HETERONUCLEAR 2-DIMENSIONAL N-15-NMR AND C-13-NMR STUDIES OF DNA OLIGOMERS AND THEIR NETROPSIN COMPLEXES USING INDIRECT PROTON DETECTION

Heteronuclear multispin coherence proton-detected two-dimensional nmr spectroscopic experiments were used to obtain information on protonated carbons nitrogens of the self-complementary d (G-G-T-A-T-A-C-C) and d (G-G-A-A-T-T-C-C) duplexes, with and without the drug netrospin dissolved in aqueous solution. Many correlations of protons coupled to C-13 nuclei on the base and sugar rings of the octanucleotides were detected, allowing the carbon resonances to be assigned based on previous homonuclear proton two-dimensional nmr studies. Imino nitrogen assignments can also be made using the proton assignments from previous one-dimensional nuclear overhauser effect experiments. Imino nitrogen shifts may be useful indicators of changes in local hydrogen-bonding interactions to base-pair edges.