The interaction of apramycin with copper at different pH values was investigated by potentiometric titrations and EPR, UV-vis and CD spectroscopic techniques. The Cu(II)-apramycin complex prevailing at pH 6.5 was further characterized by NMR spectroscopy. Metal-proton distances derived from paramagnetic relaxation enhancements were used as restraints in a conformational search procedure in order to define the structure of the complex. Longitudinal relaxation rates were measured with the IR-COSY pulse sequence, thus solving the problems due to signal overlap. At pH 6.5 apramycin binds copper(II) with a 2 : 1 stoichiometry, through the vicinal hydroxyl and deprotonated amino groups of ring III. Plasmid DNA electrophoresis showed that the Cu(II)-apramycin complex is more active than free Cu(II) in generating strand breakages. Interestingly, this complex in the presence of ascorbic acid damages DNA with a higher yield than in the presence of H2O2.

D., B., G., B., N., D., Gaggelli, E., Gaggelli, N., E., M., et al. (2009). Structural features and oxydative stress towards plasmid DNA of apramycin copper complex. DALTON TRANSACTIONS, 2009, 1123-1130 [10.1039/b815046j].

Structural features and oxydative stress towards plasmid DNA of apramycin copper complex

GAGGELLI, ELENA;GAGGELLI, NICOLA;VALENSIN, GIANNI;
2009-01-01

Abstract

The interaction of apramycin with copper at different pH values was investigated by potentiometric titrations and EPR, UV-vis and CD spectroscopic techniques. The Cu(II)-apramycin complex prevailing at pH 6.5 was further characterized by NMR spectroscopy. Metal-proton distances derived from paramagnetic relaxation enhancements were used as restraints in a conformational search procedure in order to define the structure of the complex. Longitudinal relaxation rates were measured with the IR-COSY pulse sequence, thus solving the problems due to signal overlap. At pH 6.5 apramycin binds copper(II) with a 2 : 1 stoichiometry, through the vicinal hydroxyl and deprotonated amino groups of ring III. Plasmid DNA electrophoresis showed that the Cu(II)-apramycin complex is more active than free Cu(II) in generating strand breakages. Interestingly, this complex in the presence of ascorbic acid damages DNA with a higher yield than in the presence of H2O2.
2009
D., B., G., B., N., D., Gaggelli, E., Gaggelli, N., E., M., et al. (2009). Structural features and oxydative stress towards plasmid DNA of apramycin copper complex. DALTON TRANSACTIONS, 2009, 1123-1130 [10.1039/b815046j].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11365/29316
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