Measurement of H2'-C2' and H3'-C3' dipolar couplings in RNA molecules.

The quality of nucleic acid solution structures can be significantly improved using residual dipolar coupling data. However, many of the one-bond couplings that could be used for this purpose are difficult to measure. Conventional 2D experiments are often unable to reveal one-bond H2'-C2' and H3'-C3' couplings in large RNA molecules due to spectral overlap. Here we show how to use 3D HCcH-COSY and Relay HCcH-COSY to measure one-bond H2'-C2' and H3'-C3' couplings which improved the precision of the structures obtained recently for a 42 nucleotide RNA.