OUTER-MEMBRANE PAPC MOLECULAR USHER DISCRIMINATELY RECOGNIZES PERIPLASMIC CHAPERONE PILUS SUBUNIT COMPLEXES
OUTER-MEMBRANE PAPC MOLECULAR USHER DISCRIMINATELY RECOGNIZES PERIPLASMIC CHAPERONE PILUS SUBUNIT COMPLEXES
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DOI：
10.1073/pnas.90.8.3670
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发表时间：
1993-04-15
影响因子：
11.1
通讯作者：
HULTGREN, SJ
中科院分区：
文献类型：
--
作者：
DODSON, KW;JACOBDUBUISSON, F;HULTGREN, SJ
P 菌毛是高度有序的复合结构，由端对端连接到刚性螺旋杆的细纤维尖端组成。这些毒力相关结构的产生需要周质伴侣 (PapD) 和外膜蛋白 (PapC)，后者是新认识的一类蛋白质的原型成员，我们将其命名为“分子引导者”。两项体外测定表明，PapD 与三种最远端纤维状蛋白（PapG、PapF 和 PapE）形成的预组装复合物结合 到 PapC。发现每个复合物对 PapC 的相对亲和力与尖端原纤维中亚基类型的最终位置相关。相反，PapD 与菌毛杆的主要成分 PapA 或菌毛杆起始蛋白 PapK 形成的复合物不识别 PapC。体外数据表明，伴侣蛋白亚基复合物对 PapC 的差异靶向可能是确保粘合复合菌毛正确有序组装的机制的一部分。
P pili are highly ordered composite structures consisting of thin fibrillar tips joined end-to-end to rigid helical rods. The production of these virulence-associated structures requires a periplasmic chaperone (PapD) and an outer membrane protein (PapC) that is the prototype member of a newly recognized class of proteins that we have named ''molecular ushers.'' Two in vitro assays showed that the preassembly complexes that PapD forms with the three most distal tip fibrillar proteins (PapG, PapF, and PapE) bound to PapC. The relative affinity of each complex for PapC was found to correlate with the final position of the subunit type in the tip fibrillum. In contrast, the complexes PapD forms with the major component of the pilus rod, PapA, or the pilus rod initiating protein, PapK, did not recognize PapC. The in vitro data argue that differential targeting of chaperone-subunit complexes to PapC may be part of a mechanism to ensure the correctly ordered assembly of adhesive composite pili.