FTIR STUDY OF THE SECONDARY STRUCTURE OF CYTOCHROME-C AND ITS PLATINUM-MODIFIED DERIVATIVES

The FTIR spectral measurements were carried out for native cytochrome c (cyt c) and its four platinum-modified derivatives. The influence of the platinum complex binding on the secondary structure of cyt c was discussed. It was found that the secondary structure of platinum-binde d derivatives is similar to that of native cyt c when the platinum com plex is binding on or near the surface of the protein. While in the ca se of derivatives, in which the platinum complex interacts with the se cond axial ligand of cyt c (Met 80) and causes the replacement of Met 80 by Lys 79 or solvent (H2O), great secondary structural changes were observed The results imply that the Met 80 residue is very important in controlling the secondary structure of cyt c.