Dynamics of Oxygen Binding in Hemocyanin and Tyrosinase by XANES and the Multiple Scattering Approach

The Cu K-edge X-ray Absorption Near Edge Structure (XANES) spectra of hemocyanin (He) in its deoxy- form has been simulated by the multiple scattering approach in the real space of coordinates. The features of the experimental spectra are related to structural parameters such as bond lenghts and the overall simmetry at the Cu site(s), whose changes are directly linked to the ligand binding dynamics. The experimental spectrum is compared with that of deoxy-tyrosinase, for which diffraction data are still unavailable, and the structure of its copper site(s) is inferred. These calculations, together to the previously reported ones on oxy-Hc [1], provide new theoretical support to any XANES investigation of the oxygen binding dynamics in He and its related proteins