Cisplatin Interaction with Amino Acids Cysteine and Methionine from Gas Phase to Solutions with Constant pH

This work is focused on the computational studies of reactions of hydrated forms of cisplatin with sulphur-containing amino acids cysteine and methionine. First, the appropriate model for solvation of the examined complexes was searched for. The suggested procedure employs the B3LYP density functional, 6-311++G(2df,2pd) basis set with Stuttgart-Dresden pseudopotentials on heavy atoms, the D-PCM solvation model and the UAKS cavity which uses more realistic NPA partial charges instead of formal partial charges for platinum ligands. In the second part this model is applied to the evaluation of the Legendre transformed reaction Gibbs free energy of cisplatin with cysteine and methionine in solution at constant pH.