Structural and Mechanical Properties of
            <i>Klebsiella pneumoniae</i>
            Type 3 Fimbriae

Chen, Feng Jung; Chan, Chia Han; Huang, Ying; Liu, Kuo Liang; Peng, Hwei-Ling; Chang, Hwan‐You; Liou, Gunn‐Guang; Yew, Tri‐Rung; Liu, Cheng-Hsien; Hsu, Ken-Yuh; Hsu, Lih‐Hsing

doi:10.1128/jb.01395-10

Cited by 25 publications

(35 citation statements)

References 46 publications

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“…First, unwinding and rewinding at a constant force suggests that CS2 has a helix-like macromolecular structure, similar to both CFA/I and CS20 (33). In addition, the CS2 force response, with a pattern of linear increase, constant-force plateau, linear increase, is in line with what has been observed for other helix-like fimbriae, such as P, Type 1, and Type 3 fimbriae (42,43). This specific force response was also modeled, in a recent work, using a rigid-body model assembled into a helical structure exposed to tensile force (44).…”

Section: Discussionsupporting

confidence: 72%

“…ETEC fimbriae such as CS2, CFA/I, and CS20 require <15 pN unwinding force, despite differences in their assembly mechanism (see Table S1 and our previous work (24,26)); UPEC and meningitis-associated strains of E. coli express fimbriae requiring 21-30 pN of unwinding force (33,39,42); however, Type 3 fimbriae expressed by K. pneumonia in the respiratory tract require 66 pN of unwinding force (43). One should also note that the T4 fimbriae expressed by Streptococcus pneumonia, which also colonize the respiratory tract, are significantly stiffer than UPEC-and ETEC-expressed fimbriae (45).…”

Section: Discussionmentioning

confidence: 96%

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Biomechanical and Structural Features of CS2 Fimbriae of Enterotoxigenic Escherichia coli

Mortezaei

Singh

Zakrisson

et al. 2015

Biophysical Journal

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Enterotoxigenic Escherichia coli (ETEC) are a major cause of diarrhea worldwide, and infection of children in under-developed countries often leads to high mortality rates. Isolated ETEC expresses a plethora of colonization factors (fimbriae/pili), of which CFA/I and CFA/II, which are assembled via the alternate chaperone pathway (ACP), are among the most common. Fimbriae are filamentous structures whose shafts are primarily composed of helically arranged single pilin-protein subunits, with a unique biomechanical ability to unwind and rewind. A sustained ETEC infection, under adverse conditions of dynamic shear forces, is primarily attributed to this biomechanical feature of ETEC fimbriae. Recent understanding about the role of fimbriae as virulence factors points to an evolutionary adaptation of their structural and biomechanical features. In this work, we investigated the biophysical properties of CS2 fimbriae from the CFA/II group. Homology modeling of its major structural subunit, CotA, reveals structural clues related to the niche in which they are expressed. Using optical-tweezers force spectroscopy, we found that CS2 fimbriae unwind at a constant force of 10 pN and have a corner velocity (i.e., the velocity at which the force required for unwinding rises exponentially with increased speed) of 1300 nm/s. The biophysical properties of CS2 fimbriae assessed in this work classify them into a low-force unwinding group of fimbriae together with the CFA/I and CS20 fimbriae expressed by ETEC strains. The three fimbriae are expressed by ETEC, colonize in similar gut environments, and exhibit similar biophysical features, but differ in their biogenesis. Our observation suggests that the environment has a strong impact on the biophysical characteristics of fimbriae expressed by ETEC.

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Section: Discussionsupporting

confidence: 72%

Section: Discussionmentioning

confidence: 96%

Biomechanical and Structural Features of CS2 Fimbriae of Enterotoxigenic Escherichia coli

Mortezaei

Singh

Zakrisson

et al. 2015

Biophysical Journal

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“… Data from previously published studies were taken from a ref 8 , b ref 12 , c ref 13 , and d ref 7 . F uw is the force at which the pilus unwinds. …”

Section: Figurementioning

confidence: 99%

“…The N-terminal strand of one subunit fills a hydrophobic groove of the preceding subunit, thereby producing strong non-covalent interactions along the filament. This helical filament architecture is also seen in P-pili and type 1 pili expressed on uropathogenic E. coli (UPEC) that infect the bladder and may reach the upper urinary tract and kidneys 5; 6 , as well as type 3 pili expressed by Klebsiella pneumoniae that cause respiratory tract infections 7 , and E. coli S pili, which are correlated to neonatal meningitis and urinary tract infections 8 . Adhesion pili assembled via this “donor strand exchange” mechanism 9 provide effective damping against external shear forces by unwinding of their quaternary structure while leaving the tertiary structure intact.…”

Section: Introductionmentioning

confidence: 98%

A Structural Basis for Sustained Bacterial Adhesion: Biomechanical Properties of CFA/I Pili

Andersson

Björnham

Svantesson

et al. 2012

Journal of Molecular Biology

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Enterotoxigenic Escherichia coli (ETEC) are a major cause of diarrheal disease worldwide. Adhesion pili (or fimbriae), such as the CFA/I (colonization factor antigen I) organelles that enable ETEC to attach efficiently to the host intestinal tract epithelium, are critical virulence factors for initiation of infection. We characterized at single organelle level the intrinsic biomechanical properties and kinetics of individual CFA/I pili, demonstrating that weak external forces (7.5 pN) are sufficient to unwind the intact helical filament of this prototypical ETEC pilus and that it quickly regains its original structure when the force is removed. While the general relationship between exertion of force and an increase in the filament length for CFA/I pili associated with diarrheal disease is analogous to that of P-pili and type 1 pili, associated with urinary tract and other infections, the biomechanical properties of these different pili differ in key quantitative details. Unique features of CFA/I pili, including the significantly lower force required for unwinding, the higher extension speed at which the pili enter a dynamic range of unwinding, and the appearance of sudden force drops during unwinding can be attributed to morphological features of CFA/I pili including weak layer-to-layer interactions between subunits on adjacent turns of the helix, and the approximately horizontal orientation of pilin subunits with respect to the filament axis. Our results indicate that ETEC CFA/I pili are flexible organelles optimized to withstand harsh motion without breaking, resulting in continued attachment to the intestinal epithelium by the pathogenic bacteria that express these pili.

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“…Ultimately, MrkA was chosen as a target due to its key roles in infection and persistence, (44) its presence in the majority of sequenced K. pneumoniae strains, (45)(46)(47) and, critically, its location in fimbrial rods. These rods are large extracellular structures (0.5-2 µm long, 4-to-5 nm in diameter) (48,49) that are each comprised of up to 1,000s of MrkA copies. (50) The selection of target epitopes on MrkA is illustrated in Figure 2B.…”

Section: Figure 2 (A)mentioning

confidence: 99%

Antibody-Recruiting Protein-Catalyzed Capture Agents to Combat Antibiotic-Resistant Bacteria

Idso

Akhade

Arrieta-Ortiz

et al. 2019

Preprint

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Antibiotic resistant infections are projected to cause over 10 million deaths by 2050, yet the development of new antibiotics has slowed. This points to an urgent need for methodologies for the rapid development of antibiotics against emerging drug resistant pathogens. We report on a generalizable combined computational and synthetic approach, called antibody-recruiting proteincatalyzed capture agents (AR-PCCs), to address this challenge. We applied the combinatorial PCC technology to identify macrocyclic peptide ligands against highly conserved surface protein epitopes of carbapenem-resistant Klebsiella pneumoniae, an opportunistic gram-negative pathogen with drug resistant strains. Multi-omic data combined with bioinformatic analyses identified epitopes of the highly expressed MrkA surface protein of K. pneumoniae for targeting in PCC screens. The top-performing ligand exhibited high-affinity (EC50~50 nM) to full-length MrkA, and selectively bound to MrkAexpressing K. pneumoniae, but not to other pathogenic bacterial species. AR-PCCs conjugated with immunogens promoted antibody recruitment to K. pneumoniae, leading to phagocytosis and phagocytic killing by macrophages. The rapid development of this highly targeted antibiotic implies that the integrated computational and synthetic toolkit described here can be used for the accelerated production of antibiotics against drug resistant bacteria. resistant K. pneumoniae, and that the basic technology might provide a route towards drugging "undruggable" pathogenic bacteria. Results and DiscussionMulti-omic analyses to select target a protein on K. pneumoniae Here we describe the algorithm used to identify protein targets, and epitopes on those targets, for drugging K. pneumoniae using AR-PCCs. Traditional drugging strategies tend to rely on disrupting the function of, for example, an enzyme by competing for occupancy within a strategic hydrophobic binding pocket. Our requirements are very different. Instead, favorable aspects of target proteins are high expression levels on only the pathogen of interest, plus localization of that protein to the outer membrane or extracellular space of the pathogen. Further, once such a target protein is identified, there are additional considerations regarding which epitopes of that protein present the greatest opportunities for exploiting AR-PCCs. The flow diagram in Figure 2A delineates the strategy for identifying MrkA as an ideal target protein. Protein expression levels can vary across environments and growth phases, so we analyzed the transcriptional data reported by Guilhen et al(40) to identify proteins

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Structural and Mechanical Properties of Klebsiella pneumoniae Type 3 Fimbriae

Cited by 25 publications

References 46 publications

Biomechanical and Structural Features of CS2 Fimbriae of Enterotoxigenic Escherichia coli

Biomechanical and Structural Features of CS2 Fimbriae of Enterotoxigenic Escherichia coli

A Structural Basis for Sustained Bacterial Adhesion: Biomechanical Properties of CFA/I Pili

Antibody-Recruiting Protein-Catalyzed Capture Agents to Combat Antibiotic-Resistant Bacteria

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