Facilitated assignment of adenine H2 resonances in oligonucleotides using homonuclear long-range couplings

The small homonuclear coupling constant between H2 and H8 protons of adenine (0.5 +/- 0.2 Hz) was determined and exploited to assign the H2 proton of adenine residues in DNA oligonucleotides. The utility of this approach is demonstrated for two different DNA sequences in D(2)O, for which we show a rapid and unambiguous assignment of the A H2 resonances.