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Mithramycin: a very strong metal chelating agent
C Demicheli1, A Garnier-Suillerot
1Laboratoire de Chimie Bioinorganique, LPCB (URA CNRS 198) Université Paris Nord, Bobigny, France.
Biochimica Et Biophysica Acta
|August 20, 1993
Summary
Mithramycin binds strongly to calcium and other divalent cations, forming a left-handed helix. This interaction is significant in biological contexts, influencing mithramycin
Area of Science:
- Biochemistry
- Spectroscopy
- Molecular Interactions
Background:
- Mithramycin is an antibiotic with known DNA-binding properties.
- The influence of various metal ions on mithramycin's structure and function is not fully understood.
Purpose of the Study:
- To investigate the interaction of mithramycin with different metal ions (Ca2+, Cd2+, Tb3+, Gd3+, Li+, Na+, K+).
- To elucidate the structural consequences of these interactions using spectroscopic methods.
Main Methods:
- Circular dichroism spectroscopy.
- Absorption spectroscopy.
Main Results:
- Mithramycin forms strong complexes with Ca2+, Cd2+, Tb3+, and Gd3+ in a 1:4 cation:mithramycin ratio, adopting a left-handed screw conformation.
- Mithramycin also binds to Na+ with a left-handed screw conformation, but not to Li+ or K+.
- None of the studied cations facilitated the interaction between mithramycin and DNA.
Conclusions:
- Mithramycin's interaction with divalent cations, particularly Ca2+, is a key factor in its behavior.
- The binding of mithramycin to Ca2+ is prevalent in experimental conditions, affecting drug concentration.
- Mithramycin's interaction with Na+ is observed, but Li+ and K+ do not interact, and no cation promotes mithramycin-DNA binding.