THE OCCURRENCE OF GLYCINE IN BACTERIAL LIPOPOLYSACCHARIDES

The aminoacyl analysis of endotoxic lipopolysaccharides (LPS) isolated from several bacteria revealed essential amounts of glycine, among th e inherent LPS components. Significant amounts of the glycine was dete cted in lipopolysaccharides isolated from over 30 strains of Escherich ia, Salmonella, Hafnia, Citrobacter and Shigella species. Glycine as a single amino acid was found only in a core part of LPS. Molar ratio o f glycine in core oligosaccharide fraction ranged from 0.2 to 0.6 per 3 heptoses. The oligosaccharide enriched in glycine was isolated using the HPLC. The amino acid appeared to be terminally located in a core oligosaccharide. The labelling of the lipopolysaccharide cores was ach ieved when the bacteria were cultivated in the presence of radioactive [C-14]glycine. The labelled core oligosaccharide released the radioac tivity during treatment with mild alkali or acid (0.1 M NaOH or HCl, 1 00 degrees C, 4 h). The radioactivity in SDS-polyacrylamide gel electr ophoresis migrated exclusively with LPS. The results indicate that ami no acid is an integral constituent of core oligosaccharide in lipopoly saccharide.