Mutation of Cu-coordinating amino acids can cause a trigonal site to become more tetragonal. We are interested in determining how such structural changes are tied to the biological function of these proteins. An unusual variation of the type 1 copper site has recently been observed in the X-ray crystal structure of the Cu A site of cytochrome c oxidase. As a consequence of having a second cysteine ligand, a dinuclear cluster is formed containing two copper atoms bridged by two cysteinate sulfurs. Again, Raman spectroscopy has proved ideal for identifying the distinctive spectroscopic signatures of the Cu A site and showing that its structure is highly conserved.
Work is now underway to assign the entire vibrational spectrum using normal coordinate analysis.
Techniques for Obtaining Resonance Raman Spectra of Metalloproteins. 226, Academic Press, New York, pp. Cu CT Transitions in Type 1 Copper Proteins. J. Han, T. M. Loehr, Y. Lu, J. Selverstone Valentine, B. A. Averill, and J. Sanders-Loehr, J. Am. Investigation of Type 1 Copper Site Geometry by Spectroscopy and Molecular Redesign.