A New Experiment for the Measurement of nJ(C,P) Coupling Constants Including 3J(C4′i,Pi) and 3J(C4′i,Pi+1) in Oligonucleotides

A new experiment for the measurement of nJ(C,P) coupling constants along the phosphodiester backbone in RNA and DNA based on a quantitative-J HCP experiment is presented. In addition to coupling constants, in which a carbon atom couples to only one phosphorus atom, both the intraresidual 3J(C4'i,Pi) and the sequential 3J(C4'i,Pi+1) for the C4' resonances that couple to two phosphorus atoms can be obtained. Coupling constants obtained by this new method are compared to values obtained from the P-FIDS experiment. Together with 3J(H,P) coupling constants measured using the P-FIDS experiment, the backbone angles ß and ? can be determined.