Computational Analysis of Structure and Binding Energy for Cisplatin-Loaded Proteins

Abstract Platinum-based drugs, such as cisplatin, are first-line chemotherapy treatments for patients with cancer. However, the success of these drugs is balanced with severe off-target toxicities and high dosing requirements, prompting the development of selective nanocarriers for targeted drug delivery. This study uses a computationally guided approach to examine the role of amino acids in cisplatin binding within proteins as nanocarriers. Using density functional theory, we quantify the binding of cisplatin to platinum-coordinating amino acids. We then rationally engineer a model MSH6 protein carrier, and evaluate the ability of MSH6 to bind cisplatin via molecular docking simulations. Structure predictions of the engineered MSH6 show that inserting the cisplatin-binding site has a limited impact on the nearby protein architecture of MSH6. Finally, we confirm and reveal cisplatin’s mechanism of action with DNA binding, and compare the energetic potentials of DNA binding from protein-delivered cisplatin to systemically administered cisplatin. Future studies will use these results to experimentally validate the binding of cisplatin in model protein carriers, and inform the strategic design and experimental development of a protein nanocarrier to achieve targeted drug delivery in cancer. Competing Interest Statement The authors have declared no competing interest. Footnotes In this revision, we expanded the number of modeled residues and added several figures to the work. Expansions include a TOC figure, additional methods, additions to Figure 3, and additions to Figure 5, as well as added SI figures.