Role of DegP for two-partner secretion in Bordetella
Role of DegP for two-partner secretion in Bordetella
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DOI：
10.1111/j.1365-2958.2009.06860.x
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发表时间：
2009-10-01
影响因子：
3.6
通讯作者：
Jacob-Dubuisson, F.
中科院分区：
文献类型：
--
作者：
Baud, C.;Hodak, H.;Jacob-Dubuisson, F.
蛋白质的分选是由特定的机制介导的，这些机制引导蛋白质底物朝向适当的分泌途径并确定折叠发生的区室。在革兰氏阴性菌中，双配偶体分泌（TPS）途径致力于分泌富含β-螺旋结构的大蛋白。丝状血凝素（FHA），百日咳杆菌的230 kDa粘附素的分泌，代表了一个模型TPS系统。FHA通过Sec机制输出，并以延伸构象通过周质转运。从那里，它通过其专用的转运蛋白FhaC跨外膜转运，最终以渐进的方式在细胞表面折叠成长的β-螺旋。在这项工作中，我们表明，B。缺乏周质伴侣/蛋白酶DegP的百日咳在37 ℃下具有强烈的生长缺陷，并且其外膜的完整性受到损害。虽然这两种表型都因FHA的存在而显著加重，但DegP的伴侣活性显著加重了周质应激。在体外，DegP以高亲和力结合非天然FHA。我们提出DegP陪伴周质中的扩展FHA多肽，因此参与TPS途径。
P>Sorting of proteins destined to the surface or the extracellular milieu is mediated by specific machineries, which guide the protein substrates towards the proper route of secretion and determine the compartment in which folding occurs. In Gram-negative bacteria, the two-partner secretion (TPS) pathway is dedicated to the secretion of large proteins rich in beta-helical structure. The secretion of the filamentous haemagglutinin (FHA), a 230 kDa adhesin of Bordetella pertussis, represents a model TPS system. FHA is exported by the Sec machinery and transits through the periplasm in an extended conformation. From there it is translocated across the outer membrane by its dedicated transporter FhaC to finally fold into a long beta-helix at the cell surface in a progressive manner. In this work, we show that B. pertussis lacking the periplasmic chaperone/protease DegP has a strong growth defect at 37 degrees C, and the integrity of its outer membrane is compromised. While both phenotypes are significantly aggravated by the presence of FHA, the chaperone activity of DegP markedly alleviates the periplasmic stress. In vitro, DegP binds to non-native FHA with high affinity. We propose that DegP chaperones the extended FHA polypeptide in the periplasm and is thus involved in the TPS pathway.