Pel is a cationic exopolysaccharide that cross-links extracellular DNA in the Pseudomonas aeruginosa biofilm matrix

Laura K. Jennings, Kelly M. Storek, Hannah E. Ledvina, Charlène Coulon, Lindsey S. Marmont, Irina Sadovskaya, Patrick R. Secor, Boo Shan Tseng, Michele Scian, Alain Filloux, Daniel J. Wozniak, P. Lynne Howell, Matthew R. Parsek

Research output: Contribution to journalArticlepeer-review

436 Scopus citations

Abstract

Biofilm formation is a complex, ordered process. In the opportunistic pathogen Pseudomonas aeruginosa, Psl and Pel exopolysaccharides and extracellular DNA (eDNA) serve as structural components of the biofilm matrix. Despite intensive study, Pel's chemical structure and spatial localization within mature biofilms remain unknown. Using specialized carbohydrate chemical analyses, we unexpectedly found that Pel is a positively charged exopolysaccharide composed of partially acetylated 1→4 glycosidic linkages of N-acetylgalactosamine and N-acetylglucosamine. Guided by the knowledge of Pel's sugar composition, we developed a tool for the direct visualization of Pel in biofilms by combining Pel-specificWisteria floribunda lectin stainingwith confocal microscopy. The results indicate that Pel cross-links eDNA in the biofilm stalk via ionic interactions. Our data demonstrate that the cationic charge of Pel is distinct from that of other known P. aeruginosa exopolysaccharides and is instrumental in its ability to interact with other key biofilm matrix components.

Original languageEnglish
Pages (from-to)11353-11358
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume112
Issue number36
DOIs
StatePublished - Sep 8 2015

Keywords

  • Biofilms
  • Exopolysaccharide
  • Extracellular DNA
  • Pel
  • Psl

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