Linkages between the outer membrane of Gram-negative bacteria and the peptidoglycan layer are crucial for the maintenance of cellular integrity and enable survival in challenging environments^1,2,3,4,5. The function of the outer membrane is dependent on outer membrane proteins (OMPs), which are inserted into the membrane by the β-barrel assembly machine^6,7 (BAM). Growing Escherichia coli cells segregate old OMPs towards the poles by a process known as binary partitioning, the basis of which is unknown⁸. Here we demonstrate that peptidoglycan underpins the spatiotemporal organization of OMPs. Mature, tetrapeptide-rich peptidoglycan binds to BAM components and suppresses OMP foldase activity. Nascent peptidoglycan, which is enriched in pentapeptides and concentrated at septa⁹, associates with BAM poorly and has little effect on its activity, leading to preferential insertion of OMPs at division sites. The synchronization of OMP biogenesis with cell wall growth results in the binary partitioning of OMPs as cells divide. Our study reveals that Gram-negative bacteria coordinate the assembly of two major cell envelope layers by rendering OMP biogenesis responsive to peptidoglycan maturation, a potential vulnerability that could be exploited in future antibiotic design.

革兰氏阴性菌外膜与肽聚糖层之间的联系对于维持细胞完整性至关重要，并能在具有挑战性的环境中生存^1,2,3,4,5。外膜的功能取决于外膜蛋白 (OMP)，它们由 β 桶组装机^6,7 (BAM) 插入膜中。生长的大肠杆菌细胞通过称为二元分配的过程将旧的 OMP 分离到两极，其基础未知⁸. 在这里，我们证明肽聚糖是 OMP 的时空组织的基础。成熟的、富含四肽的肽聚糖与 BAM 成分结合并抑制 OMP 折叠酶活性。富含五肽并集中在隔膜⁹的新生肽聚糖与 BAM 的结合很差，对其活性影响很小，导致 OMP 优先插入分裂位点。OMP 生物发生与细胞壁生长的同步导致 OMP 在细胞分裂时进行二元分配。我们的研究表明，革兰氏阴性菌通过使 OMP 生物发生对肽聚糖成熟有反应来协调两个主要细胞包膜层的组装，这是未来抗生素设计中可以利用的潜在漏洞。