Structure of the Pseudomonas aeruginosa XcpT pseudopilin, a major component of the type II secretion system
Structure of the Pseudomonas aeruginosa XcpT pseudopilin, a major component of the type II secretion system
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DOI：
10.1016/j.jsb.2009.09.003
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发表时间：
2010-01-01
影响因子：
3
通讯作者：
Bernard, Cedric
中科院分区：
文献类型：
--
作者：
Alphonse, Sebastien;Durand, Eric;Bernard, Cedric
细菌II型蛋白分泌（T2 S）和IV型纤毛（T4 P）系统有几个共同的特征。特别地，已经确定T2 S系统需要称为假菌毛（pseudopilus）的菌毛样结构的功能，所述菌毛样结构建立在称为假菌毛蛋白的菌毛蛋白样亚基的组装上。菌毛蛋白和假菌毛蛋白具有疏水性N-末端区域，其在延伸的亲水性C-末端区域之前。在菌毛蛋白的情况下，它表明，寡聚化和螺旋纤维的形成，发生通过疏水结构域之间的相互作用。XcpT是铜绿假单胞菌T2 S中最丰富的蛋白质，并且被认为是假单胞菌中的主要组分。在这项研究中，我们提出了高分辨率的NMR结构的亲水结构域的XcpT（XcpTp）。XcpTp缺乏在IV型菌毛蛋白中发现的C-末端二硫键桥接的“D”结构域，并且可能参与受体结合。这与含有XcpT的假菌毛是蛋白质分泌而不是细菌附着所需的想法一致。有趣的是，通过求解XcpTp的3D结构，我们发现之前称为α β环毛蛋白区域实际上在主要的II型假青霉素中高度保守，并构成了用于识别属于该家族的主要假青霉素的特定共识基序。(C)2009 Elsevier Inc. All rights reserved.
The bacterial type II protein secretion (T2S) and type IV piliation (T4P) systems share several common features. In particular, it is well established that the T2S system requires the function of a pilus-like structure, called pseudopilus, which is built upon assembly of pilin-like subunits, called pseudopilins. Pilins and pseudopilins have a hydrophobic N-terminal region, which precedes an extended hydrophilic C-terminal region. In the case of pilins, it was shown that oligomerisation and formation of helical fibers, takes place through interaction between the hydrophobic domains. XcpT, is the most abundant protein of the Pseudomonas aeruginosa T2S, and was proposed to be the main component in the pseudopilus. In this study we present the high-resolution NMR structure of the hydrophilic domain of XcpT (XcpTp). XcpTp is lacking the C-terminal disulfide bridged "D" domain found in type IV pilins and likely involved in receptor binding. This is in agreement with the idea that the XcpT-containing pseudopilus is required for protein secretion and not for bacterial attachment. Interestingly, by solving the 3D structure of XcpTp we revealed that the previously called alpha beta-loop pilin region is in fact highly conserved among major type II pseudopilins and constitutes a specific consensus motif for identifying major pseudopilins, which belong to this family. (C) 2009 Elsevier Inc. All rights reserved.