Effect of temperature on the interaction of cisplatin with the model protein hen egg white lysozyme

The products of the reaction between cisplatin (CDDP) and the model protein hen egg white lysozyme (HEWL) at 20, 37 and 55 A degrees C in pure water were studied by UV-Vis absorption spectroscopy, intrinsic fluorescence and circular dichroism, dynamic and electrophoretic light scattering and inductively coupled plasma mass spectrometry. X-ray structures were also solved for the adducts formed at 20 and 55 A degrees C. Data demonstrate that high temperature facilitates the formation of CDDP-HEWL adducts, where Pt atoms bind ND1 atom of His15 or NE2 atom of His15 and NH1 atom of Arg14. Our study suggests that high human body temperature (fever) could increase the rate of drug binding to proteins thus enhancing possible toxic side effects related to CDDP administration.