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Structure of the phenylhydrazine adduct of the quinohemoprotein amine dehydrogenase from Paracoccus denitrificans at 1.7 Å resolution.
- Source :
- Acta Crystallographica: Section D (Wiley-Blackwell); Sep2003, Vol. 59 Issue 9, p1551, 6p
- Publication Year :
- 2003
-
Abstract
- The 109 kDa quinohemoprotein amine dehydrogenase (QHNDH) from Paracoccus denitrificans contains a novel redox cofactor, cysteine tryptophylquinone (CTQ). This cofactor is derived from a pair of gene-encoded amino acids by post-translational modification and was previously identified and characterized within an 82-residue subunit by chemical methods and crystallographic analysis at 2.05 Å resolution. It contains an orthoquinone moiety bound to the indole ring and catalyzes the oxidation of aliphatic and aromatic amines through formation of a Schiff-base intermediate involving one of the quinone O atoms. This paper reports the structural analysis of the complex of QHNDH with the enzyme inhibitor phenylhydrazine determined at 1.70 Å resolution. The phenylhydrazone product is attached to the C6 position, identifying the O6 atom of CTO as the site of Schiff base formation as postulated by analogy to another amine-oxidizing enzyme, methylamine dehydrogenase. Furthermore, the inner N atom closest to the phenyl ring of phenylhydrazine forms a hydrogen bond to γASP33 in the complex, lending support to the hypothesis that this residue serves as the active-site base for proton abstraction during catalysis. [ABSTRACT FROM AUTHOR]
- Subjects :
- DEHYDROGENASES
AMINO acids
CRYSTALLOGRAPHY
AMINES
QUINONE
Subjects
Details
- Language :
- English
- ISSN :
- 09074449
- Volume :
- 59
- Issue :
- 9
- Database :
- Complementary Index
- Journal :
- Acta Crystallographica: Section D (Wiley-Blackwell)
- Publication Type :
- Academic Journal
- Accession number :
- 10842139
- Full Text :
- https://doi.org/10.1107/S090744490301429X