The accessibility of type I Cu(II) centers in laccase, azurin, and stellacyanin to exchangeable hydrogen and ambient water.

The characteristic deuterium modulation pattern was observed in the electron spin-echo envelopes for laccase, decupro laccase (from which Type 2 copper had been removed), stellacyanin, and azurin that had been exchanged against D2O. From the decay rate of the modulation pattern and from a quantitative analysis of the modulation depth, we conclude that the Cu(II) sites in these proteins are directly accessible to solvent. Similar results were obtained for laccase and decupro laccase.