Separation of 6-deoxy-heptan [correction of 6-deoxy-heptane] from a smooth-type lipopolysaccharide preparation of Burkholderia pseudomallei.

Smooth-type lipopolysaccharide (LPS) of Burkholderia pseudomallei has been reported to contain two kinds of O-antigenic polysaccharides, a 1,3-linked homopolymer of 6-deoxy-heptose and a polymer with a repeating unit of -->3)-glucose-(1-->3)-6-deoxy-talose-(1--> with O-acetyl or O-methyl modifications. A LPS preparation containing these two polysaccharides was separated by gel-permeation chromatography in this study. Chemical analysis of the separated fractions revealed the 6-deoxy-heptan [corrected] to be a polysaccharide without a lipid portion and the polymer of glucose and 6-deoxy-talose to be an O-antigenic polysaccharide of the LPS. This result was further supported by the assay of these polysaccharide molecules for macrophage activation activity. The 6-deoxy-heptan [corrected] showed no macrophage activation, indicating that this polysaccharide was not the LPS, but one of the capsular polysaccharides of B. pseudomallei.