O serotype-independent susceptibility of Pseudomonas aeruginosa to lectin-like pyocins.
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.
Affiliation: Centre of Microbial and Plant Genetics, University of Leuven, 3001, Heverlee, Belgium.Show MeSH
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Mentions: Multiple genes encoding proteins with a tandem-MMBL domain architecture were retrieved in several P. aeruginosa genomic sequences. Being only distantly related to LlpAs of other Pseudomonas species (<30% amino acid sequence identity), these proteins fall into two remote groups with borderline pairwise homology (˜28% identity) (Fig. 1A, Fig. S1, Table S3). One cluster consists of PyoL1 homologues with sequences either identical to the C1433 protein (in strain C1426, the non-mucoid progenitor of mucoid strain C1433) (Stewart et al. 2014) or sharing >86% identity to it (in strains 62, 3578, 3579, BWHPSA001, and BWHPSA016; Pseudomonas aeruginosa initiative, Broad Institute). Within the newly identified second cluster, pairwise sequence identities between the proteins from strains BK1 (Jeganathan et al. 2014), BWHPSA007 (with two homologues) and BWH033 (Pseudomonas aeruginosa initiative, Broad Institute), and VRFPA06 (Murugan et al. 2014) exceed 95%. The members of the respective clusters also differ by the presence (BWHPSA007 group) or absence (C1433 group) of an amino-terminal Sec-specific signal sequence. In this respect, PyoL1 and its homologues resemble other Pseudomonas LlpAs, lacking a discernable secretion motif, whereas the members of the second group are most likely substrates of the Sec translocon, similarly to Xanthomonas and Burkholderia LlpAs (Ghequire et al. 2012b, 2013b).
Affiliation: Centre of Microbial and Plant Genetics, University of Leuven, 3001, Heverlee, Belgium.