Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille Univ-CNRS, Marseille, France.
Laboratoire de Chimie Bactérienne, UMR7283, Institut de Microbiologie de la Méditerranée, Aix-Marseille Univ-CNRS, Marseille, France.
J Mol Biol. 2019 Aug 9;431(17):3275-3288. doi: 10.1016/j.jmb.2019.05.039. Epub 2019 May 31.
During cell division, gram-negative bacteria must coordinate inner-membrane invagination, peptidoglycan synthesis and cleavage and outer-membrane (OM) constriction. The OM constriction remains largely enigmatic, and the nature of this process, passive or active, is under debate. The proton-motive force-dependent Tol-Pal system performs a network of interactions within these three compartments. Here we confirm that the trans-envelope Tol-Pal complex accumulates at constriction site in Escherichia coli. We show that the inner-membrane complex composed of TolA, TolQ and TolR recruits the OM complex TolB-Pal to the septum, in an energy-dependent process. Pal recruitment then allows its binding to peptidoglycan and subsequently OM constriction. Our results provide evidence that the constriction of the OM is an energized process.
在细胞分裂过程中，革兰氏阴性菌必须协调内膜内陷、肽聚糖合成和裂解以及外膜（OM）收缩。OM 的收缩在很大程度上仍然是个谜，这个过程是被动的还是主动的，目前仍存在争议。质子动力依赖的 Tol-Pal 系统在这三个隔室中执行一系列相互作用。在这里，我们证实了跨膜 Tol-Pal 复合物在大肠杆菌的收缩部位积累。我们表明，由 TolA、TolQ 和 TolR 组成的内膜复合物在能量依赖的过程中招募 OM 复合物 TolB-Pal 到隔膜。Pal 的招募使其与肽聚糖结合，随后导致 OM 收缩。我们的结果提供了证据，证明 OM 的收缩是一个能量驱动的过程。
