The enzyme from Staphylococcus aureus catalyses the transfer of glycine from a charged tRNA to MurNAc-L-Ala-D-isoglutaminyl-L-Lys-D-Ala-D-Ala-diphosphoundecaprenyl-GlcNAc (lipid II), attaching it to the N6 of the L-Lys at position 3 of the pentapeptide. This is the first step in the synthesis of the pentaglycine interpeptide bridge that is used in S. aureus for the crosslinking of different glycan strands to each other. Four additional Gly residues are subsequently attached by EC 2.3.2.17 (N-acetylmuramoyl-L-alanyl-D-glutamyl-L-lysyl-(N6-glycyl)-D-alanyl-D-alanine-diphosphoundecaprenyl-N-acetylglucosamine:glycine glycyltransferase) and EC 2.3.2.18 (N-acetylmuramoyl-L-alanyl-D-glutamyl-L-lysyl-(N6-triglycine)-D-alanyl-D-alanine-diphosphoundecaprenyl-N-acetylglucosamine:glycine glycyltransferase).
