1p8o

Structural and Functional Importance of First-Shell Metal Ligands in the Binuclear Manganese Cluster of Arginase I.

spinqualitylabelsall models 1p8o, resolution 2.96Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1p8o is a 3 chain structure with sequence from Rattus norvegicus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: MN Gene: ARG1 (Rattus norvegicus) Activity: Arginase, with EC number 3.5.3.1 Resources: FirstGlance, OCA, RCSB, PDBsum Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Arginase is a binuclear manganese metalloenzyme that hydrolyzes l-arginine to form l-ornithine and urea. The three-dimensional structures of D128E, D128N, D232A, D232C, D234E, H101N, and H101E arginases I have been determined by X-ray crystallographic methods to elucidate the roles of the first-shell metal ligands in the stability and catalytic activity of the enzyme. This work represents the first structure-based dissection of the binuclear manganese cluster using site-directed mutagenesis and X-ray crystallography. Substitution of the metal ligands compromises the catalytic activity of the enzyme, either by the loss or disruption of the metal cluster or the nucleophilic metal-bridging hydroxide ion. However, the substitution of the metal ligands or the reduction of Mn(2+)(A) or Mn(2+)(B) occupancy does not compromise enzyme-substrate affinity as reflected by K(M), which remains relatively invariant across this series of arginase variants. This implicates a nonmetal binding site for substrate l-arginine in the precatalytic Michaelis complex, as proposed based on analysis of the native enzyme structure (Kanyo, Z. F., Scolnick, L. R., Ash, D. E., and Christianson, D. W. (1996) Nature 383, 554-557). Structural and functional importance of first-shell metal ligands in the binuclear manganese cluster of arginase I.,Cama E, Emig FA, Ash DE, Christianson DW Biochemistry. 2003 Jul 1;42(25):7748-58. PMID:12820884 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Arginase

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