Crystal structure of the copper-containing quercetin 2,3-dioxygenase from Aspergillus japonicus

Structure. 2002 Feb;10(2):259-68. doi: 10.1016/s0969-2126(02)00704-9.


Quercetin 2,3-dioxygenase is a copper-containing enzyme that catalyzes the insertion of molecular oxygen into polyphenolic flavonols. Dioxygenation catalyzed by iron-containing enzymes has been studied extensively, but dioxygenases employing other metal cofactors are poorly understood. We determined the crystal structure of quercetin 2,3-dioxygenase at 1.6 A resolution. The enzyme forms homodimers, which are stabilized by an N-linked heptasaccharide at the dimer interface. The mononuclear type 2 copper center displays two distinct geometries: a distorted tetrahedral coordination, formed by His66, His68, His112, and a water molecule, and a distorted trigonal bipyramidal environment, which additionally comprises Glu73. Manual docking of the substrate quercetin into the active site showed that the different geometries of the copper site might be of catalytic importance.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Aspergillus / enzymology*
  • Binding Sites
  • Copper / metabolism*
  • Crystallography, X-Ray
  • Dioxygenases*
  • Glycosylation
  • Models, Molecular
  • Molecular Sequence Data
  • Oxygenases / chemistry*
  • Oxygenases / metabolism*
  • Protein Structure, Quaternary
  • Protein Structure, Tertiary
  • Sequence Alignment
  • Static Electricity
  • Substrate Specificity


  • Copper
  • Oxygenases
  • Dioxygenases
  • quercetin 2,3-dioxygenase

Associated data

  • PDB/1JUH