Structure and genetics of a glycerol 2-phosphate-containing O-specific polysaccharide of Escherichia coli O33

Abstract

An O-specific polysaccharide was isolated by mild acid degradation of the lipopolysaccharide of Escherichia coli O33 followed by gel-permeation chromatography on Sephadex G-50. The polysaccharide was found to contain glycerol 2-phosphate (Gro-2-P), and the following structure of its tetrasaccharide repeat was established by sugar analysis, dephosphorylation, and 1D and 2D 1H and 13C NMR spectroscopy:▪The O33-antigen gene cluster was analyzed and found to be essentially consistent with the O-polysaccharide structure.