Structure of Tctex-1 and its interaction with cytoplasmic dynein intermediate chain
Structure of Tctex-1 and its interaction with cytoplasmic dynein intermediate chain
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DOI：
10.1074/jbc.m011358200
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发表时间：
2001-04-27
影响因子：
4.8
通讯作者：
Zhang, MJ
中科院分区：
文献类型：
--
作者：
Mok, YK;Lo, KWH;Zhang, MJ
负端微管马达细胞质动力蛋白含有许多低分子量轻链，包括14 kDa的Tctex-1。Tctex-1在动力蛋白复合物中的组装及其功能在很大程度上是未知的。使用部分氘代，N-15，C-13标记的蛋白质样品和横向弛豫优化的NMR光谱技术，Tctex-1的二级结构和整体拓扑结构的基础上的骨干核Overhauser效应模式和蛋白质的化学位移值确定。数据显示Tctex-1采用与马达复合物的8-kDa轻链（DLC 8）的结构非常相似的结构，尽管这两条轻链没有氨基酸序列同源性。我们进一步证明Tctex-1直接结合动力蛋白的中间链（DIC），DIC上的Tctex-1结合位点被映射到紧接DIG的第二选择性剪接位点之后的19个残基片段。用DIG衍生的肽滴定Tctex-1，该肽含有在各种Tctex-1靶蛋白中发现的共有序列R/KR/KXYR/K，表明Tctex-1以类似于DLC 8的方式结合其靶。在这项研究中提出的实验结果表明，Tctex-1很可能是一个特定的货物适配器的动力蛋白运动复合体。
The minus-ended microtubule motor cytoplasmic dynein contains a number of low molecular weight light chains including the 14-kDa Tctex-1. The assembly of Tctex-1 in the dynein complex and its function are largely unknown. Using partially deuterated, N-15,C-13-labeled protein samples and transverse relaxation-optimized NMR spectroscopic techniques, the secondary structure and overall topology of Tctex-1 were determined based on the backbone nuclear Overhauser effect pattern and the chemical shift values of the protein. The data showed that Tctex-1 adopts a structure remarkably similar to that of the 8-kDa light chain of the motor complex (DLC8), although the two light chains share no amino acid sequence homology, We further demonstrated that Tctex-1 binds directly to the intermediate chain (DIC) of dynein, The Tctex-1 binding site on DIC was mapped to a 19-residue fragment immediately following the second alternative splicing site of DIG. Titration of Tctex-1 with a peptide derived from DIG, which contains a consensus sequence R/KR/KXYR/K found in various Tctex-1 target proteins, indicated that Tctex-1 binds to its targets in a manner similar to that of DLC8. The experimental results presented in this study suggest that Tctex-1 is likely to be a specific cargo adaptor for the dynein motor complex.