Valines
Of the four valines present, only two (V5 and V70) yield both Cγ1 and Cγ2 data. Both for V5 and V70, the (Cγ1) and (Cγ2) order parameters have almost identical values. While for V70, the amplitudes of anisotropy ηrdc are very similar, those for V5 were somewhat different with η(Cγ1) = 0.28 ± 0.19 and η(Cγ1) = 0.05 ± 0.09, although they are equivalent within the experimental error. However, since V5 is involved in the packing of the core, the presence of concerted motions cannot be ruled out. V70 is also the only valine of the four to exhibit some solvent exposure; accordingly, it has the lowest order parameters of the four ((Cγ1/Cγ2) = 0.27/0.22 vs. 0.41/0.39 (V5), –/0.82 (V17), 0.62/– (V26)) and the highest level of anisotropy (ηrdc(Cγ1/Cγ2) = 0.48/0.45 vs. 0.28/0.05 (V5), –/0.04 (V17), 0.10/– (V26)), suggesting the sampling of more than one rotameric states about the χ1 torsion angle.