Probing motions between equivalent RNA domains using magnetic field induced residual dipolar couplings: accounting for correlations between motions and alignment.

Approaches developed thus for extracting structural and dynamical information from RDCs have rested on the assumption that motions do not affect molecular alignment. However, it is well established that molecular alignment in ordered media is dependent on conformation, and slowly interconverting conformational substates may exhibit different alignment properties. Neglecting these correlation effects can lead to aberrations in the structural and dynamical analysis of RDCs and diminish the utility of RDCs in probing motions between domains having similar alignment propensities.