FIMH ADHESIN OF TYPE-1 PILI IS ASSEMBLED INTO A FIBRILLAR TIP STRUCTURE IN THE ENTEROBACTERIACEAE
FIMH ADHESIN OF TYPE-1 PILI IS ASSEMBLED INTO A FIBRILLAR TIP STRUCTURE IN THE ENTEROBACTERIACEAE
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DOI：
10.1073/pnas.92.6.2081
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发表时间：
1995-03-14
影响因子：
11.1
通讯作者：
HULTGREN, SJ
中科院分区：
文献类型：
--
作者：
JONES, CH;PINKNER, JS;HULTGREN, SJ
1型丸剂是由肠杆菌科的所有成员产生的杂聚甘露糖结合纤维。纤维的主体由FimA组成。通过甘露糖亲和层析和离子交换层析从fimA（-）大肠杆菌中纯化了两种负责介导与含甘露糖受体相互作用的大分子复合物。一个复合物只含有甘露糖结合粘附素，FimH，与FimG，1型菌毛的次要成分。在另一种复合物中，FimG-FimH部分与分子伴侣-次要亚基复合物（FimC-FimF）松散缔合，可能代表尖端原纤维组装中的中间体。FimC分子伴侣也已显示与先前已纯化和表征的FimH形成预组装复合物。纯化的FimC不与FimG-FimH复合物结合，但识别从FimG-FimH复合物解离的FimH。速冻深蚀刻电子显微镜显示FimG-FimH复合物具有薄的纤维状结构。高分辨电子显微镜观察发现，在1型菌毛中，有一个16 nm的纤维尖端结构与FimG-FimH复合物的结构相同，与菌毛杆端对端相连。在fimH（-）缺失突变体中，与菌毛杆相连的尖端纤维长度约为3 nm。全长尖端原纤维的恢复与fimH基因的互补反式。的二分性质的1型菌毛也证明了从临床分离株的肠杆菌科的成员认为，这是一个保守的功能1型菌毛纯化的药丸。
Type 1 pill are heteropolymeric mannose-binding fibers produced by all members of the Enterobacteriaceae family. The bulk of the fiber is composed of FimA. Two macromolecular complexes responsible for mediating an interaction with mannose-containing receptors were purified from fimA(-) Escherichia coli by mannose affinity chromatography and ion-exchange chromatography. One complex contained only the mannose-binding adhesin, FimH, associated with FimG, a minor component of the type 1 pilus. In the other complex the FimG-FimH moiety was loosely associated with a chaperone-minor subunit complex (FimC-FimF), possibly representing an intermediate in tip fibrilla assembly, The FimC chaperone has also been shown to form a preassembly complex with FimH that has been purified and characterized previously. Purified FimC did not bind to the FimG-FimH complex but did recognize FimH dissociated from the FimG-FimH complex, Quick-freeze deep-etch electron microscopy revealed that the FimG-FimH complex had a thin fibrillar architecture. High-resolution electron microscopy of type 1 pill revealed that a 16-nm fibrillar tip structure with an architecture identical to that of the FimG-FimH complex was joined end-to-end to the pilus rod, In a fimH(-) deletion mutant, the tip fibrillae joined to pilus rods were approximate to 3 nm in length. The full-length tip fibrilla was restored by complementation with the fimH gene in trans. The bipartite nature of the type 1 pilus was also demonstrated on pill purified from clinical isolates of members of the Enterobacteriaceae family arguing that it is a conserved feature of the type 1 pilus.