A Pseudomonas aeruginosa type VI secretion phospholipase D effector targets both prokaryotic and eukaryotic cells.
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PldB is characterised as a type VI secretion phospholipase D effector with antibacterial activity directed at the prokaryotic periplasm, and it also promotes invasion of eukaryotic cells.
"Here we describe the characterization of a P. aeruginosa H3-T6SS-dependent phospholipase D effector, PldB, and its three tightly linked cognate immunity proteins. PldB targets the periplasm of prokaryotic cells and exerts an antibacterial activity."
Delivery of the Pseudomonas aeruginosa Phospholipase Effectors PldA and PldB in a VgrG- and H2-T6SS-Dependent Manner.
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PldB is encoded by PA5089, immediately downstream of vgrG5 (PA5090), and its locus tag is distinct from that of PldA (PA3487).
"vgrG5 (PA5090, blue) is encoded directly upstream of pldB (PA5089, cyan)"
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PldB secretion requires VgrG5 and PldB-mediated killing of competitor cells is abolished in a vgrG5 mutant.
"Remarkably, PldB secretion was abrogated in absence of VgrG5 (Figure 1B, middle panel, lane 5), while PldB-mediated killing was abolished when using attacker strains lacking vgrG5"
Diverse type VI secretion phospholipases are functionally plastic antibacterial effectors.
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The Tle5 family, to which PldA and PldB belong, is defined by dual HxKxxxxD motifs characteristic of phospholipase D enzymes.
"Four of the families (Tle1-4) exhibit the GxSxG motif common in esterases and many lipases, while the fifth (Tle5) possesses dual HxKxxxxD motifs found in PLD enzymes"
PA5089 (pldB) review notes
Gene Ontology annotation through association of InterPro records with GO terms
Gene Ontology annotation based on Enzyme Commission mapping
Annotation inferences using phylogenetic trees