Fujita Junso, Kasai Kazuki, Hibino Kota, Kagoshima Gota, Kamimura Natsuki, Tobita Shungo, Kato Yuki, Uehara Ryo, Namba Keiichi, Uchihashi Takayuki, Matsumura Hiroyoshi
Graduate School of Frontier Biosciences, University of Osaka, Osaka, Japan.
JEOL YOKOGUSHI Research Alliance Laboratories, University of Osaka, Osaka, Japan.
Nat Commun. 2025 Jul 1;16(1):5985. doi: 10.1038/s41467-025-60940-w.
Cell division in most bacteria is regulated by the tubulin homolog FtsZ as well as ZapA, a FtsZ-associated protein. However, how FtsZ and ZapA function coordinately has remained elusive. Here we report the cryo-electron microscopy structure of the ZapA-FtsZ complex at 2.73 Å resolution. The complex forms an asymmetric ladder-like structure, in which the double antiparallel FtsZ protofilament on one side and a single protofilament on the other side are tethered by ZapA tetramers. In the complex, the extensive interactions of FtsZ with ZapA cause a structural change of the FtsZ protofilament, and the formation of the double FtsZ protofilament increases electrostatic repulsion. High-speed atomic force microscopy analysis revealed cooperative interactions of ZapA with FtsZ at a molecular level. Our findings not only provide a structural basis for the interaction between FtsZ and ZapA but also shed light on how ZapA binds to FtsZ protofilaments without disturbing FtsZ dynamics to promote cell division.
大多数细菌中的细胞分裂由微管蛋白同源物FtsZ以及一种与FtsZ相关的蛋白ZapA调控。然而，FtsZ和ZapA如何协同发挥作用仍不清楚。在此，我们报告了ZapA-FtsZ复合物的冷冻电子显微镜结构，分辨率为2.73Å。该复合物形成一种不对称的梯状结构，其中一侧的双股反平行FtsZ原丝和另一侧的单股原丝由ZapA四聚体连接。在复合物中，FtsZ与ZapA的广泛相互作用导致FtsZ原丝发生结构变化，双股FtsZ原丝的形成增加了静电排斥力。高速原子力显微镜分析揭示了ZapA与FtsZ在分子水平上的协同相互作用。我们的研究结果不仅为FtsZ与ZapA之间的相互作用提供了结构基础，还阐明了ZapA如何在不干扰FtsZ动态变化的情况下结合到FtsZ原丝上以促进细胞分裂。
