Effect of diamminedichloroplatinum(II) on dimerization of bovine serum albumin in solution

Abstract

Complexes of cis- and trans-isomers of diamminedichloroplatinum(II) (DDP) with bovine serum albumin (BSA) were studied using electrophoretic analysis and FTIR spectroscopy. We have demonstrated that intermolecular protein complexes were formed in solutions containing excessive amount of platinum and BSA in concentrations close to the physiological one. Analysis of the IR spectra revealed that the interaction of BSA with DDP is accompanied by decreasing α-helical content of the BSA from 65 to 55% in the complexes with cis-DDP and to 48% in the case of trans-DDP; while the amount of β-structures in the protein increases from 15–20 to 20–30% in the complexes with cis-DDP and to 35–40% in the complexes with trans-DDP. Based on the data obtained we suggest, that the binding of DDP induces the changes in the protein secondary structure, which stimulates dimerization of the BSA in solution. Refs 47. Figs 3. Tables 1.