Investigation of metallodrug/protein interaction by X-ray crystallography and complementary biophysical techniques

Abstract

Protein metalation, the process by which a metal compound (or a metal ion) reacts with a protein to produce a metal/protein adduct, is at the basis of many biological events; the knowledge of this process at the atomic level is important in the design and development of new metallodrug-based therapeutic approaches. Recently, single crystal X-ray diffraction experiments have been frequently used to characterize the structures of the adducts formed upon the reaction of Pt, Au, Ru, Rh, Ir, Cu, Mn and V-based drugs with proteins. Although X-ray crystallography is certainly useful to determine the structure of these adducts, the combination with other biophysical techniques provides insights into the system behavior in solution, the reactivity of metal compounds with proteins, fate and stability of the metal/protein adduct and is often helpful for the rationalization of ambiguous or unexpected crystallographic data. Here we describe the results of selected studies carried out in the field of protein metalation, where the structural information achieved by X-ray crystallography has been complemented by data collected using mass spectrometry, vibrational spectroscopy, electron paramagnetic resonance, and computational methods, including density functional theory, docking and molecular dynamics simulations. These works allow us to define the protein metalation process at the molecular level, providing information on the factors responsible for the formation and stability of metal/protein adducts.