NMR and fluorometric characterization of mithramycin in aqueous solution.

The assignments for the resonances in the 1H and 13C NMR spectra of mithramycin in aqueous solution have been determined by a combination of 2D NMR methods. Specific NOESY contacts observed between different moieties indicate that the drug assumes a compact conformation in aqueous solution. Fluorescence measurements are consistent with a compact structure for mithramycin in water and confirm the preference of mithramycin for binding to dG-containing nucleic acids. These studies provide a basis for the further physico-chemical characterization of mithramycin-DNA complexes.