Catalyzes the incorporation of amino acid(s) into the interchain peptide bridge of peptidoglycan, using aminoacyl-tRNA as amino acid donor. beta-D-GlcNAc-(1->4)-Mur2Ac(oyl-L-Ala-D-isoglutaminyl-L-Lys-D-Ala-D-Ala)-di-trans,octa-cis-undecaprenyl diphosphate + glycyl-tRNA(Gly) = beta-D-GlcNAc-(1->4)-Mur2Ac(oyl-L-Ala-D-isoglutaminyl-L-Lys-(N(6)-Gly)-D-Ala-D-Ala)-di-trans,octa-cis-undecaprenyl diphosphate + H(+) + tRNA(Gly) Belongs to the FemABX family.