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Collagen-like proteins in pathogenic E. coli strains.

Ghosh N, McKillop TJ, Jowitt TA, Howard M, Davies H, Holmes DF, Roberts IS, Bella J - PLoS ONE (2012)

Bottom Line: Under the electron microscope, collagen-like proteins from E. coli O157:H7 show a dumbbell shape, with two globular domains joined by a hinged stalk.This morphology is consistent with their likely role as trimeric phage side-tail proteins that participate in the attachment of phage particles to E. coli target cells, either directly or through assembly with other phage tail proteins.Thus, collagen-like proteins in enterohaemorrhagic E. coli genomes may have a direct role in the dissemination of virulence-related genes through infection of harmless strains by induced bacteriophages.

View Article: PubMed Central - PubMed

Affiliation: Manchester Interdisciplinary Biocentre, University of Manchester, Manchester, United Kingdom.

ABSTRACT
The genome sequences of enterohaemorrhagic E. coli O157:H7 strains show multiple open-reading frames with collagen-like sequences that are absent from the common laboratory strain K-12. These putative collagens are included in prophages embedded in O157:H7 genomes. These prophages carry numerous genes related to strain virulence and have been shown to be inducible and capable of disseminating virulence factors by horizontal gene transfer. We have cloned two collagen-like proteins from E. coli O157:H7 into a laboratory strain and analysed the structure and conformation of the recombinant proteins and several of their constituting domains by a variety of spectroscopic, biophysical, and electron microscopy techniques. We show that these molecules exhibit many of the characteristics of vertebrate collagens, including trimer formation and the presence of a collagen triple helical domain. They also contain a C-terminal trimerization domain, and a trimeric α-helical coiled-coil domain with an unusual amino acid sequence almost completely lacking leucine, valine or isoleucine residues. Intriguingly, these molecules show high thermal stability, with the collagen domain being more stable than those of vertebrate fibrillar collagens, which are much longer and post-translationally modified. Under the electron microscope, collagen-like proteins from E. coli O157:H7 show a dumbbell shape, with two globular domains joined by a hinged stalk. This morphology is consistent with their likely role as trimeric phage side-tail proteins that participate in the attachment of phage particles to E. coli target cells, either directly or through assembly with other phage tail proteins. Thus, collagen-like proteins in enterohaemorrhagic E. coli genomes may have a direct role in the dissemination of virulence-related genes through infection of harmless strains by induced bacteriophages.

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Related in: MedlinePlus

Typical morphologies of podoviridae and siphoviridae particles (reproduced with permission from ViralZone, Swiss Institute of Bioinformatics:www.expasy.org/viralzone,[79]). The representative 933W phage and most field isolates show a podoviridae morphology, with isometric capsids of about 60–70 nm in diameter and short tails of 10–30 nm in length [12], [56]. EPclPs would be the main components on the side tail fibres.
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pone-0037872-g012: Typical morphologies of podoviridae and siphoviridae particles (reproduced with permission from ViralZone, Swiss Institute of Bioinformatics:www.expasy.org/viralzone,[79]). The representative 933W phage and most field isolates show a podoviridae morphology, with isometric capsids of about 60–70 nm in diameter and short tails of 10–30 nm in length [12], [56]. EPclPs would be the main components on the side tail fibres.

Mentions: All prophages and phages containing EPclP sequences are described as Caudovirales, or tailed bacteriophages. Bacteriophage 933W, isolated from the O157:H7 strain EDL933, was amongst the first EPclP-containing phages to be studied [53], [54], [55], [56]. Particles of 933W observed under the electron microscope show regular hexagonal heads (probably icosahedral), about 70 nm wide, and short tails 22–28 nm long and 13–17 nm wide [55], [56]. Often, 933W virions clump together through some form of tail-tail interaction [56]. Phage induction from EHEC strains results in virion particles with different morphologies [12], [34], [57], [58], that are usually classified as members of the Podoviridae or Siphoviridae families, with short or long non-contractile tails, respectively. Phages of these families often show tail fibres extending laterally from the sides of the tails (Figure 12), although none of the published electron micrographs of phages from EHEC strains has sufficient detail for their visualization. Tail fibres are often used for the phage particles to attach to the target cells, and this attachment triggers further events leading to injection of the viral DNA in the host cell periplasm.


Collagen-like proteins in pathogenic E. coli strains.

Ghosh N, McKillop TJ, Jowitt TA, Howard M, Davies H, Holmes DF, Roberts IS, Bella J - PLoS ONE (2012)

Typical morphologies of podoviridae and siphoviridae particles (reproduced with permission from ViralZone, Swiss Institute of Bioinformatics:www.expasy.org/viralzone,[79]). The representative 933W phage and most field isolates show a podoviridae morphology, with isometric capsids of about 60–70 nm in diameter and short tails of 10–30 nm in length [12], [56]. EPclPs would be the main components on the side tail fibres.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3368898&req=5

pone-0037872-g012: Typical morphologies of podoviridae and siphoviridae particles (reproduced with permission from ViralZone, Swiss Institute of Bioinformatics:www.expasy.org/viralzone,[79]). The representative 933W phage and most field isolates show a podoviridae morphology, with isometric capsids of about 60–70 nm in diameter and short tails of 10–30 nm in length [12], [56]. EPclPs would be the main components on the side tail fibres.
Mentions: All prophages and phages containing EPclP sequences are described as Caudovirales, or tailed bacteriophages. Bacteriophage 933W, isolated from the O157:H7 strain EDL933, was amongst the first EPclP-containing phages to be studied [53], [54], [55], [56]. Particles of 933W observed under the electron microscope show regular hexagonal heads (probably icosahedral), about 70 nm wide, and short tails 22–28 nm long and 13–17 nm wide [55], [56]. Often, 933W virions clump together through some form of tail-tail interaction [56]. Phage induction from EHEC strains results in virion particles with different morphologies [12], [34], [57], [58], that are usually classified as members of the Podoviridae or Siphoviridae families, with short or long non-contractile tails, respectively. Phages of these families often show tail fibres extending laterally from the sides of the tails (Figure 12), although none of the published electron micrographs of phages from EHEC strains has sufficient detail for their visualization. Tail fibres are often used for the phage particles to attach to the target cells, and this attachment triggers further events leading to injection of the viral DNA in the host cell periplasm.

Bottom Line: Under the electron microscope, collagen-like proteins from E. coli O157:H7 show a dumbbell shape, with two globular domains joined by a hinged stalk.This morphology is consistent with their likely role as trimeric phage side-tail proteins that participate in the attachment of phage particles to E. coli target cells, either directly or through assembly with other phage tail proteins.Thus, collagen-like proteins in enterohaemorrhagic E. coli genomes may have a direct role in the dissemination of virulence-related genes through infection of harmless strains by induced bacteriophages.

View Article: PubMed Central - PubMed

Affiliation: Manchester Interdisciplinary Biocentre, University of Manchester, Manchester, United Kingdom.

ABSTRACT
The genome sequences of enterohaemorrhagic E. coli O157:H7 strains show multiple open-reading frames with collagen-like sequences that are absent from the common laboratory strain K-12. These putative collagens are included in prophages embedded in O157:H7 genomes. These prophages carry numerous genes related to strain virulence and have been shown to be inducible and capable of disseminating virulence factors by horizontal gene transfer. We have cloned two collagen-like proteins from E. coli O157:H7 into a laboratory strain and analysed the structure and conformation of the recombinant proteins and several of their constituting domains by a variety of spectroscopic, biophysical, and electron microscopy techniques. We show that these molecules exhibit many of the characteristics of vertebrate collagens, including trimer formation and the presence of a collagen triple helical domain. They also contain a C-terminal trimerization domain, and a trimeric α-helical coiled-coil domain with an unusual amino acid sequence almost completely lacking leucine, valine or isoleucine residues. Intriguingly, these molecules show high thermal stability, with the collagen domain being more stable than those of vertebrate fibrillar collagens, which are much longer and post-translationally modified. Under the electron microscope, collagen-like proteins from E. coli O157:H7 show a dumbbell shape, with two globular domains joined by a hinged stalk. This morphology is consistent with their likely role as trimeric phage side-tail proteins that participate in the attachment of phage particles to E. coli target cells, either directly or through assembly with other phage tail proteins. Thus, collagen-like proteins in enterohaemorrhagic E. coli genomes may have a direct role in the dissemination of virulence-related genes through infection of harmless strains by induced bacteriophages.

Show MeSH
Related in: MedlinePlus