Sensitive ¹H-³¹P correlations with 5′ methylene protons of DNA via homonuclear double-quantum coherence

A novel pulse sequence is presented for the correlation of 5′ and 5″ protons in DNA with phosphorus. Double-quantum coherence between the methylene protons is used to generate ¹H5′-³¹P and ¹H5″-³¹ p cross peaks in an HMQC-type experiment. The resolution for these cross peaks is significantly improved over that of conventional HSQC experiments, as cross peaks between ¹H4′ and³¹ P are largely suppressed and a 3D version of the experiment can be performed with little penalty in sensitivity. In addition, sensitivity is favoured by slower relaxation of the double-quantum coherence and a more favourable multiplet fine structure in the acquisition dimension.