FtsZ fiber bundling is triggered by a conformational change in bound GTP
FtsZ fiber bundling is triggered by a conformational change in bound GTP
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DOI：
10.1074/jbc.m404944200
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发表时间：
2004-11-19
影响因子：
4.8
通讯作者：
Addinall, SG
中科院分区：
文献类型：
--
作者：
Marrington, R;Small, E;Addinall, SG
由必需的FtsZ蛋白形成的聚合物在大多数原核生物的胞质分裂中起着至关重要的作用。广泛预测这些FtsZ聚合物之间形成束或片的横向关联对于FtsZ在体内的功能极其重要。我们已经进行了研究，在体外的FtsZ聚合物的形成和捆绑使用线性二色性（LD），以评估聚合物的结构特性。我们证明了原理验证实验表明，LD可以作为一种技术，遵循FtsZ聚合，我们提出了FtsZ聚合物的LD光谱。我们随后的检查FtsZ聚合物成束诱导的钙揭示了大量增加的LD信号指示增加的聚合物长度和刚度。我们还检测到与捆绑相关的鸟嘌呤部分的特定构象变化，而聚合物内的FtsZ单体的构象和构型基本保持不变。我们表明，其他二价阳离子可以诱导这种构象变化FtsZ结合GTP与聚合物捆绑一致。因此，我们目前的"翻转"的鸟嘌呤部分FtsZ结合GTP作为一种机制，解释之间的联系，降低GTdR活性，增加聚合物的稳定性，和聚合物捆绑。
Polymer formation by the essential FtsZ protein plays a crucial role in the cytokinesis of most prokaryotes. Lateral associations between these FtsZ polymers to form bundles or sheets are widely predicted to be extremely important for FtsZ function in vivo. We have carried out a study in vitro of FtsZ polymer formation and bundling using linear dichroism (LD) to assess structural properties of the polymers. We demonstrate proof-of-principle experiments to show that LD can be used as a technique to follow FtsZ polymerization, and we present the LD spectra of FtsZ polymers. Our subsequent examination of FtsZ polymer bundling induced by calcium reveals a substantial increase in the LD signal indicative of increased polymer length and rigidity. We also detect a specific conformational change in the guanine moiety associated with bundling, whereas the conformation and configuration of the FtsZ monomers within the polymer remain largely unchanged. We demonstrate that other divalent cations can induce this conformational change in FtsZ-bound GTP coincident with polymer bundling. Therefore, we present "flipping" of the guanine moiety in FtsZ-bound GTP as a mechanism that explains the link between reduced GTPase activity, increased polymer stability, and polymer bundling.