Monitoring anthracycline binding to nucleotides by two dimensional cosy NMR experiments.

The nucleotide binding ability of the novel anthracycline drug, 3-fluoro-4-demethoxydaunomycin, has been studied by two dimensional 1H NMR correlated spectroscopy (COSY). In the COSY spectrum of the nucleotide mini-helix d(CTGCAG)2 cross-peaks are observed from the spin-coupled H6 and H5 protons of the cytidine bases. Additional cytidine H6/H5 cross-peaks are observed in the COSY spectrum of the anthracycline-d(CTGCAG)2 complex. These additional cytidine cross-peaks enable the identification of the anthracycline binding sites and the determination of the relative kinetic stability of the bound drug at each binding site.