3X40

Copper amine oxidase from Arthrobacter globiformis: Product Schiff-base form produced by anaerobic reduction in the presence of sodium chloride

Summary for 3X40

• Entry DOI: 10.2210/pdb3x40/pdb
• Descriptor: Phenylethylamine oxidase, COPPER (II) ION, CHLORIDE ION, ... (6 entities in total)
• Functional Keywords: copper amine oxidase, topaquinone, tpq, oxidoreductase
• Biological source: Arthrobacter globiformis
• Total number of polymer chains: 2
• Total formula weight: 138957.66

Authors

Okajima, T.,Nakanishi, S.,Murakawa, T.,Kataoka, M.,Hayashi, H.,Hamaguchi, A.,Nakai, T.,Kawano, Y.,Yamaguchi, H.,Tanizawa, K. (deposition date: 2015-03-10, release date: 2015-08-19, Last modification date: 2024-10-16)

Primary citation

Murakawa, T.,Hamaguchi, A.,Nakanishi, S.,Kataoka, M.,Nakai, T.,Kawano, Y.,Yamaguchi, H.,Hayashi, H.,Tanizawa, K.,Okajima, T.
Probing the Catalytic Mechanism of Copper Amine Oxidase from Arthrobacter globiformis with Halide Ions.
J.Biol.Chem., 290:23094-23109, 2015

PubMed Abstract: 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.

PubMed: 26269595
DOI: 10.1074/jbc.M115.662726

Experimental method

X-RAY DIFFRACTION (1.85 Å)