3s6k | pdb_00003s6k

Crystal structure of xcNAGS

spinqualitylabelsall models 3s6k, resolution 2.80Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3s6k is a 1 chain structure with sequence from Xanthomonas campestris pv. campestris str. 8004. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.8018Å Ligands: MSE Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function A0A0H2X8L7_XANC8 Publication Abstract from PubMed Novel bifunctional N-acetylglutamate synthase/kinases (NAGS/K) that catalyze the first two steps of arginine biosynthesis and are homologous to vertebrate N-acetylglutamate synthase (NAGS), an essential cofactor-producing enzyme in the urea cycle, were identified in Maricaulis maris and several other bacteria. Arginine is an allosteric inhibitor of NAGS but not NAGK activity. The crystal structure of M. maris NAGS/K (mmNAGS/K) at 2.7 A resolution indicates that it is a tetramer, in contrast to the hexameric structure of Neisseria gonorrhoeae NAGS. The quaternary structure of crystalline NAGS/K from Xanthomonas campestris (xcNAGS/K) is similar, and cross-linking experiments indicate that both mmNAGS/K and xcNAGS are tetramers in solution. Each subunit has an amino acid kinase (AAK) domain, which is likely responsible for N-acetylglutamate kinase (NAGK) activity and has a putative arginine binding site, and an N-acetyltransferase (NAT) domain that contains the putative NAGS active site. These structures and sequence comparisons suggest that the linker residue 291 may determine whether arginine acts as an allosteric inhibitor or activator in homologous enzymes in microorganisms and vertebrates. In addition, the angle of rotation between AAK and NAT domains varies among crystal forms and subunits within the tetramer. A rotation of 26 degrees is sufficient to close the predicted AcCoA binding site, thus reducing enzymatic activity. Since mmNAGS/K has the highest degree of sequence homology to vertebrate NAGS of NAGS and NAGK enzymes whose structures have been determined, the mmNAGS/K structure was used to develop a structural model of human NAGS that is fully consistent with the functional effects of the 14 missense mutations that were identified in NAGS-deficient patients. A Novel N-acetylglutamate synthase architecture revealed by the crystal structure of the bifunctional enzyme from Maricaulis maris.,Shi D, Li Y, Cabrera-Luque J, Jin Z, Yu X, Zhao G, Haskins N, Allewell NM, Tuchman M PLoS One. 2011;6(12):e28825. Epub 2011 Dec 12. PMID:22174908 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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