ISJ Theoretical & Applied Science 08(160) 2026

Philadelphia, USA

Tursunov, Kh.B., Turaev, Kh.Kh., Tillaev, Kh.R., Choriev, O.I., & Ashurov, J.M.

Binding of Co(II) and Cu(II) complexes based on 3-amino-1,2,4-triazole and pyromellitic acid to the β-domain of metallothionein-2: a molecular docking study.

Full Article: PDF

Scientific Object Identifier: http://s-o-i.org/1.1/TAS-08-160-3

DOI: https://dx.doi.org/10.15863/TAS.2026.08.160.3

Language: English

Citation: Tursunov, Kh.B., Turaev, Kh.Kh., Tillaev, Kh.R., Choriev, O.I., & Ashurov, J.M. (2026). Binding of Co(II) and Cu(II) complexes based on 3-amino-1,2,4-triazole and pyromellitic acid to the β-domain of metallothionein-2: a molecular docking study. ISJ Theoretical & Applied Science, 08 (160), 11-21. Soi: https://s-o-i.org/1.1/TAS-08-160-3 Doi: https://dx.doi.org/10.15863/TAS.2026.08.160.3

Pages: 11-21

Published: 30.08.2026

Abstract: Metallothioneins are small cysteine-rich proteins that act as the intracellular reservoir of zinc and copper and as a detoxification system for heavy metals. In this work the binding of Co(II) and Cu(II) coordination compounds based on 3-amino-1,2,4-triazole and pyromellitic acid to the β-domain of human metallothionein-2 (PDB 2MHU) was studied by molecular docking. Both free ligands were docked separately for comparison. Calculations were carried out in CB-Dock2 independently for each of the five cavities detected on the protein surface. The free ligands selected cavity C2 and gave low scores: ?4.8 kcal mol? ? for pyromellitic acid and ?3.4 kcal mol? ? for the triazole. Coordination to a metal centre markedly enhanced binding: ?6.4 kcal mol? ? for the Cu(II) complex in C2 and ?6.6 kcal mol? ? for the Co(II) complex in C1. This advantage was preserved in all five cavities without exception. The 0.2 kcal mol? ? difference between the complexes lies below the resolution of the method, so the two were regarded as equipotent; they differ in binding site and interaction type. The Cu(II) complex occupies the groove above the thiolate cluster and forms ?-type contacts with Cys7, Cys13 and Cys26, whereas the Co(II) complex shifts to the C1 surface and binds through hydrogen bonds alone. The difference was interpreted within Pearson’s theory. The results indicate that coordination compounds may act on metallothionein through a mechanism distinct from that of conventional chelators — as preorganised recognition elements.

Key words: metallothionein-2, molecular docking, 3-amino-1,2,4-triazole, pyromellitic acid, coordination compound, ?-sulfur interaction, Pearson’s theory.