Fig. 3.

(A) The aliphatic region of a 2D DARR ¹³C-¹³C spectrum for Sample A (500 ms mixing time). (B) Comparison of selected horizontal slices from the 2D DARR spectrum and the 2D fpRFDR spectrum (Fig. 1). The 2D DARR spectrum in Panel A shows inter-side-chain cross-peaks (correlations between atoms separated by up to ~0.6 nm) that indicate proximities between I32 and V40 and between M35 and G37. The solid colored lines in Panel A indicate single-bond exchange pathways or residue-specific assignments for V40 (pink), I32 (green), M35 (orange), and G37 (blue) identified using the 2D fpRFDR spectrum (Fig. 1). The colored circles indicate inter-residue cross-peaks, with specific residues indicated by the colors of the semicircles. The horizontal slices are at positions indicated by dashed lines in Panel A (V40 C_γ slice at 19.4 ppm, pink; M35 C_α slice at 52.7 ppm, orange) and the 2D fpRFDR spectrum (green slices at the C_β and C_γ peak positions of I32 and the blue slice at the C_α peak position of G37). The vertical dashed lines with arrowheads in Panel B indicate polarization transfers between I32 and V40 aliphatic carbons as well as the transfers between M35 and G37 aliphatic carbons.