Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX, USA.
EMBO Rep. 2018 Feb;19(2):191-193. doi: 10.15252/embr.201745627. Epub 2018 Jan 22.
The bacterial type VI secretion system (T6SS) is a multicomponent complex responsible for the translocation of effector proteins into the external milieu. The T6SS consists of an external sheath, an internal rigid tube, a baseplate, and a T6SS‐specific membrane complex. Secretion is accomplished by the contraction of the sheath, which expels the effector‐loaded tube. In this issue of , Brackmann 1 show how modifications of the sheath subunits can lock the T6SS assembly in the extended state. These findings allowed Wang 2 and Nazarov 3 to purify the T6SS sheath–tube–baseplate complex in the extended pre‐secretion state and to analyze its structure using cryo‐electron microscopy (cryoEM).
细菌的 VI 型分泌系统（T6SS）是一种多组分复合物，负责将效应蛋白转运到外部环境中。T6SS 由外部鞘、内部刚性管、底座和 T6SS 特异性膜复合物组成。通过鞘的收缩来完成分泌，这会将加载效应物的管排出。在本期的 中，Brackmann 1 展示了鞘亚基的修饰如何将 T6SS 组装锁定在延伸状态。这些发现使 Wang 2 和 Nazarov 3 能够在延伸的预分泌状态下纯化 T6SS 鞘-管-底座复合物，并使用冷冻电镜（cryoEM）分析其结构。
