Isolation and structural characterization of an 8-O-(4-amino-4-deoxy-beta-L-arabinopyranosyl)-3-deoxy-D-manno- octulosonic acid disaccharide in the lipopolysaccharide of a Proteus mirabilis deep rough mutant.

On short treatment of the lipopolysaccharide of a deep rough mutant of Proteus mirabilis (strain R45) with hydrochloric acid (0.01 M, 10 min, 100 degrees C) a compound was released which, on high-voltage paper electrophoresis, migrated slightly to the cathode (MGlcN = 0.19) and which stained with ninhydrin, alkaline silver nitrate and in the thiobarbituric acid assay. After purification and derivatization, its chemical structure was identified by combined gas-liquid chromatography/mass spectrometry and two-dimensional shift-correlated proton nuclear magnetic resonance spectroscopy as 8-O-(4-amino-4-deoxy-beta-L-arabinopyranosyl)-3-deoxy-D-manno-octu losonic acid. This disaccharide was also present in a wild-type strain of P. mirabilis.