Sensitive H-1-P-31 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'' proto ns in DNA with phosphorus. Double-quantum coherence between the methylene p rotons is used to generate (1)H5'-P-31 and (1)H5''-P-31 cross peaks in an H MQC-type experiment. The resolution for these cross peaks is significantly improved over that of conventional HSQC experiments, as cross peaks between (1)H4' and P-31 are largely suppressed and a 3D version of the experiment can be performed with little penalty in sensitivity. In addition, sensitivi ty is favoured by slower relaxation of the double-quantum coherence and a m ore favourable multiplet fine structure in the acquisition dimension.