FtsEX is a membrane complex widely conserved across diverse bacterial genera and involved in critical processes such as recruitment of division proteins and in spatial and temporal regulation of muralytic activity during cell division or sporulation. FtsEX is a member of the ABC transporter superfamily. The component FtsX is an integral membrane protein, whereas FtsE is an ATPase and is required for the transmission of a conformational signal from the cytosol through the membrane to regulate the activity of cell wall hydrolases in the periplasm. Both proteins are essential in the major human respiratory pathogenic bacterium Streptococcus pneumoniae, and FtsX interacts with the modular peptidoglycan hydrolase PcsB at the septum. Here, we report high-resolution structures of pneumococcal FtsE bound to different nucleotides. Structural analysis revealed that FtsE contains all the conserved structural motifs associated with ATPase activity and afforded interpretation of the in vivo dimeric arrangement in both the ADP and ATP states. Interestingly, three specific FtsE regions with high structural plasticity were identified that shape the cavity in which the cytosolic region of FtsX would be inserted. The residues corresponding to the FtsX coupling helix, responsible for contacting FtsE, were identified and validated by in vivo mutagenesis studies showing that this interaction is essential for cell growth and proper morphology.

中文翻译：

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肺炎链球菌中基本细胞分裂蛋白FtsE的结构表征及其与FtsX的相互作用。

FtsEX是一种膜复合物，在多种细菌属中广泛保守，并参与关键过程，例如募集分裂蛋白，以及在细胞分裂或孢子形成过程中对空肠活动的时空调节。FtsEX是ABC转运蛋白超家族的成员。FtsX组件是必不可少的膜蛋白，而FtsE是ATPase，是从细胞质通过膜传输构象信号以调节周质中细胞壁水解酶活性所必需的。这两种蛋白在主要的人类呼吸道致病菌肺炎链球菌中都是必不可少的，并且FtsX与间隔处的模块化肽聚糖水解酶PcsB相互作用。在这里，我们报告结合不同核苷酸的肺炎球菌FtsE的高分辨率结构。结构分析表明，FtsE包含与ATPase活性相关的所有保守结构基序，并提供了ADP和ATP状态下体内二聚体排列的解释。有趣的是，鉴定了三个具有高结构可塑性的特定FtsE区，它们形成了将插入FtsX胞质区的空腔。负责与FtsE接触的FtsX偶联螺旋对应的残基已通过体内诱变研究鉴定和验证，该研究表明这种相互作用对于细胞生长和适当的形态至关重要。