2D1W

Substrate Schiff-Base intermediate with tyramine in copper amine oxidase from Arthrobacter globiformis

Summary for 2D1W

• Entry DOI: 10.2210/pdb2d1w/pdb
• Related: 1IU7 2CWT 2CWU 2CWV
• Descriptor: Phenylethylamine oxidase, COPPER (II) ION (3 entities in total)
• Functional Keywords: copper, amine oxidase, topaquinone, tpq, reaction intermediate, substrate schiff-base, oxidoreductase
• Biological source: Arthrobacter globiformis
• Total number of polymer chains: 2
• Total formula weight: 141782.90

Authors

Murakawa, T.,Okajima, T.,Kuroda, S.,Nakamoto, T.,Taki, M.,Yamamoto, Y.,Hayashi, H.,Tanizawa, K. (deposition date: 2005-09-01, release date: 2006-05-02, Last modification date: 2024-10-09)

Primary citation

Murakawa, T.,Okajima, T.,Kuroda, S.,Nakamoto, T.,Taki, M.,Yamamoto, Y.,Hayashi, H.,Tanizawa, K.
Quantum mechanical hydrogen tunneling in bacterial copper amine oxidase reaction
Biochem.Biophys.Res.Commun., 342:414-423, 2006

PubMed Abstract: A key step decisively affecting the catalytic efficiency of copper amine oxidase is stereospecific abstraction of substrate alpha-proton by a conserved Asp residue. We analyzed this step by pre-steady-state kinetics using a bacterial enzyme and stereospecifically deuterium-labeled substrates, 2-phenylethylamine and tyramine. A small and temperature-dependent kinetic isotope effect (KIE) was observed with 2-phenylethylamine, whereas a large and temperature-independent KIE was observed with tyramine in the alpha-proton abstraction step, showing that this step is driven by quantum mechanical hydrogen tunneling rather than the classical transition-state mechanism. Furthermore, an Arrhenius-type preexponential factor ratio approaching a transition-state value was obtained in the reaction of a mutant enzyme lacking the critical Asp. These results provide strong evidence for enzyme-enhanced hydrogen tunneling. X-ray crystallographic structures of the reaction intermediates revealed a small difference in the binding mode of distal parts of substrates, which would modulate hydrogen tunneling proceeding through either active or passive dynamics.

PubMed: 16487484
DOI: 10.1016/j.bbrc.2006.01.150

Experimental method

X-RAY DIFFRACTION (1.74 Å)