Molecular and structural analysis of Legionella DotI gives insights into an inner membrane complex essential for type IV secretion.
Molecular and structural analysis of Legionella DotI gives insights into an inner membrane complex essential for type IV secretion.
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DOI：
10.1038/srep10912
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发表时间：
2015-06-03
影响因子：
4.6
通讯作者：
Nagai H
中科院分区：
文献类型：
--
作者：
Kuroda T;Kubori T;Thanh Bui X;Hyakutake A;Uchida Y;Imada K;Nagai H
人类病原体嗜肺军团菌使用Dot/Icm型IVB分泌系统将大量效应蛋白递送到宿主细胞中。在构成Dot/Icm系统的蛋白质中，已知内膜蛋白DotI对于分泌功能是关键的，但其结构和在IV型分泌中的作用尚未阐明。我们在这里报告了DotI周质结构域及其在质粒R64（TraM）接合系统中的直系同源物的晶体结构。这些结构揭示了一个惊人的相似性VirB 8，一个组成部分的IVA型分泌系统，这表明DotI/TraM是IVB型对应的VirB 8。我们进一步表明，DotI和它的部分paradox DotJ形成一个稳定的heterocomplex。R64 TraM由缺乏DotJ直系同源物的接合质粒编码，形成同源六聚体。DotI-DotJ复合物与核心复合物不同，核心复合物跨越内膜和外膜以形成底物导管，并且似乎不稳定地与核心复合物缔合。这些结果提供了深入了解VirB 8家族内膜蛋白的IV型分泌必不可少的，并有助于了解细菌致病所必需的分泌系统的分子基础。
The human pathogen Legionella pneumophila delivers a large array of the effector proteins into host cells using the Dot/Icm type IVB secretion system. Among the proteins composing the Dot/Icm system, an inner membrane protein DotI is known to be crucial for the secretion function but its structure and role in type IV secretion had not been elucidated. We report here the crystal structures of the periplasmic domains of DotI and its ortholog in the conjugation system of plasmid R64, TraM. These structures reveal a striking similarity to VirB8, a component of type IVA secretion systems, suggesting that DotI/TraM is the type IVB counterpart of VirB8. We further show that DotI and its partial paralog DotJ form a stable heterocomplex. R64 TraM, encoded by the conjugative plasmid lacking DotJ ortholog, forms a homo-hexamer. The DotI-DotJ complex is distinct from the core complex, which spans both inner and outer membranes to form a substrate conduit, and seems not to stably associate with the core complex. These results give insight into VirB8-family inner membrane proteins essential for type IV secretion and aid towards understanding the molecular basis of secretion systems essential for bacterial pathogenesis.
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影响因子：
11.4
作者：
Rivera-Calzada, Angel;Fronzes, Remi;Savva, Christos G.;Chandran, Vidya;Lian, Pei W.;Laeremans, Toon;Pardon, Els;Steyaert, Jan;Remaut, Han;Waksman, Gabriel;Orlova, Elena V.
通讯作者：
Orlova, Elena V.
DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
影响因子：
11.4
作者：
Nagai, H;Roy, CR
通讯作者：
Roy, CR
DOI：
10.1038/nrmicro2218
发表时间：
2009-10
期刊：
Nature reviews. Microbiology
影响因子：
--
作者：
通讯作者：
--
DOI：
10.1107/s0907444902016657
发表时间：
2002-11-01
影响因子：
2.2
作者：
Adams, PD;Grosse-Kunstleve, RW;Terwilliger, TC
通讯作者：
Terwilliger, TC