Dynamic and Thermodynamic Investigation on the Interaction of Bovine Serum Albumin with an Anticancer Pt Complex Containing Dithiocarbamate Using Molecular Docking and Spectroscopic Methods

Abstract

Cisplatin is used for human cancers treatment, such as bladder and ovarian, endometrial and cervical, head and neck, and testicular cancer, but its clinical use has been limited by some serious side effects. Therefore S,S donor ligands such as dithiocarbamates can be used to prepare anticancer Pt-drugs and reduce some side effects. The purpose of this study is the interaction ability of designed Pt complex, [Pt(bpy)(tertamyl.dtc)]NO₃, where bpy is bipyridine and tertamyl-dtc is (2-methyl butan-dithiocarbamate), with bovine serum albumin (BSA) using fluorescence emission titration, UV-Vis spectroscopy, and molecular docking methods. The obtained negative values of enthalpy, ΔH⁰_b, and entropy, ΔS⁰_b, showed that a major binding mode between Pt complex and BSA is the van der Waals and hydrogen bond. The negative value of Gibbs free energy achieved via the UV-Vis technique also exhibited a spontaneous interaction. In addition, the results related to emission titration displayed that the fluorescence quenching of protein by Pt complex is a static quenching mechanism. Moreover, the binding parameters, including apparent biomolecular quenching constant (k_q), the number of binding sites (n), and binding constant (K_b) were obtained by the Stern–Volmer equation. These values of K_b, k_q, and n were also obtained as 3 × 10⁸ M⁻¹, 3 × 10¹⁴ M⁻¹ S⁻¹, and 1.4, respectively. By the use of spectroscopic kinetics model, this interaction was studied and the result showed a second-order type. Finally, the binding of Pt complexes to BSA was verified by the molecular docking method. The binding free energy and K_i for the Pt compounds were obtained as −6.6 kcal mol⁻¹ and 14.48, respectively. The results of molecular docking demonstrate the position of binding of Pt complex on BSA is the site I in the subdomain IIA.

Graphical Abstract

Anticancer Pt(II) complex, [Pt(bpy)(tertamyl.dtc)]NO₃, has been interacted with bovine serum albumin (BSA). Binding and thermodynamic parameters have also been estimated. Molecular docking showed that this complex binds to the site II subdomain IIIA of BSA. Abbreviations: UV–Vis, ultraviolet-visible; BSA, Bovine Serum Albumin; bpy, bipyridine; dtc, Dithiocarbamate; PDB, Protein Data Bank; LGA, Lamarckian genetic algorithm; HT29, Human colon cancer cell line; Panc1, Human pancreatic cell line; IC₅₀, fifty percentage of inhibitory concentration; SD, standard deviation; Tyr, Tyrosine; Phe, Phenylalanine; Trp, Tryptophan; Asp, Aspartic; Pro, Proline; Thr, Threonine; Val, Valine; Leu, Leucine; T_m, melting temperature; vdW, van der Waals; H-bond, hydrogen bond

Keywords:

• Bovine serum albumin
• Pt complex
• anticancer
• molecular docking

Acknowledgment

We are thankful to the Research Council of Payame Noor University for their fiscal supports.

Disclosure statement

It is declared authors have no conflict of interest in cooperation.

Data availability statement

All data generated or analyzed during this study are included in this published article.

Authors’ contributions

All authors analyzed and interpreted the data and wrote the article. Also, all authors read and approved the final manuscript.

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Authors have an agreement for publishing data before submitting the paper to this journal.

Ethics approval

This article does not contain any studies with human participants or animals performed by any of the authors.

Additional information

Funding

The work was supported by Payame Noor University.