Figure 1.

¹⁵N R_1ρ relaxation dispersion for crystalline GB1. (a) Example fits based on the data from the sample without paramagnetic dopant (GB1_dia) (blue lines, k_ex = 14 ± 0.5 × 10³ s⁻¹) and the sample with paramagnetic dopant (GB1_pre) (red lines, k_ex = 15 ± 2 × 10³ s⁻¹) obtained from measurements at 600 MHz (14.1 T) and 700 MHz (16.4 T) and a sample temperature of 300 ± 2 K. For simplicity the units for the residue specific φ_ex and R_1ρ,0 are omitted in the graphs and are ×10³ rad² s⁻² and s⁻¹, respectively. (b–d) Agreement between experimental and fitted data represented by plots between fixed exchange coefficients, k_ex, and the corresponding normalized χ² values from joint fitting of relaxation dispersion curves for different groupings of residues in GB1_dia (b) and GB1_pre (c), as well as a comparison of normalised χ² values from global fits in GB1_dia and GB1_pre (d). The fits obtained from the different groupings are indicated with dotted black lines for the α-helix region, dotted purple lines for the β–sheet region and solid lines for all residues together (blue for GB1_dia and red for GB1_pre). (e, f) Correlation plots for φ_ex values based on fits of all residues together and the α-helix and β-sheet regions separately for GB1_dia (e) and GB1_pre (f). (g) Correlation plot for φ_ex values based on fits of all residues together between GB1_dia and GB1_pre. The correlation coefficient (R) is indicated in grey in each correlation plot.