31P nuclear magnetic resonance spectroscopy of lipopolysaccharides from Pseudomonas aeruginosa.

Intact lipopolysaccharide antigens isolated from seven different immunotypes of Pseudomonas aeruginosa have been examined by 31P-NMR spectroscopy. These macromolecular complexes contain phosphorus covalently attached to the carbohydrate residues present in the lipid A moiety and the 'core' oligosaccharide region. The spectral signals for various ortho- and pyrophosphoric esters were observed. All phosphate groups appeared to be monoesterified. Certain shifts characteristic for phosphate diester groups, observed in lipopolysaccharide complexes from other Gram-negative bacteria, were absent. Furthermore, no evidence was found to indicate that phosphate groups are involved in the covalent linkage of individual lipopolysaccharide complexes to form dimers or trimers.