Stabilization of G Domain Conformations in the tRNA-modifying MnmE-GidA Complex Observed with Double Electron Electron Resonance Spectroscopy
Stabilization of G Domain Conformations in the tRNA-modifying MnmE-GidA Complex Observed with Double Electron Electron Resonance Spectroscopy
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DOI：
10.1074/jbc.m109.096131
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发表时间：
2010-05-28
影响因子：
4.8
通讯作者：
Klare, Johann P.
中科院分区：
文献类型：
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作者：
Boehme, Sabine;Meyer, Simon;Klare, Johann P.
MnmE是一种在细菌和真核生物之间保守的gtp结合蛋白。它是一种二聚体三结构域蛋白，其中两个G结构域必须相互靠近才能激活钾刺激的GTPase反应。与GidA一起，在异四聚体α (2) β(2)复合体中，它参与了特定trna第一个反密码子位置的摆动尿苷碱基U34的修饰。在这里，我们使用各种自旋标记的MnmE突变体和EPR光谱显示，GidA结合诱导了MnmE的大构象和动态变化。它通过以钾不依赖的方式稳定gtp结合构象来刺激gtp酶反应。令人惊讶的是，GidA结合不仅影响gtp结合构象，还影响gtp结合构象。因此，GidA是一种新型的G蛋白二聚化激活调节剂。
MnmE is a GTP-binding protein conserved between bacteria and eukarya. It is a dimeric three-domain protein where the two G domains have to approach each other for activation of the potassium-stimulated GTPase reaction. Together with GidA, in a heterotetrameric alpha(2)beta(2) complex, it is involved in the modification of the wobble uridine base U34 of the first anticodon position of particular tRNAs. Here we show, using various spin-labeled MnmE mutants and EPR spectroscopy, that GidA binding induces large conformational and dynamic changes in MnmE. It stimulates the GTPase reaction by stabilizing the GTP-bound conformation in a potassium-independent manner. Surprisingly, GidA binding influences not only the GTP-but also the GDP-bound conformation. Thus GidA is a new type of regulator for a G protein activated by dimerization.