In Staphylococcus aureus the peptidoglycan is made up of linear glycan (polysaccharide) chains connected through short tetrapeptide and pentaglycine peptides.
The polysaccharide chain consists of alternating residues of the amino acids N-acetyl glucosamine (NAG and N acetyl muramic acid (NAM) linked in p-l, 4 glycosidic linkage.
Each NAM residue carries a short peptide chain of four amino acid residues (tetrapeptide)which are L-alanine, D-glutamine. L-lysine and D-alanine.
The tetrapeptide is unusual in that it, contains D-amino aci4s. Which are rarely found in proteins.
Neighbouring tetrapeptides are linked by pentaglycine bridge peptides, each consisting of five glycine residues.
| 
