Calcium ions induce collapse of charged O-side chains of lipopolysaccharides from Pseudomonas aeruginosa.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 19605401.
- Also identified by DOI 10.1098/rsif.2009.0190.focus and PMC identifier 2843973.
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Abstract
Lipopolysaccharide (LPS) monolayers deposited on planar, hydrophobic substrates were used as a defined model of outer membranes of Pseudomonas aeruginosa strain dps 89. To investigate the influence of ions on the (out-of-plane) monolayer structure, we measured specular X-ray reflectivity at high energy (22 keV) to ensure transmission through water. Electron density profiles were reconstructed from the reflectivity curves, and they indicate that the presence of Ca(2+) ions induces a significant change in the conformation of the charged polysaccharide head groups (O-side chains). Monte Carlo simulations based on a minimal computer model of LPS molecules allow for the modelling of 100 or more molecules over 10(-3) s and theoretically explained the tendency found by experiments.
Medical subject headings
- Calcium
- Lipopolysaccharides
- Pseudomonas aeruginosa
- X-Ray Diffraction