Visualization of single Escherichia coli FtsZ filament dynamics with atomic force microscopy
Visualization of single Escherichia coli FtsZ filament dynamics with atomic force microscopy
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DOI：
10.1074/jbc.m503059200
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发表时间：
2005-05-27
影响因子：
4.8
通讯作者：
Vélez, M
中科院分区：
文献类型：
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作者：
Mingorance, J;Tadros, M;Vélez, M
FtsZ是微管蛋白的原核同源蛋白，是一种重要的细胞分裂蛋白。在细胞中，它定位于中心，形成一个在分裂过程中收缩的环。在体外，它以依赖GTP的方式结合和水解GTP并进行聚合。我们利用原子力显微镜研究了缓冲溶液下云母表面FtsZ聚合物的结构和动力学。聚合物是高度动态和灵活的，它们在表面上不断地重新排列。观察到长丝的端到端连接和内部区域的解聚，表明碎片化和再退火可能对FtsZ组装的动力学有重要影响。重构聚合物的形状演变表现出强烈的固有曲线倾向。在不可水解的核苷酸类似物存在或在GDP和AlF3存在下形成的聚合物在结构上相似，但表现出较慢的动态行为。这些结果为最近提出的解释聚合物在溶液中的水动力学行为的单链聚合加环化模型提供了实验证据。
FtsZ, the prokaryotic homologue of tubulin, is an essential cell division protein. In the cell, it localizes at the center, forming a ring that constricts during division. In vitro, it binds and hydrolyzes GTP and polymerizes in a GTP-dependent manner. We have used atomic force microscopy to study the structure and dynamics of FtsZ polymer assembly on a mica surface under buffer solution. The polymers were highly dynamic and flexible, and they continuously rearranged over the surface. End-to-end joining of filaments and depolymerization from internal zones were observed, suggesting that fragmentation and reannealing may contribute significantly to the dynamics of FtsZ assembly. The shape evolution of the restructured polymers manifested a strong inherent tendency to curve. Polymers formed in the presence of non-hydrolyzable nucleotide analogues or in the presence of GDP and AlF3 were structurally similar but showed a slower dynamic behavior. These results provide experimental evidence supporting the model of single-strand polymerization plus cyclization recently proposed to explain the hydrodynamic behavior of the polymers in solution.