Alpha epsilon-Diaminopimelic acid in the peptide moiety of the cell wall polysaccharide of Bacillus anthracis

Bacillus anthracis contains a polysaccharide which appears to be part of the cell wall1. Ivanovics2 first isolated the polysaccharide which contained galactose 34 per cent, glucosamine 34 per cent, nitrogen 4.2 per cent and α-carboxyl amino-nitrogen 0.8 per cent. Strange and Belton3 obtained from culture filtrates of B. anthracis a polysaccharide which contained galactose 39–43 per cent, glucosamine 34 per cent, nitrogen 3.9 per cent and α-carboxyl amino-nitrogen 1.26 per cent. The differences between the total nitrogen and glucosamine nitrogen values together with the figures for α-carboxyl amino-nitrogen in these preparations indicated the presence of 5–10 per cent of amino-acid residues. Smith and Zwartouw4 obtained a polysaccharide from B. anthracisgrown in vivo. It contained galactose 38–43 per cent, glucosamine 38–44 per cent, nitrogen 4.0 per cent and α-carboxyl amino-nitrogen 0.3 per cent. Since this preparation satisfied a number of rigorous tests for homogeneity it was concluded that a small peptide moiety (2–3 per cent) was firmly attached to the polysaccharide. We are concerned here with the constitution of this peptide moiety.