Binding of polycationic antibiotics and polyamines to lipopolysaccharides of Pseudomonas aeruginosa

A. A. Peterson, Robert Hancock, E. J. McGroarty

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109 Citations (Scopus)


Polycations, such as aminoglycoside and peptide antibiotics, and naturally occurring polyamines were found to bind to the lipopolysaccharide of Pseudomonas aeruginosa and alter its packing arrangement. Binding of cations was measured by the displacement of a cationic spin probe from lipopolysaccharide into the aqueous environment upon addition of competitive cations. The level of probe displacement was dependent on the concentration and charge of the competing cation, with the more highly charged cations being more effective at displacing probe. The relative affinity of several antibiotics for lipopolysaccharide correlated with their ability to increase outer membrane permeability, while the relative affinity of several polyamines correlated with their ability to stabilize the outer membrane. Probe mobility within the lipopolysaccharide head group was shown to be decreased by cationic antibiotics and unaltered or increased by polyamines. We propose that antibiotic permeability and disruption of outer membrane integrity by polycationic antibiotics result from binding of the antibiotic to anionic groups on lipopolysaccharide with a consequent change in the conformation of lipopolysaccharide aggregate structure.

Original languageEnglish
Pages (from-to)1256-1261
Number of pages6
JournalJournal of bacteriology
Issue number3
Publication statusPublished - 1 Dec 1985
Externally publishedYes

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology

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