The pentapeptide bridge in Gram-positive bacteria consists mainly of:
Crosslinking between glycan strands in many Gram-positive pathogens involves pentaglycine bridge characteristic of Staphylococcus aureus, intensively studied because it influences vancomycin sensitivity. After polymerization, tetrapeptide side chains protrude from MurNAc. In S. aureus, FemXAB family nonribosomal peptidyl transferases add glycine residues one by one to epsilon amino group of L-lysine at position three, using glycyl-tRNA as donor, generating pentaglycine. This flexible extension then becomes substrate for transpeptidase that links glycine terminal to D-alanine of neighboring ste
Ref: Schneider et al., Mol Microbiol 2004, FemABX Pentaglycine; Pinho et al., Nature Rev Microbiol 2013, Staphylococcal Cell Wall.
