Architectures of Lipid Transport Systems for the Bacterial Outer Membrane.
Architectures of Lipid Transport Systems for the Bacterial Outer Membrane.
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DOI：
10.1016/j.cell.2017.03.019
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发表时间：
2017-04-06
期刊：
影响因子：
64.5
通讯作者：
Vale RD
中科院分区：
文献类型：
--
作者：
Ekiert DC;Bhabha G;Isom GL;Greenan G;Ovchinnikov S;Henderson IR;Cox JS;Vale RD
磷脂如何通过周质的亲水空间在细菌内膜和外膜之间运输尚不清楚。我们报告的哺乳动物细胞进入（MCE）蛋白家族的成员形成六聚体组件的中央通道能够介导脂质运输。急诊大肠杆菌MCE蛋白，MlaD，在内膜中形成与ABC转运蛋白复合物相关的环。可溶性脂质结合蛋白MlaC在MlaD和外膜蛋白复合物之间运送脂质。与此相反，其他两个E.大肠杆菌MCE蛋白显示，YebT形成由七个堆叠的MCE环组成的细长管，PqiB采用类似双螺旋的结构。YebT和PqiB都产生足够长度的通道以跨越周质空间。这项工作揭示了高度保守的蛋白质为基础的通道的不同架构，涉及在细菌和一些真核细胞器的膜之间的脂质运输。
How phospholipids are trafficked between the bacterial inner and outer membranes through the hydrophilic space of the periplasm is not known. We report that members of the mammalian cell entry (MCE) protein family form hexameric assemblies with a central channel capable of mediating lipid transport. The E. coli MCE protein, MlaD, forms a ring associated with an ABC transporter complex in the inner membrane. A soluble lipid-binding protein, MlaC, ferries lipids between MlaD and an outer membrane protein complex. In contrast, EM structures of two other E. coli MCE proteins show that YebT forms an elongated tube consisting of seven stacked MCE rings, and PqiB adopts a syringe-like architecture. Both YebT and PqiB create channels of sufficient length to span the periplasmic space. This work reveals diverse architectures of highly conserved protein-based channels implicated in the transport of lipids between the membranes of bacteria and some eukaryotic organelles.