Unfolding and refolding properties of S pili on extraintestinal pathogenic Escherichia coli
Unfolding and refolding properties of S pili on extraintestinal pathogenic Escherichia coli
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DOI：
10.1007/s00249-009-0552-8
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发表时间：
2010-07-01
影响因子：
2
通讯作者：
Andersson, Magnus
中科院分区：
文献类型：
--
作者：
Castelain, Mickael;Sjostrom, Annika E.;Andersson, Magnus
S皮利是分子伴侣-引导通路组装的皮利家族的成员，其主要与新生儿脑膜炎（S-II）相关，并被认为在上行性尿路感染（S-I）中起作用。我们使用测力光镊来表征S-II和S-I皮利的内在生物力学特性和动力学。在稳态条件下，螺旋状杆中各层的顺序展开发生在稍微不同的力下，S-II皮利为26 pN，S-I皮利为21 pN，动力学上有明显差异，1.3和8.8 Hz。用新识别的sfa基因（斯法克斯（II））缺陷的细菌进行的测试表明，斯法克斯（II）基因的缺失轻微地减弱了fimmunoglobulin的相互作用并降低了动力学。将S-I的数据与先前评估的与尿路感染相关的原发性皮利、P和I型皮利的数据进行比较。S皮利具有比P和1型皮利两者更弱的层-层键，分别为21、28和30 pN。此外，S型皮利的动力学类似于P型皮利的动力学快10倍，并且类似于1型皮利的动力学快550倍。我们的研究结果还表明，从实验室菌株（HB 101）中的质粒异位表达的皮利和从临床分离株（IHE 3034）的染色体表达的皮利的生物力学性质是相同的。此外，我们证明，它是可能的区分，通过分析力延伸数据，不同类型的皮利表达的单个细胞的临床细菌分离。
S pili are members of the chaperone-usher-pathway-assembled pili family that are predominantly associated with neonatal meningitis (S-II) and believed to play a role in ascending urinary tract infections (S-I). We used force-measuring optical tweezers to characterize the intrinsic biomechanical properties and kinetics of S-II and S-I pili. Under steady-state conditions, a sequential unfolding of the layers in the helix-like rod occurred at somewhat different forces, 26 pN for S-II pili and 21 pN for S-I pili, and there was an apparent difference in the kinetics, 1.3 and 8.8 Hz. Tests with bacteria defective in a newly recognized sfa gene (sfaX (II)) indicated that absence of the sfaX (II) gene weakens the interactions of the fimbrium slightly and decreases the kinetics. Data of S-I are compared with those of previously assessed pili primary associated with urinary tract infections, the P and type 1 pili. S pili have weaker layer-to-layer bonds than both P and type 1 pili, 21, 28 and 30 pN, respectively. In addition, the S pili kinetics are similar to 10 times faster than the kinetics of P pili and similar to 550 times faster than the kinetics of type 1 pili. Our results also show that the biomechanical properties of pili expressed ectopically from a plasmid in a laboratory strain (HB101) and pili expressed from the chromosome of a clinical isolate (IHE3034) are identical. Moreover, we demonstrate that it is possible to distinguish, by analyzing force-extension data, the different types of pili expressed by an individual cell of a clinical bacterial isolate.