FT-RAMAN STUDIES ON THE TRANSFORMATION OF G-ACTIN TO F-ACTIN, THE BINDING OF CISPLATIN AND TRANSPLATIN TO F-ACTIN AND THE EFFECTS OF THE CONFORMATION OF F-ACTIN

The conformation change of G-actin to F-actin and the binding modes of cisplatin and transplatin to F-actin have been studied by FT-Raman sp ectroscopy. The studies show that the process of polymerization is rel ated to the vibration of C-S Gauche mode (similar to 650 cm(-1)), whic h indicates that the methionine (Met) contributes to the polymerizatio n of actin. The relative intensity of I(925)/I(803), reflecting the co nformation of actin secondary structure, does not change during the po lymerization process. The effect of cisplatin and transplatin on F-act in is dependent on the species and their concentrations. Cisplatin, at high concentrations, affects the conformation of F-actin mainly by bi nding with the sulphur of methionine. Transplatin, even at low concent rations, obviously affects the F-actin's conformation due to it's mult iple binding sites, on N-containing sites in addition to S-methionine sites. These results relate to the differences in pharmacology and tox icology effects of the complexes. (C) 1997 Elsevier Science B.V.