Aims
In this work, we aim to expand and validate the use of combined experimental-theoretical approaches in studying copper-based drug1,2 interactions with proteins.3
Methods
A tetra-coordinated Cu(II) complex has been employed as a practical case study, and its interactions with several relevant proteins using different experimental and computational techniques have been evaluated, including electron paramagnetic resonance spectroscopy, mass spectrometry, density functional theory, and protein-ligand docking calculations.
Results
Experimental data highlight interactions of the Cu(II) complex with albumin, myoglobin, and cytochrome C. Further insights into the preferential modes of binding were evaluated by density functional theory and docking calculations, which revealed three main outer surface binding sites for both albumin and myoglobin, as well as three preferential inner pockets in the case of albumin. The most relevant binding modes found for both proteins include non-coordinative interactions with the Cu(II) dimeric structure intact upon binding, as well as metal-ligand exchange and direct metal-amino acid coordination, mainly to glutamate/aspartate residues after cleavage of the dimer.
Conclusions
This study highlights how the development of modeling frameworks for bioinorganic systems in combination with experimental techniques allows further characterization of metallodrug-protein interactions and can contribute to the understanding of metallodrug speciation and its targets in biological systems. This can eventually help in the prediction of therapeutic performance and assist in the design of more effective metallodrugs.