Biomaterial Database

Structure of the phenylhydrazine adduct of the quinohemoprotein amine dehydrogenase from Paracoccus denitrificans at 1.7 A resolution. 2003

Saumen Datta, and Tokuji Ikeda, and Kenji Kano, and F Scott Mathews

Washington University School of Medicine, St Louis, MO 63110, USA.

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.

UI	MeSH Term	Description	Entries
D008958	Models, Molecular	Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.	Molecular Models,Model, Molecular,Molecular Model
D010231	Paracoccus denitrificans	A species of bacteria isolated from soil.	Micrococcus denitrificans
D010659	Phenylhydrazines	Diazo derivatives of aniline, used as a reagent for sugars, ketones, and aldehydes. (Dorland, 28th ed)
D011487	Protein Conformation	The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).	Conformation, Protein,Conformations, Protein,Protein Conformations
D003460	Crystallization	The formation of crystalline substances from solutions or melts. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Crystalline Polymorphs,Polymorphism, Crystallization,Crystal Growth,Polymorphic Crystals,Crystal, Polymorphic,Crystalline Polymorph,Crystallization Polymorphism,Crystallization Polymorphisms,Crystals, Polymorphic,Growth, Crystal,Polymorph, Crystalline,Polymorphic Crystal,Polymorphisms, Crystallization,Polymorphs, Crystalline
D000587	Oxidoreductases Acting on CH-NH Group Donors	Enzymes catalyzing the dehydrogenation of secondary amines, introducing a C	Secondary Amine Oxidoreductases,Amine Oxidoreductases, Secondary Amine,Amine Oxidoreductases, Secondary,Oxidoreductases Acting on CH NH Group Donors,Oxidoreductases, Secondary Amine
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining
D018360	Crystallography, X-Ray	The study of crystal structure using X-RAY DIFFRACTION techniques. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	X-Ray Crystallography,Crystallography, X Ray,Crystallography, Xray,X Ray Crystallography,Xray Crystallography,Crystallographies, X Ray,X Ray Crystallographies
D021122	Protein Subunits	Single chains of amino acids that are the units of multimeric PROTEINS. Multimeric proteins can be composed of identical or non-identical subunits. One or more monomeric subunits may compose a protomer which itself is a subunit structure of a larger assembly.	Protomers,Protein Subunit,Protomer,Subunit, Protein,Subunits, Protein