Figure 9.

Distribution of NMR-detected perturbations in the four mutants described (upper left, 2S; upper right, 3M; lower left, 4M; lower right, 4M2S). Color coding: yellow, slight resonance shifts (< 0.1 ppm in either the ¹H or ¹⁵N dimension); orange, significant shifts (> 0.1 ppm in either dimension); red, strongly broadened or not observable. The positions of the mutations are indicated in blue for each structure. All structures are identical, and in approximately the same orientation as in Figure 2.