Mechanism of IS200/IS605 family DNA transposases:: Activation and transposon-directed target site selection
Mechanism of IS200/IS605 family DNA transposases:: Activation and transposon-directed target site selection
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DOI：
10.1016/j.cell.2007.12.029
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发表时间：
2008-01-25
期刊：
影响因子：
64.5
通讯作者：
Dyda, Fred
中科院分区：
文献类型：
--
作者：
Barabas, Orsolya;Ronning, Donald R.;Dyda, Fred
已知的最小的DNA转座酶是IS200/IS605家族的转座酶。在这里，我们展示了蛋白质和DNA的相互作用如何激活TnpA，幽门螺杆菌IS608转座酶，用于催化。首先，转座子末端结合引起构象变化，使活性部位内具有催化作用的重要蛋白质残基对齐。随后在左右两端的精确切割，即将转座子从供体部位释放出来的步骤，不涉及特定部位的DNA结合域。相反，切割位点的识别是通过与TnpA结合的亚末端转座子DNA片段进行互补碱基配对来进行的。因此，酶活性部位是由蛋白质和DNA组成的，这让人想起核糖体中蛋白质和RNA的相互依赖。我们的结构结果解释了为什么转座子末端是不对称的，以及转座子是如何选择目标位置进行整合的，它们允许我们为整个转座反应提出一个分子模型。
The smallest known DNA transposases are those from the IS200/IS605 family. Here we show how the interplay of protein and DNA activates TnpA, the Helicobacter pylori IS608 transposase, for catalysis. First, transposon end binding causes a conformational change that aligns catalytically important protein residues within the active site. Subsequent precise cleavage at the left and right ends, the steps that liberate the transposon from its donor site, does not involve a site-specific DNA-binding domain. Rather, cleavage site recognition occurs by complementary base pairing with a TnpA-bound subterminal transposon DNA segment. Thus, the enzyme active site is constructed from elements of both protein and DNA, reminiscent of the interdependence of protein and RNA in the ribosome. Our structural results explain why the transposon ends are asymmetric and how the transposon selects a target site for integration, and they allow us to propose a molecular model for the entire transposition reaction.