This is a review of our group's studies on the electronic structure of the blue copper site and its contribution to function. It starts with the known crystallographic results and demonstrates how spectroscopy allows these results to be extended to obtain fundamental insight into reactivity. These studies: (1) demonstrate that the unique spectral features associated with the oxidized blue copper site reflect a novel ground state wavefunction with high anisotropic covalency which plays a ...

Self consistent field-Xα-scattered wave (SCF-Xα-SW) calculations have been used to characterize the bonding between the Cu(II) ion and the axial methionine residue in blue copper proteins. In addition, the interaction of an axial carbonyl oxygen of a glycine residue found at ∼3 Å. from the copper center in azurins has also been considered. Seven blue copper model sites were constructed to probe various changes in copper coordination and to examine the effects of Zn(II) substituted for ...

We have seen from the previous discussion that absorption spectral studies in the ligand field region probe the energy splittings of the d orbitals and that this relates to the geometry of the metal center. The energies and intensities of ligand-to-metal charge transfer transitions sensitively probe bonding interactions of the ligand with the metal center. Charge transfer transitions can be used both qualitatively to observe ligand binding to a metal center, owing to the requirement of ...

Many metalloenzymes exhibit distinctive spectral features that are now becoming well understood. These reflect active site electronic structures that can make significant contributions to catalysis. Copper proteins provide well-characterized examples in which the unusual electronic structures of their active sites contribute to rapid, long-range electron transfer reactivity, oxygen binding and activation, and the multielectron reduction of dioxygen to water.