Covalent linkage of the type- and group-specific antigens to the peptide moiety of the peptidoglycan of serotype III group BStreptococcus

The attachment sites for the two major cell wall polysaccharides, the type-and group-specific antigens of a serotype III group B streptococcus (GBS) were investigated with 14C]lysine to label the peptide portion of the peptidoglycan and 3H]acetate to label both polysaccharide antigens as well as the glycan backbone of the peptidoglycan. Mutanolysin-treated cell walls were subjected to trypsin digestion, followed by exhaustive beta-elimination with 6N ammonium hydroxide at 37°C. The resulting products were purified by column chromatography prior to chemical, immunological, and high-voltage electrophoresis analyses. Data from these studies indicated that both cell wall polymers are covalently attached to the peptidoglycan via the peptide unit. Additionally, during synthesis and assembly both antigens attached only to nascent peptidoglycan.