Impact of Cu(II) ions on the structure and antimicrobial properties of sisomicin, an aminoglycoside antibiotic

The formation of copper(II) complexes of an aminoglycoside antibiotic – sisomicin – was studied by potentiometry and spectroscopic techniques (UV–Vis, CD, NMR and EPR). At physiological pH, Cu(II) is bound to both amino functions and hydroxyl oxygen of the 2-deoxystreptamine moiety. When pH increases slightly, another amino group located at the aminosugar ring becomes engaged in the coordination process. Microbiological studies with the use of Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa showed that copper(II) does not interfere with the bactericidal action of sisomicin.

The coordination pattern of the Cu(II)–sisomicin complex was characterized and was found unique in comparison with the complexes of other aminoglycosides. This feature undoubtedly originates from the specific structure and stereochemical properties of sisomicin. The influence of Cu(II) on the antimicrobial activity of aminoglycoside was also tested.Figure optionsDownload as PowerPoint slide