Bacterial cell division protein FtsZ assembles into protofilament sheets and minirings, structural homologs of tubulin polymers
Bacterial cell division protein FtsZ assembles into protofilament sheets and minirings, structural homologs of tubulin polymers
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DOI：
10.1073/pnas.93.1.519
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发表时间：
1996-01-09
影响因子：
11.1
通讯作者：
Bramhill, D
中科院分区：
文献类型：
--
作者：
Erickson, HP;Taylor, DW;Bramhill, D
细菌细胞分裂蛋白FtsZ是微管蛋白的同源物，但尚未确定FtsZ聚合物是否与微管晶格在结构上相关。在本研究中，我们获得了两种FtsZ聚合物的高分辨率电子显微图，它们与微管蛋白聚合物具有显着的相似性。第一个是二维原丝片，其晶格与微管壁非常相似。第二种是采矿，由单个原丝组成。FtsZ是一种急剧弯曲的平面构象，与微管分解后形成的微管环非常相似，但直径约为微管的一半，这表明弯曲构象发生在每个FtsZ亚基上，但在微管环中，弯曲构象发生在β -或α -微管亚基上，而不是同时发生在两者上。我们得出结论，FtsZ在细菌细胞分裂中的功能聚合物是一个长而薄的原丝片，大肠杆菌中有足够的FtsZ形成环绕细胞20倍的原丝。由FtsZ和微管蛋白形成的聚合物的相似性表明，原丝片是一个古老的细胞骨架系统，最初在细菌细胞分裂中起作用，后来被修饰成微管。
The bacterial cell division protein FtsZ is a homolog of tubulin, but it has not been determined whether FtsZ polymers are structurally related to the microtubule lattice. In the present study, we have obtained high-resolution electron micrographs of two FtsZ polymers that show remarkable similarity to tubulin polymers, The first is a two-dimensional sheet of protofilaments with a lattice very similar to that of the microtubule wall. The second is a miniring, consisting of a single protofilament in. a sharply curved, planar conformation, FtsZ minirings are very similar to tubulin rings that are formed upon disassembly of microtubules but are about half the diameter, This suggests that the curved conformation occurs at every FtsZ subunit, but in tubulin rings the conformation occurs at either beta- or alpha-tubulin subunits but not both. We conclude that the functional polymer of FtsZ in bacterial cell division is a long thin sheet of protofilaments, There is sufficient FtsZ in Escherichia coli to form a protofilament that encircles the cell 20 times. The similarity of polymers formed by FtsZ and tubulin implies that the protofilament sheet is an ancient cytoskeletal system, originally functioning in bacterial cell division and later modified to make microtubules.