Figure 10.

Experimental (a-f) and simulated (g-l) ¹⁵N CSA/¹H-¹⁵N dipolar correlation spectra of ¹³C, ¹⁵N N-formyl-Met-Leu-Phe (MLF) tripeptide, extracted from the corresponding 3D experiments along the ¹⁵N isotropic chemical shift for Phe (a, d), Leu (b, e) and Met (c, f) residues. 3D R18₁⁷/R14₂⁵ and R18₁⁷/R14₂³ pulse sequences were used to record the experimental (a - c) and (d - f) spectra, respectively, and the same sequences were employed to generate the simulated (g – i) and (j – l) spectra, respectively. The sample was spun at a MAS frequency of 10 kHz. ¹H-¹⁵N dipolar and ¹⁵N CSA parameters used in the simulations were extracted from 1D R18 dipolar and 1D R14 CSA pattern simulations, and fixed during the calculations. The orientation of the ¹⁵N CSA relative to ¹H-¹⁵N dipolar tensor was optimized. The best-fit relative orientations between the ¹H-¹⁵N dipolar and ¹⁵N CSA are shown in Table 2.