Novel lectin-like bacteriocins of biocontrol strain Pseudomonas fluorescens Pf-5.
Bacteriocin LlpA, produced by Pseudomonas sp. strain BW11M1, is a peculiar antibacterial protein due to its homology to mannose-binding lectins mostly found in monocots (A. H. A. Parret, G. Schoofs, P. Proost, and R. De Mot, J. Bacteriol. 185:897-908, 2003). Biocontrol strain Pseudomonas fluorescens Pf-5 contains two llpA-like genes, named llpA1(Pf-5) and llpA2(Pf-5). Recombinant Escherichia coli cells expressing llpA1(Pf-5) or llpA2(Pf-5) acquired bacteriocin activity and secreted a 31-kDa protein cross-reacting with LlpA(BW11M1) antibodies. Antibacterial activity of the recombinant proteins was evidenced by gel overlay assays. Analysis of the antimicrobial spectrum indicated that LlpA1(Pf-5) and LlpA2(Pf-5) are able to inhibit P. fluorescens strains, as well as the related mushroom pathogen Pseudomonas tolaasii. LlpA-type bacteriocins are characterized by a domain structure consisting of tandem monocot mannose-binding lectin (MMBL) domains. Molecular phylogeny of these MMBL domains suggests that the individual MMBL domains within an LlpA protein have evolved separately toward a specific, as yet unknown, function or, alternatively, were acquired from different ancestral sources. Our observations are consistent with earlier observations, which hinted that MMBL-like bacteriocins represent a new family of antibacterial proteins, probably with a novel mode of action.
Parret
Annabel H A
AH
Centre of Microbial and Plant Genetics, Katholieke Universiteit Leuven, Kasteelpark Arenberg 20, B-3001 Heverlee, Belgium.
Temmerman
Koen
K
De Mot
René
R
D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D001430:Bacteriocins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D037241:Mannose-Binding Lectins / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010572:Pest Control, Biological; D010935:Plant Diseases / Q000382:microbiology*; D011549:Pseudomonas / Q000187:drug effects / Q000254:growth & development*; D011551:Pseudomonas fluorescens / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*
D000900:Anti-Bacterial Agents; D001430:Bacteriocins; D037241:Mannose-Binding Lectins