Direct observation by EPR of a reductively decoupled type 3 site in type 2 copper depleted laccase.
New epr features consistent with a novel type of Cu(II) are observed in partially reduced Type 2 copper depleted laccase molecules. Cu(II) hyperfine lines appear near 2590 G and 2770 G, and a rhombic g1 feature is also observed. These reflect a Cu(II) emergent on reductive disruption of the binuclear Type 3 site in T2D laccase. Additionally, much of the new, magnetically isolated Cu(II) is retained on full reoxidation of partly reduced Type 2 copper depleted laccase. The proportion of disrupted Type 3 Cu(II) sites remaining after reoxidation appears to depend on the prior distribution of electrons within T2D laccase.
D000332:Aerobiosis; D000693:Anaerobiosis; D001665:Binding Sites; D003300:Copper / Q000032:analysis*; D004578:Electron Spin Resonance Spectroscopy; D042845:Laccase; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000378:metabolism*; D010947:Plants, Toxic; D011485:Protein Binding; D013053:Spectrophotometry; D012251:Toxicodendron / Q000201:enzymology
D003300:Copper; D010088:Oxidoreductases; D042845:Laccase