Molecular tiling on the surface of a bacterial spore - the exosporium of the Bacillus anthracis/cereus/thuringiensis group.
Molecular tiling on the surface of a bacterial spore - the exosporium of the Bacillus anthracis/cereus/thuringiensis group.
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DOI：
10.1111/mmi.13650
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发表时间：
2017-05
影响因子：
3.6
通讯作者：
Bullough PA
中科院分区：
文献类型：
--
作者：
Terry C;Jiang S;Radford DS;Wan Q;Tzokov S;Moir A;Bullough PA
芽孢杆菌属和梭菌属的细菌形成高度抗性的孢子，其在某些病原体的情况下充当感染剂。外孢壁形成一些孢子的最外层;它在保护、粘附、传播、病原体中的宿主靶向和萌发控制中起作用。蜡状芽孢杆菌组的外孢壁，包括炭疽病原体，包含一个2D结晶基底层，覆盖着毛茸茸的绒毛。BclA和相关蛋白形成毛状绒毛，并且需要ExsFA（BxpB）用于它们在基底层上的定位。到目前为止，基底层的主要结构蛋白成分的身份是未知的。我们在这里证明，ExsY形成的重要组成部分之一。通过在大肠杆菌中的异源表达，我们还证明了ExsY可以自组装成有序的二维阵列，模拟外孢壁基底层的结构。自组装可能在外孢壁的构建中发挥重要作用。ExsY阵列对热和化学变性剂稳定，形成坚固的层，有助于整体抗孢子性。我们的结构分析还为锚定在外孢子壁上的其他分子组分（例如BclA和ExsFA）的位置提供了新的见解。
Bacteria of the genera Bacillus and Clostridium form highly resistant spores, which in the case of some pathogens act as the infectious agents. An exosporium forms the outermost layer of some spores; it plays roles in protection, adhesion, dissemination, host targeting in pathogens and germination control. The exosporium of the Bacillus cereus group, including the anthrax pathogen, contains a 2D‐crystalline basal layer, overlaid by a hairy nap. BclA and related proteins form the hairy nap, and require ExsFA (BxpB) for their localization on the basal layer. Until now, the identity of the main structural protein components of the basal layer was unknown. We demonstrate here that ExsY forms one of the essential components. Through heterologous expression in Escherichia coli, we also demonstrate that ExsY can self‐assemble into ordered 2D arrays that mimic the structure of the exosporium basal layer. Self‐assembly is likely to play an important role in the construction of the exosporium. The ExsY array is stable to heat and chemical denaturants, forming a robust layer that would contribute to overall spore resistance. Our structural analysis also provides novel insight into the location of other molecular components anchored onto the exosporium, such as BclA and ExsFA.