[en] The wall peptidoglycans in Gaffkya homari ATCC 10400 and in Aerococcus viridans 201 Evans and ATCC 11563 are made up of peptide units L-alanyl-γ-D-glutamyl-L-lysyl-D-alanine and L-alanyl-D-isoglutaminyl-L-lysyl-D-alanine. The yields of the peptide fragments obtained after enzymatic degradations of the walls are consistent with a peptidoglycan structure in which all the N-acetylmuramic acid residues in the glycan strands are peptide-substituted and in which about half of the peptide units occur as uncross-linked monomers whereas the others form dimers by means of Nє-(D-alanyl)-L-lysine linkages. These walls are the first known examples of lysine-containing peptidoglycans of chemotype I.