Figure 9.

Extent of rotamer averaging plotted on the E:FOL:NADP⁺ structure (3QL3). Going clockwise, each quadrant shows a 90° rotation about the vertical axis in the plane of the page. FOL is shown as yellow sticks; NADP⁺ is orange sticks. Spheres representing side chain heavy atoms are shown for all aromatic, Ile, Thr, and Val residues. Residues with statistically significant variations in rotamer averaging, with uncertainties in ³J values taken into account, in one or more DHFR complexes are colored green (with green residue labels). Residues that show similar rotamer averaging for each of the DHFR complexes studied are labeled in red and colored white to red to indicate the extent of averaging, with red coloring denoting the most rotamer averaging. The gradient goes from white (p_major = 1.0) to red (p_major = 0.6), where p_major = max[p₁₈₀, p₋₆₀, p₊₆₀] as determined according to Eqs 1–3. In cases where rotamer hopping is not expected (e.g. Trp22 and other aromatics), this p_major is considered a measure of the extent of local motions within a single rotamer well (see Figure 6B for an illustration of the effect this has on ³J values).