In bacteria such as Pseudomonas aeruginosa and Escherichia coli, tripartite membrane machineries, or pumps, determine the efflux of small noxious molecules, such as detergents, heavy metals, and antibiotics, and the export of large proteins including toxins. They are therefore influential in bacterial survival, particularly during infections caused by multidrug-resistant pathogens. In these tripartite pumps an inner membrane transporter, typically an ATPase or proton antiporter, binds and translocates export or efflux substrates. In cooperation with a periplasmic adaptor protein it recruits and opens a TolC family cell exit duct, which is anchored in the outer membrane and projects across the periplasmic space between inner and outer membranes. Assembled tripartite pumps thus span the entire bacterial cell envelope. We review the atomic structures of each of the three pump components and discuss how these have allowed high-resolution views of tripartite pump assembly, operation, and possible inhibition.

中文翻译：

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细菌三联泵的结构和操作。

在铜绿假单胞菌和大肠杆菌等细菌中，三方膜机械或泵可确定有害小分子（如洗涤剂、重金属和抗生素）的流出，以及包括毒素在内的大蛋白质的输出。因此，它们对细菌存活有影响，特别是在由多重耐药病原体引起的感染期间。在这些三联泵中，内膜转运蛋白，通常是 ATP 酶或质子反向转运蛋白，结合并转移输出或流出底物。它与周质衔接蛋白合作，招募并打开一个 TolC 家族细胞出口管，该管固定在外膜中，并穿过内膜和外膜之间的周质空间。因此组装的三方泵跨越整个细菌细胞包膜。