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

Abstract

(1) H 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 broadband decoupling techniques with the promise of enhanced resolution at full sensitivity have allowed us to investigate the application of homonuclear 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 (1) H and HOBS-2D [(1) H, (1) H] NOESY NMR data is reported for three example small DNA molecules. Comparisons of (1) H T1 and integrals of signals from HOBS-1D (1) H and HOBS-2D [(1) H, (1) H] NOESY NMR data with those of standard data collection methods are also reported. The results show that homonuclear 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 (1) H NMR data for small DNA samples may be achieved without recourse to higher magnetic field strength at full sensitivity in a band-selected manner.