Structure of the O16 antigen of Stenotrophomonas maltophilia

A polysaccharide containing D-ribose, N-acetyl-D-glucosamine, and N-acetyl- D-mannosamine was isolated from the phenol-soluble lipopolysaccharide extra cted from defatted cell walls of the reference strain (560) for serogroup O 16 of Stenotrophomas maltophilia. The results of methylation analysis, chem ical degradations, and NMR spectroscopy showed that the polysaccharide is b ased on a branched trisaccharide repeating-unit of the structure shown belo w. Although ribose was absent from about half of the units in the isolated polymer, the regularity and spacing of the ladder observed on SDS-PAGE of t he parent lipopolysaccharide indicate that this was an artefact of the mild acid hydrolysis used to release the polymer. On the other hand, the effect s of mild alkaline hydrolysis on the polymer indicated partial O-acetylatio n. [GRAPHICS] (C) 2001 Elsevier Science Ltd. All rights reserved.