EPR study of the dinuclear active copper site of tyrosinase from Streptomyces antibioticus

FEBS Letters

Groenen, Edgar J.J.³  Vijgenboom, Erik²  van Gastel, Maurice³  Canters, Gerard W.²  Bubacco, Luigi¹ 

[1] Department of Biology, University of Padova, Via Trieste 75, 30121 Padua, Italy;Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands;Centre for the Study of Excited States of Molecules, Huygens Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands

关键词: Tyrosinase;    Half-met;    Electron paramagnetic resonance;    Hyperfine sublevel correlation spectroscopy;    Type 3 copper protein;   

DOI  :  10.1016/S0014-5793(00)01609-4

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The [Cu(I)–Cu(II)] half-met form of the dinuclear copper site of tyrosinase has been probed by continuous wave electron paramagnetic resonance (EPR) and hyperfine sublevel correlation (HYSCORE) spectroscopy in the presence and absence of inhibitors. In all cases the EPR spectrum is indicative of a dx ²−y ² ground state for the unpaired electron. From the cross-peaks observed in the HYSCORE spectra, proton hyperfine coupling constants were obtained that are compatible with a hydroxide ion in an equatorial coordination position of the paramagnetic copper. After changing the water solvent to D₂O or after addition of the inhibitors p-nitrophenol or L-mimosine, the proton signals disappear. The relevance of these findings for understanding the catalytic cycle is discussed.

【 授权许可】

Unknown