Figure 3.

(a) QM/MM calculated Ile61N isotropic shifts are plotted as a function of I60ψ from 100 minimized snapshots from the MD trajectory (red, circle). Three ψ values were measured experimentally at three ¹⁵N shift positions for Ile60 in low temperature DNP-enhanced NMR experiments¹⁹ and are shown here depicted with stars. The correlation between ψ angles and chemical shifts from both prior experimental and these computational results match well. The side chain torsion angle I60χ1 was plotted with ¹⁵N shifts for snapshots with similar backbone torsion angle ψ, 120° < I60ψ < 125° (b). Ile61N shifts vary up to 5 ppm with a 5° range of I60ψ, and I60χ1 is likely to contribute to this variation.