Figure 5. 3D (H)CCH-TOCSY correlation for the seven proline residues of FKBP12.

Spectral region for the proline ¹³C^β and ¹³C^γ (upper panels) and ¹³C^α (lower panels) resonances that are correlated to the intraresidue ¹³C^δ resonances at three frequencies within a 3D (H)CCH-TOCSY experiment. Complete connectivity patterns are observed for all seven proline residues in the major slow exchange state and for the resolved resonances of Pro⁸⁸ and Pro⁹² in the minor slow exchange state. The small (4.0 p.p.m.) chemical shift differences for ¹³C^β–¹³C^γ indicate that these two proline residues remain in a trans-peptide conformation in the minor slow exchange state.