Absolute configuration of 3-hydroxy fatty acids present in lipopolysaccharides from various bacterial groups

The absolute configuration of 3-hydroxy fatty acids has been studied, which are present in the lipopolysaccharides of the following bacteria: Phodopseudomonas gelatinosa, Rh. viridis, Rhodospirillum tenue, Chromobacterium violaceum, Pseudomonas aeruginosa, Bordetella pertussis, Vibrio metchnikovii, Vibrio cholerae, Salmonella spp., Escherichia coli, Shigella flexneri, Proteus mirabilis, Yersinia enterocolitica and Fusobacterium nucleatum. The 3-hydroxy acids were liberated by strong alkaline hydrolysis, converted to 3-methoxy acid L-phenylethylamides and analyzed by gas-liquid chromatography. With the aid of authentic D-3-hydroxy fatty acids it was shown for all lipopolysaccharides that the 3-hydroxy acids, regardless of chain lengths, branching, 3-O-substitution or type of linkage, possess the D-configuration. 2-Hydroxydodecanoic acid, which is present in some lipopolysaccharides, was analyzed in an analogous way and shown to possess the L-configuration.