Detection of the reaction intermediates catalyzed by a copper amine oxidase
| Autor: | Hiroshi Yamaguchi, Toshihide Okajima, Ayuko Tominaga, Katsuyuki Tanizawa, Misumi Kataoka, Masayuki Otsu, Hiroko Oya |
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| Rok vydání: | 2010 |
| Předmět: |
Diffraction Structural Biology
Nuclear and High Energy Physics Reaction mechanism Reaction intermediate Crystallography X-Ray Photochemistry Chemical reaction copper amine oxidase Catalysis X-ray crystal structure analysis Chemical kinetics chemistry.chemical_compound reaction intermediate X-Ray Diffraction Phenethylamines Arthrobacter topaquinone Instrumentation Schiff Bases Phenylacetaldehyde Radiation Chemistry single-crystal microspectroscopy Amine oxidase (copper-containing) Substrate (chemistry) AGAO Dihydroxyphenylalanine Amine Oxidase (Copper-Containing) |
| Zdroj: | Journal of Synchrotron Radiation |
| ISSN: | 0909-0495 |
| DOI: | 10.1107/s0909049510034989 |
| Popis: | Consecutive temporal analyses of enzyme structure have been performed during reactions in order to clarify the structure-based reaction mechanism. Four intermediate structures have been determined. To reveal the chemical changes and geometry changes of active-site residues that cooperate with a reaction is important for understanding the functional mechanism of proteins. Consecutive temporal analyses of enzyme structures have been performed during reactions to clarify structure-based reaction mechanisms. Phenylethylamine oxidase from Arthrobacter globiformis (AGAO) contains a copper ion and topaquinone (TPQox). The catalytic reaction of AGAO catalyzes oxidative deaminations of phenylethylamine and consists of reductive and oxidative half-reactions. In the reduction step, TPQox reacts with a phenylethylamine (PEA) substrate giving rise to a topasemiquinone (TPQsq) formed Schiff-base and produces phenylacetaldehyde. To elucidate the mechanism of the reductive half-reaction, an attempt was made to trap the reaction intermediates in order to analyze their structures. The reaction proceeded within the crystals when AGAO crystals were soaked in a PEA solution and freeze-trapped in liquid nitrogen. The reaction stage of each crystal was confirmed by single-crystal microspectrometry, before X-ray diffraction measurements were made of four reaction intermediates. The structure at 15 min after the onset of the reaction was analyzed at atomic resolution, and it was shown that TPQox and some residues in the substrate channel were alternated via catalytic reductive half-reactions. |
| Databáze: | OpenAIRE |
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