3x3x

Copper amine oxidase from Arthrobacter globiformis anaerobically reduced by phenylethylamine

spinqualitylabelsall models 3x3x, resolution 1.57Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3x3x is a 2 chain structure with sequence from Arthrobacter globiformis. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.57Å Ligands: CU, GOL, NA, PEL, TYQ Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function PAOX_ARTGO Publication Abstract from PubMed The catalytic reaction of copper amine oxidase proceeds through a ping-pong mechanism comprising two half-reactions. In the initial half-reaction, the substrate amine reduces the Tyr-derived cofactor, topa quinone (TPQ), to an aminoresorcinol form (TPQamr) that is in equilibrium with a semiquinone radical (TPQsq) via an intramolecular electron transfer to the active-site copper. We have analyzed this reductive half-reaction in crystals of the copper amine oxidase from Arthrobacter globiformis. Anerobic soaking of the crystals with an amine substrate shifted the equilibrium toward TPQsq in an "on-copper" conformation, in which the 4-OH group ligated axially to the copper center, which was probably reduced to Cu(I). When the crystals were soaked with substrate in the presence of halide ions, which act as uncompetitive and noncompetitive inhibitors with respect to the amine substrate and dioxygen, respectively, the equilibrium in the crystals shifted toward the "off-copper" conformation of TPQamr. The halide ion was bound to the axial position of the copper center, thereby preventing TPQamr from adopting the on-copper conformation. Furthermore, transient kinetic analyses in the presence of viscogen (glycerol) revealed that only the rate constant in the step of TPQamr/TPQsq interconversion is markedly affected by the viscogen, which probably perturbs the conformational change. These findings unequivocally demonstrate that TPQ undergoes large conformational changes during the reductive half-reaction. Probing the Catalytic Mechanism of Copper Amine Oxidase from Arthrobacter globiformis with Halide Ions.,Murakawa T, Hamaguchi A, Nakanishi S, Kataoka M, Nakai T, Kawano Y, Yamaguchi H, Hayashi H, Tanizawa K, Okajima T J Biol Chem. 2015 Sep 18;290(38):23094-109. doi: 10.1074/jbc.M115.662726. Epub, 2015 Aug 11. PMID:26269595 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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