HOBS methods for enhancing resolution and sensitivity in small DNA oligonucleotide NMR studies

1H NMR spectra from biopolymers give chemical shifts classified according to proton type and often suffer from signal degeneracy. Data from nucleic acids are particularly prone to this failing. Recent developments in proton broad-band decoupling techniques with the promise of enhanced resolution at full sensitivity have allowed us to investigate the application of homo-nuclear band-selective (HOBS) decoupling to the study of small synthetic DNA molecules and to compare these with results from classical and Pure Shift techniques. Improved signal resolution at full sensitivity in both HOBS-1D ¹H and HOBS-2D [¹H, ¹H] NOESY NMR data are reported for three example small DNA molecules. Comparisons of ¹H T₁ and integrals of signals from HOBS-1D ¹H and HOBS-2D [¹H, ¹H] NOESY NMR data with those of standard data collection methods are also reported. The results show that homo-nuclear HOBS-NOESY data are useful for data assignment purposes and have some merit for quantification purposes. In general we show that resolution and sensitivity enhancement of ¹H NMR data for small DNA samples may be achieved without recourse to higher magnetic field strengths at full sensitivity in a band-selected manner.