The rotating frame nuclear Overhauser effect spectroscopy experiment as an aid to determining solution structures of DNA oligomers

Important intrinsic characteristics of the rotating frame nuclear Overhauser effect spectroscopy (ROESY) experiment were found to be advantageous in DNA solution structure determination. In a ROESY experiment, the different mechanisms of relaxation result in different signs of cross peaks, enabling a clear distinction between H2' resonances and H2" resonances of the DNA sugar backbone. This method is of particular importance in crowded spectra, for purine resonances whose H2', H2" protons typically resonate closely, as well as in conditions where line broadening makes coupling constants in a correlated spectroscopy experiment impossible to determine. By observing the signs of cross peaks in the base proton to H2', H2" sugar proton region, the ROESY spectrum can be used to distinguish A-form, B-form, and Z-form DNA.