The accessibility of a type I Cu(II) centers in Laccase, Azurin and Stellacyanin to exchangeable hydrogen and ambient water.

From a comparison of the electron spin echo decay envelopes for a number of type I Cu(II) containing proteins in D20 and in H20, we have obtained the deuterium modulation pattern for exchangeable deuterons close to the metal centers. From the decay rate of the modulation, pattern, and from a quantitative analyses of the modulation depth, it is concluded that the Cu(II) sites in these proteins are directly accessible to solvent.