Comparative XANES study of serotransferrin and ovotransferrin at CuK-edge:evidence of interactions among the metal sites

The Cu site structure of human serotransferrin and hen ovotransferrin using XANES spectroscopy has been investigated. Although the transferrin family proteins have been extensively studied, the results reported herein are the first concerning the structure of the metal site in C-terminal and N-termi nal in the whole protein. Our structural data show that these proteins diff er with regard to the independence of the two binding sites and the geometr y of copper coordination, ranging from a poorly to a significantly distorte d octahedron.