first sphere of their active sites have been well characterized. However, little attention has been paid to the second-sphere residues that are potentially important in defining the intrinsic activity and substrate specificity of PTPs. Here, we find that a conserved second-sphere residue, Thr263, located in the surface Q-loop is important for both the function and activity of PTPs. Using PTP1B as a study model, we found that mutations of Thr263 impaired the negative regulation role of PTP1B in insulin signaling. A detailed mechanistic study utilizing steady-state kinetics, Brønsted analysis and pH dependence in the presence ofpNPP or phosphopeptide substrates revealed that Thr263 is required for the stabilization of the leaving group during catalysis. Further crystallographic studies and structural comparison revealed that Thr263 regulates the general acid function through modulation of the WPD-loop by the T263:F182/Y/H interaction pair, which is conserved in 26 out of 32 classical PTPs. In addition, the hydrophobic interaction between Thr263 and Arg1159 of the insulin receptor contributes to the substrate specificity of PTP1B. Taken together, our findings demonstrate the general role of the second-sphere residue Thr263 in PTP catalysis. Our findings suggest that the second sphere residues of PTP active site may play important roles in PTP-mediated function in both normal and diseased states.
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DOI：
10.1074/jbc.273.10.5484
发表时间：
1998-03
期刊：
The Journal of Biological Chemistry
影响因子：
--
作者：
Y. Zhao;Li Wu;S. Noh;K. Guan;Zhon-Yin Zhang
通讯作者：
Y. Zhao;Li Wu;S. Noh;K. Guan;Zhon-Yin Zhang
影响因子：
3.4
作者：
Wei-qing Wang;Jin-Peng Sun;Zhon-Yin Zhang
通讯作者：
Wei-qing Wang;Jin-Peng Sun;Zhon-Yin Zhang
影响因子：
2.9
作者：
Z. Zhang;B. Palfey;Li Wu;Y. Zhao
通讯作者：
Z. Zhang;B. Palfey;Li Wu;Y. Zhao
影响因子：
4.8
作者：
Sun, JP;Fedorov, AA;Zhang, ZY
通讯作者：
Zhang, ZY
影响因子：
56.9
作者：
GUAN, KL;DIXON, JE
通讯作者：
DIXON, JE