The CS6 colonization factor of human enterotoxigenic Escherichia coli contains two heterologous major subunits

Wolf, Marcia K.; Haan, Louise A.M. de; Cassels, Frederick J.; Willshaw, G. A.; Warren, Richard L.; Boedeker, Edgar C.; Gaastra, Wim

doi:10.1111/j.1574-6968.1997.tb10263.x

Cited by 56 publications

(34 citation statements)

References 18 publications

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“…The Hly plasmids belonged to different incompatibility groups, which suggested that IS91 was involved in the dissemination of these pathogenicity determinants (21,37,53,114). IS91 or very closely related isoforms have also been found adjacent to various other virulence genes in enteropathogenic, enterohemolytic, and enterotoxigenic strains of E. coli (16,42,109), including the eltAB toxin-encoding genes of the heat-labile enterotoxin (89). Furthermore, direct movement of eltAB genes by IS91 has been demonstrated (89).…”

Section: Is91 and Virulence Factorsmentioning

confidence: 99%

IS CR Elements: Novel Gene-Capturing Systems of the 21st Century?

Toleman

Bennett

Walsh

2006

Microbiol Mol Biol Rev

528

481

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SUMMARY “Common regions” (CRs), such as Orf513, are being increasingly linked to mega-antibiotic-resistant regions. While their overall nucleotide sequences show little identity to other mobile elements, amino acid alignments indicate that they possess the key motifs of IS91-like elements, which have been linked to the mobility ent plasmids in pathogenic Escherichia coli. Further inspection reveals that they possess an IS91-like origin of replication and termination sites (terIS), and therefore CRs probably transpose via a rolling-circle replication mechanism. Accordingly, in this review we have renamed CRs as ISCRs to give a more accurate reflection of their functional properties. The genetic context surrounding ISCRs indicates that they can procure 5′ sequences via misreading of the cognate terIS, i.e., “unchecked transposition.” Clinically, the most worrying aspect of ISCRs is that they are increasingly being linked with more potent examples of resistance, i.e., metallo-β-lactamases in Pseudomonas aeruginosa and co-trimoxazole resistance in Stenotrophomonas maltophilia. Furthermore, if ISCR elements do move via “unchecked RC transposition,” as has been speculated for ISCR1, then this mechanism provides antibiotic resistance genes with a highly mobile genetic vehicle that could greatly exceed the effects of previously reported mobile genetic mechanisms. It has been hypothesized that bacteria will surprise us by extending their “genetic construction kit” to procure and evince additional DNA and, therefore, antibiotic resistance genes. It appears that ISCR elements have now firmly established themselves within that regimen.

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Section: Is91 and Virulence Factorsmentioning

confidence: 99%

IS CR Elements: Novel Gene-Capturing Systems of the 21st Century?

Toleman

Bennett

Walsh

2006

Microbiol Mol Biol Rev

528

481

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“…Representatives of the ␥ 3 -fimbrial clade include AfaC-3, AfaC-7, AfaC-8, AggC, Agg3C, CS3-2, CssD, DraC, and HdaC of E. coli (32,39,76,105,158,187,189,190,238,239,293,361,363,366) (199,254,370) (Fig. 5).…”

Section: The ␥-Fimbriaementioning

confidence: 99%

“…The css operon encodes the CS6 antigen of human enterotoxigenic E. coli, which is present on the cell surface but has a morphology that is beyond the limits of resolution by electron microscopy (205,361). The css operon contains two major subunit genes, and the encoded proteins (CssA and CssB) are present at a 3:1 ratio on the bacterial surface (363,366). The assembly of this surface structure results in the binding of E. coli to human enterocytes (132).…”

Section: The ␥-Fimbriaementioning

confidence: 99%

Evolution of the Chaperone/Usher Assembly Pathway: Fimbrial Classification Goes Greek

Nuccio

Bäumler

2007

Microbiol Mol Biol Rev

298

456

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SUMMARY Many Proteobacteria use the chaperone/usher pathway to assemble proteinaceous filaments on the bacterial surface. These filaments can curl into fimbrial or nonfimbrial surface structures (e.g., a capsule or spore coat). This article reviews the phylogeny of operons belonging to the chaperone/usher assembly class to explore the utility of establishing a scheme for subdividing them into clades of phylogenetically related gene clusters. Based on usher amino acid sequence comparisons, our analysis shows that the chaperone/usher assembly class is subdivided into six major phylogenetic clades, which we have termed α-, β-, γ-, κ-, π-, and σ-fimbriae. Members of each clade share related operon structures and encode fimbrial subunits with similar protein domains. The proposed classification system offers a simple and convenient method for assigning newly discovered chaperone/usher systems to one of the six major phylogenetic groups.

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“…CssC and CssD proteins, encoded by the same gene cluster cssABCD, play the role of chaperone and usher proteins, respectively, and facilitate the assembly and translocation of structural subunits to the bacterial surface (Wolf et al, 1997;Tobias et al, 2008;Wajima et al, 2011). These structural subunits are synthesized from a precursor polypeptide and transferred into the periplasm, where CssA forms a complex with CssB and CssC that is finally recognized by CssD (Tobias et al, 2008;Wajima et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

“…CS6 is a hetero-dimeric protein and is composed of two subunits, CssA and CssB, in equal stoichiometry (Wolf et al, 1997;Ghosal et al, 2009). CssC and CssD proteins, encoded by the same gene cluster cssABCD, play the role of chaperone and usher proteins, respectively, and facilitate the assembly and translocation of structural subunits to the bacterial surface (Wolf et al, 1997;Tobias et al, 2008;Wajima et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Characterization of oligomeric assembly of colonization factor CS6 from enterotoxigenic Escherichia coli

et al. 2016

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The widely distributed colonization factor (CF) CS6 of enterotoxigenic Escherichia coli (ETEC) has gained importance over the years in terms of its structure and function. CS6 is an afimbrial assembly in contrast to the other ETEC CFs, which are mostly fimbrial. A recent study predicted a linear fibre model for recombinant chimeric CS6 and formation of oligomers in solution. In this study, we characterized the oligomeric assembly of CS6, purified from a clinical ETEC isolate and identified its existence in the WT strain. We found that purified CS6 forms a continuous array of higher order oligomers composed of two tightly associated subunits, CssA and CssB in an equal (1:1) stoichiometry. This oligomerization occurs by formation of (CssA-CssB) n complex where 'n' increases with the concentration. The diameter of CS6 oligomers also proportionally increases with concentration. More significantly, we showed CS6 oligomers to be spherical in shape instead of being linear fibres as predicted earlier and this was further confirmed by electron microscopy. We also showed CS6 assembled on the bacterial surface in the form of an oligomeric complex. This process depends on the expression of properly folded CssA and CssB together, guided by the chaperone CssC and usher CssD. In conclusion, our results provide evidence for the existence of concentration-dependent, spherical oligomers of CS6 comprising both the structural subunits in equal stoichiometry and the CS6 oligomeric complex on the ETEC surface.

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The CS6 colonization factor of human enterotoxigenic Escherichia coli contains two heterologous major subunits

Cited by 56 publications

References 18 publications

IS CR Elements: Novel Gene-Capturing Systems of the 21st Century?

IS CR Elements: Novel Gene-Capturing Systems of the 21st Century?

Evolution of the Chaperone/Usher Assembly Pathway: Fimbrial Classification Goes Greek

Characterization of oligomeric assembly of colonization factor CS6 from enterotoxigenic Escherichia coli

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