Related Experiment Video
Updated: Aug 19, 2026

Production of Disulfide-stabilized Transmembrane Peptide Complexes for Structural Studies
Published on: March 6, 2013
Mithramycin forms a stable dimeric complex by chelating with Fe(II): DNA-interacting characteristics, cellular
Ming-Hon Hou1, Andrew H-J Wang
1Institute of Biological Chemistry, Academia Sinica Taipei, 115 Taiwan.
Abstract:
Mith (mithramycin) forms a 2:1 stoichiometry drug-metal complex through the chelation with Fe(II) ion as studied using circular dichroism spectroscopy. The binding affinity between Mith and Fe(II) is much greater than other divalent metal ions, including Mg(II), Zn(II), Co(II), Ni(II) and Mn(II). The [(Mith)2-Fe(II)] complex binds to DNA and induces a conformational change of DNA. Kinetic analysis of surface plasmon resonance studies revealed that the [(Mith)2-Fe(II)] complex binds to DNA duplex with higher affinity compared with the [(Mith)2-Mg(II)] complex. A molecular model of the Mith-DNA-Metal(II) complex is presented. DNA-break assay showed that the [(Mith)2-Fe(II)] complex was capable of promoting the one-strand cleavage of plasmid DNA in the presence of hydrogen peroxide. Intracellular Fe(II) assays and fluorescence microscopy studies using K562 indicated that this dimer complex maintains its structural integrity and permeates into the inside of K562 cells, respectively. The [(Mith)2-Fe(II)] complex exhibited higher cytotoxicity than the drug alone in some cancer cell lines, probably related to its higher DNA-binding and cleavage activity. Evidences obtained in this study suggest that the biological effects caused by the [(Mith)2-Fe(II)] complex may be further explored in the future.
Related Concept Videos
Inhibitors of Bacterial Protein Synthesis
Inhibitors of Bacterial DNA Synthesis
EDTA: Chemistry and Properties
Structural Isomerism
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can be...

