Lack of functional complementation between Bordetella pertussis filamentous hemagglutinin and Proteus mirabilis HpmA hemolysin secretion machineries
Lack of functional complementation between Bordetella pertussis filamentous hemagglutinin and Proteus mirabilis HpmA hemolysin secretion machineries
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DOI：
10.1128/jb.179.3.775-783.1997
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发表时间：
1997-02-01
影响因子：
3.2
通讯作者：
Locht, C
中科院分区：
文献类型：
--
作者：
JacobDubuisson, F;Buisine, C;Locht, C
革兰氏阴性菌百日咳博德特氏菌已适应其主要分泌蛋白的每一个特定的分泌机制。特别地，丝状血凝素（FHA）的高效分泌由辅助蛋白FhaC介导。FhaC属于外膜蛋白家族，其参与几种革兰氏阴性细菌的大粘附素的分泌或Ca2+非依赖性溶血素的活化和分泌。FHA与这些溶血素共享一个115个残基长的氨基近端区域，该区域对其分泌至关重要。为了比较这些溶血素和FHA的分泌途径，我们尝试了FhaC和奇异变形杆菌溶血素辅助蛋白HpmB之间的功能互补。HpmB不能促进FHA衍生物的分泌。同样，FhaC被证明不能介导HpmA（HpmB的同源分泌伴侣）的分泌和活化。与此相反，ShlB，密切相关的粘质沙雷氏菌溶血素的辅助蛋白，能够激活和分泌HpmA。两个不变的天冬酰胺残基位于分泌蛋白共享的同源性区域，并被证明是必不可少的分泌和激活的溶血素被替换在FHA的定点诱变。这些残基的替换表明两者都参与FHA分泌，但只有第一个残基对FHA分泌至关重要。这种轻微的差异以及功能互补的缺乏证明了溶血素和FHA分泌机制之间的主要差异。
The gram-negative bacterium Bordetella pertussis has adapted specific secretion machineries for each of its major secretory proteins. In particular, the highly efficient secretion of filamentous hemagglutinin (FHA) is mediated by the accessory protein FhaC. FhaC belongs to a family of outer membrane proteins which are involved in the secretion of large adhesins or in the activation and secretion of Ca2+-independent hemolysins by several gram-negative bacteria. FHA shares with these hemolysins a 115-residue-long amino-proximal region essential for its secretion. To compare the secretory pathways of these hemolysins and FHA, we attempted functional transcomplementation between FhaC and the Proteus mirabilis hemolysin accessory protein HpmB. HpmB could not promote the secretion of FHA derivatives. Likewise, FhaC proved to be unable to mediate secretion and activation of HpmA, the cognate secretory partner of HpmB. In contrast, ShlB, the accessory protein of the closely related Serratia marcescens hemolysin, was able to activate and secrete HpmA. Two invariant asparagine residues lying in the region of homology shared by secretory proteins and shown to be essential for the secretion and activation of the hemolysins were replaced in FHA by site-directed mutagenesis. Replacements of these residues indicated that both are involved in, but only the first one is crucial to, FHA secretion, This slight discrepancy together with the lack of functional complementation demonstrates major differences between the hemolysins and FHA secretion machineries.