Enterohaemorrhagic Escherichia coli haemolysin is cleaved and inactivated by serine protease EspPα
Enterohaemorrhagic Escherichia coli haemolysin is cleaved and inactivated by serine protease EspPα
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DOI：
10.1111/j.1462-2920.2011.02431.x
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发表时间：
2011-05-01
影响因子：
5.1
通讯作者：
Karch, Helge
中科院分区：
文献类型：
--
作者：
Brockmeyer, Jens;Aldick, Thomas;Karch, Helge
肠出血性大肠杆菌溶血素（EHEC-Hly）和丝氨酸蛋白酶EspP α是EHEC的假定毒力因子。我们研究了这些分泌因子之间的相互作用，并证明EspP α切割107 kDa的大EHEC-Hly。当将纯化的EspP α添加到EHEC-Hly表达菌株的生长培养物中时，观察到降解，分离的蛋白质和共表达菌株，并且与EHEC血清型无关。EHEC-Hly分解是一个多阶段过程，形成相对分子质量类似于82 kDa和/或类似于84 kDa和类似于34 kDa的特征片段。最初的切割发生在N-末端疏水结构域之间的Leu 235和Ser 236，并取消其溶血活性。在细胞感染系统中，当EspP α共表达时，EHEC-Hly分泌重组菌株的溶细胞潜力被消除。与人肠上皮细胞接触的EHEC同时上调其EHEC-Hly和EspP，表明这两种分子可能在生理条件下相互作用。我们提出了细菌效应分子干扰（BEMI）的概念，反映了毒力因子的协同相互作用。效应分子之间的干扰可能是调节毒力功能的另一种方式，并增加了单分子表型的复杂性。
P>The haemolysin from enterohaemorrhagic Escherichia coli (EHEC-Hly) and the serine protease EspP alpha are putative virulence factors of EHEC. We investigated the interplay between these secreted factors and demonstrate that EspP alpha cleaves the 107 kDa large EHEC-Hly. Degradation was observed when purified EspP alpha was added to a growing culture of an EHEC-Hly-expressing strain, with isolated proteins and with coexpressing strains, and was independent of the EHEC serotype. EHEC-Hly breakdown occurred as a multistage process with the formation of characteristic fragments with relative molecular masses of similar to 82 kDa and/or similar to 84 kDa and similar to 34 kDa. The initial cleavage occurred in the N-terminal hydrophobic domain of EHEC-Hly between Leu235 and Ser236 and abolished its haemolytic activity. In a cellular infection system, the cytolytic potential of EHEC-Hly-secreting recombinant strains was abolished when EspP alpha was coexpressed. EHEC in contact with human intestinal epithelial cells simultaneously upregulated their EHEC-Hly and EspP indicating that both molecules might interact under physiological conditions. We propose the concept of bacterial effector molecule interference (BEMI), reflecting the concerted interplay of virulence factors. Interference between effector molecules might be an additional way to regulate virulence functions and increases the complexity of monomolecular phenotypes.