1PBY: Structure Of The Phenylhydrazine Adduct Of The Quinohemoprotein Amine Dehydrogenase From Paracoccus Denitrificans At 1.7 A Resolution

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 A 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 A resolution. The phenylhydrazone product is attached to the C6 position, identifying the O6 atom of CTQ 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 gammaAsp33 in the complex, lending support to the hypothesis that this residue serves as the active-site base for proton abstraction during catalysis.
PDB ID: 1PBYDownload
MMDB ID: 23772
PDB Deposition Date: 2003/5/15
Updated in MMDB: 2017/11
Experimental Method:
x-ray diffraction
Resolution: 1.7  Å
Source Organism:
Similar Structures:
Biological Unit for 1PBY: trimeric; determined by author and by software (PISA)
Molecular Components in 1PBY
Label Count Molecule
Proteins (3 molecules)
Quinohemoprotein Amine Dehydrogenase 60 KDA Subunit
Molecule annotation
Quinohemoprotein Amine Dehydrogenase 40 KDA Subunit
Molecule annotation
Quinohemoprotein Amine Dehydrogenase 9 KDA Subunit
Molecule annotation
Chemicals (6 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB