Molecular Dynamic Simulation and Spectroscopic Investigation of Some Cytotoxic Palladium(II) Complexes Interaction with Human Serum Albumin

Studies on the interactions between metallodrugs and human serum albumin (HSA), as carrier for drugs and biological molecules, are extremely important to design and discover new drugs. The interaction of three novel synthesized complexes of [Pd(phen)(R-gly)]NO3, where R-gly is methyl-, propyl-, and amyl-glycine and phen is 1,10- phenanthroline, with HSA were investigated using spectroscopic studies in combination with a molecular dynamic simulation. These water soluble complexes can denature HSA at ~50 µM. According to the results obtained for the isothermal titration at 27 and 37°C, it was found that there are 10, 8, and 6 binding sites (g) for methyl-, propyl-, and amyl-glycine complexes on the HSA with positive cooperativity in binding, respectively. Also, the binding and thermodynamic parameters were analyzed. We found a good consistency between secondary structure and simulation data with spectroscopic studies, and the experimental data are confirmed by molecular simulation results. In addition, the results related to helix, beta sheets, and coil percentages revealed that all complexes decrease the helix structure and increase the beta structure; and that the amyl derivative is more effective in denaturing the HSA structure.