Department of Chemistry, Imperial College of Science and Technology, University of London, U.K.
The electron paramagnetic resonance (EPR) spectra of type 1 copper(II) in 63Cu-enriched Coriolus versicolor laccase A (benzenediol:oxygen oxidoreductase, EC 188.8.131.52) have been studied. The X-band EPR spectrum in type 2 copper-depleted [63Cu]laccase A exhibited well-resolved ligand superhyperfine structure in the g perpendicular region. This structure was assigned to an interaction with two nitrogens and two protons, an assignment which is consistent with a model in which the two nitrogens belong to two histidine ligands and the two protons are the methylene protons of a coordinating cysteine. It also requires the delocalization of a substantial amount of the type 1 copper(II) unpaired electron density onto the cysteine sulphur.
PMID: 2825790 [PubMed – indexed for MEDLINE]