Fig. 3.

a ¹H–¹³C HMQC spectrum of U-[²H,¹²C], Ala-[¹³CH₃], Ile-δ1-[¹³CH₃], Met-[¹³CH₃], Val-Leu-[¹³CH₃, ¹²CD₃] EIN. b Two views of the 3D structure of EIN with methyl groups displayed as spheres. The color coding of the methyl groups used in both panels is as follows: Ala blue; Ile yellow; Met green; Leu/Val red. Classification of the methyl cross-peaks based on residue type was obtained by running methyl-TROSY experiments on samples D–G (Table 1)