Schumacher Maria A, Ohashi Tomoo, Corbin Lauren, Erickson Harold P
Department of Biochemistry, Duke University School of Medicine, Box 3711, DUMC, Durham, NC 27710, USA.
Department of Cell Biology, Duke University School of Medicine, Box 3711, DUMC, Durham, NC 27710, USA.
Acta Crystallogr F Struct Biol Commun. 2020 Feb 1;76(Pt 2):94-102. doi: 10.1107/S2053230X20001132. Epub 2020 Feb 5.
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.
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环由FtsZ原丝的小斑块组成，这些斑块通过踏车运动在细菌细胞周围移动。踏车运动涉及从有利于单体的松弛（R）状态转变为有利于缔合形成细丝的紧张（T）构象。在许多单体FtsZ晶体结构中观察到了R构象，在金黄色葡萄球菌FtsZ以组装细丝形式结晶时观察到了T构象。然而，虽然大肠杆菌一直是研究Z环及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。为了填补这一空白，分别以1.35 Å和1.40 Å的分辨率测定了结合GDP和GTP的大肠杆菌FtsZ突变体FtsZ（L178E）的结构。大肠杆菌FtsZ（L178E）的结构均以亚基处于R构象的直细丝形式结晶。这些高分辨率结构可用于促进大肠杆菌中实验性细胞分裂研究及其解释。
