This enzyme catalyses the successive transfer of two glycine moieties from charged tRNAs to MurNAc-L-Ala-D-isoglutaminyl-L-Lys-(N6-Gly)-D-Ala-D-Ala-diphospho-ditrans,octacis-undecaprenyl-GlcNAc, attaching them to a glycine residue previously attached by EC 2.3.2.16 (FemX) to the N6 of the L-lysine at position 3 of the pentapeptide. This is the second step in the synthesis of the pentaglycine interpeptide bridge that is used by Staphylococcus aureus for the crosslinking of different glycan strands to each other. The next step is catalysed by EC 2.3.2.18 (FemB). This enzyme is essential for methicillin resistance [1].