title: Genetic and biochemical analyses of the Pseudomonas aeruginosa Psl exopolysaccharide reveal overlapping roles for polysaccharide synthesis enzymes in Psl and LPS production.
abstract: Exopolysaccharides contribute significantly to attachment and biofilm formation in the opportunisitc pathogen Pseudomonas aeruginosa. The Psl polysaccharide, which is synthesized by the polysaccharide synthesis locus (psl), is required for biofilm formation in non-mucoid strains that do not rely on alginate as the principal biofilm polysaccharide. In-frame deletion and complementation studies of individual psl genes revealed that 11 psl genes, pslACDEFGHIJKL, are required for Psl production and surface attachment. We also present the first structural analysis of the psl-dependent polysaccharide, which consists of a repeating pentasaccharide containing d-mannose, d-glucose and l-rhamnose: [See text]. In addition, we identified the sugar nucleotide precursors involved in Psl generation and demonstrated the requirement for GDP-d-mannose, UDP-d-glucose and dTDP-l-rhamnose in Psl production and surface attachment. Finally, genetic analyses revealed that wbpW restored Psl production in a pslB mutant and pslB promoted A-band LPS synthesis in a wbpW mutant, indicating functional redundancy and overlapping roles for these two enzymes. The structural and genetic data presented here provide a basis for further investigation of the Psl proteins and potential roles for Psl in the biology and pathogenesis of P. aeruginosa.
authors: Department of Microbiology and Immunology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
authors: Matthew S
authors: MS
authors: Byrd
authors: Irina
authors: I
authors: Sadovskaya
authors: Evgueny
authors: E
authors: Vinogradov
authors: Haiping
authors: H
authors: Lu
authors: April B
authors: AB
authors: Sprinkle
authors: Stephen H
authors: SH
authors: Richardson
authors: Luyan
authors: L
authors: Ma
authors: Brad
authors: B
authors: Ralston
authors: Matthew R
authors: MR
authors: Parsek
authors: Erin M
authors: EM
authors: Anderson
authors: Joseph S
authors: JS
authors: Lam
authors: Daniel J
authors: DJ
authors: Wozniak
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018441:Biofilms; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D008070:Lipopolysaccharides / Q000096:biosynthesis*; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism*; D016296:Mutagenesis; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis*; D011550:Pseudomonas aeruginosa / Q000201:enzymology* / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D008070:Lipopolysaccharides; D009097:Multienzyme Complexes; D011135:Polysaccharides, Bacterial; C115749:WbpW protein, Pseudomonas aeruginosa; C064841:exopolysaccharide, Pseudomonas