Journal article
Trapping of a Dopaquinone Intermediate in the TPQ Cofactor Biogenesis in a Copper-Containing Amine Oxidase from Arthrobacter globiformis
Journal of the American Chemical Society, Vol.129(37), pp.11524-11534
09/01/2007
DOI: 10.1021/ja0731165
PMID: 17715921
Abstract
The biogenesis of the topaquinone (TPQ) cofactor of copper amine oxidase (CAO) is self-catalyzed and requires copper and molecular oxygen. A dopaquinone intermediate has been proposed to undergo 1,4-addition of a copper-associated water molecule to form the reduced form of TPQ (TPQred), followed by facile oxidation by O2 to yield the mature TPQ (TPQox). In this study, we have incorporated a lysine residue in the active site of Arthrobacter globiformis CAO (AGAO) by site-directed mutagenesis to produce D298K-AGAO. The X-ray crystal structure of D298K-AGAO at 1.7-Å resolution revealed that a covalent linkage formed between the ε-amino side chain of Lys298 and the C2 position of a dopaquinone derived from Tyr382, a precursor to TPQox. We assigned the species as an iminoquinone tautomer (LTI) of lysine tyrosylquinone (LTQ), the organic cofactor of lysyl oxidase (LOX). The time course of the formation of LTI at pH 6.8 was followed by UV/vis and resonance Raman spectroscopies. In the early phase of the reaction, an LTQ-like intermediate was observed. This intermediate then slowly converted to LTI in an isosbestic manner. Not only is the presence of a dopaquinone intermediate in the TPQ biogenesis confirmed, but it also provides strong support for the proposed intermediacy of a dopaquinone in the biogenesis of LTQ in LOX. Further, this study indicates that the dopaquinone intermediate in AGAO is mobile and can swing from the copper site into the active-site wedge to react with Lys298. © 2007 American Chemical Society.
Details
- Title: Subtitle
- Trapping of a Dopaquinone Intermediate in the TPQ Cofactor Biogenesis in a Copper-Containing Amine Oxidase from Arthrobacter globiformis
- Creators
- Robyn H. Moore - University of KansasM. Ashley Spies - University of KansasMatthew B. Culpepper - Nara Institute of Science and TechnologyTakeshi Murakawa - Nara Institute of Science and TechnologyShun Hirota - Nara Institute of Science and TechnologyToshihide Okajima - Nara Institute of Science and TechnologyKatsuyuki Tanizawa - Nara Institute of Science and TechnologyMinae Mure - Nara Institute of Science and Technology
- Resource Type
- Journal article
- Publication Details
- Journal of the American Chemical Society, Vol.129(37), pp.11524-11534
- DOI
- 10.1021/ja0731165
- PMID
- 17715921
- ISSN
- 0002-7863
- eISSN
- 1520-5126
- Language
- English
- Date published
- 09/01/2007
- Academic Unit
- Pharmaceutical Sciences and Experimental Therapeutics; Biochemistry and Molecular Biology; Medicinal and Natural Products Chemistry
- Record Identifier
- 9984288724002771
Metrics
39 Record Views