Limits...
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.

Show MeSH

Related in: MedlinePlus

Collagen-like proteins from prophages embedded in the genomes of E. coli O157:H7 and other EHEC strains, referred here as EPclA to EPclD (EHEC Prophage collagen-like A to D).(A) Domain architectures. The collagen triple helical domains are labelled “Col”, and domains predicted to adopt an α-helical coiled-coil conformation (see text) are labelled “PCoil” (for phage coiled-coils). Key to other domain labels (Table 1): PfN, phage fibre N-terminal domain; PfC, phage fibre C-terminal domain; PfC2, phage fibre C-terminal domain, variant 2; Pf2, phage fibre repeat 2. (B) Sequence of a representative collagen-like protein with EPclA architecture (ECs2717), from the genome of E. coli O157:H7 Sakai. (C) Sequence of a representative collagen-like protein with EPclB architecture (Z1483), from the genome of E. coli O157:H7 EDL933. Amino acid sequences corresponding to the different predicted domains are colour-coded as in (A).
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3368898&req=5

pone-0037872-g001: Collagen-like proteins from prophages embedded in the genomes of E. coli O157:H7 and other EHEC strains, referred here as EPclA to EPclD (EHEC Prophage collagen-like A to D).(A) Domain architectures. The collagen triple helical domains are labelled “Col”, and domains predicted to adopt an α-helical coiled-coil conformation (see text) are labelled “PCoil” (for phage coiled-coils). Key to other domain labels (Table 1): PfN, phage fibre N-terminal domain; PfC, phage fibre C-terminal domain; PfC2, phage fibre C-terminal domain, variant 2; Pf2, phage fibre repeat 2. (B) Sequence of a representative collagen-like protein with EPclA architecture (ECs2717), from the genome of E. coli O157:H7 Sakai. (C) Sequence of a representative collagen-like protein with EPclB architecture (Z1483), from the genome of E. coli O157:H7 EDL933. Amino acid sequences corresponding to the different predicted domains are colour-coded as in (A).

Mentions: Several open reading frames potentially encoding collagen-like proteins have been identified by automatic sequence annotation in the genomes of EHEC strains. Those from the Sakai and EDL933 genomes will be discussed here, but many related sequences have been identified in other strains. Their primary structures show one or more collagen-like domains (Col) with the repeating collagen signature sequence (Gly-X-Y)n, flanked at both ends by a series of non-collagenous, conserved domains (Figure 1 and Table 1). Domains PfN, Pf2 and PfC have been described on the basis of sequence conservation and are associated to fibre tail proteins from phages. They appear in automatic annotation of EPclPs. Figure 1 shows the different protein architectures and the nomenclature used here to refer to them, plus two representative sequences. The most common architecture (EPclA) appears in multiple copies in each genome, with more than 90% amino acid sequence identity across copies. Table 2 gives the complete list of EPclP sequences from the Sakai and EDL933 genomes, whereas representative examples of other architectures and strains are given in Table 3.


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)

Collagen-like proteins from prophages embedded in the genomes of E. coli O157:H7 and other EHEC strains, referred here as EPclA to EPclD (EHEC Prophage collagen-like A to D).(A) Domain architectures. The collagen triple helical domains are labelled “Col”, and domains predicted to adopt an α-helical coiled-coil conformation (see text) are labelled “PCoil” (for phage coiled-coils). Key to other domain labels (Table 1): PfN, phage fibre N-terminal domain; PfC, phage fibre C-terminal domain; PfC2, phage fibre C-terminal domain, variant 2; Pf2, phage fibre repeat 2. (B) Sequence of a representative collagen-like protein with EPclA architecture (ECs2717), from the genome of E. coli O157:H7 Sakai. (C) Sequence of a representative collagen-like protein with EPclB architecture (Z1483), from the genome of E. coli O157:H7 EDL933. Amino acid sequences corresponding to the different predicted domains are colour-coded as in (A).
© Copyright Policy
Related In: Results  -  Collection

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

pone-0037872-g001: Collagen-like proteins from prophages embedded in the genomes of E. coli O157:H7 and other EHEC strains, referred here as EPclA to EPclD (EHEC Prophage collagen-like A to D).(A) Domain architectures. The collagen triple helical domains are labelled “Col”, and domains predicted to adopt an α-helical coiled-coil conformation (see text) are labelled “PCoil” (for phage coiled-coils). Key to other domain labels (Table 1): PfN, phage fibre N-terminal domain; PfC, phage fibre C-terminal domain; PfC2, phage fibre C-terminal domain, variant 2; Pf2, phage fibre repeat 2. (B) Sequence of a representative collagen-like protein with EPclA architecture (ECs2717), from the genome of E. coli O157:H7 Sakai. (C) Sequence of a representative collagen-like protein with EPclB architecture (Z1483), from the genome of E. coli O157:H7 EDL933. Amino acid sequences corresponding to the different predicted domains are colour-coded as in (A).
Mentions: Several open reading frames potentially encoding collagen-like proteins have been identified by automatic sequence annotation in the genomes of EHEC strains. Those from the Sakai and EDL933 genomes will be discussed here, but many related sequences have been identified in other strains. Their primary structures show one or more collagen-like domains (Col) with the repeating collagen signature sequence (Gly-X-Y)n, flanked at both ends by a series of non-collagenous, conserved domains (Figure 1 and Table 1). Domains PfN, Pf2 and PfC have been described on the basis of sequence conservation and are associated to fibre tail proteins from phages. They appear in automatic annotation of EPclPs. Figure 1 shows the different protein architectures and the nomenclature used here to refer to them, plus two representative sequences. The most common architecture (EPclA) appears in multiple copies in each genome, with more than 90% amino acid sequence identity across copies. Table 2 gives the complete list of EPclP sequences from the Sakai and EDL933 genomes, whereas representative examples of other architectures and strains are given in Table 3.

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