Characterization of Copper(II) Interactions with Sinefungin, a Nucleoside Antibiotic: Combined Potentiometric, Spectroscopic and DFT Studies
Interactions between sinefungin and copper(II) ions were investigated. Stoichiometry and stability constants of the metal-free system and two mononuclear complexes present in solution were determined on the basis of potentiometric data analysis. The results were compared to the Cu(II)-ornithine sys...
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| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Wiley
2007-01-01
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| Series: | Bioinorganic Chemistry and Applications |
| Online Access: | http://dx.doi.org/10.1155/2007/53521 |
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| Summary: | Interactions between sinefungin and copper(II) ions were investigated. Stoichiometry and stability
constants of the metal-free system and two mononuclear complexes present in solution were determined on the basis
of potentiometric data analysis. The results were compared to the Cu(II)-ornithine system due to structural similarities
between both molecules. Combined spectroscopic and theoretical studies allowed for determination of coordination
pattern for the Cu(II)-sinefungin complexes. At acidic pH, copper is bound in “glycine-like” coordination
mode, identical with that of ornithine. This involves α-amino group and the carboxyl oxygen. At higher pH, a “bis-complex” is formed
by two sinefungin molecules. The second ligand binds in equatorial position displacing two water molecules, what
results in the stable {2N,2O} coordination. Both axial positions are supposed to be occupied by N1
nitrogen donors of adenine moiety, what is confirmed by DFT calculations. They interact indirectly with copper(II) through water
molecules as the result of dominant syn conformation of purine. |
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| ISSN: | 1565-3633 1687-479X |