Single-crystal EPR study at 95 GHz of the type 2 copper site of the inhibitor-bound quercetin 2,3-dioxygenase.

ABSTRACT: An electron-spin-echo-detected, electron-paramagnetic-resonance study has been performed on the type 2 copper site of quercetin 2,3-dioxygenase from Aspergillus japonicus. In the protein, copper is coordinated by three histidine nitrogens and two sulfurs from the inhibitor diethyldithiocarbamate. A single crystal of the protein was studied at 95 GHz and the complete g-tensor determined. The electron-paramagnetic-resonance data are compatible with two orientations of the principal g-axes in the copper center, one of which is preferred on the basis of an analysis of the copper coordination and the d-orbitals that are involved in the unpaired-electron orbital. For this orientation, the principal z-axis of the g-tensor makes an angle of 19 degrees with the Cu-N(His112) bond and the N of His112

SUBMITTER: Fittipaldi M 

PROVIDER: S-EPMC1303705 | biostudies-literature | 2003 Dec

REPOSITORIES: biostudies-literature