The mechanism of outer membrane penetration by the eubacterial flagellum and implications for spirochete evolution
The mechanism of outer membrane penetration by the eubacterial flagellum and implications for spirochete evolution
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DOI：
10.1101/gad.1571607
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发表时间：
2007-09-15
影响因子：
10.5
通讯作者：
Hughes, Kelly T.
中科院分区：
文献类型：
--
作者：
Chevance, Fabienne F. V.;Takahashi, Noriko;Hughes, Kelly T.
细菌鞭毛的杆状成分从内膜聚合，穿过周质空间，在外膜的长度为25 nm处停止。套管结构，P环和L环，在远端杆周围聚合，并在外膜上形成一个孔。然后将鞭毛钩结构添加到生长在细胞外的远端杆上。当棒钩结构长度接近80 nm时，钩子聚合停止。这项研究描述了远端杆状蛋白FlgG的突变，该突变未能终止杆状生长。突变的FlgG亚单位继续聚合，接近正常杆钩结构的长度80 nm。这些丝状杆状结构有多个P环，不能在外膜形成L环孔。鞭毛生长在周质内，类似于螺旋体鞭毛。这提供了一种简单的方法来进化细胞内的鞭毛，就像螺旋体一样。将杆生长终止和外膜穿透耦合到环组件和外膜穿透的机制例证了在构建复杂的大分子机器时停止点的重要性，该机器有助于有效地耦合到组装路径中的下一步。
The rod component of the bacterial flagellum polymerizes from the inner membrane across the periplasmic space and stops at a length of 25 nm at the outer membrane. Bushing structures, the P- and L-rings, polymerize around the distal rod and form a pore in the outer membrane. The flagellar hook structure is then added to the distal rod growing outside the cell. Hook polymerization stops after the rod-hook structure reaches similar to 80 nm in length. This study describes mutants in the distal rod protein FlgG that fail to terminate rod growth. The mutant FlgG subunits continue to polymerize close to the length of the normal rod-hook structure of 80 nm. These filamentous rod structures have multiple P- rings and fail to form the L-ring pore at the outer membrane. The flagella grow within the periplasm similar to spirochete flagella. This provides a simple method to evolve intracellular flagella as in spirochetes. The mechanism that couples rod growth termination to the ring assembly and outer membrane penetration exemplifies the importance of stopping points in the construction of a complex macromolecular machine that facilitate efficient coupling to the next step in the assembly pathway.