Difficulty in resolving degeneracies in determining the average orientation of TAR helices using multiple RDC data sets. Shown are the experimental order tensor frames (Sxx, Syy, and Szz, in green, blue, and purple, respectively) determined for helix I (open circles) and II (filled circles) using (a) EI(3)-TARm and (b) EI(22)-TARm RDCs shown relative to the PAS of the order tensor determined using the TARm RDCs. The different orientational solutions were generated by rotating helix II in the TARm PAS 180° degrees about the x, y, and z axis.