Helical structure of the needle of the type III secretion system of Shigella flexneri
Helical structure of the needle of the type III secretion system of Shigella flexneri
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DOI：
10.1074/jbc.m300091200
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发表时间：
2003-05-09
影响因子：
4.8
通讯作者：
Lea, SM
中科院分区：
文献类型：
--
作者：
Cordes, FS;Komoriya, K;Lea, SM
革兰氏阴性细菌通常使用III型分泌系统(TTSS)与动植物宿主相互作用，在感染过程中将蛋白质转移到真核细胞中。在25个TTSS编码基因中，有10个与细菌鞭毛基体的成分同源，TTSS针复合体在形态上与细菌鞭毛基体相似。这表明有共同的祖先，尽管没有发现编码鞭毛的基因的TTSS序列同源。在这里，我们提出了一种类似于16埃结构的TTSS的中心部件--针。尽管针状亚基明显较小，并且与鞭毛钩和鞭毛细丝没有序列同源性，但它有一个共同的螺旋结构(类似于5.6个亚基/圈，24埃螺旋间距)。这种共同的架构意味着，在这两个细菌系统的功能上将会有进一步的机械类比。
Gram-negative bacteria commonly interact with animal and plant hosts using type III secretion systems (TTSSs) for translocation of proteins into eukaryotic cells during infection. 10 of the 25 TTSS-encoding genes are homologous to components of the bacterial flagellar basal body, which the TTSS needle complex morphologically resembles. This indicates a common ancestry, although no TTSS sequence homologues for the genes encoding the flagellum are found. We here present an similar to16-Angstrom structure of the central component, the needle, of the TTSS. Although the needle subunit is significantly smaller and shares no sequence homology with the flagellar hook and filament, it shares a common helical architecture (similar to5.6 subunits/turn, 24-Angstrom helical pitch). This common architecture implies that there will be further mechanistic analogies in the functioning of these two bacterial systems.