Bacterial cytokinesis is mediated by the Z-ring, which is formed by the prokaryotic tubulin homolog FtsZ. Recent data indicate that the Z-ring is composed of small patches of FtsZ protofilaments that travel around the bacterial cell by treadmilling. Treadmilling involves a switch from a relaxed (R) state, favored for monomers, to a tense (T) conformation, which is favored upon association into filaments. The R conformation has been observed in numerous monomeric FtsZ crystal structures and the T conformation in Staphylococcus aureus FtsZ crystallized as assembled filaments. However, while Escherichia coli has served as a main model system for the study of the Z-ring and the associated divisome, a structure has not yet been reported for E. coli FtsZ. To address this gap, structures were determined of the E. coli FtsZ mutant FtsZ(L178E) with GDP and GTP bound to 1.35 and 1.40 Å resolution, respectively. The E. coli FtsZ(L178E) structures both crystallized as straight filaments with subunits in the R conformation. These high-resolution structures can be employed to facilitate experimental cell-division studies and their interpretation in E. coli.

中文翻译：

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与 GDP 和 GTP 结合的大肠杆菌 FtsZ 的高分辨率晶体结构。


细菌胞质分裂由 Z 环介导，Z 环由原核微管蛋白同源物 FtsZ 形成。最近的数据表明，Z 形环由小片 FtsZ 原丝组成，通过跑步在细菌细胞周围移动。跑步涉及从有利于单体的松弛（R）状态到有利于结合成丝的紧张（T）构象的转变。在许多单体 FtsZ 晶体结构中观察到 R 构象，在金黄色葡萄球菌 FtsZ 中观察到 T 构象，结晶为组装丝。然而，虽然大肠杆菌已成为研究 Z 环和相关分裂体的主要模型系统，但尚未报道大肠杆菌 FtsZ 的结构。为了解决这一问题，我们确定了大肠杆菌 FtsZ 突变体 FtsZ(L178E) 的结构，其 GDP 和 GTP 分辨率分别为 1.35 和 1.40 Å。大肠杆菌 FtsZ(L178E) 结构均结晶为直丝，亚基呈 R 构象。这些高分辨率结构可用于促进实验性细胞分裂研究及其在大肠杆菌中的解释。