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O serotype-independent susceptibility of Pseudomonas aeruginosa to lectin-like pyocins.

Ghequire MG, Dingemans J, Pirnay JP, De Vos D, Cornelis P, De Mot R - Microbiologyopen (2014)

Bottom Line: The recombinant proteins exhibit species-specific antagonistic activities down to nanomolar concentrations against clinical and environmental P. aeruginosa strains, including several multidrug-resistant isolates.No correlation was found between L pyocin susceptibility and phylogenetic relatedness of P. aeruginosa isolates.Sensitive strains were retrieved in 13 out of 15 O serotypes tested, excluding the possibility that the highly variable and immunogenic O serotype antigen of the LPS coating would represent a dominant susceptibility-discriminating factor.

View Article: PubMed Central - PubMed

Affiliation: Centre of Microbial and Plant Genetics, University of Leuven, 3001, Heverlee, Belgium.

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Domain structure of L pyocins (A) and carbohydrate-binding sites in pseudomonad tandem-monocot mannose-binding lectin (MMBLs) (B). (A) The cleavable secretion signal sequence, if present, is indicated by an orange box. The amino-terminal MMBL domain is colored red, the carboxy-terminal MMBL domain blue and the C-terminal extension green. The six candidate carbohydrate-binding sites, with their corresponding designations, are marked by gray boxes. Alternative site names are indicated between parentheses (McCaughey et al. 2014). (B) Sequence alignments of the carbohydrate-binding sites corresponding to the consensus motif QxDxNxVxY in LlpAs and L pyocins (derived from sequence alignment in Fig. S1) are shown in differential shading, corresponding to sequence conservation. The sequence logo graph visualizes the degree of consensus for each residue. Sequence designations are specified in the legend of Figure 1.
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fig02: Domain structure of L pyocins (A) and carbohydrate-binding sites in pseudomonad tandem-monocot mannose-binding lectin (MMBLs) (B). (A) The cleavable secretion signal sequence, if present, is indicated by an orange box. The amino-terminal MMBL domain is colored red, the carboxy-terminal MMBL domain blue and the C-terminal extension green. The six candidate carbohydrate-binding sites, with their corresponding designations, are marked by gray boxes. Alternative site names are indicated between parentheses (McCaughey et al. 2014). (B) Sequence alignments of the carbohydrate-binding sites corresponding to the consensus motif QxDxNxVxY in LlpAs and L pyocins (derived from sequence alignment in Fig. S1) are shown in differential shading, corresponding to sequence conservation. The sequence logo graph visualizes the degree of consensus for each residue. Sequence designations are specified in the legend of Figure 1.

Mentions: The MMBL domains within each P. aeruginosa tandem display pronounced sequence divergence (<28% amino acid identity; Fig. 1B), similar to previously characterized LlpAs in Pseudomonas (Ghequire et al. 2012a). This consistent domain segregation reflects a functional specialization of the MMBL modules and experimental evidence in support of this was reported for P. putida and P. protegens LlpAs (Ghequire et al. 2013a). The QxDxNxVxY motifs defining the rhamnose-binding pockets IIIC and IIC of pyoL1 are well conserved across both P. aeruginosa groups, suggesting a similar binding potential of the carboxy-terminal MMBL domain (Fig. 2). However, at sites IC, IN, and IIIN, the C1433 and BWHPSA007 groups carry quite dissimilar sequences. While the IIIN motif of the C1433 group resembles well the corresponding sequences of non-P. aeruginosa LlpAs, the reverse is true for the IN and IC motifs that are better preserved in BWHPSA007. The functional implications of this apparent group-linked motif differentiation are not clear. Sites IN and IC are not surface-exposed, excluding their involvement in the carbohydrate-binding function of the bacteriocin, and the weak binding to site IIIN is probably of little physiological significance, if any (Ghequire et al. 2013a; McCaughey et al. 2014). The highly degenerate IIN site likely lost its carbohydrate-binding potential completely in all pseudomonads.


O serotype-independent susceptibility of Pseudomonas aeruginosa to lectin-like pyocins.

Ghequire MG, Dingemans J, Pirnay JP, De Vos D, Cornelis P, De Mot R - Microbiologyopen (2014)

Domain structure of L pyocins (A) and carbohydrate-binding sites in pseudomonad tandem-monocot mannose-binding lectin (MMBLs) (B). (A) The cleavable secretion signal sequence, if present, is indicated by an orange box. The amino-terminal MMBL domain is colored red, the carboxy-terminal MMBL domain blue and the C-terminal extension green. The six candidate carbohydrate-binding sites, with their corresponding designations, are marked by gray boxes. Alternative site names are indicated between parentheses (McCaughey et al. 2014). (B) Sequence alignments of the carbohydrate-binding sites corresponding to the consensus motif QxDxNxVxY in LlpAs and L pyocins (derived from sequence alignment in Fig. S1) are shown in differential shading, corresponding to sequence conservation. The sequence logo graph visualizes the degree of consensus for each residue. Sequence designations are specified in the legend of Figure 1.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4263511&req=5

fig02: Domain structure of L pyocins (A) and carbohydrate-binding sites in pseudomonad tandem-monocot mannose-binding lectin (MMBLs) (B). (A) The cleavable secretion signal sequence, if present, is indicated by an orange box. The amino-terminal MMBL domain is colored red, the carboxy-terminal MMBL domain blue and the C-terminal extension green. The six candidate carbohydrate-binding sites, with their corresponding designations, are marked by gray boxes. Alternative site names are indicated between parentheses (McCaughey et al. 2014). (B) Sequence alignments of the carbohydrate-binding sites corresponding to the consensus motif QxDxNxVxY in LlpAs and L pyocins (derived from sequence alignment in Fig. S1) are shown in differential shading, corresponding to sequence conservation. The sequence logo graph visualizes the degree of consensus for each residue. Sequence designations are specified in the legend of Figure 1.
Mentions: The MMBL domains within each P. aeruginosa tandem display pronounced sequence divergence (<28% amino acid identity; Fig. 1B), similar to previously characterized LlpAs in Pseudomonas (Ghequire et al. 2012a). This consistent domain segregation reflects a functional specialization of the MMBL modules and experimental evidence in support of this was reported for P. putida and P. protegens LlpAs (Ghequire et al. 2013a). The QxDxNxVxY motifs defining the rhamnose-binding pockets IIIC and IIC of pyoL1 are well conserved across both P. aeruginosa groups, suggesting a similar binding potential of the carboxy-terminal MMBL domain (Fig. 2). However, at sites IC, IN, and IIIN, the C1433 and BWHPSA007 groups carry quite dissimilar sequences. While the IIIN motif of the C1433 group resembles well the corresponding sequences of non-P. aeruginosa LlpAs, the reverse is true for the IN and IC motifs that are better preserved in BWHPSA007. The functional implications of this apparent group-linked motif differentiation are not clear. Sites IN and IC are not surface-exposed, excluding their involvement in the carbohydrate-binding function of the bacteriocin, and the weak binding to site IIIN is probably of little physiological significance, if any (Ghequire et al. 2013a; McCaughey et al. 2014). The highly degenerate IIN site likely lost its carbohydrate-binding potential completely in all pseudomonads.

Bottom Line: The recombinant proteins exhibit species-specific antagonistic activities down to nanomolar concentrations against clinical and environmental P. aeruginosa strains, including several multidrug-resistant isolates.No correlation was found between L pyocin susceptibility and phylogenetic relatedness of P. aeruginosa isolates.Sensitive strains were retrieved in 13 out of 15 O serotypes tested, excluding the possibility that the highly variable and immunogenic O serotype antigen of the LPS coating would represent a dominant susceptibility-discriminating factor.

View Article: PubMed Central - PubMed

Affiliation: Centre of Microbial and Plant Genetics, University of Leuven, 3001, Heverlee, Belgium.

Show MeSH
Related in: MedlinePlus