3zxr

From Proteopedia

Crystal structure of Mycobacterium Tuberculosis Glutamine Synthetase in complex with tri-substituted imidazole inhibitor (3-(2-tert-butyl- 5-(pyridin-4-yl)-1H-imidazol-4-yl)quinoline) and L-methionine-S- sulfoximine phosphate.

Structural highlights

3zxr is a 6 chain structure with sequence from Mycobacterium tuberculosis H37Rv. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 2.15Å
Ligands:	, , , ,
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

GLN1B_MYCTU Involved in nitrogen metabolism via ammonium assimilation. Catalyzes the ATP-dependent biosynthesis of glutamine from glutamate and ammonia (PubMed:7937767, PubMed:12819079). Also able to use GTP (PubMed:7937767). D-glutamate is a poor substrate, and DL-glutamate shows about 50% of the standard specific activity (PubMed:7937767). Also plays a key role in controlling the ammonia levels within infected host cells and so contributes to the pathogens capacity to inhibit phagosome acidification and phagosome-lysosome fusion (PubMed:7937767, PubMed:12819079). Involved in cell wall biosynthesis via the production of the major component poly-L-glutamine (PLG) (PubMed:7937767, PubMed:10618433). PLG synthesis in the cell wall occurs only in nitrogen limiting conditions and on the contrary high nitrogen conditions inhibit PLG synthesis (Probable).^[1] ^[2] ^[3] ^[4]

Publication Abstract from PubMed

Mycobacterium tuberculosis glutamine synthetase (MtGS) is a promising target for antituberculosis drug discovery. In a recent high-throughput screening study we identified several classes of MtGS inhibitors targeting the ATP-binding site. We now explore one of these classes, the 2-tert-butyl-4,5-diarylimidazoles, and present the design, synthesis, and X-ray crystallographic studies leading to the identification of MtGS inhibitors with submicromolar IC(50) values and promising antituberculosis MIC values.

Trisubstituted Imidazoles as Mycobacterium tuberculosis Glutamine Synthetase Inhibitors.,Gising J, Nilsson MT, Odell LR, Yahiaoui S, Lindh M, Iyer H, Sinha AM, Srinivasa BR, Larhed M, Mowbray SL, Karlen A J Med Chem. 2012 Mar 22;55(6):2894-8. Epub 2012 Mar 8. PMID:22369127^[5]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Harth G, Zamecnik PC, Tang JY, Tabatadze D, Horwitz MA. Treatment of Mycobacterium tuberculosis with antisense oligonucleotides to glutamine synthetase mRNA inhibits glutamine synthetase activity, formation of the poly-L-glutamate/glutamine cell wall structure, and bacterial replication. Proc Natl Acad Sci U S A. 2000 Jan 4;97(1):418-23. PMID:10618433 doi:10.1073/pnas.97.1.418
↑ Tullius MV, Harth G, Horwitz MA. Glutamine synthetase GlnA1 is essential for growth of Mycobacterium tuberculosis in human THP-1 macrophages and guinea pigs. Infect Immun. 2003 Jul;71(7):3927-36. PMID:12819079 doi:10.1128/IAI.71.7.3927-3936.2003
↑ Harth G, Clemens DL, Horwitz MA. Glutamine synthetase of Mycobacterium tuberculosis: extracellular release and characterization of its enzymatic activity. Proc Natl Acad Sci U S A. 1994 Sep 27;91(20):9342-6. PMID:7937767 doi:10.1073/pnas.91.20.9342
↑ Harth G, Horwitz MA. Expression and efficient export of enzymatically active Mycobacterium tuberculosis glutamine synthetase in Mycobacterium smegmatis and evidence that the information for export is contained within the protein. J Biol Chem. 1997 Sep 5;272(36):22728-35. PMID:9278431 doi:10.1074/jbc.272.36.22728
↑ Gising J, Nilsson MT, Odell LR, Yahiaoui S, Lindh M, Iyer H, Sinha AM, Srinivasa BR, Larhed M, Mowbray SL, Karlen A. Trisubstituted Imidazoles as Mycobacterium tuberculosis Glutamine Synthetase Inhibitors. J Med Chem. 2012 Mar 22;55(6):2894-8. Epub 2012 Mar 8. PMID:22369127 doi:10.1021/jm201212h