Reaction: ATP + β-D-GlcNAc-(1→4)-Mur2Ac(oyl-L-Ala-γ-D-Glu-L-Lys-D-Ala-D-Ala)-diphospho-ditrans,octacis-undecaprenol + L-glutamine + H2O = ADP + phosphate + β-D-GlcNAc-(1→4)-MurNAc-L-Ala-D-isoglutaminyl-L-Lys-D-Ala-D-Ala-diphospho-ditrans,octacis-undecaprenol + L-glutamate (overall reaction)
(1a) L-glutamine + H2O = L-glutamate + NH3
(1b) ATP + β-D-GlcNAc-(1→4)-Mur2Ac(oyl-L-Ala-γ-D-Glu-L-Lys-D-Ala-D-Ala)-diphospho-ditrans,octacis-undecaprenol = ADP + β-D-GlcNAc-(1→4)-MurNAc-L-Ala-γ-D-O-P-Glu-L-Lys-D-Ala-D-Ala-diphospho-ditrans,octacis-undecaprenol
(1c) β-D-GlcNAc-(1→4)-Mur2Ac(oyl-L-Ala-γ-D-O-P-Glu-L-Lys-D-Ala-D-Ala)-diphospho-ditrans,octacis-undecaprenol + NH3 = β-D-GlcNAc-(1→4)-MurNAc-L-Ala-D-isoglutaminyl-L-Lys-D-Ala-D-Ala-diphospho-ditrans,octacis-undecaprenol + phosphate
Glossary: lipid II = undecaprenyldiphospho-N-acetyl-(N-acetylglucosaminyl)muramoyl peptide; the peptide element refers to L-alanyl-D-γ-glutamyl-L-lysyl/meso-2,6-diaminopimelyl-D-alanyl-D-alanine or a modified version thereof = undecaprenyldiphospho-4-O-(N-acetyl-β-D-glucosaminyl)-3-O-peptidyl-α-N-acetylmuramate; the peptide element refers to L-alanyl-D-γ-glutamyl-L-lysyl/meso-2,6-diaminopimelyl-D-alanyl-D-alanine or a modified version thereof
Other name(s): MurT/GatD; MurT/GatD complex
Systematic name: β-D-GlcNAc-(1→4)-Mur2Ac(oyl-L-Ala-γ-D-Glu-L-Lys-D-Ala-D-Ala)-diphospho-ditrans,octacis-undecaprenol:L-glutamine amidoligase (ADP-forming)
Comments: The enzyme complex, found in Gram-positive bacteria, consists of two subunits. A glutaminase subunit (cf. EC 3.5.1.2, glutaminase) produces an ammonia molecule that is channeled to a ligase subunit, which adds it to the activated D-glutamate residue of lipid II, converting it to an isoglutamine residue.
Links to other databases: BRENDA, EXPASY, ExplorEnz, KEGG, MetaCyc, PDB, CAS registry number:
References:
1. Munch, D., Roemer, T., Lee, S.H., Engeser, M., Sahl, H.G. and Schneider, T. Identification and in vitro analysis of the GatD/MurT enzyme-complex catalyzing lipid II amidation in Staphylococcus aureus. PLoS Pathog. 8 (2012) e1002509. [PMID: 22291598]
2. Noldeke, E.R., Muckenfuss, L.M., Niemann, V., Muller, A., Stork, E., Zocher, G., Schneider, T. and Stehle, T. Structural basis of cell wall peptidoglycan amidation by the GatD/MurT complex of Staphylococcus aureus. Sci Rep 8 (2018) 12953. [PMID: 30154570]
3. Morlot, C., Straume, D., Peters, K., Hegnar, O.A., Simon, N., Villard, A.M., Contreras-Martel, C., Leisico, F., Breukink, E., Gravier-Pelletier, C., Le Corre, L., Vollmer, W., Pietrancosta, N., Havarstein, L.S. and Zapun, A. Structure of the essential peptidoglycan amidotransferase MurT/GatD complex from Streptococcus pneumoniae. Nat Commun 9 (2018) 3180. [PMID: 30093673]