Structural investigations on the inner core region of lipopolysaccharides from Salmonella minnesota rough mutants

Abstract

The structure of the inner core region (L-glycero-D-mannoheptose/2-keto-3-deoxy-D-mannooctulosonic acid region) of lipopolysaccharides from Salmonella minnesota rough mutants was investigated. Using conventional methods (neutral sugar analysis, Smith degradation and methylation analysis) combined with gas chromatography/mass spectrometry (GC/MS) of higher oligosaccharides (up to tetrasaccharide), the linkages of the core sugars of lipopolysaccharides from S. minnesota rough mutants, strains R4 (Rd2P-), R7 (Rd1P-) and R5 (RcP-) were determined as: (formula see text) with R representing H in R4, L-glycero-D-mannoheptopyranosyl in R7, and D-glucopyranosyl-(1----3)-L-glycero-D-mannoheptopyranosyl in R5, respectively. In addition, it is shown that heterogeneity within the neutral sugar part of these lipopolysaccharides is low.