Structure of the serine-containing capsular poly-saccharide K40 antigen from Escherichia coli O8:K40:H9

The structure of the K40 antigenic capsular polysaccharide (K40 antigen) of E. coli O8:K40:H9 was elucidated by determination of the composition, ¹H- and ¹³C-n.m.r. spectroscopy, periodate oxidation and Smith degradation, and methylation analysis. The K40 polysaccharide consists of [(O-β--glucopyranosyluronic acid)-(1→4)-O-(2-acetamido-2-deoxy---glucopyranosyl)-(1→6)-O-(2-acetamido-2-deoxy---glucopyranosyl)-(1→4)] repeating units. All of the glucuronic acid residues are substituted amidically with -serine.