[en] Peptidoglycans in walls of Micrococcus lysodeikticus, Micrococcus flavus, Micrococcus citreus, and Sarcina lutea are, composed of Nα-[L-alanyl-γ-(α-D-glutamylglycine)]-L-lysyl-D-alanine subunits, cross-linked through D-alanyl-L-alanine and Nє-(D-alanyl)-L-lysine linkages, and do not contain any additional intervening amino acids. The D-alanyl-L-alanine peptide cross-linkages largely predominate. Although the number of peptide subunits is generally, but not always, greater than the number of disaccharide units in the glycan moiety, not all of the N-acetylmuramic acid residues are peptide substituted. Such a structure is of taxonomic importance since it differentiates the four aforementioned species from other members of the family Micrococcaceae. In Micrococcus lysodeikticus, Micrococcus flavus, and Sarcina lutea, segments of the glycan, consisting of 8-18 disaccharide units, are linked through 1 muramic acid phosphate to a segment, consisting of about 10 glucose residues, of a second wall polymer.