BfpL is essential for type IV bundle-forming pilus biogenesis and interacts with the periplasmic face of BfpC.
BfpL is essential for type IV bundle-forming pilus biogenesis and interacts with the periplasmic face of BfpC.
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BfpL 对于 IV 型束形成菌毛生物发生至关重要，并与 BfpC 的周质面相互作用。
DOI：
10.1099/mic.0.060889-0
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Donnenberg,MichaelS
中科院分区：
文献类型：
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作者：
DeMasi,Leon;Szmacinski,Henryk;Schreiber,Wiebke;Donnenberg,MichaelS
肠致病性大肠杆菌 (EPEC) 会导致发展中国家的婴儿腹泻。成束菌毛 (BFP) 是 EPEC 表面发现的 IV 型菌毛，对于典型 EPEC 菌株的完全毒力至关重要。 BFP 组装和功能的机制由 14 个基因的操纵子编码。在这里，我们研究了 BfpL 在菌毛生物发生中的作用，BfpL 是一种小蛋白，具有单个 N 末端预测跨膜结构域，让人想起菌毛样蛋白。我们证实 abfpLmutant 缺乏 BFP，以及相关的自动聚集和局部粘附表型。此外，我们发现无法同时表达假定的回缩 ATP 酶 BfpF 和 BfpL 的双突变体也缺乏 BFP 和相关表型，从而将 BfpL 与菌毛蛋白样蛋白区分开来。剪切菌毛制剂的蛋白质印迹并未表明 BfpL 是 BFP 的组成部分。使用 C 端截短和双报告基因的拓扑研究表明，大部分 BfpL 蛋白位于周质中。此外，我们通过酵母双杂交测定证明并通过荧光各向异性证实 BfpL 与 BfpC 的周质面相互作用。因此，BfpL 具有与菌毛样蛋白不同的功能，并且是内膜亚装配复合物的一部分，据信该复合物从内膜提取束蛋白（主要菌毛亚基）以掺入 BFP 中。
EnteropathogenicEscherichia coli(EPEC) causes diarrhoea among infants in developing countries. The bundle-forming pilus (BFP), a type IV pilus found on the surface of EPEC, is essential for full virulence of typical EPEC strains. The machinery for BFP assembly and function is encoded by an operon of 14 genes. Here we investigate the role in pilus biogenesis of BfpL, a small protein with a single N-terminal predicted transmembrane domain reminiscent of pilin-like proteins. We confirmed that abfpLmutant lacks BFP, and associated auto-aggregation and localized adherence phenotypes. Furthermore, we found that a double mutant unable to express both the putative retraction ATPase BfpF and BfpL also lacks BFP and associated phenotypes, distinguishing BfpL from pilin-like proteins. Western blots of sheared pilus preparations did not suggest that BfpL is a component of BFP. Topology studies using C-terminal truncations and a dual reporter revealed that most of the BfpL protein resides in the periplasm. Further, we demonstrated through yeast two-hybrid assays and confirmed by fluorescence anisotropy that BfpL interacts with the periplasmic face of BfpC. Thus, BfpL has a function distinct from those of pilin-like proteins and is instead part of an inner-membrane subassembly complex that is believed to extract bundlin, the main pilus subunit, from the inner membrane to be incorporated into BFP.