The unfolding of the P pili quaternary structure by stretching is reversible, not plastic

Fällman, Erik; Schedin, Staffan; Jaß, Jana; Uhlin, Bernt Eric; Axner, Ove

doi:10.1038/sj.embor.7400310

Cited by 67 publications

(107 citation statements)

References 29 publications

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“…The CU pilus rod also contributes to UPEC persistence in the urinary tract by dissipating hydrodynamic forces through the reversible uncoiling of its helical rod structure [45][46][47][48] .…”

Section: Structure Of the Pilus Rodmentioning

confidence: 99%

A comprehensive guide to pilus biogenesis in Gram-negative bacteria

2017

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Pili are critical virulence factors of many Gram-negative pathogens. These surface structures provide bacteria with a link to their outside environments, allowing bacteria to interact with their hosts, other surfaces or with each other. They can even provide a conduit for the exchange of information. The surface chemistries and other biophysical properties of pili are uniquely adapted to the environmental challenges faced by bacteria. The assembly of these surface structures presents a molecular engineering challenge, which bacteria have solved in a variety of unique ways. In this review, we examine recent advances in our structural understanding of various Gram-negative pilus systems and discuss their functional implications.

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Section: Structure Of the Pilus Rodmentioning

confidence: 99%

A comprehensive guide to pilus biogenesis in Gram-negative bacteria

2017

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“…In keeping with the binding strategies of proposed adhesion models for various other piliated Gram-negative and Gram-positive bacteria, we suggest that only after the elongated mucus-specific pilus fibers make their initial contact and attach L. rhamnosus GG cells to the mucosal surface will MBF proteins be in such close proximity that their binding also becomes a possibility. However, unlike Gramnegative pili, which, due to the structural elasticity of their subunit constituents, would be able to retract reversibly and pull microbes closer to the host cells (17,20,26), pili from Gram-positive bacteria appear to consist of inextensible pilin subunits (2), making them more rigid and less apt to function in a similar manner. Consequently, the SpaCBA pilus-mediated binding in L. rhamnosus GG that brings LPXTG-like surface adhesins (e.g., MBF and MabA) closer to the mucus layer could expectedly be less dynamic and more arbitrary, possibly relying on the "zipper-like" mechanistic explanation of adhesion in piliated Gram-positive pathogens described previously (38).…”

Section: Vol 77 2011 Mucus-specific Surface Adhesin From L Rhamnosmentioning

confidence: 99%

Functional Characterization of a Mucus-Specific LPXTG Surface Adhesin from Probiotic Lactobacillus rhamnosus GG

Ossowski

Satokari

Reunanen

et al. 2011

Appl Environ Microbiol

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In spite of the wealth of clinical evidence supporting the health benefits of Lactobacillus rhamnosus GG in humans, there is still a lack of understanding of the molecular mechanisms behind its probiosis. Current knowledge suggests that the health-promoting effects of this probiotic strain might be partly dependent on its persistence in the intestine and adhesion to mucosal surfaces. Moreover, L. rhamnosus GG contains mucusbinding pili that might also explain the occupation of its ecological niche as a comparatively less stringent allochthonous intestine-dwelling bacterium. To uncover additional surface proteins involved in mucosal adhesion, we investigated the adherence properties of the only predicted protein (LGG_02337) in L. rhamnosus GG that exhibits homology with a known mucus-binding domain. We cloned a recombinant form of the gene for this putative mucus adhesin and established that the purified protein readily adheres to human intestinal mucus. We also showed that this mucus adhesin is visibly distributed throughout the cell surface and participates in the adhesive interaction between L. rhamnosus GG and mucus, although less prominently than the mucus-binding pili in this strain. Based on primary structural comparisons, we concluded that the current annotation of the LGG_02337 protein likely does not accurately reflect its predicted properties, and we propose that this mucus-specific adhesin be called the mucus-binding factor (MBF). Finally, we interpret our results to mean that L. rhamnosus GG MBF, as an active mucus-specific surface adhesin with a presumed ancillary involvement in pilus-mediated mucosal adhesion, plays a part in the adherent mechanisms during intestinal colonization by this probiotic.The commensal Gram-positive lactobacilli are one of the first groups of bacteria to inhabit the human gastrointestinal (GI) tract (16) and include some strains (autochthonous) that colonize the intestine stably throughout the lifetime of the host (31). In addition, there are those strains, called allochthonous, that persist only briefly in the intestine, many of these being probiotics (1, 9, 13) and understood to stimulate health-benefiting immune responses in host intestinal cells (for a review, see reference 14) or cause competitive displacement of invading pathogens (for a review, see reference 35). Thus far, the precise molecular mechanisms that differentiate the colonization ability between autochthonous and allochthonous intestinal lactobacilli remain undefined (42), although they are likely to be partly dependent on a diverse range of cell surface adhesion molecule-mediated interactions with the host intestinal mucosa. With that being said, there are a growing number of reports in the literature that indicate that lactobacillar adherence to the intestinal mucosal layer is mediated by surface proteins with a mucus-binding capacity (15,21,22,25,30,32,33,41). Moreover, homology-driven genome mining in several Lactobacillus spp. (3,7,8,11,33) has identified the presence of various-sized putative mucus ...

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“…The mechanical elasticity of E. coli P fimbriae was first determined experimentally with optical tweezers (OT) in 2004 (16,24). The force-extension curve (FEC) of a single P fimbria can be divided into three phases (Fig.…”

mentioning

confidence: 99%

Structural and Mechanical Properties of Klebsiella pneumoniae Type 3 Fimbriae

et al. 2011

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This study investigated the structural and mechanical properties of Klebsiella pneumoniae type 3 fimbriae, which constitute a known virulence factor for the bacterium. Transmission electron microscopy and optical tweezers were used to understand the ability of the bacterium to survive flushes. An individual K. pneumoniae type 3 fimbria exhibited a helix-like structure with a pitch of 4.1 nm and a three-phase force-extension curve. The fimbria was first nonlinearly stretched with increasing force. Then, it started to uncoil and extended several micrometers at a fixed force of 66 ؎ 4 pN (n ‫؍‬ 22). Finally, the extension of the fimbria shifted to the third phase, with a characteristic force of 102 ؎ 9 pN (n ‫؍‬ 14) at the inflection point. Compared with the P fimbriae and type 1 fimbriae of uropathogenic Escherichia coli, K. pneumoniae type 3 fimbriae have a larger pitch in the helix-like structure and stronger uncoiling and characteristic forces.

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The unfolding of the P pili quaternary structure by stretching is reversible, not plastic

Cited by 67 publications

References 29 publications

A comprehensive guide to pilus biogenesis in Gram-negative bacteria

A comprehensive guide to pilus biogenesis in Gram-negative bacteria

Functional Characterization of a Mucus-Specific LPXTG Surface Adhesin from Probiotic Lactobacillus rhamnosus GG

Structural and Mechanical Properties of Klebsiella pneumoniae Type 3 Fimbriae

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