Covalent linkage of polyamines to peptidoglycan in Anaerovibrio lipolytica

Spermidine and cadaverine were found to be constituents of the cell wall pe ptidoglycan of Anaerovibrio lipolytica, a strictly anaerobic bacterium. The peptidoglycan was degraded with the N-acetylmuramyl-L-alanine amidase and endopeptidase into two peptide fragments, peptide I and peptide II, at a mo lar ratio of 4:1. Peptides I and II were identified as L-alanine-D-glutamic acid(<(alpha)under bar>-cadaverine) <(gamma)over bar>meso-diaminopimelic a cid (DAP)-D-alanine and L-alanine-D-glutamic acid (<(alpha)over bar>spermid ine)<(gamma)over bar>meso-DAP-D-alanine, respectively. The N-1-amino group of spermidine was linked to the alpha-carboxyl group of the D-glutamic acid residue of peptide II.