Department of Clinical Laboratory, Zhongnan Hospital of Wuhan University, School of Pharmaceutical Sciences, Wuhan University, Wuhan, China.
Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and School of Pharmaceutical Sciences, Wuhan University, Wuhan, China.
PLoS Biol. 2024 May 30;22(5):e3002628. doi: 10.1371/journal.pbio.3002628. eCollection 2024 May.
The peptidoglycan (PG) layer is a critical component of the bacterial cell wall and serves as an important target for antibiotics in both gram-negative and gram-positive bacteria. The hydrolysis of septal PG (sPG) is a crucial step of bacterial cell division, facilitated by FtsEX through an amidase activation system. In this study, we present the cryo-EM structures of Escherichia coli FtsEX and FtsEX-EnvC in the ATP-bound state at resolutions of 3.05 Å and 3.11 Å, respectively. Our PG degradation assays in E. coli reveal that the ATP-bound conformation of FtsEX activates sPG hydrolysis of EnvC-AmiB, whereas EnvC-AmiB alone exhibits autoinhibition. Structural analyses indicate that ATP binding induces conformational changes in FtsEX-EnvC, leading to significant differences from the apo state. Furthermore, PG degradation assays of AmiB mutants confirm that the regulation of AmiB by FtsEX-EnvC is achieved through the interaction between EnvC-AmiB. These findings not only provide structural insight into the mechanism of sPG hydrolysis and bacterial cell division, but also have implications for the development of novel therapeutics targeting drug-resistant bacteria.
肽聚糖 (PG) 层是细菌细胞壁的关键组成部分，是革兰氏阴性菌和革兰氏阳性菌中抗生素的重要靶标。隔膜 PG (sPG) 的水解是细菌细胞分裂的关键步骤，FtsEX 通过酰胺酶激活系统促进其水解。在这项研究中，我们展示了大肠杆菌 FtsEX 和 FtsEX-EnvC 在 ATP 结合状态下的冷冻电镜结构，分辨率分别为 3.05 Å 和 3.11 Å。我们在大肠杆菌中的 PG 降解实验表明，FtsEX 的 ATP 结合构象激活了 EnvC-AmiB 的 sPG 水解，而单独的 EnvC-AmiB 则表现出自抑制。结构分析表明，ATP 结合诱导了 FtsEX-EnvC 的构象变化，与无配体状态相比存在显著差异。此外，AmiB 突变体的 PG 降解实验证实，FtsEX-EnvC 通过 EnvC-AmiB 之间的相互作用来调节 AmiB。这些发现不仅为 sPG 水解和细菌细胞分裂的机制提供了结构见解，也为针对耐药菌的新型治疗药物的开发提供了思路。
