Fig. 5
The 2D 1H-13C HSQC spectra of the aromatic region recorded on (a) δ- or (b) ε-SAIL Tyr-labeled FKBP12 in the apo (c, d), rapamycin-bound (e, f), and FK506-bound (g, h) states at 30 °C. Separated signals of Tyr26 were observed due to the slower ring-flipping motion upon FK506 binding (Reproduced from Yang et al. [44] with permission)